1
|
Zero AM, Paris MT, Rice CL. Differential effects of stimulation frequency on isometric and concentric isotonic contractile function in human quadriceps. J Appl Physiol (1985) 2024; 137:111-124. [PMID: 38841755 DOI: 10.1152/japplphysiol.00075.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 04/26/2024] [Accepted: 05/28/2024] [Indexed: 06/07/2024] Open
Abstract
Electrically evoked contractions are used to assess the relationship between frequency input and contractile output to characterize inherent muscle function, and these have been done mostly with isometric contractions (i.e., no joint rotation). The purpose was to compare the electrically stimulated frequency and contractile function relationship during isometric (i.e., torque) with isotonic (i.e., concentric torque, angular velocity, and mechanical power) contractions. The knee extensors of 16 (5 female) young recreationally active participants were stimulated (∼1-2.5 s) at 14 frequencies from 1 to 100 Hz. This was done during four conditions, which were isometric and isotonic at loads of 0 (unloaded), 7.5%, and 15% isometric maximal voluntary contraction (MVC), and repeated on separate days. Comparisons across contractile parameters were made as a % of 100 Hz. Independent of the load, the mechanical power-frequency relationship was rightward shifted compared with isometric torque-frequency, concentric torque-frequency, and velocity-frequency relationships (all P ≤ 0.04). With increasing load (0%-15% MVC), the isotonic concentric torque-frequency relationship was shifted leftward systematically from 15 to 30 Hz (all P ≤ 0.04). Conversely, the same changes in load caused a rightward shift in the velocity-frequency relationship from 1 to 40 Hz (all P ≤ 0.03). Velocity was leftward shifted of concentric torque in the unloaded isotonic condition from 10 to 25 Hz (all P ≤ 0.03), but concentric torque was leftward shifted of velocity at 15% MVC isotonic condition from 10 to 50 Hz (all P ≤ 0.03). Therefore, isometric torque is not a surrogate to evaluate dynamic contractile function. Interpretations of evoked contractile function differ depending on contraction type, load, and frequency, which should be considered relative to the specific task.NEW & NOTEWORTHY In whole human muscle, we showed that the electrically stimulated power-frequency relationship was rightward shifted of the stimulated isometric torque-frequency relationship independent of isotonic load, indicating that higher stimulation frequencies are needed to achieve tetanus. Therefore, interpretations of evoked contractile function differ depending on contraction type (isometric vs. dynamic), load, and frequency. And thus, isometric measures may not be appropriate as a surrogate assessment when evaluating dynamic isotonic contractile function.
Collapse
Affiliation(s)
- Alexander M Zero
- Faculty of Health Sciences, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada
| | - Michael T Paris
- Faculty of Health Sciences, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada
- Faculty of Health, School of Kinesiology & Health Science, York University, Toronto, Ontario, Canada
| | - Charles L Rice
- Faculty of Health Sciences, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
2
|
Robertson CM, Pullinger SA, Robinson WR, Smith ME, Burniston JG, Edwards BJ. Circadian variation in muscle force output in males using isokinetic, isometric dynamometry: can we observe this in multi-joint movements using the muscleLab force-velocity encoder and are they similar in peak and magnitude? Chronobiol Int 2024; 41:709-724. [PMID: 38722075 DOI: 10.1080/07420528.2024.2348011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 04/19/2024] [Indexed: 05/22/2024]
Abstract
We have investigated the magnitude of circadian variation in Isokinetic and Isometric strength of the knee extensors and flexors, as well as back squat and bench press performance using the MuscleLab force velocity transducer. Ten resistance-trained males (mean±SD: age 21.5 ± 1.1 years; body mass 78.3 ± 5.2 kg; height 1.71 ± 0.07 m) underwent a) three to four familiarization sessions on each dynamometer and b) four sessions at different times of day (03:00, 09:00, 15:00 and 21:00 h). Each session was administered in a counterbalanced order and included a period when Perceived onset of mood states (POMS), then rectal and muscle temperature (Trec, Tm) was measured at rest, after which a 5-min standardized 150 W warm-up was performed on a cycle ergometer. Once completed, Isokinetic (60 and 240°·s-1 for extension and flexion) and Isometric dynamometry with peak torque (PT), time-to-peak-torque (tPT) and peak force (PF) and % activation was measured. Lastly, Trec and Tm were measured before the bench press (at 30, 50 and 70 kg) and back squat (at 40, 60 and 80 kg) exercises. A linear encoder was attached to an Olympic bar used for the exercises and average force (AF), peak velocity (PV) and time-to-peak-velocity (tPV) were measured (MuscleLab software; MuscleLab Technology, Langesund, Norway) during the concentric phase of the movements. Five-min recovery was allowed between each set with three repetitions being completed. General linear models with repeated measures and cosinor analysis were used to analyse the data. Values for Trec and Tm at rest were higher in the evening compared to morning values (Acrophase Φ: 16:35 and 17:03 h, Amplitude A: 0.30 and 0.23°C, Mesor M: 36.64 and 37.43°C, p < 0.05). Vigor, happy and fatigue mood states responses showed Φ 16:11 and 16:03 h and 02:05 h respectively. Circadian rhythms were apparent for all variables irrespective of equipment used where AF, PF and PT values peaked between 16:18 and 18:34 h; PV, tPV and tPT peaked between 05:54 and 08:03 h (p < 0.05). In summary, circadian rhythms in force output (force, torque, power, and velocity) were shown for isokinetic, isometric dynamometers and complex multi-joint movements (using a linear encoder); where tPV and tPT occur in the morning compared to the evening. Circadian rhythms in strength can be detected using a portable, low-cost instrument that shows similar cosinor characteristics as established dynamometers. Hence, muscle-strength can be measured in a manner that is more directly transferable to the world of athletic and sports performance.
Collapse
Affiliation(s)
- Colin M Robertson
- Sport, School of Health, Social Work and Sport, University of Central Lancashire, Preston, UK
| | - Samuel A Pullinger
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
- Sport Science Department, Inspire Institute of Sport, Bellary, India
| | - William R Robinson
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Matt E Smith
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Jatin G Burniston
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Ben J Edwards
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| |
Collapse
|
3
|
Collimore AN, Alvarez JT, Sherman DA, Gerez LF, Barrow N, Choe DK, Binder-Macleod S, Walsh CJ, Awad LN. A Portable, Neurostimulation-Integrated, Force Measurement Platform for the Clinical Assessment of Plantarflexor Central Drive. Bioengineering (Basel) 2024; 11:137. [PMID: 38391623 PMCID: PMC10885982 DOI: 10.3390/bioengineering11020137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/15/2024] [Accepted: 01/26/2024] [Indexed: 02/24/2024] Open
Abstract
Plantarflexor central drive is a promising biomarker of neuromotor impairment; however, routine clinical assessment is hindered by the unavailability of force measurement systems with integrated neurostimulation capabilities. In this study, we evaluate the accuracy of a portable, neurostimulation-integrated, plantarflexor force measurement system we developed to facilitate the assessment of plantarflexor neuromotor function in clinical settings. Two experiments were conducted with the Central Drive System (CEDRS). To evaluate accuracy, experiment #1 included 16 neurotypical adults and used intra-class correlation (ICC2,1) to test agreement of plantarflexor strength capacity measured with CEDRS versus a stationary dynamometer. To evaluate validity, experiment #2 added 26 individuals with post-stroke hemiparesis and used one-way ANOVAs to test for between-limb differences in CEDRS' measurements of plantarflexor neuromotor function, comparing neurotypical, non-paretic, and paretic limb measurements. The association between paretic plantarflexor neuromotor function and walking function outcomes derived from the six-minute walk test (6MWT) were also evaluated. CEDRS' measurements of plantarflexor neuromotor function showed high agreement with measurements made by the stationary dynamometer (ICC = 0.83, p < 0.001). CEDRS' measurements also showed the expected between-limb differences (p's < 0.001) in maximum voluntary strength (Neurotypical: 76.21 ± 13.84 ft-lbs., Non-paretic: 56.93 ± 17.75 ft-lbs., and Paretic: 31.51 ± 14.08 ft-lbs.), strength capacity (Neurotypical: 76.47 ± 13.59 ft-lbs., Non-paretic: 64.08 ± 14.50 ft-lbs., and Paretic: 44.55 ± 14.23 ft-lbs.), and central drive (Neurotypical: 88.73 ± 1.71%, Non-paretic: 73.66% ± 17.74%, and Paretic: 52.04% ± 20.22%). CEDRS-measured plantarflexor central drive was moderately correlated with 6MWT total distance (r = 0.69, p < 0.001) and distance-induced changes in speed (r = 0.61, p = 0.002). CEDRS is a clinician-operated, portable, neurostimulation-integrated force measurement platform that produces accurate measurements of plantarflexor neuromotor function that are associated with post-stroke walking ability.
Collapse
Affiliation(s)
- Ashley N Collimore
- Department of Physical Therapy, Sargent College of Health and Rehabilitation Sciences, Boston University, Boston, MA 02215, USA
| | - Jonathan T Alvarez
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - David A Sherman
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
- Section of Rheumatology, Boston University, Boston, MA 02215, USA
| | - Lucas F Gerez
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Noah Barrow
- Department of Physical Therapy, Sargent College of Health and Rehabilitation Sciences, Boston University, Boston, MA 02215, USA
| | - Dabin K Choe
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | | | - Conor J Walsh
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Louis N Awad
- Department of Physical Therapy, Sargent College of Health and Rehabilitation Sciences, Boston University, Boston, MA 02215, USA
| |
Collapse
|
4
|
Cho SY, Myong Y, Park S, Cho M, Kim S. A portable articulated dynamometer for ankle dorsiflexion and plantar flexion strength measurement: a design, validation, and user experience study. Sci Rep 2023; 13:22221. [PMID: 38097727 PMCID: PMC10721896 DOI: 10.1038/s41598-023-49263-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 12/06/2023] [Indexed: 12/17/2023] Open
Abstract
Monitoring ankle strength is crucial for assessing daily activities, functional ability, and preventing lower extremity injuries. However, the current methods for measuring ankle strength are often unreliable or not easily portable to be used in clinical settings. Therefore, this study proposes a portable dynamometer with high reliability capable of measuring ankle dorsiflexion and plantar flexion. The proposed portable dynamometer comprised plates made of aluminum alloy 6061 and a miniature tension-compression load cell. A total of 41 healthy adult participants applied maximal isometric dorsiflexor and plantar flexor forces on a Lafayette Handheld Dynamometer (HHD) and the portable dynamometer. The results were cross-validated, using change in mean, and two independent examiners evaluated the inter-rater and test-retest reliabilities in separate sessions using intraclass correlation coefficients, standard error of measurement, and minimal detectable change. Both dorsiflexion and plantar flexion measurements demonstrated a strong correlation with the HHD (r = 0.827; r = 0.973) and showed high inter-rater and test-retest reliabilities. Additionally, the participant responses to the user experience questionnaire survey indicated vastly superior positive experiences with the portable dynamometer. The study findings suggest that the designed portable dynamometer can provide accurate and reliable measurements of ankle strengths, making it a potential alternative to current methods in clinical settings.
Collapse
Affiliation(s)
- Seung Yeon Cho
- Interdisciplinary Program in Bioengineering, The Graduate School, Seoul National University, Seoul, South Korea
| | - Youho Myong
- Department of Biomedical Engineering, Seoul National University College of Medicine, 103 Daehak-Ro, Jongno-Gu, Seoul, 03080, South Korea
- Department of Rehabilitation Medicine, Seoul National University Hospital, Seoul, South Korea
| | - Sungwoo Park
- Interdisciplinary Program in Bioengineering, The Graduate School, Seoul National University, Seoul, South Korea
- Institute of Innovative Medical Technology, Seoul National University Hospital Biomedical Research Institute, Seoul, South Korea
| | - Minwoo Cho
- Department of Transdisciplinary Medicine, Seoul National University Hospital, 101 Daehak-Ro, Jongno-Gu, Seoul, 03080, South Korea.
- Department of Medicine, Seoul National University College of Medicine, Seoul, South Korea.
| | - Sungwan Kim
- Interdisciplinary Program in Bioengineering, The Graduate School, Seoul National University, Seoul, South Korea.
- Department of Biomedical Engineering, Seoul National University College of Medicine, 103 Daehak-Ro, Jongno-Gu, Seoul, 03080, South Korea.
- Institute of Bioengineering, Seoul National University, Seoul, South Korea.
| |
Collapse
|
5
|
Dutra YM, Lopes JPF, Murias JM, Zagatto AM. Within- and between-day reliability and repeatability of neuromuscular function assessment in females and males. J Appl Physiol (1985) 2023; 135:1372-1383. [PMID: 37916269 DOI: 10.1152/japplphysiol.00539.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/31/2023] [Accepted: 10/31/2023] [Indexed: 11/03/2023] Open
Abstract
The study evaluated the reliability and repeatability of the force and surface electromyography activity (EMG) outcomes obtained through voluntary and electrically evoked contractions of knee extensors in females (n = 18) and males (n = 20) and compared these data between sexes. Maximal isometric voluntary contractions (iMVCs) of knee extensors associated with electrical stimulation of the femoral nerve were performed over 4 days (48-h interval), with the first day involving familiarization procedures, the second involving three trials (1-h interval), and the third and fourth involving just one trial. The intraclass correlation coefficient (ICC), coefficient of variation (CV), and repeatability of outcomes from within- and between-day trials were determined for each sex. Females presented lower maximal voluntary force during iMVC (iMVCForce) and associated vastus lateralis EMG activity (root mean square, RMSVL), force evoked by potentiated doublet high-frequency (Db100Force) and single stimuli (Qtw), and M-wave amplitude than males (P ≤ 0.01, partial eta squared ≥0.94). Voluntary activation (VA) and RMSVL/M-wave amplitude did not differ between sexes. iMVCForce, VA, Db100Force, Qtw, and M-wave amplitude were the most reliable outcomes in within-day trials, with similar results between sexes (ICC > 0.62; CV < 6.4%; repeatability: 12.2%-22.6%). When investigating between-day trials, the iMVCForce, VA, Db100Force, and Qtw were the most reliable (ICC > 0.66; CV < 7.5%; repeatability: 13.2%-33.45%) with similar results between sexes. In conclusion, females presented lower iMVCForce and evoked response than males. Although reliability and repeatability statistics vary between trials, data (e.g., from EMG or force signal), and sexes, most of the outcomes obtained through this technique are reliable in females and males.NEW & NOTEWORTHY Although reliability and repeatability of knee extensors vary according to the type of neuromuscular function outcome (e.g., from force or EMG responses), the trial intervals (i.e., hours or days), and the sex of the participant, most force and EMG outcomes obtained through these neuromuscular assessment protocols present ICC > 0.75, very good CV (<10%), and repeatability <25% in within- and between-day trials in both sexes.
Collapse
Affiliation(s)
- Yago Medeiros Dutra
- Department of Physical Education, Laboratory of Physiology and Sport Performance (LAFIDE), School of Sciences, São Paulo State University (UNESP), Bauru, Brazil
| | - João Pedro Fialho Lopes
- Department of Physical Education, Laboratory of Physiology and Sport Performance (LAFIDE), School of Sciences, São Paulo State University (UNESP), Bauru, Brazil
| | - Juan M Murias
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Alessandro Moura Zagatto
- Department of Physical Education, Laboratory of Physiology and Sport Performance (LAFIDE), School of Sciences, São Paulo State University (UNESP), Bauru, Brazil
| |
Collapse
|
6
|
Hunter SK, S Angadi S, Bhargava A, Harper J, Hirschberg AL, D Levine B, L Moreau K, J Nokoff N, Stachenfeld NS, Bermon S. The Biological Basis of Sex Differences in Athletic Performance: Consensus Statement for the American College of Sports Medicine. Med Sci Sports Exerc 2023; 55:2328-2360. [PMID: 37772882 DOI: 10.1249/mss.0000000000003300] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2023]
Abstract
ABSTRACT Biological sex is a primary determinant of athletic performance because of fundamental sex differences in anatomy and physiology dictated by sex chromosomes and sex hormones. Adult men are typically stronger, more powerful, and faster than women of similar age and training status. Thus, for athletic events and sports relying on endurance, muscle strength, speed, and power, males typically outperform females by 10%-30% depending on the requirements of the event. These sex differences in performance emerge with the onset of puberty and coincide with the increase in endogenous sex steroid hormones, in particular testosterone in males, which increases 30-fold by adulthood, but remains low in females. The primary goal of this consensus statement is to provide the latest scientific knowledge and mechanisms for the sex differences in athletic performance. This review highlights the differences in anatomy and physiology between males and females that are primary determinants of the sex differences in athletic performance and in response to exercise training, and the role of sex steroid hormones (particularly testosterone and estradiol). We also identify historical and nonphysiological factors that influence the sex differences in performance. Finally, we identify gaps in the knowledge of sex differences in athletic performance and the underlying mechanisms, providing substantial opportunities for high-impact studies. A major step toward closing the knowledge gap is to include more and equitable numbers of women to that of men in mechanistic studies that determine any of the sex differences in response to an acute bout of exercise, exercise training, and athletic performance.
Collapse
Affiliation(s)
- Sandra K Hunter
- Exercise Science Program, Department of Physical Therapy, and Athletic and Human Performance Center, Marquette University, Milwaukee, WI
| | | | - Aditi Bhargava
- Department of Obstetrics and Gynecology, Center for Reproductive Sciences, University of California, San Francisco, CA
| | - Joanna Harper
- Loughborough University, Loughborough, UNITED KINGDOM
| | - Angelica Lindén Hirschberg
- Department of Women's and Children's Health, Karolinska Institutet, and Department of Gynecology and Reproductive Medicine, Karolinska University Hospital, Stockholm, SWEDEN
| | - Benjamin D Levine
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, and the Department of Internal Medicine, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Kerrie L Moreau
- Department of Medicine, Division of Geriatric Medicine, University of Colorado Anschutz Medical Campus, and Eastern Colorado Health Care System, Geriatric Research Education and Clinical Center, Aurora, CO
| | - Natalie J Nokoff
- Department of Pediatrics, Section of Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Nina S Stachenfeld
- The John B. Pierce Laboratory and Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, New Haven, CT
| | - Stéphane Bermon
- Health and Science Department, World Athletics, Monaco and the LAMHESS, University Côte d'Azur, Nice, FRANCE
| |
Collapse
|
7
|
Zero AM, Fanous J, Rice CL. Acute and prolonged competing effects of activation history on human motor unit firing rates during contractile impairment and recovery. J Physiol 2023; 601:5689-5703. [PMID: 37962903 DOI: 10.1113/jp285189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 10/26/2023] [Indexed: 11/15/2023] Open
Abstract
The purpose of this study was to investigate the effect of inducing post-activation potentiation (PAP) during prolonged low-frequency force depression (PLFFD) on motor unit (MU) firing rates. In 10 participants, grouped firing rates of 3027 MUs from the tibialis anterior were recorded with tungsten microelectrodes. Baseline MU firing rates at 25% isometric maximal voluntary contraction (MVC) were ∼14 Hz. A 1 min dorsiflexion MVC reduced torque and maximal MU firing rates (36 Hz) by 49% and 52%, respectively. Following task completion, firing rates at 25% of baseline MVC torque and torque in response to electrically evoked (single twitch, 10 Hz and 50 Hz) stimulation were assessed before and after a 5 s MVC (to induce PAP) every 10 min for 60 min. From 10 to 60 min after task completion, the torque ratios (twitch:50 Hz and 10:50 Hz) were depressed (∼30%) relative to baseline (P < 0.001), indicating PLFFD; and firing rates were higher by ∼15% relative to baseline (P < 0.001). This occurred despite recovery of MVC rates (∼99%) and torque (∼95%) by 10 min (P > 0.3). Inducing PAP during PLFFD increased both low to high torque ratios (twitch and 10:50 Hz) by ∼200% and ∼135%, respectively (P < 0.001) and firing rates were ∼18% lower relative to PLFFD rates (P < 0.001), despite a speeding of evoked contractile properties (P = 0.001). Thus, firing rates appear strongly matched to alterations in torque, rather than contractile speed when modified by contractile history, and lower rates during PAP may be a mechanism to mitigate effects of PLFFD. The effect of activation history on contractile function demonstrates acute compensatory responses of motoneuron output. KEY POINTS: Prolonged low frequency force depression (PLFFD) following a sustained 1 min isometric maximal voluntary contraction causes an increase in submaximal mean motor unit (MU) firing rates. Inducing post-activation potentiation (PAP) during PLFFD, however, causes a reduction in mean submaximal MU firing rates to a level below those at baseline. The mean firing rate reduction during PAP occurs despite a speeding of evoked contractile properties and thus firing rates are more strongly matched to alterations in torque, rather than contractile speed when modified by various contractile histories. The reductions in firing rates during PAP may mitigate the effects of PLFFD during voluntary contractions. These results demonstrate that firing rates are highly responsive to opposing influences on the contractile state and can make rapid compensatory rate adjustments dependent on the active state of the muscle.
Collapse
Affiliation(s)
- Alexander M Zero
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario, Canada
| | - Jacob Fanous
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario, Canada
| | - Charles L Rice
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario, Canada
- Department of Anatomy and Cell Biology, Schulich School of Medicine, and Dentistry, University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
8
|
Paris MT, Kulkarni SV, Rice CL. Electrically Evoked Isotonic Plantar Flexion Contractions Are Impaired Less than Voluntary After a Dynamic Fatiguing Task. Med Sci Sports Exerc 2023; 55:2096-2102. [PMID: 37379258 DOI: 10.1249/mss.0000000000003243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2023]
Abstract
PURPOSE Evaluating central and peripheral processes responsible for reduced power after dynamic fatiguing tasks are often limited to isometric torque, which may not accurately reflect dynamic contractile performance. Here, we compare voluntary and electrically evoked peak power (and its determinants: dynamic torque and velocity) and rate of velocity development (RVD) before and after a dynamic fatiguing task using concentric Plantar flexion contractions. METHODS Young (18-32 yr) males ( n = 11) and females ( n = 2) performed maximal-effort isotonic Plantar flexion contractions using a load of 20% isometric torque until an approximately 75% reduction in peak power. Voluntary and electrically evoked (300 Hz tibial nerve stimulation) contractions loaded to 20% and 40% isometric torque through 25° ankle joint range of motion were compared before and 0, 2.5, 5, and 10 min after task termination. RESULTS At task termination, peak power and RVD of voluntary contractions at both loads were reduced more (~40% to 50% reduction) than electrically evoked (~25% to 35% reduction) contractions ( P < 0.001 and P = 0.003). Throughout the recovery period, electrically evoked peak power and RVD returned to baseline sooner (<5 min) than voluntary contractions, which were still depressed at 10 min. Reductions in peak power for the 20% load were equally due to impaired dynamic torque and velocity, whereas velocity was impaired more than dynamic torque ( P < 0.001) for the 40% load. CONCLUSIONS The relative preservation of electrically evoked power and RVD compared with voluntary contractions at task termination and quicker recovery to baseline indicates that the reductions in dynamic contractile performance after task termination are due to both central and peripheral processes; however, the relative contribution of dynamic torque and velocity is load dependent.
Collapse
Affiliation(s)
- Michael T Paris
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, CANADA
| | - Sohum V Kulkarni
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, CANADA
| | | |
Collapse
|
9
|
Mouth rinsing and ingesting salty or bitter solutions does not influence corticomotor excitability or neuromuscular function. Eur J Appl Physiol 2023; 123:1179-1189. [PMID: 36700971 DOI: 10.1007/s00421-023-05141-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 01/13/2023] [Indexed: 01/27/2023]
Abstract
PURPOSE To explore the effect of tasting unpleasant salty or bitter solutions on lower limb corticomotor excitability and neuromuscular function. METHODS Nine females and eleven males participated (age: 27 ± 7 years, BMI: 25.3 ± 4.0 kg m-2). Unpleasant salty (1 M) and bitter (2 mM quinine) solutions were compared to water, sweetened water, and no solution, which functioned as control conditions. In a non-blinded randomized cross-over order, each solution was mouth rinsed (10 s) and ingested before perceptual responses, instantaneous heart rate (a marker of autonomic nervous system activation), quadricep corticomotor excitability (motor-evoked potential amplitude) and neuromuscular function during a maximal voluntary contraction (maximum voluntary force, resting twitch force, voluntary activation, 0-50 ms impulse, 0-100 impulse, 100-200 ms impulse) were measured. RESULTS Hedonic value (water: 47 ± 8%, sweet: 23 ± 17%, salt: 71 ± 8%, bitter: 80 ± 10%), taste intensity, unpleasantness and increases in heart rate (no solution: 14 ± 5 bpm, water: 18 ± 5 bpm, sweet: 20 ± 5 bpm, salt: 24 ± 7 bpm, bitter: 23 ± 6 bpm) were significantly higher in the salty and bitter conditions compared to control conditions. Nausea was low in all conditions (< 15%) but was significantly higher in salty and bitter conditions compared to water (water: 3 ± 5%, sweet: 6 ± 13%, salt: 7 ± 9%, bitter: 14 ± 16%). There was no significant difference between conditions in neuromuscular function or corticomotor excitability variables. CONCLUSION At rest, unpleasant tastes appear to have no influence on quadricep corticomotor excitability or neuromuscular function. These data question the mechanisms via which unpleasant tastes are proposed to influence exercise performance.
Collapse
|
10
|
Diong J, Kishimoto KC, Butler JE, Héroux ME. Muscle electromyographic activity normalized to maximal muscle activity, not to Mmax, better represents voluntary activation. PLoS One 2022; 17:e0277947. [PMID: 36409688 PMCID: PMC9678282 DOI: 10.1371/journal.pone.0277947] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 11/07/2022] [Indexed: 11/22/2022] Open
Abstract
In human applied physiology studies, the amplitude of recorded muscle electromyographic activity (EMG) is often normalized to maximal EMG recorded during a maximal voluntary contraction. When maximal contractions cannot be reliably obtained (e.g. in people with muscle paralysis, anterior cruciate ligament injury, or arthritis), EMG is sometimes normalized to the maximal compound muscle action potiential evoked by stimulation, the Mmax. However, it is not known how these two methods of normalization affect the conclusions and comparability of studies. To address this limitation, we investigated the relationship between voluntary muscle activation and EMG normalized either to maximal EMG or to Mmax. Twenty-five able-bodied adults performed voluntary isometric ankle plantarflexion contractions to a range of percentages of maximal voluntary torque. Ankle torque, plantarflexor muscle EMG, and voluntary muscle activation measured by twitch interpolation were recorded. EMG recorded at each contraction intensity was normalized to maximal EMG or to Mmax for each plantarflexor muscle, and the relationship between the two normalization approaches quantified. A slope >1 indicated EMG amplitude normalized to maximal EMG (vertical axis) was greater than EMG normalized to Mmax (horizontal axis). Mean estimates of the slopes were large and had moderate precision: soleus 8.7 (95% CI 6.9 to 11.0), medial gastrocnemius 13.4 (10.5 to 17.0), lateral gastrocnemius 11.4 (9.4 to 14.0). This indicates EMG normalized to Mmax is approximately eleven times smaller than EMG normalized to maximal EMG. Normalization to maximal EMG gave closer approximations to the level of voluntary muscle activation assessed by twitch interpolation.
Collapse
Affiliation(s)
- Joanna Diong
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, New South Wales, Australia
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
- * E-mail:
| | - Kenzo C. Kishimoto
- School of Health Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, New South Wales, Australia
| | - Jane E. Butler
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Martin E. Héroux
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, Kensington, New South Wales, Australia
| |
Collapse
|
11
|
Comparison of prolonged low-frequency force depression assessed using isometric torque and isotonic power following a dynamic fatiguing task. Eur J Appl Physiol 2022; 122:2597-2606. [PMID: 36098858 DOI: 10.1007/s00421-022-05042-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 09/05/2022] [Indexed: 11/03/2022]
Abstract
PURPOSE Prolonged low-frequency force depression (PLFFD) occurs following both dynamic and static fatiguing tasks, but it has been assessed predominately using measures of isometric torque. However, it is unknown whether PLFFD induced during dynamic tasks is adequately characterized by isometric torque, which excludes velocity and power. The purpose of this study was to compare PLFFD assessed using isometric torque and isotonic power following a concentric fatiguing task. METHODS Young (18-31 years) males (n = 9) and females (n = 4) performed isotonic plantar flexion contractions until a ~ 75% reduction in peak power. Isotonic and isometric contractions were electrically evoked at 10 Hz and 50 Hz via tibial nerve stimulation. Isotonic and isometric PLFFD was assessed as the ratio of 10 to 50 Hz for power and torque, respectively. Recovery was assessed immediately, and at 2.5, 5, 10, 20, and 30 min after task termination. RESULTS Relative to baseline, 10:50 Hz ratio assessed using isotonic power was reduced more than isometric torque (30 min 41 ± 17 vs. 25 ± 12% reduction, p = 0.001); however, both contraction modes displayed similar trajectories throughout recovery (p = 0.906). The larger reduction in isotonic 10:50 Hz ratio was due to greater impairments in 10 Hz power compared to 10 Hz isometric torque (30 min 38 ± 20 vs. 21 ± 11% reduction, p < 0.001). CONCLUSION The similar trajectories of 10:50 Hz ratios throughout recovery indicate that PLFFD can be adequately characterized using either isometric torque or isotonic power.
Collapse
|
12
|
Dragoi II, Petrita T, Popescu FG, Alexa F, Barac S, Bowling FL, Reeves ND, Bondor CI, Ionac M. A Signal Processing Method for Assessing Ankle Torque with a Custom-Made Electronic Dynamometer in Participants Affected by Diabetic Peripheral Neuropathy. SENSORS (BASEL, SWITZERLAND) 2022; 22:6310. [PMID: 36016070 PMCID: PMC9416663 DOI: 10.3390/s22166310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/18/2022] [Accepted: 08/19/2022] [Indexed: 06/15/2023]
Abstract
Portable, custom-made electronic dynamometry for the foot and ankle is a promising assessment method that enables foot and ankle muscle function to be established in healthy participants and those affected by chronic conditions. Diabetic peripheral neuropathy (DPN) can alter foot and ankle muscle function. This study assessed ankle toque in participants with diabetic peripheral neuropathy and healthy participants, with the aim of developing an algorithm for optimizing the precision of data processing and interpretation of the results and to define a reference frame for ankle torque measurement in both healthy participants and those affected by DPN. This paper discloses the software chain and the signal processing methods used for voltage-torque conversion, filtering, offset detection and the muscle effort type identification, which further allowed for a primary statistical report. The full description of the signal processing methods will make our research reproducible. The applied algorithm for signal processing is proposed as a reference frame for ankle torque assessment when using a custom-made electronic dynamometer. While evaluating multiple measurements, our algorithm permits for a more detailed parametrization of the ankle torque results in healthy participants and those affected by DPN.
Collapse
Affiliation(s)
- Iulia Iovanca Dragoi
- Department of Vascular Surgery and Reconstructive Microsurgery, “Victor Babes” University of Medicine and Pharmacy, 2 Eftimie Murgu Square, 300041 Timisoara, Romania
| | - Teodor Petrita
- Department of Communications, Politehnica University Timisoara, 2 Vasile Parvan, 300223 Timisoara, Romania
| | - Florina Georgeta Popescu
- Discipline of Occupational Health, “Victor Babes” University of Medicine and Pharmacy, 2 Eftimie Murgu Square, 300041 Timisoara, Romania
| | - Florin Alexa
- Department of Communications, Politehnica University Timisoara, 2 Vasile Parvan, 300223 Timisoara, Romania
| | - Sorin Barac
- Department of Vascular Surgery and Reconstructive Microsurgery, “Victor Babes” University of Medicine and Pharmacy, 2 Eftimie Murgu Square, 300041 Timisoara, Romania
| | - Frank L. Bowling
- Department of Vascular Surgery and Reconstructive Microsurgery, “Victor Babes” University of Medicine and Pharmacy, 2 Eftimie Murgu Square, 300041 Timisoara, Romania
- Department of Surgery & Translational Medicine, Faculty of Medical and Human Sciences, University of Manchester, Oxford Rd., Manchester M13 9PL, UK
| | - Neil D. Reeves
- Research Centre for Musculoskeletal Science & Sports Medicine, Department of Life Sciences, Faculty of Science and Engineering, Manchester Metropolitan University, Oxford Rd., Manchester M1 5GD, UK
- Institute of Sport, Manchester Metropolitan University, Manchester M1 5GD, UK
| | - Cosmina Ioana Bondor
- Department of Medical Informatics and Biostatistics, University of Medicine and Pharmacy “Iuliu Hațieganu”, 8 Victor Babeș, 400000 Cluj-Napoca, Romania
| | - Mihai Ionac
- Department of Vascular Surgery and Reconstructive Microsurgery, “Victor Babes” University of Medicine and Pharmacy, 2 Eftimie Murgu Square, 300041 Timisoara, Romania
| |
Collapse
|
13
|
Fanous J, Zero AM, Rice CL. Muscle fatigability and post-acute COVID-19 syndrome: A case study. Physiol Rep 2022; 10:e15391. [PMID: 35980017 PMCID: PMC9387111 DOI: 10.14814/phy2.15391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/18/2022] [Accepted: 06/24/2022] [Indexed: 11/24/2022] Open
Abstract
The acute phase of COVID-19 has been well studied, however with increasing post-acute COVID-19 syndrome, much is unknown about its long-term effects. A common symptom in both the acute and post-acute phases has been fatigue, assessed predominantly qualitatively. Here we present a case study objectively assessing neuromuscular fatiguability in a young male (27 year, 1.85 m, 78 kg) who continues to experience COVID-19 related fatigue and cognitive dysfunction, including other symptoms, 12+ months post-infection. Prior to infection, he was part of a neuromuscular study forming the basis of our pre-COVID-19 results. The study was repeated 12 months post-COVID-19 infection. Muscle strength, endurance, torque steadiness, voluntary activation, twitch properties, electromyography, and compound muscle action potential were obtained and compared pre- and post-COVID-19. All measurements were done using a dorsiflexion dynamometer in which the participant also was asked to produce a one-minute fatiguing maximal voluntary contraction. Muscle strength, voluntary activation, and fatigability (slope of torque) showed no meaningful differences, suggesting intrinsic neuromuscular properties are not affected. However, torque steadiness was impaired three-fold in the post- compared with pre-COVID-19 test. The participant also reported a higher level of perceived exertion subjectively and a continued complaint of fatigue. These findings indicate that muscle fatiguability in post-acute COVID-19 syndrome may not be a limitation of the muscle and its activation, but a perceptual disconnect caused by cognitive impairments relating to physical efforts. This case report suggests the potential value of larger studies designed to assess these features in post-acute COVID-19 syndrome.
Collapse
Affiliation(s)
- Jacob Fanous
- School of KinesiologyThe University of Western OntarioLondonOntarioCanada
| | - Alexander M. Zero
- School of KinesiologyThe University of Western OntarioLondonOntarioCanada
| | - Charles L. Rice
- School of KinesiologyThe University of Western OntarioLondonOntarioCanada
- Department of Anatomy and Cell Biology, Schulich School of Medicine and DentistryThe University of Western OntarioLondonOntarioCanada
| |
Collapse
|
14
|
Zero AM, Paris MT, Rice CL. Frequency dependent coexistence of muscle fatigue and potentiation assessed by concentric isotonic contractions in human plantar flexors. J Appl Physiol (1985) 2022; 133:490-505. [PMID: 35796610 DOI: 10.1152/japplphysiol.00214.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose was to investigate whether post-activation potentiation (PAP) mitigates power (i.e., torque x angular velocity) loss during dynamic fatiguing contractions and subsequent recovery by enhancing either muscle torque or angular velocity in human plantar flexors. In 12 participants, electrically stimulated (1, 10 and 50 Hz) dynamic contractions were done during a voluntary isotonic fatiguing protocol (20 and 50% voluntary decreases) until a 75% loss in voluntary peak power, and throughout 30 minutes of recovery. At the initial portion of fatigue (20% decrease), power responses of evoked low frequencies (1 and 10 Hz) were enhanced due to PAP (156 and 137%, respectively, P<0.001), while voluntary maximal efforts were depressed due to fatiguing mechanisms. Following the fatiguing task, prolonged low-frequency force depression (PLFFD) was evident by reduced 10:50 Hz peak power ratios (21 - 24%) from 3-min onwards during the 30-min recovery (P<0.005). Inducing PAP with maximal voluntary contractions during PLFFD enhanced the peak power responses of low frequencies (1 and 10 Hz) by 128 - 160 %, P<0.01. This PAP response mitigated the effects of PLFFD as the 1:50 (P<0.05) and 10:50 (P>0.4) Hz peak power ratios were greater or not different from the pre-fatigue values. Additionally, PAP enhanced peak torque more than peak angular velocity during both baseline and fatigue measurements (P<0.03). These results indicate that PAP can ameliorate PLFFD acutely when evaluated during concentric isotonic contractions and that peak torque is enhanced to a greater degree compared to peak angular velocity at baseline and in a fatigued state.
Collapse
Affiliation(s)
- Alexander M Zero
- School of Kinesiology, Faculty of Health Sciences, grid.39381.30Western University, London, ON, Canada
| | - Michael T Paris
- School of Kinesiology, Faculty of Health Sciences, grid.39381.30Western University, London, ON, Canada
| | - Charles L Rice
- Department of Anatomy and Cell Biology, grid.443228.bWestern University, London, Ontario, Canada
| |
Collapse
|
15
|
Kirk EA, Castellani CA, Doherty TJ, Rice CL, Singh SM. Local and systemic transcriptomic responses from acute exercise induced muscle damage of the human knee extensors. Physiol Genomics 2022; 54:305-315. [PMID: 35723223 DOI: 10.1152/physiolgenomics.00146.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Skeletal muscle is adaptable to a direct stimulus of exercise-induced muscle damage (EIMD). Local muscle gene networks and systemic circulatory factors respond to EIMD within days, mediating anti-inflammation and cellular proliferation. Here we show in humans that local EIMD of one muscle group is associated with a systemic response of gene networks that regulate muscle structure and cellular development in non-local homologous muscle not directly altered by EIMD. In the non-dominant knee-extensors of seven males, EIMD was induced through voluntary contractions against an electric motor that lengthened muscles. Neuromuscular assessments, vastus lateralis muscle biopsies and blood draws occurred at two days prior, and one and two days post the EIMD intervention. From the muscle and blood plasma samples, RNA-seq measured transcriptome changes of differential expression using bioinformatic analyses.Relative to the time of the EIMD intervention, local muscle that was mechanically damaged had 475 genes differentially expressed, as compared to 33 genes in the non-local homologous muscle. Gene and network analysis showed that activity of the local muscle was related to structural maintenance, repair, and energetic processes, whereas gene and network activity of the non-local muscle (that was not directly modified by the EIMD) were related to muscle cell development, stress response, and structural maintenance. Altered expression of two novel miRNAs related to the EIMD response supported that systemic factors were active. Together, these results indicate that the expression of genes and gene networks that control muscle contractile structure can be modified in response to non-local EIMD in humans.
Collapse
Affiliation(s)
- Eric A Kirk
- School of Kinesiology, Faculty of Health Sciences, Western University, London, Ontario, Canada.,Molecular Genetics Unit, Department of Biology, Western University, London, Ontario, Canada
| | - Christina A Castellani
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.,Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Timothy J Doherty
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.,Department of Physical Medicine and Rehabilitation, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Charles L Rice
- School of Kinesiology, Faculty of Health Sciences, Western University, London, Ontario, Canada.,Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Canada
| | - Shiva M Singh
- Molecular Genetics Unit, Department of Biology, Western University, London, Ontario, Canada
| |
Collapse
|
16
|
Garcia SA, Rodriguez KM, Brown SR, Palmieri-Smith RM, Krishnan C. Estimates of voluntary activation in individuals with anterior cruciate ligament reconstruction: Effects of type of stimulator, number of stimuli, and quantification technique. JOURNAL OF SPORT AND HEALTH SCIENCE 2022; 11:85-93. [PMID: 32692315 PMCID: PMC8847978 DOI: 10.1016/j.jshs.2019.12.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 10/15/2019] [Accepted: 11/12/2019] [Indexed: 06/11/2023]
Abstract
BACKGROUND Accurate quantification of voluntary activation is important for understanding the extent of quadriceps dysfunction in individuals with anterior cruciate ligament reconstruction (ACLR). Voluntary activation has been quantified using both percent activation derived from the interpolated twitch technique and central activation ratio (CAR) derived from the burst superimposition technique, as well as by using different types of electrical stimulators and pulse train conditions. However, it is unclear how these parameters affect voluntary activation estimates in individuals with ACLR. This study was performed to fill this important knowledge gap in the anterior cruciate ligament literature. METHODS Quadriceps strength and voluntary activation were examined in 18 ACLR participants (12 quadriceps/patellar tendon graft, 6 hamstring tendon graft; time since ACLR: 1.06 ± 0.82 years, mean ± SD) at 90° of knee flexion using 2 stimulators (Digitimer and Grass) and pulse train conditions (3-pulse and 10-pulse). Voluntary activation was quantified by calculating both CAR and percent activation. RESULTS Results indicated that voluntary activation was significantly overestimated by CAR when compared with percent activation (p < 0.001). Voluntary activation estimates were not affected by pulse train conditions when using percent activation; however, 3-pulse stimuli resulted in greater overestimation than 10-pulse stimuli when using CAR (p = 0.003). Voluntary activation did not differ between stimulators (p > 0.05); however, the Digitimer evoked greater torque at rest than the Grass (p < 0.001). CONCLUSION These results indicate that percent activation derived from the interpolated twitch technique provides superior estimates of voluntary activation than CAR derived from burst superimposition and is less affected by pulse train conditions or stimulators in individuals with ACLR.
Collapse
Affiliation(s)
- Steven A Garcia
- School of Kinesiology, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Scott R Brown
- Neuromuscular and Rehabilitation Robotics Laboratory (NeuRRo Lab), Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, MI 48108, USA
| | - Riann M Palmieri-Smith
- School of Kinesiology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Orthopaedic Surgery, Michigan Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Chandramouli Krishnan
- School of Kinesiology, University of Michigan, Ann Arbor, MI 48109, USA; Neuromuscular and Rehabilitation Robotics Laboratory (NeuRRo Lab), Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, MI 48108, USA; Robotics Institute, University of Michigan, Ann Arbor, MI 48109, USA.
| |
Collapse
|
17
|
Zero AM, Kirk EA, Rice CL. Firing rate trajectories of human motor units during activity-dependent muscle potentiation. J Appl Physiol (1985) 2021; 132:402-412. [PMID: 34913736 DOI: 10.1152/japplphysiol.00672.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During activity-dependent potentiation (ADP) motor unit firing rates (MUFRs) are lower, however, the mechanism for this response is not known. During increasing torque isometric contractions at low contraction intensities, MUFR trajectories initially accelerate and saturate demonstrating a non-linear response due to the activation of persistent inward currents (PICs) at the motoneuron. The purpose was to assess whether PICs are a factor in the reduction of MUFRs during ADP. To assess this, MUFR trajectories were fit with competing functions of linear regression and a rising exponential (i.e., acceleration and saturation). Using fine-wire electrodes, discrete MU potential trains were recorded in the tibialis anterior during slowly increasing dorsiflexion contractions to 10% of maximal voluntary contraction following both voluntary (post-activation potentiation; PAP) and evoked (post-tetanic potentiation; PTP) contractions. In 8 participants, 25 MUs were recorded across both ADP conditions and compared to the control with no ADP effect. During PAP and PTP, the average MUFRs were 16.4% and 9.2% lower (both P≤ 0.001), respectively. More MUFR trajectories were better fit to the rising exponential during control (16/25) compared to PAP (4/25, P<0.001) and PTP (8/25, P=0.03). The MU samples that had a rising exponential MUFR trajectory during PAP and PTP displayed an ~11% lower initial acceleration compared to control (P<0.05). Thus, synaptic amplification and MUFR saturation due to PIC properties are attenuated during ADP regardless of the type of conditioning contraction. This response may contribute to lower MUFRs and likely occurred because synaptic input is reduced when contractile function is enhanced.
Collapse
Affiliation(s)
- Alexander M Zero
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, ON, Canada
| | - Eric A Kirk
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, ON, Canada
| | - Charles L Rice
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, ON, Canada.,Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
18
|
Zero AM, Rice CL. Post-activation potentiation induced by concentric contractions at three speeds in humans. Exp Physiol 2021; 106:2489-2501. [PMID: 34569107 DOI: 10.1113/ep089613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 09/23/2021] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Is the degree of in human muscle affected by different shortening velocities, or contraction type? What are the main findings and their importance? The PAP response following maximal concentric contractions was independent of velocity. Slow and moderate velocity maximal contractions produced PAP responses like those from maximal isometric contractions when matched for contraction duration. Despite contraction type differences in cross-bridge and Ca2+ kinetics, maximal contractions, regardless of contraction modality, likely generate sufficient Ca2+ to induce maximal PAP. ABSTRACT Post-activation potentiation (PAP) is the acute enhancement of contractile properties following a brief (<10 s) high-intensity contraction. Compared with isometric contractions, little is known about the PAP response induced by concentric conditioning contractions (CCs) and the effect of velocity. In the dorsiflexors of 11 participants, twitch responses were measured following 5 s of maximal effort concentric CCs at each of 10, 20 and 50°/s. Concentric PAP responses were compared to a maximal isometric voluntary contraction (MVC) matched for contraction time. Additionally, concentric CCs were compared to isometric CCs matched for mean torque, contraction area and time. The PAP response following maximal concentric CCs was independent of velocity and there was no difference in the PAP response between concentric CCs and an isometric MVC. During maximal contractions, regardless of contraction modality, there is likely sufficient Ca2+ to induce a similar full PAP response, and thus there was no difference between speeds or contraction type. Following concentric CCs there was a significantly larger peak twitch torque than following their isometric torque matches (49-58%), and faster maximal rates of torque development at the three speeds (62-77%). However, these responses are likely related to greater EMG in concentric contractions, 125-129% of isometric maximum compared to 38-54%, and not to contraction modality per se. Thus, PAP responses following maximal concentric CCs are not affected by velocity and responses are not different from an isometric MVC. This indicates maximal CCs of 5 s produce a maximal PAP response independent of contraction type (isometric vs. concentric) or shortening velocity.
Collapse
Affiliation(s)
- Alexander M Zero
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, ON, Canada
| | - Charles L Rice
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, ON, Canada.,Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada
| |
Collapse
|
19
|
Trinity JD, Craig JC, Fermoyle CC, McKenzie AI, Lewis MT, Park SH, Rondina MT, Richardson RS. Impact of presymptomatic COVID-19 on vascular and skeletal muscle function: a case study. J Appl Physiol (1985) 2021; 130:1961-1970. [PMID: 34002634 PMCID: PMC8213510 DOI: 10.1152/japplphysiol.00236.2021] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The impact of COVID-19 has been largely described after symptom development. Although the SARS-CoV-2 virus elevates heart rate (HR) prior to symptom onset, whether this virus evokes other presymptomatic alterations is unknown. This case study details the presymptomatic impact of COVID-19 on vascular and skeletal muscle function in a young woman [24 yr, 173.5 cm, 89 kg, body mass index (BMI): 29.6 kg·m-2]. Vascular and skeletal muscle function were assessed as part of a separate study with the first and second visits separated by 2 wk. On the evening following the second visit, the participant developed a fever and a rapid antigen test confirmed a positive COVID-19 diagnosis. Compared with the first visit, the participant presented with a markedly elevated HR (∼30 beats/min) and a lower mean blood pressure (∼8 mmHg) at the second visit. Vascular function measured by brachial artery flow-mediated dilation, reactive hyperemia, and passive leg movement were all noticeably attenuated (25%-65%) as was leg blood flow during knee extension exercise. Muscle strength was diminished as was ADP-stimulated respiration (30%), assessed in vitro, whereas there was a 25% increase in the apparent Km. Lastly, an elevation in IL-10 was observed prior to symptom onset. Notably, 2.5 mo after diagnosis symptoms of fatigue and cough were still present. Together, these findings provide unique insight into the physiological responses immediately prior to onset of COVID-19 symptoms; they suggest that SARS-CoV-2 negatively impacts vascular and skeletal muscle function prior to the onset of common symptoms and may set the stage for the widespread sequelae observed following COVID-19 diagnosis.NEW & NOTEWORTHY This unique case study details the impact of SARS-CoV-2 infection on vascular and skeletal muscle function in a young predominantly presymptomatic woman. Prior to COVID-19 diagnosis, substantial reductions in vascular, skeletal muscle, and mitochondrial function were observed along with an elevation in IL-10. This integrative case study indicates that the presymptomatic impact of COVID-19 is widespread and may help elucidate the acute and long-term sequelae of this disease.
Collapse
Affiliation(s)
- Joel D. Trinity
- 1Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, Utah,2Division of Geriatrics, Department of Internal Medicine, grid.223827.eUniversity of Utah, Salt Lake City, Utah,3Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Jesse C. Craig
- 1Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, Utah,2Division of Geriatrics, Department of Internal Medicine, grid.223827.eUniversity of Utah, Salt Lake City, Utah
| | - Caitlin C. Fermoyle
- 1Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, Utah,2Division of Geriatrics, Department of Internal Medicine, grid.223827.eUniversity of Utah, Salt Lake City, Utah
| | - Alec I. McKenzie
- 1Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, Utah,2Division of Geriatrics, Department of Internal Medicine, grid.223827.eUniversity of Utah, Salt Lake City, Utah
| | - Matthew T. Lewis
- 1Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, Utah,2Division of Geriatrics, Department of Internal Medicine, grid.223827.eUniversity of Utah, Salt Lake City, Utah
| | - Soung Hun Park
- 1Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, Utah,3Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Matthew T. Rondina
- 1Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, Utah,2Division of Geriatrics, Department of Internal Medicine, grid.223827.eUniversity of Utah, Salt Lake City, Utah,4Molecular Medicine Program, Division of General Internal Medicine, Departments of Internal Medicine and Pathology, University of Utah, Salt Lake City, Utah
| | - Russell S. Richardson
- 1Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, Utah,2Division of Geriatrics, Department of Internal Medicine, grid.223827.eUniversity of Utah, Salt Lake City, Utah,3Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| |
Collapse
|
20
|
Dotan R, Woods S, Contessa P. On the reliability and validity of central fatigue determination. Eur J Appl Physiol 2021; 121:2393-2411. [PMID: 33966110 DOI: 10.1007/s00421-021-04700-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/24/2021] [Indexed: 11/30/2022]
Abstract
Physical performance fatigue can be ascribed to both peripheral and central components. Central fatigue, however, is an elusive entity, consisting of cognitive/sensory component and presumably also a neuro-physiological component that are difficult to tease apart and assess independently of each other. The most widely accepted method for the assessment of central fatigue is based on the premise that decreasing volitional muscle activation (VA), as determined by the interpolated twitch technique (ITT) in fatiguing muscles, reflects increasing central fatigue. Suffering its own shortcomings, the validity of VA determination under fatigued conditions has never been proven and is only assumed. This review presents evidence that questions ITT's reliability and validity in reflecting VA in the fatiguing muscle and, consequently, VA's validity for central fatigue assessment. Specifically highlighted is the paradox of children and endurance athletes, who share striking endurance characteristics, being claimed as more centrally fatigable than untrained adults. Further research and new directions are needed for confirming and quantifying central fatigue and teasing apart its psychologic and neuromotor components.
Collapse
Affiliation(s)
- Raffy Dotan
- Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, St Catharines, ON, Canada.
| | - Stacey Woods
- Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, St Catharines, ON, Canada
| | | |
Collapse
|
21
|
Kishimoto KC, Héroux ME, Gandevia SC, Butler JE, Diong J. Estimation of maximal muscle electromyographic activity from the relationship between muscle activity and voluntary activation. J Appl Physiol (1985) 2021; 130:1352-1361. [PMID: 33600280 DOI: 10.1152/japplphysiol.00557.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Maximal muscle activity recorded with surface electromyography (EMG) is an important neurophysiological measure. It is frequently used to normalize EMG activity recorded during passive or active movement. However, the true maximal muscle activity cannot be determined in people with impaired capacity to voluntarily activate their muscles. Here, we determined whether maximal muscle activity can be estimated from muscle activity produced during submaximal voluntary activation. Twenty-five able-bodied adults (18 males, mean age 29 yr, range 19-64 yr) participated in the study. Participants were seated with the knee flexed 90° and the ankle in 5° of dorsiflexion from neutral. Participants performed isometric voluntary ankle plantarflexion contractions at target torques, in random order: 1, 5, 10, 15, 25, 50, 75, 90, 95, and 100% of maximal voluntary torque. Ankle torque, muscle activity in soleus, medial and lateral gastrocnemius muscles, and voluntary muscle activation determined using twitch interpolation were recorded. There was a strong loge-linear relationship between measures of muscle activation and muscle activity in all three muscles tested. Linear mixed models were fitted to muscle activation and loge-transformed EMG data. Each 1% increase in muscle activation increased muscle activity by a mean of 0.027 ln(mV) [95% confidence interval (CI) 0.025 to 0.029 ln(mV)] in soleus, 0.025 ln(mV) [0.022 to 0.028 ln(mV)] in medial gastrocnemius, and 0.028 ln(mV) [0.026 to 0.030 ln(mV)] in lateral gastrocnemius. The relationship between voluntary muscle activation and muscle activity can be described with simple mathematical functions. In future, it should be possible to normalize recorded muscle activity using these types of functions.NEW & NOTEWORTHY Muscle activity is often normalized to maximal muscle activity; however, it is difficult to obtain accurate measures of maximal muscle activity in people with impaired voluntary neural drive. We determined the relationship between voluntary muscle activation and plantarflexor muscle activity across a broad range of muscle activation values in able-bodied people. The relationship between voluntary muscle activation and muscle activity can be described with simple mathematical functions capable of estimating maximal muscle activity.
Collapse
Affiliation(s)
- Kenzo C Kishimoto
- Discipline of Physiotherapy, Faculty of Health Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Martin E Héroux
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia.,School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Simon C Gandevia
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia.,Prince of Wales Clinical School, University of New South Wales, Sydney, New South Wales, Australia
| | - Jane E Butler
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia.,School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Joanna Diong
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia.,Discipline of Anatomy and Histology, Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, New South Wales, Australia
| |
Collapse
|
22
|
González-Hernández JM, García-Ramos A, Colomer-Poveda D, Tvarijonaviciute A, Cerón J, Jiménez-Reyes P, Márquez G. Resistance Training to Failure vs. Not to Failure: Acute and Delayed Markers of Mechanical, Neuromuscular, and Biochemical Fatigue. J Strength Cond Res 2021; 35:886-893. [PMID: 33306589 DOI: 10.1519/jsc.0000000000003921] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT González-Hernández, JM, García-Ramos, A, Colomer-Poveda, D, Tvarijonaviciute, A, Cerón, J, Jiménez-Reyes, P, and Márquez, G. Resistance training to failure vs. not to failure: acute and delayed markers of mechanical, neuromuscular, and biochemical fatigue. J Strength Cond Res 35(4): 886-893, 2021-This study aimed to compare acute and delayed markers of mechanical, neuromuscular, and biochemical fatigue between resistance training sessions leading to or not to failure. Twelve resistance-trained men completed 2 sessions that consisted of 6 sets of the full-squat exercise performed against the 10 repetitions maximum load. In a randomized order, in one session the sets were performed to failure and in the other session the sets were not performed to failure (5 repetitions per set). Mechanical fatigue was quantified through the recording of the mean velocity during all repetitions. The neuromuscular function of the knee extensors was assessed through a maximal voluntary contraction and the twitch interpolation technique before training, immediately after each set, and 1, 24, and 48 hours post-training. Serum creatine kinase (CK) and aspartate aminotransferase (AST) were measured before training and 1, 24, and 48 hours post-training to infer muscle damage. Alpha was set at a level of 0.05. A higher velocity loss between sets was observed during the failure protocol (-21.7%) compared with the nonfailure protocol (-3.5%). The markers of peripheral fatigue were generally higher and long lasting for the failure protocol. However, the central fatigue assessed by the voluntary activation was comparable for both protocols and remained depressed up to 48 hours post-training. The concentrations of CK and AST were higher after the failure protocol revealing higher muscle damage compared with the nonfailure protocol. These results support the nonfailure protocol to reduce peripheral fatigue and muscle damage, whereas the central fatigue does not seem to be affected by the set configuration.
Collapse
Affiliation(s)
- Jorge M González-Hernández
- Faculty of Health Science, European University of Canarias, Tenerife, Spain.,Department of Physical Education and Sport, Faculty of Sport Sciences, Catholic University of Murcia (UCAM), Murcia, Spain
| | - Amador García-Ramos
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain.,Department of Sports Sciences and Physical Conditioning, Faculty of Education, Catholic University of the Most Holy Concepcion, Concepción, Chile
| | - David Colomer-Poveda
- Department of Physical Education and Sport, Faculty of Sport Sciences, Catholic University of Murcia (UCAM), Murcia, Spain
| | - Asta Tvarijonaviciute
- Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, Regional Campus of International Excellence "Campus Mare Nostrum," University of Murcia, Murcia, Spain
| | - José Cerón
- Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, Regional Campus of International Excellence "Campus Mare Nostrum," University of Murcia, Murcia, Spain
| | | | - Gonzalo Márquez
- Department of Physical Education and Sport, Faculty of Sport Sciences, Catholic University of Murcia (UCAM), Murcia, Spain.,Department of Physical Education, Faculty of Sport Sciences and Physical Education, University of A Coruña, A Coruña, Spain
| |
Collapse
|
23
|
Reliability of Tibialis Anterior Muscle Voluntary Activation Using the Interpolated Twitch Technique and the Central Activation Ratio in People with Stroke. Brain Sci 2021; 11:brainsci11020176. [PMID: 33535411 PMCID: PMC7912757 DOI: 10.3390/brainsci11020176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 01/24/2021] [Accepted: 01/26/2021] [Indexed: 12/04/2022] Open
Abstract
Voluntary activation (VA) is measured by applying supramaximal electrical stimulation to a muscle during a maximal voluntary contraction (MVC). The amplitude of the evoked muscle twitch is used to determine any VA deficit, and indicates incomplete central neural drive to the motor units. People with stroke experience VA deficits and greater levels of central fatigue, which is the decrease in VA that occurs following exercise. This study investigated the between-session reliability of VA and central fatigue of the tibialis anterior muscle (TA) in people with chronic stroke (n = 12), using the interpolated twitch technique (ITT), adjusted-ITT, and central activation ratio (CAR) methods. On two separate sessions, supramaximal electrical stimulation was applied to the TA when it was at rest and maximally activated, at the start and end of a 30-s isometric dorsiflexor MVC. The most reliable measures of VA were obtained using the CAR calculation on transformed data, which produced an ICC of 0.92, and a lower bound confidence interval in the good range (95% CI 0.77 to 0.98). Reliability was lower for the CAR calculation on non-transformed data (ICC 0.82, 95% CI 0.63 to 0.91) and the ITT and adjusted-ITT calculations on transformed data (ICCs 0.82, 95% CIs 0.51 to 0.94), which had lower bound confidence intervals in the moderate range. The two ITT calculations on non-transformed data demonstrated the poorest reliability (ICCs 0.62, 95% CI 0.25 to 0.74). Central fatigue measures demonstrated very poor reliability. Thus, the reliability for VA in people with chronic stroke ranged from good to poor, depending on the calculation method and statistical analysis method, whereas the reliability for central fatigue was very poor.
Collapse
|
24
|
Hali K, Zero AM, Rice CL. Effect of ankle joint position on triceps surae contractile properties and motor unit discharge rates. Physiol Rep 2021; 8:e14680. [PMID: 33356017 PMCID: PMC7757371 DOI: 10.14814/phy2.14680] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 10/31/2020] [Accepted: 11/14/2020] [Indexed: 11/25/2022] Open
Abstract
The triceps surae (TS) length-tension relationship can be altered by changing the knee joint position, ankle joint position or both. However, studies exploring the effect of muscle length on neuromuscular properties have focused only on knee joint position changes affecting two of the three muscle components of the TS. Thus, the purpose of this study is to compare the neuromuscular properties of the three TS muscles during plantar flexion contractions at two ankle joint positions, 20° dorsiflexed (DF) and 20° plantar flexed (PF). Maximal isometric voluntary strength (MVC), voluntary activation, and evoked contractile properties of the ankle plantar flexors were compared between both ankle joint positions. Additionally, soleus, medial (MG), and lateral (LG) gastrocnemii motor unit discharge rates (MUDRs) were sampled during plantar flexion contractions at 25%, 50%, 75%, and 100% MVC using indwelling tungsten electrodes. MVC and peak twitch torque were lower by ~61% and 70%, respectively, whereas the maximal rate of torque relaxation was 39% faster in the PF compared with the DF position. Voluntary activation (~95%) was unaffected by changes in ankle joint position. LG MUDRs showed no differences between ankle joint positions, regardless of contraction intensity. Submaximal MG and soleus MUDRs showed no differences between the two ankle joint positions, however both muscles had 9% and 20% higher MUDRs in the DF position, respectively. These results provide further evidence for the differential activation among the three components of the TS with the greatest increases in soleus MUDRs compared with the gastrocnemii when the muscles are lengthened.
Collapse
Affiliation(s)
- Kalter Hali
- Faculty of Health SciencesSchool of KinesiologyThe University of Western OntarioLondonONCanada
| | - Alexander M. Zero
- Faculty of Health SciencesSchool of KinesiologyThe University of Western OntarioLondonONCanada
| | - Charles L. Rice
- Faculty of Health SciencesSchool of KinesiologyThe University of Western OntarioLondonONCanada
- Department of Anatomy and Cell BiologySchulich School of Medicine and DentistryThe University of Western OntarioLondonONCanada
| |
Collapse
|
25
|
Pereira HM, de Lima FF, Silva BM, Kohn AF. Sex differences in fatigability after ischemic preconditioning of non-exercising limbs. Biol Sex Differ 2020; 11:59. [PMID: 33109241 PMCID: PMC7590792 DOI: 10.1186/s13293-020-00338-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 10/18/2020] [Indexed: 12/11/2022] Open
Abstract
Background Ischemic preconditioning (IPC) is suggested to decrease fatigability in some individuals but not others. Sex differences in response to IPC may account for this variability and few studies systematically investigated the effects of IPC in men and women. The goal of this study was to determine if time to task failure, perception of pain, and neuromuscular mechanisms of fatigability were altered by IPC in men and women. Methods Ten women (29 ± 5 years old) and 10 men (28 ± 6 years old) performed isometric contractions with the plantar flexor muscles of the dominant leg at 20% of maximal voluntary contraction until task failure. We used a repeated measures design where each individual performed 3 randomized and counterbalanced test sessions: (A) IPC session, cuff inflation and deflation (5 min each repeated 3 times) performed before the exercise by inflating cuffs to the non-dominant leg and arm; (B) sham session, cuffs were inflated for a short period (1 min); and (C) control session, no cuffs were involved. Results Compared with control, IPC increased time to task failure in men (mean difference, 5 min; confidence interval (CI) of mean difference, 2.2; 7.8 min; P = 0.01) but not women (mean difference, − 0.6 min; CI of mean difference, − 3.5; 2.4 min; P = 0.51). In men, but not women, the IPC-induced increase in time to task failure was associated with lower response to pressure pain (r = − 0.79). IPC further exposed sex differences in arterial pressure during fatiguing contractions (session × sex: P < 0.05). Voluntary activation, estimated with the twitch interpolation technique, and presynaptic inhibition of leg Ia afferents were not altered after IPC for men and women. The tested variables were not altered with sham. Conclusions The ergogenic effect of IPC on time to task failure was observed only in men and it was associated with reductions in the perception of pain. This pilot data suggest the previously reported inter-individual variability in exercise-induced fatigability after IPC could be a consequence of the sex and individual response to pain.
Collapse
Affiliation(s)
- Hugo M Pereira
- Department of Health and Exercise Science, University of Oklahoma, 1401 Asp Ave, Norman, OK, 73019, USA.
| | - Felipe F de Lima
- Biomedical Engineering Laboratory/EPUSP, University of São Paulo, São Paulo, SP, Brazil
| | - Bruno M Silva
- Department of Physiology, Federal University of São Paulo, São Paulo, SP, Brazil
| | - André F Kohn
- Biomedical Engineering Laboratory/EPUSP, University of São Paulo, São Paulo, SP, Brazil
| |
Collapse
|
26
|
Wolke R, Kuhtz-Buschbeck JP, Deuschl G, Margraf NG. Insufficiency of trunk extension and impaired control of muscle force in Parkinson's disease with camptocormia. Clin Neurophysiol 2020; 131:2621-2629. [PMID: 32932021 DOI: 10.1016/j.clinph.2020.07.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 07/04/2020] [Accepted: 07/12/2020] [Indexed: 01/03/2023]
Abstract
OBJECTIVE To examine the aetiology of parkinsonian camptocormia, a non-fixed pathological forward bending of the trunk, by measuring trunk muscle activation and force regulation in Parkinson patients with (PD + CC) and without (PD) camptocormia matched for disease severity, and in age- and sex-matched healthy controls (HC). METHODS The isometric forces of trunk extension and flexion were measured in PD + CC, PD and HC. Neuromuscular efficiency (increase of extension force per increase of paravertebral muscle surface electromyography signal) and the ability to maintain a constant submaximal trunk extension force were examined. RESULTS Peak trunk extension force was significantly lower in PD + CC and PD than in HC, with PD + CC non-significantly weaker than PD. Compared with HC and with PD, the neuromuscular efficiency of trunk extension was significantly reduced in PD + CC. The variability of the force output (coefficient of variation) was significantly larger for PD + CC than for HC or PD. CONCLUSION The reduced neuromuscular efficiency of trunk extension separates PD + CC from PD. Moreover, control of the trunk extensor force is impaired in PD + CC. SIGNIFICANCE There is weakness and a force control deficit in parkinsonian camptocormia suggesting a disturbed sensory-motor integration, which may contribute to myopathic changes in the trunk extensor muscles.
Collapse
Affiliation(s)
- R Wolke
- Department of Neurology, Kiel University, UKSH, Germany
| | | | - G Deuschl
- Department of Neurology, Kiel University, UKSH, Germany.
| | - N G Margraf
- Department of Neurology, Kiel University, UKSH, Germany
| |
Collapse
|
27
|
Olsen S, Signal N, Niazi IK, Rashid U, Alder G, Mawston G, Nedergaard RB, Jochumsen M, Taylor D. Peripheral Electrical Stimulation Paired With Movement-Related Cortical Potentials Improves Isometric Muscle Strength and Voluntary Activation Following Stroke. Front Hum Neurosci 2020; 14:156. [PMID: 32499686 PMCID: PMC7242792 DOI: 10.3389/fnhum.2020.00156] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 04/09/2020] [Indexed: 12/18/2022] Open
Abstract
Background Endogenous paired associative stimulation (ePAS) is a neuromodulatory intervention that has potential to aid stroke recovery. ePAS involves pairing endogenous electroencephalography (EEG) signals known as movement-related cortical potentials (MRCPs), with peripheral electrical stimulation. Previous studies have used transcranial magnetic stimulation (TMS) to demonstrate changes in corticomotor excitability following ePAS. However, the use of TMS as a measure in stroke research is limited by safety precautions, intolerance, and difficulty generating a measurable response in more severely affected individuals. We were interested in evaluating the effect of ePAS using more feasible measures in people with stroke. This study asks whether ePAS produces immediate improvements in the primary outcomes of maximal voluntary isometric contraction (MVIC) and total neuromuscular fatigue of the dorsiflexor muscles, and in the secondary outcomes of muscle power, voluntary activation (VA), central fatigue, peripheral fatigue, and electromyography activity. Method In this repeated-measures cross-over study, 15 participants with chronic stroke completed two interventions, ePAS and sham, in a randomized order. During ePAS, 50 repetitions of visually cued dorsiflexion were completed, while single pulses of electrical stimulation were delivered to the deep branch of the common peroneal nerve. Each somatosensory volley was timed to arrive in the primary motor cortex at the peak negativity of the MRCP. Univariate and multivariate linear mixed models were used to analyze the primary and secondary data, respectively. Results There was a statistically significant increase in dorsiflexor MVIC immediately following the ePAS intervention (mean increase 7 N), compared to the sham intervention (mean change 0 N) (univariate between-condition analysis p = 0.047). The multivariate analysis revealed a statistically significant effect of ePAS on VA of the tibialis anterior muscle, such that ePAS increased VA by 7 percentage units (95% confidence interval 1.3–12.7%). There was no statistically significant effect on total neuromuscular fatigue, muscle power, or other secondary measures. Conclusion A single session of ePAS can significantly increase isometric muscle strength and VA in people with chronic stroke. The findings confirm that ePAS has a central neuromodulatory mechanism and support further exploration of its potential as an adjunct to stroke rehabilitation. In addition, the findings offer alternative, feasible outcome measures for future research. Clinical trial registration Australia New Zealand Clinical Trials Registry ACTRN12617000838314 (www.anzctr.org.au), Universal Trial Number U111111953714.
Collapse
Affiliation(s)
- Sharon Olsen
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
| | - Nada Signal
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
| | - Imran K Niazi
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand.,Centre for Chiropractic Research, New Zealand College of Chiropractic, Auckland, New Zealand.,Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Usman Rashid
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
| | - Gemma Alder
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
| | - Grant Mawston
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
| | - Rasmus B Nedergaard
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.,Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Aalborg, Denmark
| | - Mads Jochumsen
- Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Denise Taylor
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
| |
Collapse
|
28
|
Hali K, Dalton BH, Harwood B, Fessler AF, Power GA, Rice CL. Differential Modulation of Motor Unit Properties from the Separate Components of the Triceps Surae in Humans. Neuroscience 2020; 428:192-198. [PMID: 31917353 DOI: 10.1016/j.neuroscience.2019.12.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 12/11/2019] [Accepted: 12/12/2019] [Indexed: 10/25/2022]
Abstract
The triceps surae is comprised of the soleus, and medial (MG) and lateral (LG) gastrocnemii. Modulation of triceps surae motor units (MUs) is context- and muscle-dependent, yet it is unknown how the disparate components of the triceps surae work together to achieve the common goal of high-intensity voluntary isometric plantar flexion torque gradation. Thus, the purpose was to assess the interrelationships between MU recruitment thresholds (MURTs) and MU discharge rates (MUDRs) among these three muscles during contractions from low to high intensities. We sampled 157 MU action potential trains from the MG (68), LG (38) and soleus (51) using fine-wire intramuscular electromyography (EMG) during voluntary ramp isometric contractions up to 100% maximal voluntary contraction (MVC). The soleus exhibited 41% and 54% lower MURTs compared to the MG (p < 0.0001) and LG (p < 0.0001), respectively, whereas MG MURTs were 22% lower than the LG (p < 0.0001). Initial MUDRs were 35% and 26% greater for the LG compared with the MG (p < 0.0001) and soleus (p < 0.0001), but no difference was detected between the MG and soleus (p = 0.28). Finally, initial MUDRs displayed a positive relationship with MURTs for each independent triceps surae component (p ≤ 0.002). The relative differences in MU properties of each muscle in this synergistic group illustrate that MU control strategies are likely optimized with respect to the relative contribution of each muscle to plantar flexion torque or functional roles.
Collapse
Affiliation(s)
- Kalter Hali
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada
| | - Brian H Dalton
- School of Health and Exercise Sciences, The University of British Columbia Okanagan, Kelowna, British Columbia, Canada.
| | - Brad Harwood
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada
| | - Andrew F Fessler
- Department of Human Physiology, University of Oregon, Eugene, OR, United States
| | - Geoffrey A Power
- Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Charles L Rice
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada; Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
29
|
Wrightson JG, Twomey R, Yeung STY, Millet GY. No effect of tDCS of the primary motor cortex on isometric exercise performance or perceived fatigue. Eur J Neurosci 2020; 52:2905-2914. [DOI: 10.1111/ejn.14651] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/27/2019] [Accepted: 12/06/2019] [Indexed: 12/30/2022]
Affiliation(s)
- James Graeme Wrightson
- Faculty of Kinesiology University of Calgary Calgary AB Canada
- Hotchkiss Brain Institute University of Calgary Calgary AB Canada
| | - Rosie Twomey
- Faculty of Kinesiology University of Calgary Calgary AB Canada
| | | | - Guillaume Yves Millet
- Faculty of Kinesiology University of Calgary Calgary AB Canada
- Inter‐university Laboratory of Human Movement Biology Univ Lyon, UJM‐Saint‐Etienne Saint‐Etienne France
| |
Collapse
|
30
|
Oranchuk DJ, Koral J, da Mota GR, Wrightson JG, Soares R, Twomey R, Millet GY. Effect of blood flow occlusion on neuromuscular fatigue following sustained maximal isometric contraction. Appl Physiol Nutr Metab 2019; 45:698-706. [PMID: 31809198 DOI: 10.1139/apnm-2019-0579] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Sustained isometric maximal voluntary contractions (IMVCs) have blood flow occlusive effects on the microvasculature. However, it is unknown if this effect would be magnified with additional blood flow restriction via a cuff and what the influence on fatigue development would be. Twelve healthy male participants performed a 1-min IMVC of the knee extensors with and without additional blood flow occlusion induced by pneumatic cuff in counterbalanced order on separate days. Vastus lateralis muscle deoxygenation was estimated via near-infrared spectroscopy-derived tissue oxygen saturation (SmO2) throughout the fatiguing contraction. Central and peripheral measures of neuromuscular fatigue (NMF) were assessed via surface electromyography (EMG) and force responses to voluntary contractions and peripheral nerve/transcranial magnetic stimulations before, immediately after, and throughout an 8-min recovery period. SmO2, force, and EMG amplitude decreased during the 1-min IMVC, but there were no between-condition differences. Similarly, no significant (p > 0.05) between-condition differences were detected for any dependent variable immediately after the fatiguing contraction. Transcranial magnetic stimulation (TMS)-derived voluntary activation was lower (p < 0.05) in the no-cuff condition during the recovery period. Sustained IMVC results in a similar degree of muscle deoxygenation and NMF as IMVCs with additional occlusion, providing further evidence that a sustained IMVC induces full ischemia. Novelty NMF etiology, muscle oxygenation, and corticospinal factors during an IMVC are similar with or without an occlusion cuff. Contrary to all other measures, TMS-evaluated voluntary activation returned to baseline faster following the occluded condition.
Collapse
Affiliation(s)
- Dustin J Oranchuk
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada.,Sports Performance Research Institute New Zealand, Auckland University of Technology, Auckland 0632, New Zealand
| | - Jérôme Koral
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada.,Université of Lyon, UJM-Saint-Etienne, Laboratoire Interuniversitaire de Biologie de la Motricité, EA 7424, F-42023, Saint-Etienne, France
| | - Gustavo R da Mota
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada.,Department of Sport Sciences, Institute of Health Sciences, Federal University of Triângulo Mineiro, Uberaba 38025-180, Brazil
| | - James G Wrightson
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Rogério Soares
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Rosie Twomey
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Guillaume Y Millet
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada.,Université of Lyon, UJM-Saint-Etienne, Laboratoire Interuniversitaire de Biologie de la Motricité, EA 7424, F-42023, Saint-Etienne, France
| |
Collapse
|
31
|
Effects of Ankle Joint Motion on Pelvis-Hip Biomechanics and Muscle Activity Patterns of Healthy Individuals in Knee Immobilization Gait. JOURNAL OF HEALTHCARE ENGINEERING 2019; 2019:3812407. [PMID: 31737239 PMCID: PMC6815642 DOI: 10.1155/2019/3812407] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 08/15/2019] [Accepted: 09/07/2019] [Indexed: 11/18/2022]
Abstract
The purpose of the study was to investigate the pelvis-hip biomechanics and trunk and lower limb muscle activity patterns between healthy people walking in two gaits and evaluate the effects of ankle joint motion on these two gaits. The two gaits included walking with combined knee and ankle immobilization and with individual knee immobilization. Ten healthy participants were recruited and asked to walk along a 10 m walk away at their comfortable speeds in the two gaits. Kinematic data, ground reaction force, and electromyography waveforms of trunk and lower limb muscles on the right side were collected synchronously. Compared to individual knee immobilization gait, people walking in the combined knee and ankle immobilization gait increased the range and average angle of the anterior pelvic tilt during the first double support and the single support phase, respectively. The combined knee and ankle immobilization gait also increased the range of hip abduction during the second double support phase. These kinematic alternations caused changes in trunk and lower limb muscle activity patterns. The ankle immobilization increased the range of gluteus maximus activation in the first double support phase, the range of rectus abdominis activation, the average amplitude of rectus femoris activation in the single support phase, and the range of rectus femoris activation in swing phase and decreased the range of and tibialis anterior activation in the first double support phase. The ankle immobilization also increased the average values of proximodistal component in AKI gait during the single support phase. This study revealed significant differences in pelvis-hip biomechanics and trunk and lower limb muscle activity patterns between the two gaits.
Collapse
|
32
|
Diong J, Gandevia SC, Nguyen D, Foo Y, Kastre C, Andersson K, Butler JE, Héroux ME. Small amounts of involuntary muscle activity reduce passive joint range of motion. J Appl Physiol (1985) 2019; 127:229-234. [DOI: 10.1152/japplphysiol.00168.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
When assessing passive joint range of motion in neurological conditions, concomitant involuntary muscle activity is generally regarded small enough to ignore. This assumption is untested. If false, many clinical and laboratory studies that rely on these assessments may be in error. We determined to what extent small amounts of involuntary muscle activity limit passive range of motion in 30 able-bodied adults. Subjects were seated with the knee flexed 90° and the ankle in neutral, and predicted maximal plantarflexion torque was determined using twitch interpolation. Next, with the knee flexed 90° or fully extended, the soleus muscle was continuously electrically stimulated to generate 1, 2.5, 5, 7.5, and 10% of predicted maximal torque, in random order, while the ankle was passively dorsiflexed to a torque of 9 N·m by a blinded investigator. A trial without stimulation was also performed. Ankle dorsiflexion torque-angle curves were obtained at each percent of predicted maximal torque. On average (mean, 95% confidence interval), each 1% increase in plantarflexion torque decreases ankle range of motion by 2.4° (2.0 to 2.7°; knee flexed 90°) and 2.3° (2.0 to 2.5°; knee fully extended). Thus 5% of involuntary plantarflexion torque, the amount usually considered small enough to ignore, decreases dorsiflexion range of motion by ~12°. Our results indicate that even small amounts of involuntary muscle activity will bias measures of passive range and hinder the differential diagnosis and treatment of neural and nonneural mechanisms of contracture. NEW & NOTEWORTHY The soleus muscle in able-bodied adults was tetanically stimulated while the ankle was passively dorsiflexed. Each 1% increase in involuntary plantarflexion torque at the ankle decreases the range of passive movement into dorsiflexion by >2°. Thus the range of ankle dorsiflexion decreases by ~12° when involuntary plantarflexion torque is 5% of maximum, a torque that is usually ignored. Thus very small amounts of involuntary muscle activity substantially limit passive joint range of motion.
Collapse
Affiliation(s)
- Joanna Diong
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, New South Wales, Australia
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
| | - Simon C. Gandevia
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
- Prince of Wales Clinical School, University of New South Wales, New South Wales, Australia
| | - David Nguyen
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
| | - Yanni Foo
- Faculty of Health Sciences, The University of Sydney, New South Wales, Australia
| | | | | | - Jane E. Butler
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, New South Wales, Australia
| | - Martin E. Héroux
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, New South Wales, Australia
| |
Collapse
|
33
|
Ansdell P, Brownstein CG, Škarabot J, Hicks KM, Simoes DCM, Thomas K, Howatson G, Hunter SK, Goodall S. Menstrual cycle-associated modulations in neuromuscular function and fatigability of the knee extensors in eumenorrheic women. J Appl Physiol (1985) 2019; 126:1701-1712. [DOI: 10.1152/japplphysiol.01041.2018] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Sex hormone concentrations of eumenorrheic women typically fluctuate across the menstrual cycle and can affect neural function such that estrogen has neuroexcitatory effects, and progesterone induces inhibition. However, the effects of these changes on corticospinal and intracortical circuitry and the motor performance of the knee extensors are unknown. The present two-part investigation aimed to 1) determine the measurement error of an exercise task, transcranial magnetic stimulation (TMS)-, and motor nerve stimulation (MNS)-derived responses in women ingesting a monophasic oral contraceptive pill (hormonally-constant) and 2) investigate whether these measures were modulated by menstrual cycle phase (MCP), by examining them before and after an intermittent isometric fatiguing task (60% of maximal voluntary contraction, MVC) with the knee extensors until task failure in eumenorrheic women on days 2, 14, and 21 of the menstrual cycle. The repeatability of neuromuscular measures at baseline and fatigability ranged between moderate and excellent in women taking the oral contraceptive pill. MVC was not affected by MCP ( P = 0.790). Voluntary activation (MNS and TMS) peaked on day 14 ( P = 0.007 and 0.008, respectively). Whereas corticospinal excitability was unchanged, short-interval intracortical inhibition was greatest on day 21 compared with days 14 and 2 ( P < 0.001). Additionally, time to task failure was longer on day 21 than on both days 14 and 2 (24 and 36%, respectively, P = 0.030). The observed changes were larger than the associated measurement errors. These data demonstrate that neuromuscular function and fatigability of the knee extensors vary across the menstrual cycle and may influence exercise performance involving locomotor muscles. NEW & NOTEWORTHY The present two-part study first demonstrated the repeatability of transcranial magnetic stimulation- and electrical motor nerve stimulation-evoked variables in a hormonally constant female population. Subsequently, it was demonstrated that the eumenorrheic menstrual cycle affects neuromuscular function. Changing concentrations of neuroactive hormones corresponded to greater voluntary activation on day 14, greater intracortical inhibition on day 21, and lowest fatigability on day 21. These alterations of knee extensor neuromuscular function have implications for locomotor activities.
Collapse
Affiliation(s)
- Paul Ansdell
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Callum G. Brownstein
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
- Université Lyon, UJM-Saint-Etienne, Inter-university Laboratory of Human Movement Biology, Saint-Etienne, France
| | - Jakob Škarabot
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Kirsty M. Hicks
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Davina C. M. Simoes
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Kevin Thomas
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Glyn Howatson
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
- Water Research Group, School of Environmental Sciences and Development, Northwest University, Potchefstroom, South Africa
| | - Sandra K. Hunter
- Exercise Science Program, Department of Physical Therapy, Marquette University, Milwaukee, Wisconsin
| | - Stuart Goodall
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| |
Collapse
|
34
|
Nuzzo JL, Taylor JL, Gandevia SC. CORP: Measurement of upper and lower limb muscle strength and voluntary activation. J Appl Physiol (1985) 2019; 126:513-543. [DOI: 10.1152/japplphysiol.00569.2018] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Muscle strength, the maximal force-generating capacity of a muscle or group of muscles, is regularly assessed in physiological experiments and clinical trials. An understanding of the expected variation in strength and the factors that contribute to this variation is important when designing experiments, describing methodologies, interpreting results, and attempting to replicate methods of others and reproduce their findings. In this review (Cores of Reproducibility in Physiology), we report on the intra- and inter-rater reliability of tests of upper and lower limb muscle strength and voluntary activation in humans. Isometric, isokinetic, and isoinertial strength exhibit good intra-rater reliability in most samples (correlation coefficients ≥0.90). However, some tests of isoinertial strength exhibit systematic bias that is not resolved by familiarization. With the exception of grip strength, few attempts have been made to examine inter-rater reliability of tests of muscle strength. The acute factors most likely to affect muscle strength and serve as a source of its variation from trial-to-trial or day-to-day include attentional focus, breathing technique, remote muscle contractions, rest periods, temperature (core, muscle), time of day, visual feedback, body and limb posture, body stabilization, acute caffeine consumption, dehydration, pain, fatigue from preceding exercise, and static stretching >60 s. Voluntary activation, the nervous system’s ability to drive a muscle to create its maximal force, exhibits good intra-rater reliability when examined with twitch interpolation (correlation coefficients >0.80). However, inter-rater reliability has not been formally examined. The methodological factors most likely to influence voluntary activation are myograph compliance and sensitivity; stimulation location, intensity, and inadvertent stimulation of antagonists; joint angle (muscle length); and the resting twitch.
Collapse
Affiliation(s)
- James L. Nuzzo
- Neuroscience Research Australia, Randwick, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Janet L. Taylor
- Neuroscience Research Australia, Randwick, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, Sydney, Australia
- School of Medical and Health Sciences, Edith Cowan University, Perth, Western Australia, Australia
| | - Simon C. Gandevia
- Neuroscience Research Australia, Randwick, New South Wales, Australia
- Prince of Wales Hospital Clinical School, University of New South Wales, Sydney, Australia
| |
Collapse
|
35
|
Kirk EA, Singh SM, Rice CL. ATP2A2 rs3026468 does not associate with quadriceps contractile properties and acute muscle potentiation in humans. Physiol Genomics 2019; 51:10-11. [PMID: 30526312 PMCID: PMC6383552 DOI: 10.1152/physiolgenomics.00085.2018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ATP2A2 gene encodes the SERCA protein required for active calcium reuptake to the sarcoplasmic reticulum in cardiac and slow-twitch skeletal muscle. The ATP2A2 rs3026468 variant has been associated with voluntary strength phenotypes in humans but requires further validation. Here we investigated a homogenous cohort of 80 young, healthy, active Caucasian males who were assessed for maximal isometric strength, voluntary activation, stimulated contractile properties, and muscle potentiation in the quadriceps. A dynamometer was used to record knee extensions, and electrical stimulation was applied to the thigh to elicit a twitch response. DNA was isolated from cheek swabs, and the rs3026468 genotypes were assessed by TaqMan primer quantitative PCR. The results show no association between ATP2A2 rs3026468 variants and muscle strength measures. We conclude there is no effect of the rs3026468 variant in our cohort and that functional influences do not likely contribute to contractile property differences in young healthy men.
Collapse
Affiliation(s)
- Eric A Kirk
- School of Kinesiology, Faculty of Health Sciences, the University of Western Ontario , London , Canada
| | - Shiva M Singh
- Department of Biology, Molecular Genetics Unit, The University of Western Ontario , London , Canada
| | - Charles L Rice
- School of Kinesiology, Faculty of Health Sciences, the University of Western Ontario , London , Canada.,Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario , London , Canada
| |
Collapse
|
36
|
MacDonald AJ, Miller J, Ramage MI, Greig C, Stephens NA, Jacobi C, Preston T, Fearon KCH, Skipworth RJE. Cross sectional imaging of truncal and quadriceps muscles relates to different functional outcomes in cancer. Clin Nutr 2018; 38:2875-2880. [PMID: 30612853 PMCID: PMC6876543 DOI: 10.1016/j.clnu.2018.12.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 12/15/2018] [Accepted: 12/18/2018] [Indexed: 12/25/2022]
Abstract
Introduction Following the consensus definition of cancer cachexia, more studies are using CT scan analysis of truncal muscles as a marker of muscle wasting. However, how CT-derived body composition relates to function, strength and power in patients with cancer is largely unknown. Aims We aimed to describe the relationship between CT truncal (L3) skeletal muscle index (SMI) and MRI quadriceps cross sectional area with lower limb strength, power and measures of complex function. Methods Patients undergoing assessment for potentially curative surgery for oesophagogastric or pancreatic cancer were recruited from the regional upper gastrointestinal (UGI) or hepatopancreaticobiliary (HPB) multi-disciplinary team meetings. Maximum Isometric Knee Extensor Strength (IKES) and Maximum Leg Extensor Power (Nottingham Power Rig) (LEP) were used as measures of lower limb performance. Both Sit to Stand (STS) and Timed Up and Go (TUG) were used as measures of global complex muscle function. Muscle SMI was measured from routine CT scans at the level of the third lumbar vertebrae (L3) and MRI scan was used for the assessment of quadriceps muscles. Linear regression analysis was performed for CT SMI or MRI quadriceps as a predictor of each measure of performance. Results Forty-four patients underwent assessment. Height and weight were significantly related to function in terms of quadriceps power, while only weight was associated with strength (P < 0.001). CT SMI was not related to measures of quadriceps strength or power but had significant association with more complex functional measures (P = 0.006, R2 = 0.234 and 0.0019, R2 = 0.175 for STS and TUG respectively). In comparison, both gross and fat-subtracted measures of quadriceps muscle mass from MRI were significantly correlated with quadriceps strength and power (P < 0.001), but did not show any significant association with complex functional measures. Conclusion CT SMI and MRI quadriceps have been shown to reflect different aspects of functional ability with CT SMI being a marker of global muscle function and MRI quadriceps being specific to quadriceps power and strength. This should therefore be considered when choosing outcome measures for trials or definitions of muscle mass and function.
Collapse
Affiliation(s)
- A J MacDonald
- Clinical and Surgical Sciences, University of Edinburgh, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh EH16 4SA, United Kingdom
| | - J Miller
- Clinical and Surgical Sciences, University of Edinburgh, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh EH16 4SA, United Kingdom.
| | - M I Ramage
- Clinical and Surgical Sciences, University of Edinburgh, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh EH16 4SA, United Kingdom
| | - C Greig
- School of Sport, Exercise, and Rehabilitation Sciences, MRC-Arthritis Research UK Centre for Musculoskeletal Ageing Research, NIHR Birmingham BRC, University of Birmingham, B15 2TT, United Kingdom
| | - N A Stephens
- Clinical and Surgical Sciences, University of Edinburgh, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh EH16 4SA, United Kingdom
| | - C Jacobi
- Musculoskeletal Diseases Area, Muscle Group, Novartis Pharma AG, Novartis Campus, WSJ- 152.2.72.04, CH-4056, Basel, Switzerland
| | - T Preston
- Stable Isotope Biochemistry Laboratory, Scottish Universities Environmental Research Centre, The University of Glasgow, East Kilbride, G75 0QF, United Kingdom
| | - K C H Fearon
- Clinical and Surgical Sciences, University of Edinburgh, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh EH16 4SA, United Kingdom
| | - R J E Skipworth
- Clinical and Surgical Sciences, University of Edinburgh, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh EH16 4SA, United Kingdom
| |
Collapse
|
37
|
Kirk EA, Gilmore KJ, Rice CL. Response to "An objective criterion for stimulation intensity may be necessary to properly assess muscle contractile properties". J Neurophysiol 2018; 120:3288. [PMID: 30557102 DOI: 10.1152/jn.00743.2018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Eric A Kirk
- Neuromuscular Laboratory, School of Kinesiology, The University of Western Ontario , London, Ontario , Canada
| | - Kevin J Gilmore
- Neuromuscular Laboratory, School of Kinesiology, The University of Western Ontario , London, Ontario , Canada
| | - Charles L Rice
- Neuromuscular Laboratory, School of Kinesiology, The University of Western Ontario , London, Ontario , Canada.,Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario , London, Ontario , Canada.,The Canadian Centre for Activity and Ageing, The University of Western Ontario , London, Ontario , Canada
| |
Collapse
|
38
|
Gilmore KJ, Doherty TJ, Kimpinski K, Rice CL. Reductions in muscle quality and quantity in chronic inflammatory demyelinating polyneuropathy patients assessed by magnetic resonance imaging. Muscle Nerve 2018; 58:396-401. [DOI: 10.1002/mus.26159] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 05/01/2018] [Accepted: 05/05/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Kevin J. Gilmore
- School of Kinesiology; The University of Western Ontario; London Ontario Canada
| | - Timothy J. Doherty
- Department of Clinical Neurological Sciences; Schulich School of Medicine and Dentistry, The University of Western Ontario; London Ontario Canada
- Department of Physical Medicine and Rehabilitation; Schulich School of Medicine and Dentistry, The University of Western Ontario; London Ontario Canada
| | - Kurt Kimpinski
- School of Kinesiology; The University of Western Ontario; London Ontario Canada
| | - Charles L. Rice
- School of Kinesiology; The University of Western Ontario; London Ontario Canada
- Department of Anatomy and Cell Biology; Schulich School of Medicine and Dentistry, The University of Western Ontario; London Ontario Canada
| |
Collapse
|
39
|
Kirk EA, Gilmore KJ, Rice CL. Neuromuscular changes of the aged human hamstrings. J Neurophysiol 2018; 120:480-488. [PMID: 29668388 PMCID: PMC6139447 DOI: 10.1152/jn.00794.2017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 04/13/2018] [Accepted: 04/14/2018] [Indexed: 01/13/2023] Open
Abstract
Despite the life-long importance for posture and locomotion, neuromuscular properties of the hamstrings muscle have not been explored with adult aging. The purpose of this study was to assess and compare age-related effects on contractile function, spinal motor neuron output expressed as motor unit (MU) discharge rates in the hamstrings of 11 young (26 ± 4 yr) and 10 old (80 ± 5 yr) men. Maximal voluntary isometric contractions (MVC), stimulated contractile properties, and surface and intramuscular electromyography (EMG) from submaximal to MVC were recorded in the biceps femoris (BF) and semimembranosus-semitendinosus (SS) muscles. MVC torque was ~50% less in the old with both age groups attaining ≥93% mean voluntary activation. Evoked twitches in the old were ~50% lower in amplitude and >150% longer in duration compared with those in the young. At successive voluntary contractions of 25, 50, and 100% MVC, MU discharge rates were up to 45% lower in old, with no differences in relative submaximal surface EMG between age groups. Furthermore, the old had significantly lower MU discharge rates in the SS at all contraction intensities compared with the BF muscle. Men in their 8th to 10th decades of life demonstrate substantially lower strength and MU discharge rates in this functionally important large lower limb muscle group, with greater age-related effect on discharge rates in the medial hamstrings. These findings, compared with those in other muscles studied, highlight that the neuromuscular properties of limb muscles, and indeed within functionally similar portions of a muscle group, are not all affected equally by the aging process. NEW & NOTEWORTHY In the hamstrings, we found that both contractile function and motor unit discharge rates across the range of voluntary intensities were lower in the old. The differences in discharge rates due to age were greater in the medial hamstrings muscle group compared with the lateral hamstrings. Compared with previous studies, these results highlight that not all muscles are affected equally by aging and there may be compartmental differences within functionally similar muscles.
Collapse
Affiliation(s)
- Eric A Kirk
- Neuromuscular Laboratory, School of Kinesiology, The University of Western Ontario, London, Ontario , Canada
| | - Kevin J Gilmore
- Neuromuscular Laboratory, School of Kinesiology, The University of Western Ontario, London, Ontario , Canada
| | - Charles L Rice
- Neuromuscular Laboratory, School of Kinesiology, The University of Western Ontario, London, Ontario , Canada
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario , London, Ontario , Canada
- The Canadian Centre for Activity and Ageing, The University of Western Ontario , London, Ontario , Canada
| |
Collapse
|
40
|
Husi H, MacDonald A, Skipworth RJE, Miller J, Cronshaw A, Greig C, Fearon KCH, Ross JA. Urinary diagnostic proteomic markers for dynapenia in cancer patients. Biomed Rep 2018; 8:547-556. [PMID: 29904611 DOI: 10.3892/br.2018.1092] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 04/19/2018] [Indexed: 12/24/2022] Open
Abstract
Dynapenia is defined as the age-related loss of muscle strength, and plays a significant role in the loss of physical function and increased risk of disability among older individuals. The need for an early diagnosis supports the search for a biomarker that reflects muscle 'weakening'. This has previously proven difficult due to patient heterogeneity at presentation and lack of understanding of the underlying molecular mechanisms. The aim of the present study was to identify potential urinary biomarkers of dynapenia in patients undergoing potentially curative surgery for upper gastrointestinal cancer. Maximum isometric knee extensor strength (strain gauge) and maximum leg extensor power (Nottingham power rig) measurements were taken. Cut-off values for dynapenia were based on the Allied Dunbar national fitness survey. Values below the 5th percentile for the population matched for age and sex on the Allied Dunbar national fitness survey were used to stratify the cohort into dynapenic or normal. Urine samples taken at induction of anaesthesia were analysed by SELDI-TOF mass spectrometry using CM10 and IMAC30 chip-types to establish statistically significant m/z peak fingerprint patterns, followed by in-gel LC-MS/MS to identify molecular constituents. Statistical analysis of decision-tree calculations using Biomarker Pattern software resulted in models with sensitivities of 86 and 96%, specificities of 81 and 89%, and overall correctness of 84 and 93%, when applied to the entire cohort for power and strength measurement-based stratifications using the IMAC30 chip-type and the CM10 chip-type, respectively. The molecular identities of 10 peaks of interest were further investigated. After subtraction of potentially unrelated proteins, they were identified as fragments of Annexin A1, collagen α-1 (XV), perlecan and myotrophin. These results demonstrate that urinary screening can be used to define cancer-associated muscle weakness, and the identification of potential biomarkers could be invaluable in establishing a rapid test to measure and assess dynapenia in the clinical setting.
Collapse
Affiliation(s)
- Holger Husi
- Department of Diabetes and Cardiovascular Science, University of the Highlands and Islands, Centre for Health Science, IV2 3JH Inverness, UK
| | - Alisdair MacDonald
- School of Clinical Sciences, University of Edinburgh, EH16 4SB Edinburgh, UK
| | | | - Janice Miller
- School of Clinical Sciences, University of Edinburgh, EH16 4SB Edinburgh, UK
| | - Andrew Cronshaw
- School of Biological Sciences, University of Edinburgh, EH16 4SB Edinburgh, UK
| | - Carolyn Greig
- School of Clinical Sciences, University of Edinburgh, EH16 4SB Edinburgh, UK
| | - Kenneth C H Fearon
- School of Clinical Sciences, University of Edinburgh, EH16 4SB Edinburgh, UK
| | - James A Ross
- School of Clinical Sciences, University of Edinburgh, EH16 4SB Edinburgh, UK
| |
Collapse
|
41
|
Rudsits BL, Hopkins WG, Hautier CA, Rouffet DM. Force-velocity test on a stationary cycle ergometer: methodological recommendations. J Appl Physiol (1985) 2018; 124:831-839. [DOI: 10.1152/japplphysiol.00719.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Force-velocity tests performed on stationary cycle ergometers are widely used to assess the torque- and power-generating capacities of the lower limbs. The aim of this study was to identify how testing and modeling procedures influence the assessment of individual torque-cadence and power-cadence relationships. Seventeen males completed 62 ± 16 pedal cycles from six 6-s all-out efforts interspersed with 5 min of rest. True measures of maximal power for a particular cadence were obtained for 24 ± 3 pedal cycles, while power was only 94 ± 3% of the true maximum in 19 ± 5 pedal cycles. Pedal cycles showing maximal levels of power also displayed higher levels of electromyography (EMG: 89 ± 7 vs . 87 ± 7%) and coactivation (34 ± 11 vs . 31 ± 10 arbitrary units), as well as lower variability in crank torque and EMG profiles. Compared with the linear and second-order polynomial models that are traditionally used, a better goodness of fit was obtained when the torque-cadence and power-cadence relationships were predicted using second- and third-order polynomials, respectively. The later modeling procedures also revealed an asymmetry in the power-cadence relationship in most participants (i.e., 15 out of 17) and provided a better estimation of maximal cadence [Cmax: 214 ± 20 revolutions/min (rpm)] from the x-intercept of power-cadence relationships (C0: 214 ± 14 rpm). Therefore, we recommend predicting the individual shapes of torque- and power-cadence relationships using second- and third-order polynomial regressions after having selected pedal cycles during which true measures of cadence-specific maximal power were recorded. NEW & NOTEWORTHY This study is the first to demonstrate that suboptimal activation of the lower limb muscles accompanied reductions in cadence-specific levels of torque and power produced during a force-velocity test performed on a stationary cycle ergometer. This research is also the first to show that, in most noncyclist participants, torque-cadence relationships are not linear, whereas power-cadence relationships display asymmetric shapes, with power production decreasing rapidly when cadence increases beyond 180 revolutions/min.
Collapse
Affiliation(s)
- Briar L. Rudsits
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Australia
| | - Will G. Hopkins
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Australia
| | - Christophe A. Hautier
- Laboratoire Inter-universitaire de Biologie de la Motricité, Université de Lyon, France
| | - David M. Rouffet
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Australia
- Australian Institute for Musculoskeletal Science, Victoria University, Melbourne, Australia
| |
Collapse
|
42
|
DOYLE-BAKER DOUGLAS, TEMESI JOHN, MEDYSKY MARYE, HOLASH ROBERTJ, MILLET GUILLAUMEY. An Innovative Ergometer to Measure Neuromuscular Fatigue Immediately after Cycling. Med Sci Sports Exerc 2018; 50:375-387. [DOI: 10.1249/mss.0000000000001427] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
43
|
Neuromuscular fatigue during exercise: Methodological considerations, etiology and potential role in chronic fatigue. Neurophysiol Clin 2017; 47:95-110. [PMID: 28434551 DOI: 10.1016/j.neucli.2017.03.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The term fatigue is used to describe a distressing and persistent symptom of physical and/or mental tiredness in certain clinical populations, with distinct but ultimately complex, multifactorial and heterogenous pathophysiology. Chronic fatigue impacts on quality of life, reduces the capacity to perform activities of daily living, and is typically measured using subjective self-report tools. Fatigue also refers to an acute reduction in the ability to produce maximal force or power due to exercise. The classical measurement of exercise-induced fatigue involves neuromuscular assessments before and after a fatiguing task. The limitations and alternatives to this approach are reviewed in this paper in relation to the lower limb and whole-body exercise, given the functional relevance to locomotion, rehabilitation and activities of daily living. It is suggested that under some circumstances, alterations in the central and/or peripheral mechanisms of fatigue during exercise may be related to the sensations of chronic fatigue. As such, the neurophysiological correlates of exercise-induced fatigue are briefly examined in two clinical examples where chronic fatigue is common: cancer survivors and people with multiple sclerosis. This review highlights the relationship between objective measures of fatigability with whole-body exercise and perceptions of fatigue as a priority for future research, given the importance of exercise in relieving symptoms of chronic fatigue and/or overall disease management. As chronic fatigue is likely to be specific to the individual and unlikely to be due to a simple biological or psychosocial explanation, tailored exercise programmes are a potential target for therapeutic intervention.
Collapse
|
44
|
The assessment of neuromuscular fatigue during 120 min of simulated soccer exercise. Eur J Appl Physiol 2017; 117:687-697. [DOI: 10.1007/s00421-017-3561-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 02/01/2017] [Indexed: 10/20/2022]
|
45
|
Suzuki T, Shioda K, Kinugasa R, Fukashiro S. Simultaneous Knee Extensor Muscle Action Induces an Increase in Voluntary Force Generation of Plantar Flexor Muscles. J Strength Cond Res 2017; 31:365-371. [DOI: 10.1519/jsc.0000000000001513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
46
|
Kirk EA, Rice CL. Contractile function and motor unit firing rates of the human hamstrings. J Neurophysiol 2017; 117:243-250. [PMID: 27784806 PMCID: PMC5220116 DOI: 10.1152/jn.00620.2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 10/19/2016] [Indexed: 11/22/2022] Open
Abstract
Neuromuscular properties of the lower limb in health, aging, and disease are well described for major lower limb muscles comprising the quadriceps, triceps surae, and dorsiflexors, with the notable exception of the posterior thigh (hamstrings). The purpose of this study was to further characterize major muscles of the lower limb by comprehensively exploring contractile properties in relation to spinal motor neuron output expressed as motor unit firing rates (MUFRs) in the hamstrings of 11 (26.5 ± 3.8) young men. Maximal isometric voluntary contraction (MVC), voluntary activation, stimulated contractile properties including a force-frequency relationship, and MUFRs from submaximal to maximal voluntary contractile intensities were assessed in the hamstrings. Strength and MUFRs were assessed at two presumably different muscle lengths by varying the knee joint angles (90° and 160°). Knee flexion MVCs were 60-70% greater in the extended position (160°). The frequency required to elicit 50% of maximum tetanic torque was 16-17 Hz. Mean MUFRs at 25-50% MVC were 9-31% less in the biceps femoris compared with the semimembranosus-semitendinosus group. Knee joint angle (muscle length) influenced MUFRs such that mean MUFRs were greater in the shortened (90°) position at 50% and 100% MVC. Compared with previous reports, mean maximal MUFRs in the hamstrings are greater than those in the quadriceps and triceps surae and somewhat less than those in the tibialis anterior. Mean maximal MUFRs in the hamstrings are influenced by changes in knee joint angle, with lower firing rates in the biceps femoris compared with the semimembranosus-semitendinosus muscle group. NEW & NOTEWORTHY We studied motor unit firing rates (MUFRs) at various voluntary contraction intensities in the hamstrings, one of the only major lower limb muscles to have MUFRs affected by muscle length changes. Within the hamstrings muscle-specific differences have greater impact on MUFRs than length changes, with the biceps femoris having reduced neural drive compared with the semimembranosus-semimembranosus. Comparing our results to other lower limb muscles, flexors have inherently higher firing rate compared with extensors.
Collapse
Affiliation(s)
- Eric A Kirk
- Neuromuscular Laboratory, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada; and
| | - Charles L Rice
- Neuromuscular Laboratory, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada; and
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
47
|
Brøchner Nielsen NP, Hug F, Guével A, Fohanno V, Lardy J, Dorel S. Motor adaptations to unilateral quadriceps fatigue during a bilateral pedaling task. Scand J Med Sci Sports 2016; 27:1724-1738. [PMID: 28000312 DOI: 10.1111/sms.12811] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2016] [Indexed: 11/30/2022]
Abstract
This study was designed to investigate how motor coordination adapts to unilateral fatigue of the quadriceps during a constant-load bilateral pedaling task. We first hypothesized that this local fatigue would not be compensated within the fatigued muscles leading to a decreased knee extension power. Then, we aimed to determine whether this decrease would be compensated by between-joints compensations within the ipsilateral leg and/or an increased contribution of the contralateral leg. Fifteen healthy volunteers were tested during pedaling at 350 W before and after a fatigue protocol consisting of 15 minutes of electromyostimulation on the quadriceps muscle. Motor coordination was assessed from myoelectrical activity (22 muscles) and joint powers calculated through inverse dynamics. Maximal knee extension torque decreased by 28.3%±6.8% (P<.0005) immediately after electromyostimulation. A decreased knee extension power produced by the ipsilateral leg was observed during pedaling (-22.8±12.3 W, -17.0%±9.4%; P<.0005). To maintain the task goal, participants primarily increased the power produced by the non-fatigued contralateral leg during the flexion phase. This was achieved by an increase in hip flexion power confirmed by a higher activation of the tensor fascia latae. These results suggest no adjustment of neural drive to the fatigued muscles and demonstrate no concurrent ipsilateral compensation by the non-fatigued muscles involved in the extension pedaling phase. Although interindividual variability was observed, findings provide evidence that participants predominantly adapted by compensating with the contralateral leg during its flexion phase. Both neural (between legs) and mechanical (between pedals) couplings and the minimization of cost functions might explain these results.
Collapse
Affiliation(s)
- N-P Brøchner Nielsen
- Laboratory "Movement, Interactions, Performance" (EA4334), Faculty of Sport Sciences, University of Nantes, Nantes, France
| | - F Hug
- Laboratory "Movement, Interactions, Performance" (EA4334), Faculty of Sport Sciences, University of Nantes, Nantes, France.,School of Health and Rehabilitation Sciences, NHMRC Centre of Clinical Research Excellence in Spinal Pain, Injury and Health, The University of Queensland, Brisbane, Qld, Australia
| | - A Guével
- Laboratory "Movement, Interactions, Performance" (EA4334), Faculty of Sport Sciences, University of Nantes, Nantes, France
| | - V Fohanno
- Laboratory "Movement, Interactions, Performance" (EA4334), Faculty of Sport Sciences, University of Nantes, Nantes, France
| | - J Lardy
- Laboratory "Movement, Interactions, Performance" (EA4334), Faculty of Sport Sciences, University of Nantes, Nantes, France
| | - S Dorel
- Laboratory "Movement, Interactions, Performance" (EA4334), Faculty of Sport Sciences, University of Nantes, Nantes, France
| |
Collapse
|
48
|
Kirk EA, Moore CW, Chater-Diehl EJ, Singh SM, Rice CL. Human COL5A1 polymorphisms and quadriceps muscle-tendon mechanical stiffness in vivo. Exp Physiol 2016; 101:1581-1592. [PMID: 27717059 DOI: 10.1113/ep085974] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/20/2016] [Indexed: 12/13/2022]
Abstract
NEW FINDINGS What is the central question of the study? Do COL5A1 gene variants, previously reported to have diminished transcript stability, manifest in physiological phenotypes of quadriceps muscle-tendon contractile properties and mechanical stiffness in humans? What is the main finding and its importance? COL5A1 gene variants influence mechanical stiffness, not seeming to affect low-level contractile properties in humans. Functional differences in COL5A1 manifest during moderate- to high-level contractions. Polymorphisms of the collagen type V alpha 1 chain (COL5A1) gene are purported to influence mechanical properties of collagenous tissues. Our purpose was to assess musculotendinous contractile properties of the quadriceps in relationship to the genetic influence of mechanical stiffness. Eighty recreationally active males (aged 19-31 years) were assessed for the presence of three genetic polymorphisms associated with COL5A1 mRNA stability (rs4919510, rs1536482 and rs12722). Genotypes were determined using real-time PCR. Stiffness and contractile properties of the knee musculotendinous complex were assessed by maximal isometric voluntary contractions, ramp isometric voluntary contractions, electrically stimulated contractile events and ultrasonography. All genotype groups were able to activate their knee extensors fully (>97%) as assessed by the interpolated twitch technique and presented no differences in muscle-tendon contractile properties at low submaximal contraction intensities. For the quadriceps muscle-tendon at moderate ramp contractions of 50 and 60% maximal voluntary contraction, the rs12722 CT and TT genotypes had ∼30% greater mean stiffness. The rs1536482 AG and GG genotypes showed a similar trend, but did not achieve statistical significance. Variants of the COL5A1 gene seem to influence quadriceps muscle-tendon stiffness but do not affect low-level contractile properties.
Collapse
Affiliation(s)
- Eric A Kirk
- School of Kinesiology, Faculty of Health Sciences, the University of Western Ontario, London, Ontario, Canada, N6A 5B7
| | - Colin W Moore
- School of Kinesiology, Faculty of Health Sciences, the University of Western Ontario, London, Ontario, Canada, N6A 5B7
| | - Eric J Chater-Diehl
- Department of Biology, the University of Western Ontario, London, Ontario, Canada, N6A 5B7
| | - Shiva M Singh
- Department of Biology, the University of Western Ontario, London, Ontario, Canada, N6A 5B7
| | - Charles L Rice
- School of Kinesiology, Faculty of Health Sciences, the University of Western Ontario, London, Ontario, Canada, N6A 5B7.,Department of Anatomy & Cell Biology, Schulich School of Medicine and Dentistry, the University of Western Ontario, London, Ontario, Canada, N6A 5B7
| |
Collapse
|
49
|
Kirk EA, Copithorne DB, Dalton BH, Rice CL. Motor unit firing rates of the gastrocnemii during maximal and sub-maximal isometric contractions in young and old men. Neuroscience 2016; 330:376-85. [DOI: 10.1016/j.neuroscience.2016.05.059] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 05/30/2016] [Accepted: 05/31/2016] [Indexed: 11/16/2022]
|
50
|
Morat T, Gilmore KJ, Rice CL. Neuromuscular function in different stages of sarcopenia. Exp Gerontol 2016; 81:28-36. [PMID: 27108183 DOI: 10.1016/j.exger.2016.04.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 04/14/2016] [Accepted: 04/18/2016] [Indexed: 01/06/2023]
Abstract
This study applied the screening tool developed by the European Working Group on Sarcopenia in Older People (EWGSOP) on seniors aged over 65years and concurrently tested various laboratory-based indices of neuromuscular function. Twenty-four healthy and independent living older adults (9 men, 15 women) with a mean age of 79.1±5.8years participated. Based on gait speed, handgrip strength and muscle mass all subjects were categorized into one of the three conceptual sarcopenia stages (pre-sarcopenia, sarcopenia, severe sarcopenia). Maximal strength of dorsiflexors in the left leg was measured and voluntary activation was assessed by the interpolated twitch technique. In addition, isometric evoked contractile properties were recorded. Skeletal muscle mass was assessed by ultrasound from nine sites. There were roughly equal number of subjects in each sarcopenic category, and age was not different among the 3 groups. There were no differences in handgrip strength and skeletal muscle mass index among the 3 groups. Gait speed was significantly slower (p<0.01) in the severe sarcopenic subjects compared to the pre-sarcopenic group. With no differences in voluntary activation among the groups, the maximal voluntary contractions (MVCs) for severe sarcopenic subjects were 29% lower (p=0.02) and with 19% slower (p=0.02) voluntary rates of torque development (RTD) compared to sarcopenic subjects. Furthermore, the severe group was 34% lower (p=0.04) with 36% slower (p=0.02) RTD compared to pre-sarcopenic subjects. Peak twitch tension was 54% lower (p<0.01) in the severe group compared with the pre-sarcopenic group. Maximal twitch RTD were 40% (p=0.03) slower for the severe group compared to the sarcopenia group, and 51% slower (p=0.03) compared with the pre-sarcopenia group, but when normalized to peak torques there were no statistical differences. The laboratory tests found neuromuscular differences among the 3 groups which generally supported the classification scheme and helped to illustrate some key factors that could explain differences in functional capacities. These initial findings support the assumption that this categorization is relevant for identifying older adults with different neuromuscular properties. However, further studies are needed to provide more insight into the specific neuromuscular changes in the three sarcopenia stages, and how these changes relate to functional capacity. Such studies could ultimately contribute to identifying optimal interventions to improve neuromuscular functioning.
Collapse
Affiliation(s)
- Tobias Morat
- Canadian Centre for Activity and Aging, School of Kinesiology, Faculty of Health Sciences, Arthur & Sonia Labatt Health Sciences, Rm. 411D, London, ON N6A 5B9, Canada; German Sport University Cologne, Institute of Movement and Sport Gerontology, Am Sportpark Muengersdorf 6, 50933 Cologne, Germany.
| | - Kevin J Gilmore
- Canadian Centre for Activity and Aging, School of Kinesiology, Faculty of Health Sciences, Arthur & Sonia Labatt Health Sciences, Rm. 411D, London, ON N6A 5B9, Canada.
| | - Charles L Rice
- Canadian Centre for Activity and Aging, School of Kinesiology, Faculty of Health Sciences, Arthur & Sonia Labatt Health Sciences, Rm. 411D, London, ON N6A 5B9, Canada; Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada.
| |
Collapse
|