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Nishikawa Y, Watanabe K, Holobar A, Kitamura R, Maeda N, Hyngstrom AS. Sex differences in laterality of motor unit firing behavior of the first dorsal interosseous muscle in strength-matched healthy young males and females. Eur J Appl Physiol 2024; 124:1979-1990. [PMID: 38366213 PMCID: PMC11199256 DOI: 10.1007/s00421-024-05420-7] [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: 04/28/2023] [Accepted: 01/11/2024] [Indexed: 02/18/2024]
Abstract
PURPOSE The purpose of this study was to compare laterality in motor unit firing behavior between females and males. METHODS Twenty-seven subjects (14 females) were recruited for this study. The participants performed ramp up and hold isometric index finger abduction at 10, 30, and 60% of their maximum voluntary contraction (MVC). High-density surface electromyography (HD-sEMG) signals were recorded in the first dorsal interosseous (FDI) muscle and decomposed into individual motor unit (MU) firing behavior using a convolution blind source separation method. RESULTS In total, 769 MUs were detected (females, n = 318 and males, n = 451). Females had a significantly higher discharge rate than males at each relative torque level (10%: male dominant hand, 13.4 ± 2.7 pps vs. female dominant hand, 16.3 ± 3.4 pps; 30%: male dominant hand, 16.1 ± 3.9 pps vs. female dominant hand, 20.0 ± 5.0 pps; and 60%: male dominant hand, 19.3 ± 3.8 vs. female dominant hand, 25.3 ± 4.8 pps; p < 0.0001). The recruitment threshold was also significantly higher in females than in males at 30 and 60% MVC. Furthermore, males exhibited asymmetrical discharge rates at 30 and 60% MVC and recruitment thresholds at 30 and 60% MVC, whereas no asymmetry was observed in females. CONCLUSION In the FDI muscle, compared to males, females exhibited different neuromuscular strategies with higher discharge rates and recruitment thresholds and no asymmetrical MU firing behavior. Notably, the findings that sex differences in neuromuscular activity also occur in healthy individuals provide important information for understanding the pathogenesis of various diseases.
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Affiliation(s)
- Yuichi Nishikawa
- Faculty of Frontier Engineering, Institute of Science & Engineering, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan.
| | - Kohei Watanabe
- Laboratory of Neuromuscular Biomechanics, School of Health and Sport Sciences, Chukyo University, Nagoya, Japan
| | - Aleš Holobar
- Faculty of Electrical Engineering and Computer Science, University of Maribor, Maribor, Slovenia
| | - Ryoka Kitamura
- Graduate School of Frontier Engineering, Kanazawa University, Kanazawa, Japan
| | - Noriaki Maeda
- Division of Sports Rehabilitation, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
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Pereira HM, Keenan KG, Hunter SK. Influence of visual feedback and cognitive challenge on the age-related changes in force steadiness. Exp Brain Res 2024; 242:1411-1419. [PMID: 38613669 DOI: 10.1007/s00221-024-06831-w] [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: 11/19/2023] [Accepted: 04/05/2024] [Indexed: 04/15/2024]
Abstract
Force steadiness can be influenced by visual feedback as well as presence of a cognitive tasks and potentially differs with age and sex. This study determined the impact of altered visual feedback on force steadiness in the presence of a difficult cognitive challenge in young and older men and women. Forty-nine young (19-30 yr; 25 women, 24 men) and 25 older (60-85 yr; 15 women; 10 men) performed low force (5% of maximum) static contractions with the elbow flexor muscles in the presence and absence of a cognitive challenge (counting backwards by 13) either with low or high visual feedback gain. The cognitive challenge reduced force steadiness (increased force fluctuation amplitude) particularly in women (cognitive challenge × sex: P < 0.05) and older individuals (cognitive challenge × age: P < 0.05). Force steadiness improved with high-gain visual feedback compared with low-gain visual feedback (P < 0.01) for all groups (all interactions: P > 0.05). Manipulation of visual feedback had no influence on the reduced force steadiness in presence of the cognitive challenge for all groups (all P > 0.05). These findings indicate that older individuals and women have greater risk of impaired motor performance of the upper extremity if steadiness is required during a low-force static contraction. Manipulation of visual feedback had minimal effects on the reduced force steadiness in presence of a difficult cognitive challenge.
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Affiliation(s)
- Hugo M Pereira
- Department of Health and Exercise Science, University of Oklahoma, Norman, OK, USA.
| | - Kevin G Keenan
- Joseph J. Zilber College of Public Health, University of Wisconsin-Milwaukee, Milwaukee, USA
| | - Sandra K Hunter
- Exercise Science Program, Department of Physical Therapy, Marquette University, Milwaukee, USA
- Athletic and Human Performance Research Center, Marquette University, Milwaukee, USA
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3
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Colosio M, Botter A. Exploring sex differences in performance: expanding the concept of force unsteadiness. J Appl Physiol (1985) 2024; 136:1273. [PMID: 38743392 DOI: 10.1152/japplphysiol.00224.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 03/27/2024] [Indexed: 05/16/2024] Open
Affiliation(s)
- Marta Colosio
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Alberto Botter
- Laboratory for Engineering of the Neuromuscular System (LISiN), Department of Electronics and Telecommunication, Politecnico di Torino, Turin, Italy
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Tyagi O, Mehta RK. Sex-specific Neural Strategies During Fatiguing Work in Older Adults. HUMAN FACTORS 2024; 66:1490-1503. [PMID: 36898850 DOI: 10.1177/00187208231159526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
BACKGROUND Historical biases in ergonomics-related studies have been attributed to lack of participant diversity and sensitivity of measurements to capture variability between diverse groups. We posit that a neuroergonomics approach, that is, study of brain-behavior relationships during fatiguing work, allows for unique insights on sex differences in fatigue mechanisms that are not available via traditional "neck down" measurement approaches. OBJECTIVE This study examined the supraspinal mechanisms of exercise performance under fatigue and determined if there were any sex differences in these mechanisms. METHODS Fifty-nine older adults performed submaximal handgrip contractions until voluntary fatigue. Traditional ergonomics measures, namely, force variability, electromyography (EMG) of arm muscles, and strength and endurance times, and prefrontal and motor cortex hemodynamic responses were recorded. RESULTS There were no significant differences observed between older males and females in fatigability outcomes (i.e., endurance times, strength loss, and EMG activity) and brain activation. Effective connectivity from prefrontal to motor areas was significant for both sexes throughout the task, but during fatigue, males had higher interregional connectivity than females. DISCUSSION While traditional metrics of fatigue were comparable between the sexes, we observed distinct sex-specific neuromotor strategies (i.e., information flow between frontal-motor regions) that were adopted by older adults to maintain motor performance. APPLICATION The findings from this study offer insights into the capabilities and adaptation strategies of older men and women under fatiguing conditions. This knowledge can facilitate in the development of effective and targeted ergonomic strategies that accommodate for the varying physical capacities of diverse worker demographics.
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Affiliation(s)
- Oshin Tyagi
- Department of Industrial and Systems Engineering, Texas A&M University, College Station, TX, USA
| | - Ranjana K Mehta
- Department of Industrial and Systems Engineering, Texas A&M University, College Station, TX, USA
- Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA
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Marsala MJ, Gabriel DA, Greig Inglis J, Christie AD. How many motor units is enough? An assessment of the influence of the number of motor units on firing rate calculations. J Electromyogr Kinesiol 2024; 75:102872. [PMID: 38458102 DOI: 10.1016/j.jelekin.2024.102872] [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: 09/15/2023] [Revised: 02/25/2024] [Accepted: 03/02/2024] [Indexed: 03/10/2024] Open
Abstract
The number of motor units included in calculations of mean firing rates varies widely in the literature. It is unknown how the number of decomposed motor units included in the calculation of firing rate per participant compares to the total number of active motor units in the muscle, and if this is different for males and females. Bootstrapped distributions and confidence intervals (CI) of mean motor unit firing rates decomposed from the tibialis anterior were used to represent the total number of active motor units for individual participants in trials from 20 to 100 % of maximal voluntary contraction. Bootstrapped distributions of mean firing rates were constructed using different numbers of motor units, from one to the maximum number for each participant, and compared to the CIs. A probability measure for each number of motor units involved in firing rate was calculated and then averaged across all individuals. Motor unit numbers required for similar levels of probability increased as contraction intensity increased (p < 0.001). Increased levels of probability also required higher numbers of motor units (p < 0.001). There was no effect of sex (p ≥ 0.97) for any comparison. This methodology should be repeated in other muscles, and aged populations.
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Affiliation(s)
- Michael J Marsala
- School of Kinesiology, University of Western Ontario, 1151 Richmond St., London, Ontario N6A 3K7, Canada
| | - David A Gabriel
- Department of Kinesiology, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
| | - J Greig Inglis
- Department of Kinesiology, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
| | - Anita D Christie
- School of Kinesiology, University of Western Ontario, 1151 Richmond St., London, Ontario N6A 3K7, Canada.
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Kim C, Wile DJ, Kraeutner SN, Larocque KA, Jakobi JM. Short term effects of contralateral tendon vibration on motor unit discharge rate variability and force steadiness in people with Parkinson's disease. Front Aging Neurosci 2024; 16:1301012. [PMID: 38529054 PMCID: PMC10962053 DOI: 10.3389/fnagi.2024.1301012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Accepted: 01/25/2024] [Indexed: 03/27/2024] Open
Abstract
Background Vibration of one limb affects motor performance of the contralateral limb, and this may have clinical implications for people with lateralized motor impairments through vibration-induced increase in cortical activation, descending neural drive, or spinal excitability. Objective The objective of this study was to evaluate the effects of acute biceps brachii tendon vibration on force steadiness and motor unit activity in the contralateral limb of persons with Parkinson's disease. Methods Ten participants with mild to moderate Parkinson's disease severity performed a ramp, hold and de-ramp isometric elbow flexion at 5% of maximum voluntary contraction with the more-affected arm while vibration was applied to the distal biceps brachii tendon on the contralateral, less-affected arm. Using intramuscular fine wire electrodes, 33 MUs in the biceps brachii were recorded across three conditions (baseline, vibration, and post-vibration). Motor unit recruitment & derecruitment thresholds, discharge rates & variability, and elbow flexion force steadiness were compared between conditions with and without vibration. Results Coefficient of variation of force and discharge rate variability decreased 37 and 17%, respectively in post-vibration compared with baseline and vibration conditions. Although the motor unit discharge rates did not differ between conditions the total number of motor units active at rest after de-ramp were fewer in the post-vibration condition. Conclusion Contralateral tendon vibration reduces MU discharge rate variability and enhances force control on the more affected side in persons with Parkinson's disease.
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Affiliation(s)
- Changki Kim
- Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
- Healthy Exercise and Aging Laboratory, Aging in Place Research Cluster, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Daryl J. Wile
- Centre for Chronic Disease Prevention and Management, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Sarah N. Kraeutner
- Department of Psychology, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Kaylee A. Larocque
- Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Jennifer M. Jakobi
- Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
- Healthy Exercise and Aging Laboratory, Aging in Place Research Cluster, University of British Columbia Okanagan, Kelowna, BC, Canada
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7
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Marsala MJ, Christie AD. Neuromuscular behaviour in the first dorsal interosseus following mental fatigue. Exp Physiol 2024; 109:416-426. [PMID: 38130030 PMCID: PMC10988746 DOI: 10.1113/ep091349] [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: 06/13/2023] [Accepted: 11/28/2023] [Indexed: 12/23/2023]
Abstract
We examined sex-specific changes to neuromuscular function in response to mental fatigue. Twenty-five young, healthy adults (13 F, 12 M) performed a mentally fatiguing task and control condition for 30 min on two separate days. Neuromuscular function was assessed in the first dorsal interosseous before and after each condition. Reaction time decreased after the mentally fatiguing task (P < 0.001, η2 = 0.47). Males and females reported higher levels of subjective fatigue after the mentally fatiguing task (P < 0.02, η2 = 0.07). Motor unit firing rate increased over time at 10% maximal voluntary contraction (MVC; P < 0.04, η2 = 0.16), and decreased over time at 50% MVC (P < 0.01, η2 = 0.14); however, this was not unique to either sex. During a variable force contraction, error decreased in females over time and increased in males (P < 0.05, η2 = 0.13), although changes were not unique to mental fatigue. Physiological function of the neuromuscular system was not specifically affected by mental fatigue in males or females.
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Affiliation(s)
- Michael J. Marsala
- School of Kinesiology, Faculty of Health SciencesThe University of Western OntarioOntarioCanada
| | - Anita D. Christie
- School of Kinesiology, Faculty of Health SciencesThe University of Western OntarioOntarioCanada
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8
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Carr JC, King AC. Sex differences in the fractal dynamics of force control during maximal handgrip. Neurosci Lett 2024; 820:137588. [PMID: 38086520 DOI: 10.1016/j.neulet.2023.137588] [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: 07/01/2023] [Revised: 12/04/2023] [Accepted: 12/06/2023] [Indexed: 12/17/2023]
Abstract
This work examines the temporal structure of force fluctuations during maximal handgrip with detrended fluctuation analysis (DFA α). Here, we assess the influence of fatigue and sex on force complexity during unimanual handgrip for the fatigued and the contralateral, non-fatigued hand. Participants randomly completed experimental sessions requiring fatiguing handgrip contractions or control measurements only. Maximal unimanual forces of both hands were measured before and after the fatigue trial or a time-matched control visit. DFA revealed substantially lower alpha values for females (PRE = 1.15, POST = 1.25) compared to males (PRE = 1.30, POST = 1.33) regardless of fatigue (p < 0.01, d = 0.738) for the dominant hand with a similar pattern observed for the contralateral, non-fatigued hand (p = 0.045, d = 0.561). Females also showed greater alpha changes (Δ = 0.09) versus males (Δ = 0.01) following fatigue (p = 0.028, ηp2 = 0.151). The data provide evidence of reduced force complexity during successive maximal handgrip contractions for females, but not males. Our findings highlight task-specific factors involving force control and demonstrate the utility of complexity analyses to provide insights regarding the influence of sex on motor control strategies.
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Affiliation(s)
- Joshua C Carr
- Texas Christian University, Department of Kinesiology, Fort Worth, TX, United States; Anne Burnett Marion School of Medicine at Texas Christian University, Department of Medical Education, Fort Worth, TX, United States.
| | - Adam C King
- Texas Christian University, Department of Kinesiology, Fort Worth, TX, United States; Anne Burnett Marion School of Medicine at Texas Christian University, Department of Medical Education, Fort Worth, TX, United States.
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9
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Harrison S, Clark NC, Ansdell P, Pethick J. Sex differences in knee extensor torque control. J Electromyogr Kinesiol 2023; 72:102806. [PMID: 37566938 DOI: 10.1016/j.jelekin.2023.102806] [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: 02/20/2023] [Revised: 05/30/2023] [Accepted: 08/01/2023] [Indexed: 08/13/2023] Open
Abstract
There is currently equivocal evidence regarding sex-related differences in measures of muscle force and torque control. To that end, we investigated sex differences in knee extensor muscle torque control, using both magnitude- and complexity-based measures, across contraction intensities typical of activities of daily living. 50 participants (25 male, median age [and interquartile range] 23.0 [20.0-33.0]; 25 female, median age [and interquartile range] 21.0 [20.0-40.5]) performed a series of intermittent isometric knee extensor contractions at 10, 20 and 40% maximal voluntary contraction (MVC). Torque was measured in N·m and torque control was quantified according to the magnitude (standard deviation [SD], coefficient of variation [CV]) and complexity (approximate entropy [ApEn], detrended fluctuation analysis [DFA] α) of torque fluctuations. Males exhibited a significantly greater absolute magnitude (i.e., SD) of knee extensor torque fluctuations during contractions at 10% (P = 0.011), 20% (P = 0.002) and 40% MVC (P = 0.003), though no sex differences were evident when fluctuations were normalised to mean torque output (i.e., CV). Males exhibited significantly lower ApEn during contractions at 10% (P = 0.002) and 20% MVC (P = 0.024) and significantly greater DFA α during contractions at 10% (P = 0.003) and 20% MVC (P = 0.001). These data suggest sex differences in muscle torque control strategies and highlight the need to consider both the magnitude and complexity of torque fluctuations when examining sex differences in muscle force control.
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Affiliation(s)
- Savanna Harrison
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester, UK
| | - Nicholas C Clark
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester, UK
| | - Paul Ansdell
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, UK
| | - Jamie Pethick
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester, UK.
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10
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Zancanaro LL, Cid MM, Côté JN, Oliveira AB. Sex differences in torque steadiness, accuracy and activation of the shoulder girdle muscles during isometric shoulder scaption. J Biomech 2023; 155:111638. [PMID: 37216896 DOI: 10.1016/j.jbiomech.2023.111638] [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: 07/26/2022] [Revised: 05/03/2023] [Accepted: 05/10/2023] [Indexed: 05/24/2023]
Abstract
Females present more neck/shoulder musculoskeletal disorders and have different activation strategies of the shoulder girdle muscles than males. However, the sensorimotor performance and potential sex differences are still largely unexplored. The aim of this study was to investigate sex differences in torque steadiness and accuracy during isometric shoulder scaption. We also examined the amplitude and variability of the activation of the trapezius, serratus anterior (SA), and anterior deltoid muscles during torque output evaluation. Thirty-four asymptomatic adults (17 females) participated. Torque steadiness and accuracy were evaluated during submaximal contractions at 20 % and 35 % of peak torque (PT). There was no sex difference in torque coefficient of variation, but females had significantly lower torque standard deviation (SD) values than males at the two intensities evaluated (p < 0.001) and lower torque median frequency values compared to males, regardless of intensity (p < 0.01). Females had significantly lower absolute error values than males for torque output at 35 %PT (p < 0.01) and lower constant error values compared to males, regardless of intensity (p = 0.01). Females had significantly higher muscle amplitude values than males, except for SA (p = 0.10) and in general, females showed higher muscle activation SD values compared to males (p < 0.05). Females may require more complex muscle activation patterns to achieve a more stable and accurate torque output. Therefore, these sex differences may reflect control mechanisms that may also be at play when explaining the greater risk of neck/shoulder musculoskeletal disorders in females than males.
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Affiliation(s)
- Lucas Leonardo Zancanaro
- Laboratory of Clinical and Occupational Kinesiology (LACO), Department of Physical Therapy, Federal University of São Carlos, Rodovia Washington Luís, km 235 - SP-310, São Carlos, São Paulo, Brazil
| | - Marina Machado Cid
- Laboratory of Clinical and Occupational Kinesiology (LACO), Department of Physical Therapy, Federal University of São Carlos, Rodovia Washington Luís, km 235 - SP-310, São Carlos, São Paulo, Brazil
| | - Julie N Côté
- Department of Kinesiology and Physical Education, McGill University, 475 Pine Avenue West, Montreal, Quebec H2W 1S4, Canada
| | - Ana Beatriz Oliveira
- Laboratory of Clinical and Occupational Kinesiology (LACO), Department of Physical Therapy, Federal University of São Carlos, Rodovia Washington Luís, km 235 - SP-310, São Carlos, São Paulo, Brazil.
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11
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Yamaguchi T, Xu J, Sasaki K. Age and sex differences in force steadiness and intermuscular coherence of lower leg muscles during isometric plantar flexion. Exp Brain Res 2023; 241:277-288. [PMID: 36484793 DOI: 10.1007/s00221-022-06517-1] [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: 06/15/2022] [Accepted: 11/24/2022] [Indexed: 12/13/2022]
Abstract
Age- and sex-related alterations in the control of multiple muscles during contractions are not well understood. The purpose of the present study was to examine the age and sex differences in force steadiness and intermuscular coherence (IMC), and thereby to clarify the functional role of IMC during plantar flexion. Twenty-six young (YNG, 23-34 years), thirty middle-aged (MID, 35-64 years) and twenty-four older adults (OLD, 65-82 years) performed submaximal isometric contractions of plantar flexion, while electromyography was recorded from the soleus (SOL), gastrocnemius lateralis/medialis (GL/GM) and tibialis anterior (TA) muscles. Coefficient of variation (CV) of torque and IMC in the alpha, beta and gamma bands was calculated. We found that OLD demonstrated significantly higher torque CV than YNG and MID, and males demonstrated significantly higher torque CV than females (both p < 0.05). The IMC in the gamma band (five out of the six pairs) was significantly higher in YNG than MID and/or OLD (p < 0.05), while the gamma band IMC between GL and SOL was significantly higher in females. However, age or sex differences were not detected in the alpha or beta band. Moreover, the gamma band IMC between SOL and TA had a weak (r = - 0.229) but significant (p < 0.05) negative correlation with torque CV. These results suggest that force steadiness differs with age and sex, and that the higher gamma band IMC may contribute to more stable force control during plantar flexion.
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Affiliation(s)
- Tatsuhiro Yamaguchi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, 153-8902, Japan.
| | - Jierui Xu
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, 153-8902, Japan
| | - Kazushige Sasaki
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, 153-8902, Japan
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12
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Lulic-Kuryllo T, Greig Inglis J. Sex differences in motor unit behaviour: A review. J Electromyogr Kinesiol 2022; 66:102689. [DOI: 10.1016/j.jelekin.2022.102689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 07/28/2022] [Accepted: 07/29/2022] [Indexed: 10/15/2022] Open
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13
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Kowalski KL, Connelly DM, Jakobi JM, Sadi J. Shoulder electromyography activity during push-up variations: a scoping review. Shoulder Elbow 2022; 14:326-340. [PMID: 35599715 PMCID: PMC9121296 DOI: 10.1177/17585732211019373] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 04/27/2021] [Indexed: 12/14/2022]
Abstract
BACKGROUND Push-ups (PU) are a common closed chain exercise used to enhance shoulder girdle stability, with variations that alter the difficulty or target specific muscles. To appropriately select and prescribe PU exercises, an understanding of muscle activity during variations of the PU is needed. The purpose of this scoping review was to identify common PU variations and describe their muscle activation levels. METHODS Databases searched included PubMed, CINAHL, Scopus, and SPORTDiscus for articles published between January 2000 and November 2019. RESULTS Three hundred three articles were screened for eligibility with 30 articles included in the analysis. Six PU types and five muscles met the criteria for analysis. Weighted mean electromyography (EMG) amplitude was calculated for each muscle across PU types and for each PU type as a measure of global muscle activity. Triceps and pectoralis major had the highest EMG amplitude during unstable, suspension, incline with hands on a ball and the standard PU. Serratus anterior had the highest EMG amplitude during PU plus and incline PU. The greatest global EMG amplitude occurred during unstable surface PU. DISCUSSION These results provide clinicians with a framework for prescribing PU to target specific muscles and scale exercise difficulty to facilitate rehabilitation outcomes.
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Affiliation(s)
- Katie L Kowalski
- School of Kinesiology, University of
Western Ontario, London, Ontario, Canada
| | - Denise M Connelly
- School of Physical Therapy, University
of Western Ontario, London, Ontario, Canada,Denise M Connelly, School of Physical
Therapy, University of Western Ontario, 1151 Richmond Street London, Ontario N6A
3K7, Canada.
| | - Jennifer M Jakobi
- School of Health and Exercise Sciences,
University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Jackie Sadi
- School of Physical Therapy, University
of Western Ontario, London, Ontario, Canada
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14
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Harms RL, Ferrari A, Meier IB, Martinkova J, Santus E, Marino N, Cirillo D, Mellino S, Catuara Solarz S, Tarnanas I, Szoeke C, Hort J, Valencia A, Ferretti MT, Seixas A, Santuccione Chadha A. Digital biomarkers and sex impacts in Alzheimer's disease management - potential utility for innovative 3P medicine approach. EPMA J 2022; 13:299-313. [PMID: 35719134 PMCID: PMC9203627 DOI: 10.1007/s13167-022-00284-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 05/10/2022] [Indexed: 11/29/2022]
Abstract
Digital biomarkers are defined as objective, quantifiable physiological and behavioral data that are collected and measured by means of digital devices. Their use has revolutionized clinical research by enabling high-frequency, longitudinal, and sensitive measurements. In the field of neurodegenerative diseases, an example of a digital biomarker-based technology is instrumental activities of daily living (iADL) digital medical application, a predictive biomarker of conversion from mild cognitive impairment (MCI) due to Alzheimer's disease (AD) to dementia due to AD in individuals aged 55 + . Digital biomarkers show promise to transform clinical practice. Nevertheless, their use may be affected by variables such as demographics, genetics, and phenotype. Among these factors, sex is particularly important in Alzheimer's, where men and women present with different symptoms and progression patterns that impact diagnosis. In this study, we explore sex differences in Altoida's digital medical application in a sample of 568 subjects consisting of a clinical dataset (MCI and dementia due to AD) and a healthy population. We found that a biological sex-classifier, built on digital biomarker features captured using Altoida's application, achieved a 75% ROC-AUC (receiver operating characteristic - area under curve) performance in predicting biological sex in healthy individuals, indicating significant differences in neurocognitive performance signatures between males and females. The performance dropped when we applied this classifier to more advanced stages on the AD continuum, including MCI and dementia, suggesting that sex differences might be disease-stage dependent. Our results indicate that neurocognitive performance signatures built on data from digital biomarker features are different between men and women. These results stress the need to integrate traditional approaches to dementia research with digital biomarker technologies and personalized medicine perspectives to achieve more precise predictive diagnostics, targeted prevention, and customized treatment of cognitive decline. Supplementary Information The online version contains supplementary material available at 10.1007/s13167-022-00284-3.
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Affiliation(s)
| | | | | | - Julie Martinkova
- Women’s Brain Project, Guntershausen, Switzerland
- Memory Clinic, Department of Neurology, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic
| | - Enrico Santus
- Women’s Brain Project, Guntershausen, Switzerland
- Bayer, NJ USA
| | - Nicola Marino
- Women’s Brain Project, Guntershausen, Switzerland
- Dipartimento Di Scienze Mediche E Chirurgiche, Università Degli Studi Di Foggia, Foggia, Italy
| | - Davide Cirillo
- Women’s Brain Project, Guntershausen, Switzerland
- Barcelona Supercomputing Center, Plaça Eusebi Güell, 1-3, 08034 Barcelona, Spain
| | | | | | - Ioannis Tarnanas
- Altoida Inc., Houston, TX USA
- Global Brain Health Institute, Dublin, Ireland
| | - Cassandra Szoeke
- Women’s Brain Project, Guntershausen, Switzerland
- Centre for Medical Research, Faculty of Medicine, Dentistry and Health Science, University of Melbourne, Melbourne, Australia
| | - Jakub Hort
- Memory Clinic, Department of Neurology, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic
- International Clinical Research Center, St Anne’s University Hospital Brno, Brno, Czech Republic
| | - Alfonso Valencia
- Barcelona Supercomputing Center, Plaça Eusebi Güell, 1-3, 08034 Barcelona, Spain
- ICREA - Institució Catalana de Recerca I Estudis Avançats, Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | | | - Azizi Seixas
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL 33136 USA
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15
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Augsburger GR, Soloveva A, Carr JC. Sex and limb comparisons of neuromuscular function in the morning versus the evening. Physiol Rep 2022; 10:e15260. [PMID: 35581749 PMCID: PMC9114651 DOI: 10.14814/phy2.15260] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 03/20/2022] [Accepted: 03/23/2022] [Indexed: 06/04/2023] Open
Abstract
The time-of-day influence on neuromuscular function is well-documented, but important details remain elusive. It is currently unknown whether males and females differ in their diurnal variation for optimal neuromuscular performance. The purpose of this study is to identify the time-of-day influence on neuromuscular function between sexes and determine whether these responses differ for the upper versus lower limbs. A group of males (n = 12) and females (n = 15) completed neuromuscular performance testing in the morning (07:00-09:00) and evening (17:00-19:00) on separate days in a randomized order. Maximal force, the normalized rate of force development, EMG, normalized EMG rise, and submaximal force steadiness were compared between morning and evening hours. The main findings show that maximal force was greater in the evening for the knee extensors (d = 0.570, p < 0.01) but not the elbow flexors (d = 0.212, p = 0.281), whereas maximal muscle excitation was greater in the evening for the biceps brachii (d = 0.348, p < 0.01) but not the vastus lateralis (d = 0.075, p = 0.526) with no influence of sex. However, force steadiness during knee extension was superior in the evening versus the morning for males (d = 0.734, p = 0.025) and compared to evening values for females (g = 1.19, p = 0.032). Overall, these findings show that time-of-day affects the knee extensors more than the elbow flexors and that diurnal variability between sexes appears to be task-dependent.
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Affiliation(s)
| | - Alisa Soloveva
- Kinesiology DepartmentTexas Christian UniversityFort WorthTexasUSA
| | - Joshua C. Carr
- Kinesiology DepartmentTexas Christian UniversityFort WorthTexasUSA
- Department of Medical EducationTexas Christian University School of MedicineFort WorthTexasUSA
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16
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Mercier LJ, Batycky J, Campbell C, Schneider K, Smirl J, Debert CT. Autonomic dysfunction in adults following mild traumatic brain injury: A systematic review. NeuroRehabilitation 2022; 50:3-32. [PMID: 35068421 DOI: 10.3233/nre-210243] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Increasing evidence suggests autonomic nervous system (ANS) dysfunction may occur following mild traumatic brain injury (mTBI). Measures of heart rate, heart rate variability, blood pressure and baroreceptor sensitivity can be used to evaluate ANS dysfunction following mTBI. OBJECTIVE Summarize the evidence for ANS dysfunction in adults following mTBI. METHODS A search of Embase, MEDLINE, Cochrane Central Register, PsycINFO, CINAHL and SPORTDiscus databases was conducted. Search topics included: mTBI and ANS. Identified abstracts were independently reviewed by 2 reviewers followed by full text screening. Risk of bias was assessed using a modified SIGN checklist. A structured synthesis was performed. RESULTS Thirty-nine studies (combined 1,467 participants diagnosed with mTBI) evaluating ANS function were included. ANS function was evaluated under various conditions including: rest, during exertion, cold pressor test, Valsalva maneuver, using face cooling and eyeball pressure paradigms. Short-term or ultra-short-term recordings were most common. The majority of studies (28/39) were rated as "unacceptable" for quality of evidence. CONCLUSIONS Altered parameters of ANS function have been reported in multiple conditions following mTBI, both acutely and in the post-acute/chronic stages of recovery. However, due to methodological limitations, conclusions regarding the severity and timing of ANS dysfunction following mTBI cannot be drawn.
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Affiliation(s)
- Leah J Mercier
- Department of Clinical Neurosciences, Division of Physical Medicine and Rehabilitation, University of Caglary, Calgary, AB, Canada
| | - Julia Batycky
- Department of Clinical Neurosciences, Division of Physical Medicine and Rehabilitation, University of Caglary, Calgary, AB, Canada
| | - Christina Campbell
- Department of Clinical Neurosciences, Division of Physical Medicine and Rehabilitation, University of Caglary, Calgary, AB, Canada
| | - Kathryn Schneider
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada.,Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Jonathan Smirl
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada.,Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.,Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.,Libin Cardiovascular Institute of Alberta, Univeristy of Calgary, Calgary, AB, Canada
| | - Chantel T Debert
- Department of Clinical Neurosciences, Division of Physical Medicine and Rehabilitation, University of Caglary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
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17
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Devries MC, Jakobi JM. Importance of considering sex and gender in exercise and nutrition research. Appl Physiol Nutr Metab 2021; 46:iii-vii. [PMID: 34125618 DOI: 10.1139/apnm-2021-0298] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | - Jennifer M Jakobi
- School of Health and Exercise Sciences, The University of British Columbia Okanagan, Kelowna, BC, Canada
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18
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Toumi A, Smart R, Elie D, Bassement J, Leteneur S, Simoneau-Buessinger E, Jakobi J. Contribution of Achilles tendon mechanical properties to torque steadiness in persons with transfemoral amputation. Prosthet Orthot Int 2021; 45:170-177. [PMID: 33158397 DOI: 10.1177/0309364620966431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 08/28/2020] [Indexed: 02/03/2023]
Abstract
BACKGROUND How Achilles tendon mechanics and plantar flexion strength and torque steadiness are altered in the intact leg of persons with trauma-related amputation is unknown. Understanding Achilles tendon mechanics following amputation will further inform rehabilitation approaches to enhance posture, balance, and force control. OBJECTIVE Conduct a pilot study to quantify plantar flexion maximal voluntary contraction torque, torque steadiness, and Achilles tendon mechanics in persons with unilateral trauma-related transfemoral amputation and controls without amputation. STUDY DESIGN Cross-sectional study. METHODS Isometric plantar flexion maximal voluntary contractions were performed with the intact leg of ten males with transfemoral amputation (48 ± 14 years) and the dominant leg of age-matched male controls without amputation. Torque steadiness was calculated as the coefficient of variation in torque over 6 s during submaximal tracking tasks (5%, 10%, 25%, 50%, and 75% maximal voluntary contraction). Achilles tendon elongation and cross-sectional area were recorded with ultrasound to calculate strain, stress, and stiffness. RESULTS Maximal voluntary contraction and torque steadiness did not differ between persons with amputation (90.6 ± 31.6 N m, 3.7 ± 2.0%) and controls (95.8 ± 26.8 N m, 2.9 ± 1.2%; p > 0.05). Tendon stiffness (21.1 ± 18.2 N/mm) and strain (5.2 ± 1.3%) did not differ between groups (p > 0.05). Tendon cross-sectional area was 10% greater in persons with amputation leading to 29% lower stress (p = 0.021). Maximal voluntary contraction was a predictor of a lower coefficient of variation in torque (R2 = 0.11, p < 0.05). CONCLUSION Persons with trauma-related transfemoral amputation do not differ in plantar flexion maximal voluntary contraction and torque steadiness of the intact leg compared with controls without amputation. Larger tendon cross-sectional area reduces stress and enables distribution of force across a greater area.
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Affiliation(s)
- Anis Toumi
- Laboratoire d'Automatique de Mécanique et d'Informatique industrielles et Humaines (LAMIH), UMR CNRS 8201, Université Polytechnique Hauts-de-France, Valenciennes, France.,School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Rowan Smart
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Dimitri Elie
- Laboratoire d'Automatique de Mécanique et d'Informatique industrielles et Humaines (LAMIH), UMR CNRS 8201, Université Polytechnique Hauts-de-France, Valenciennes, France
| | - Jennifer Bassement
- Laboratoire d'Automatique de Mécanique et d'Informatique industrielles et Humaines (LAMIH), UMR CNRS 8201, Université Polytechnique Hauts-de-France, Valenciennes, France
| | - Sébastien Leteneur
- Laboratoire d'Automatique de Mécanique et d'Informatique industrielles et Humaines (LAMIH), UMR CNRS 8201, Université Polytechnique Hauts-de-France, Valenciennes, France
| | - Emilie Simoneau-Buessinger
- Laboratoire d'Automatique de Mécanique et d'Informatique industrielles et Humaines (LAMIH), UMR CNRS 8201, Université Polytechnique Hauts-de-France, Valenciennes, France
| | - Jennifer Jakobi
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, Canada
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19
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Suzuki R, Kanehisa H, Washino S, Watanabe H, Shinohara M, Yoshitake Y. Reconstruction of net force fluctuations from surface EMGs of multiple muscles in steady isometric plantarflexion. Exp Brain Res 2021; 239:601-612. [PMID: 33388812 DOI: 10.1007/s00221-020-05987-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 11/13/2020] [Indexed: 12/22/2022]
Abstract
The purposes of this study were to clarify if force fluctuations during steady multi-muscle contractions have a temporal correlation with a low-frequency component of rectified surface EMG (rEMG) in the involved muscles and collection of that component across muscles allows for the reconstruction of force fluctuations across a wide range of contraction intensities. Healthy young men (n = 15) exerted steady isometric plantarflexion force at 5-60% of maximal force. Surface EMG was recorded from the medial and lateral gastrocnemii, soleus, peroneus longus, abductor hallucis, and tibialis anterior muscles. The cross-correlation function (CCF) between plantarflexion force fluctuations and low-pass filtered rEMG in each muscle was calculated for 8 s. To reconstruct force fluctuations from rEMGs, the product of rEMG and an identified constant factor were summed across muscles with time-lag compensation for electro-mechanical delay. A distinct peak of the CCF was found between plantarflexion force fluctuations and rEMG in most cases except for the tibialis anterior. The CCF peak was greatest in the medial gastrocnemius and soleus. Reconstructed force from rEMGs was temporally correlated with measured force fluctuations across contraction intensities (average CCF peak: r = 0.65). The results indicate that individual surface rEMG has a low-frequency component that is temporally correlated with net force fluctuations during steady multi-muscle contractions and contributes to the reconstruction of force fluctuations across a wide range of contraction intensities. It suggests a potential applicability of individual surface EMGs for identifying the contributing muscles to controlling or disturbing isometric steady force in multi-muscle contractions.
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Affiliation(s)
- Ryosei Suzuki
- Graduate School of Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano, 3860018, Japan
| | - Hiroaki Kanehisa
- School of Sports and Health Sciences, Ritsumeikan University, 1-1-1 Nozihigashi, Kusatsu, Shiga, 5258577, Japan
| | - Sohei Washino
- Human Augmentation Research Center, National Institute of Advanced Industrial Science and Technology, 6-2-3 Kashiwanoha, Kashiwa, Chiba, 2770882, Japan
| | - Hironori Watanabe
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama, 3508585, Japan
| | - Minoru Shinohara
- School of Biological Sciences, Georgia Institute of Technology, 555 14th St NW, Atlanta, GA, 30332, USA
| | - Yasuhide Yoshitake
- Graduate School of Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano, 3860018, Japan. .,School of Human Movement and Nutrition Sciences, The University of Queensland, St Lucia, Brisbane, QLD, 4072, Australia.
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20
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Inglis JG, Gabriel DA. Sex differences in motor unit discharge rates at maximal and submaximal levels of force output. Appl Physiol Nutr Metab 2020; 45:1197-1207. [DOI: 10.1139/apnm-2019-0958] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study evaluated potential sex differences in motor unit (MU) behaviour at maximal and submaximal force outputs. Forty-eight participants, 24 females and 24 males, performed isometric dorsiflexion contractions at 20%, 40%, 60%, 80%, and 100% of a maximum voluntary contraction (MVC). Tibialis anterior electromyography was recorded both by surface and intramuscular electrodes. Compared with males, females had a greater MU discharge rate (MUDR) averaged across all submaximal intensities (Δ 0.45 pps, 2.56%). Males exhibited greater increases in MUDR above 40% MVC, surpassing females at 100% MVC (p’s < 0.01). Averaged across all force outputs, females had a greater incidence of doublet and rapid discharges and a greater percentage of MU trains with doublet and rapid (5–10 ms) discharges (Δ 75.55% and 61.48%, respectively; p’s < 0.01). A subset of males (n = 8) and females (n = 8), matched for maximum force output, revealed that females had even greater MUDR (Δ 1.38 pps, 7.47%) and percentage of MU trains with doublet and rapid discharges (Δ 51.62%, 56.68%, respectively; p’s < 0.01) compared with males at each force output, including 100% MVC. Analysis of the subset of strength-matched males and females suggest that sex differences in MU behaviour may be a result of females needing to generate greater neural drive to achieve fused tetanus. Novelty Females had higher MUDRs and greater percentage of MU trains with doublets across submaximal force outputs (20%–80% MVC). Differences were even greater for a strength matched subset. Differences in motor unit behaviour may arise from musculoskeletal differences, requiring greater neural drive in females.
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Affiliation(s)
- J. Greig Inglis
- Electromyographic Kinesiology Laboratory, Kinesiology Department, Brock University, St. Catharines, ON L2S 3A1, Canada
- Electromyographic Kinesiology Laboratory, Kinesiology Department, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - David A. Gabriel
- Electromyographic Kinesiology Laboratory, Kinesiology Department, Brock University, St. Catharines, ON L2S 3A1, Canada
- Electromyographic Kinesiology Laboratory, Kinesiology Department, Brock University, St. Catharines, ON L2S 3A1, Canada
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21
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Ansdell P, Thomas K, Hicks KM, Hunter SK, Howatson G, Goodall S. Physiological sex differences affect the integrative response to exercise: acute and chronic implications. Exp Physiol 2020; 105:2007-2021. [PMID: 33002256 DOI: 10.1113/ep088548] [Citation(s) in RCA: 143] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/24/2020] [Accepted: 09/28/2020] [Indexed: 12/13/2022]
Abstract
NEW FINDINGS What is the topic of this review? We review sex differences within physiological systems implicated in exercise performance; specifically, how they integrate to determine metabolic thresholds and fatigability. Thereafter, we discuss the implications that these sex differences might have for long-term adaptation to exercise. What advances does it highlight? The review collates evidence from recent physiological studies that have investigated sex as a biological variable, demonstrating that the physiological response to equivalent 'dosages' of exercise is not the same in males and females; thus, highlighting the need to research diversity in physiological responses to interventions. ABSTRACT The anatomical and physiological differences between males and females are thought to determine differences in the limits of human performance. The notion of studying sex as a biological variable has recently been emphasized in the biosciences as a vital step in enhancing human health. In this review, we contend that the effects of biological sex on acute and chronic responses must be studied and accounted for when prescribing aerobic exercise, much like any intervention targeting the optimization of physiological function. Emerging evidence suggests that the response of physiological systems to exercise differs between males and females, potentially mediating the beneficial effects in healthy and clinical populations. We highlight evidence that integrative metabolic thresholds during exercise are influenced by phenotypical sex differences throughout many physiological systems. Furthermore, we discuss evidence that female skeletal muscle is more resistant to fatigue elicited by equivalent dosages of high-intensity exercise. How the different acute responses affect the long-term trainability of males and females is considered, with discussion about tailoring exercise to the characteristics of the individual presented within the context of biological sex. Finally, we highlight the influence of endogenous and exogenous sex hormones on physiological responses to exercise in females. Sex is one of many mediating influences on the outcomes of exercise, and with careful experimental designs, physiologists can advance the collective understanding of diversity in physiology and optimize outcomes for both sexes.
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Affiliation(s)
- Paul Ansdell
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - Kevin Thomas
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - Kirsty M Hicks
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - Sandra K Hunter
- Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
| | - Glyn Howatson
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK.,Water Research Group, School of Environmental Sciences and Development, North-West University, Potchefstroom, South Africa
| | - Stuart Goodall
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK
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22
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Kumar RI, Forman GN, Forman DA, Mugnosso M, Zenzeri J, Button DC, Holmes MWR. Dynamic Wrist Flexion and Extension Fatigue Induced via Submaximal Contractions Similarly Impairs Hand Tracking Accuracy in Young Adult Males and Females. Front Sports Act Living 2020; 2:574650. [PMID: 33345137 PMCID: PMC7739657 DOI: 10.3389/fspor.2020.574650] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 09/01/2020] [Indexed: 11/22/2022] Open
Abstract
We evaluated the effects of muscle fatigue on hand-tracking performance in young adults. Differences were quantified between wrist flexion and extension fatigability, and between males and females. Participants were evaluated on their ability to trace a pattern using a 3-degrees-of-freedom robotic manipulandum before (baseline) and after (0, 1, 2, 4, 6, 8, and 10 mins) a submaximal-intensity fatigue protocol performed to exhaustion that isolated the wrist flexors or extensors on separate days. Tracking tasks were performed at all time points, while maximal voluntary contractions (MVCs) were performed at baseline, and 2, 6-, and 10-mins post-task termination. We evaluated movement smoothness (jerk ratio, JR), shape reproduction (figural error, FE), and target tracking accuracy (tracking error, TE). MVC force was significantly lower in females (p < 0.05), lower than baseline for all timepoints after task termination (p < 0.05), with no muscle group-dependent differences. JR did not return to baseline until 10-mins post-task termination (most affected), while FE returned at 4-mins post-task termination, and TE at 1-min post-task termination. Males tracked the target with significantly lower JR (p < 0.05), less TE (p < 0.05), and less FE (p < 0.05) than females. No muscle group-dependent changes in hand-tracking performance were observed. Based on this work, hand tracking accuracy is similarly impaired following repetitive submaximal dynamic wrist flexion or extension. The differences between male and female fatigability was independent of the changes in our tracking metrics.
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Affiliation(s)
- Robert I. Kumar
- Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, Canada
| | - Garrick N. Forman
- Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, Canada
| | - Davis A. Forman
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, ON, Canada
| | - Maddalena Mugnosso
- Robotics, Brain and Cognitive Sciences, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Jacopo Zenzeri
- Robotics, Brain and Cognitive Sciences, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Duane C. Button
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Michael W. R. Holmes
- Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, Canada
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23
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Importance of Maximal Strength and Muscle-Tendon Mechanics for Improving Force Steadiness in Persons with Parkinson's Disease. Brain Sci 2020; 10:brainsci10080471. [PMID: 32708012 PMCID: PMC7464786 DOI: 10.3390/brainsci10080471] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/14/2020] [Accepted: 07/18/2020] [Indexed: 11/17/2022] Open
Abstract
Although plantar flexion force steadiness (FS) is reduced in persons with Parkinson’s disease (PD), the underlying causes are unknown. The aim of this exploratory design study was to ascertain the influence of maximal voluntary contraction (MVC) force and gastrocnemius-Achilles muscle-tendon unit behaviour on FS in persons with PD. Nine persons with PD and nine age- and sex-matched non-PD controls (~70 years, 6 females per group) performed plantar flexion MVCs and sub-maximal tracking tasks at 5, 10, 25, 50 and 75% MVC. Achilles tendon elongation and medial gastrocnemius fascicle lengths were recorded via ultrasound during contraction. FS was quantified using the coefficient of variation (CV) of force. Contributions of MVC and tendon mechanics to FS were determined using multiple regression analyses. Persons with PD were 35% weaker during MVC (p = 0.04) and had 97% greater CV (p = 0.01) with 47% less fascicle shortening (p = 0.004) and 38% less tendon elongation (p = 0.002) than controls. Reduced strength was a direct contributor to lower FS in PD (ß = 0.631), and an indirect factor through limiting optimal muscle-tendon unit interaction. Interestingly, our findings indicate an uncoupling between fascicle shortening and tendon elongation in persons with PD. To better understand limitations in FS and muscle-tendon unit behavior, it is imperative to identify the origins of MVC decrements in persons with PD.
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24
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Haynes EMK, Neubauer NA, Cornett KMD, O'Connor BP, Jones GR, Jakobi JM. Age and sex-related decline of muscle strength across the adult lifespan: a scoping review of aggregated data. Appl Physiol Nutr Metab 2020; 45:1185-1196. [PMID: 32598857 DOI: 10.1139/apnm-2020-0081] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Muscle strength is sex-related and declines with advancing age; yet, a comprehensive comparative evaluation of age-related strength loss in human females and males has not been undertaken. To do so, segmented piecewise regression analysis was performed on aggregated data from studies published from 1990 to 2018 and are available in CINAHL, EMBASE, MEDLINE, and PsycINFO databases. The search identified 5613 articles that were reviewed for physical assessment results stratified by sex and age. Maximal isometric and isokinetic 60°·s-1 knee extension (KE) and knee flexion (KF) contractions from 57 studies and 15 283 subjects (N = 7918 females) had sufficient data reported on females and males for meaningful statistical evaluation to be undertaken. The analysis revealed that isometric KE and KF strength undergo similar rapid declines in both sexes late in the sixth decade of life. Yet, there is an abrupt age-related decline in KE 60°·s-1 peak torque earlier in females (aged 41.8 years) than males (aged 66.7 years). In the assessment of KF peak torque, an age-related acceleration in strength loss was only identified in males (aged 49.3 years). The results suggest that age-related isometric strength loss is similar between sexes while the characteristics of KE and KF peak torque decline are sex-related, which likely explains the differential rate of age-related functional decline. Novelty Inclusion of muscle strength and torque of KE and KF data from >15 000 subjects. Isometric KE and KF strength loss are similar between sexes. Isokinetic 60°·s-1 KE torque decline accelerates 25 years earlier in females and female age-related KF peak torque decline does not accelerate with age.
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Affiliation(s)
- E M K Haynes
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC V1V 1V7, Canada
| | - N A Neubauer
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC V1V 1V7, Canada
| | - K M D Cornett
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC V1V 1V7, Canada
| | - B P O'Connor
- Psychology, School of Arts and Sciences, University of British Columbia Okanagan, Kelowna, BC V1V 1V7, Canada
| | - G R Jones
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC V1V 1V7, Canada
| | - J M Jakobi
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC V1V 1V7, Canada
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25
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Renberg J, Wiggen ØN, Oksa J, Dyb KB, Reinertsen RE, Roeleveld K. The effect of mild whole-body cold stress on isometric force control during hand grip and key pinch tasks. J Therm Biol 2020; 89:102537. [PMID: 32364982 DOI: 10.1016/j.jtherbio.2020.102537] [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: 11/01/2019] [Revised: 02/12/2020] [Accepted: 02/12/2020] [Indexed: 11/28/2022]
Abstract
Prolonged exposure to cold can impair manual performance, which in turn can affect work task performance. We investigated whether mild whole-body cold stress would affect isometric force control during submaximal hand grip and key pinch tasks. Twelve male participants performed isometric hand grip and key pinch tasks at 10% and 30% of maximal voluntary contraction (MVC) for 30 and 10 s respectively, in cold (8 °C) and control (25 °C) conditions. Finger temperature decreased significantly by 18.7 ± 2.1 °C and continuous low-intensity shivering in the upper trunk increased significantly in intensity and duration during cold exposure. Rectal temperature decreased similarly for the 8 °C and 25 °C exposures. Force variability (FCv) was <2% for the hand grip tasks, and <3% for the key pinch tasks. No significant changes in FCv or force accuracy were found between the ambient temperatures. In conclusion, isometric force control during hand grip and key pinch tasks was maintained when participants experienced mild whole-body cold stress compared with when they were thermally comfortable.
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Affiliation(s)
- Julie Renberg
- Department of Health Research, SINTEF, NO-7465, Trondheim, Norway; Department of Biology, Norwegian University of Science and Technology (NTNU), NO-7491, Trondheim, Norway.
| | | | - Juha Oksa
- Department of Workability and Working Careers, Finnish Institute of Occupational Health (FIHO), FIN, 90220, Oulu, Finland.
| | - Kristine Blomvik Dyb
- Department of Biology, Norwegian University of Science and Technology (NTNU), NO-7491, Trondheim, Norway.
| | - Randi Eidsmo Reinertsen
- Department of Health Research, SINTEF, NO-7465, Trondheim, Norway; Department of Biology, Norwegian University of Science and Technology (NTNU), NO-7491, Trondheim, Norway.
| | - Karin Roeleveld
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), NO-7491, Trondheim, Norway.
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26
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Jakobi JM, Kuzyk SL, McNeil CJ, Dalton BH, Power GA. Motor unit contributions to activation reduction and torque steadiness following active lengthening: a study of residual torque enhancement. J Neurophysiol 2020; 123:2209-2216. [PMID: 32347154 DOI: 10.1152/jn.00394.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Following active lengthening, steady-state isometric (ISO) torque is greater than a purely ISO contraction at the same muscle length, this is referred to as residual torque enhancement (rTE). A phenomenon of rTE is activation reduction, characterized by reduced electromyography (EMG) amplitude for a given torque output. We hypothesized that lower motor unit discharge rates would contribute to activation reduction and lessening torque steadiness. Ten young male subjects performed ISO dorsiflexion contractions at 10 and 20% of maximal voluntary contraction (MVC) torque. During rTE trials, the muscle was activated at 10° of plantar flexion, then the ankle was rotated to the ISO position at 40°. Fine wire electrodes recorded motor unit (MU)-discharge rates and variability from the tibialis anterior. Surface EMG quantified activation reduction, and steadiness was determined as the coefficient of variation of torque. The activation reduction was 44 and 24% at 10 and 20% MVC, respectively (P < 0.05). Fewer MUs were recorded in the rTE than ISO condition at 10% (~47%) and 20% (~36%) MVC (P < 0.05). Discharge rates were 19 and 26% lower in the rTE compared with the ISO condition for 10 and 20% MVC, respectively (P < 0.05), with no difference in variability between conditions (P > 0.05). Steadiness was ~22 and 18% lower for the rTE than ISO condition at 10 and 20% MVC (P < 0.05). Our findings indicate that activation reduction may be attributed to lower MU discharge rate and fewer detectable MUs and that this theoretically contributes to a reduction in steadiness in the rTE condition.NEW & NOTEWORTHY Our findings indicate that lower electromyographic activity during the torque enhanced condition following active lengthening compared with a purely isometric contraction arises from fewer active motor units and a lower discharge rate of those that are active. We used an acute condition of increased torque capacity to induce a decrease in net output of the motor neuron pool during a submaximal task to demonstrate, in humans, the impact of motor unit activity on torque steadiness.
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Affiliation(s)
- Jennifer M Jakobi
- School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia, Okanagan, British Columbia, Canada
| | - Samantha L Kuzyk
- School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia, Okanagan, British Columbia, Canada
| | - Chris J McNeil
- School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia, Okanagan, British Columbia, Canada
| | - Brian H Dalton
- School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia, Okanagan, British Columbia, Canada
| | - Geoffrey A Power
- Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, Ontario, Canada
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Kowalski KL, Anita D C. Force Control and Motor Unit Firing Behavior Following Mental Fatigue in Young Female and Male Adults. Front Integr Neurosci 2020; 14:15. [PMID: 32296312 PMCID: PMC7137823 DOI: 10.3389/fnint.2020.00015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/09/2020] [Indexed: 11/29/2022] Open
Abstract
Purpose: The neuromuscular mechanisms leading to impaired motor performance in the presence of mental fatigue remain unclear. It is also unknown if mental fatigue differentially impacts motor performance in males and females. The purpose of this study was to assess the impact of mental fatigue on force production and motor unit (MU) firing behavior in males and females. Methods: Nineteen participants performed 10-s isometric dorsiflexion (DF) contractions at 20 and 50% maximum voluntary contraction (MVC) before, during, and after completing 22 min of the psychomotor vigilance task (PVT), to induce mental fatigue. The DF force and indwelling MU firing behavior of the tibialis anterior (TA) was measured before and immediately following the PVT and within the first and final minutes of the PVT. Results: Force steadiness and motor unit firing rate (MUFR) variability did not change during or following the PVT at either contraction intensity (p ≥ 0.16). Overall, females had more variability than males in MUFR during the 20% MVCs (15.98 ± 2.19 vs. 13.64 ± 2.19%, p = 0.03), though no sex differences were identified during the 50% MVCs (p = 0.20). Mean MUFR decreased following mental fatigue in both sexes in the 20% MVC condition (14.79 ± 3.20 vs. 12.92 ± 2.53 Hz, p = 0.02), but only in males during the 50% MVC condition (18.65 ± 5.21 vs. 15.03 ± 2.60 Hz, p = 0.01). Conclusions: These results suggest possible sex and contraction intensity-specific neuromuscular changes in the presence of mental fatigue.
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Affiliation(s)
- Katie L Kowalski
- School of Kinesiology, University of Western Ontario, London, ON, Canada
| | - Christie Anita D
- School of Kinesiology, University of Western Ontario, London, ON, Canada
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28
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Yacyshyn AF, Kuzyk S, Jakobi JM, McNeil CJ. The effects of forearm position and contraction intensity on cortical and spinal excitability during a submaximal force steadiness task of the elbow flexors. J Neurophysiol 2020; 123:522-528. [PMID: 31774348 DOI: 10.1152/jn.00349.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Elbow flexor force steadiness is less with the forearm pronated (PRO) compared with neutral (NEU) or supinated (SUP) and may relate to neural excitability. Although not tested in a force steadiness paradigm, lower spinal and cortical excitability was observed separately for biceps brachii in PRO, possibly dependent on contractile status at the time of assessment. This study aimed to investigate position-dependent changes in force steadiness as well as spinal and cortical excitability at a variety of contraction intensities. Thirteen males (26 ± 7 yr; means ± SD) performed three blocks (PRO, NEU, and SUP) of 24 brief (~6 s) isometric elbow flexor contractions (5, 10, 25 or 50% of maximal force). During each contraction, transcranial magnetic stimulation or transmastoid stimulation was delivered to elicit a motor-evoked potential (MEP) or cervicomedullary motor-evoked potential (CMEP), respectively. Force steadiness was lower in PRO compared with NEU and SUP (P ≤ 0.001), with no difference between NEU and SUP. Similarly, spinal excitability (CMEP/maximal M wave) was lower in PRO than NEU (25 and 50% maximal force; P ≤ 0.010) and SUP (all force levels; P ≤ 0.004), with no difference between NEU and SUP. Cortical excitability (MEP/CMEP) did not change with forearm position (P = 0.055); however, a priori post hoc testing for position showed excitability was 39.8 ± 38.3% lower for PRO than NEU at 25% maximal force (P = 0.006). The data suggest that contraction intensity influences the effect of forearm position on neural excitability and that reduced spinal and, to a lesser extent, cortical excitability could contribute to lower force steadiness in PRO compared with NEU and SUP.NEW & NOTEWORTHY To address conflicting reports about the effect of forearm position on spinal and cortical excitability of the elbow flexors, we examine the influence of contraction intensity. For the first time, excitability data are considered in a force steadiness context. Motoneuronal excitability is lowest in pronation and this disparity increases with contraction intensity. Cortical excitability exhibits a similar pattern from 5 to 25% of maximal force. Lower corticospinal excitability likely contributes to relatively poor force steadiness in pronation.
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Affiliation(s)
- Alexandra F Yacyshyn
- School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Samantha Kuzyk
- School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Jennifer M Jakobi
- School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Chris J McNeil
- School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
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29
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Jakobi JM, Dempsey JA, Hellsten Y, Monette R, Kalmar JM. On the horizon of aging and physical activity research. Appl Physiol Nutr Metab 2019; 45:113-117. [PMID: 31314999 DOI: 10.1139/apnm-2018-0738] [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]
Abstract
This viewpoint is the result of a Horizon Round Table discussion of Exercise and Aging held during the 2017 Saltin International Graduate School in Exercise and Clinical Physiology in Gatineau, Quebec. This expert panel discussed key issues and approaches to future research into aging, across human physiological systems, current societal concerns, and funding approaches. Over the 60-min round table discussion, 3 major themes emerged that the panel considered to be "On the Horizon" of aging research. These themes include (i) aging is a process that extends from womb to tomb; (ii) the importance of longitudinal experimental studies; and (iii) the ongoing need to investigate multiple systems using an integrative approach between scientists, clinicians, and knowledge brokers. With a focus on these themes, we aim to identify critical questions, challenges, and opportunities that face scientists in advancing the understanding of exercise and aging.
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Affiliation(s)
- Jennifer M Jakobi
- Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC V1V 1V7, Canada
| | - Jerome A Dempsey
- Department of Population Health Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53706-1532, USA
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Nørre Allé 51, 2200 København N, August Krogh Bygningen, Universitetsparken 13, 2100 Københav, Building: 2 sal, Denmark
| | | | - Jayne M Kalmar
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada
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30
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Pereira HM, Schlinder-DeLap B, Keenan KG, Negro F, Farina D, Hyngstrom AS, Nielson KA, Hunter SK. Oscillations in neural drive and age-related reductions in force steadiness with a cognitive challenge. J Appl Physiol (1985) 2019; 126:1056-1065. [PMID: 30817244 DOI: 10.1152/japplphysiol.00821.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
A cognitive challenge when imposed during a low-force isometric contraction will exacerbate sex- and age-related decreases in force steadiness, but the mechanism is not known. We determined the role of oscillations in the common synaptic input to motor units on force steadiness during a muscle contraction with a concurrent cognitive challenge. Forty-nine young adults (19-30 yr; 25 women, 24 men) and 36 old adults (60-85 yr; 19 women, 17 men) performed a cognitive challenge (counting backward by 13) during an isometric elbow flexion task at 5% of maximal voluntary contraction. Single-motor units were decomposed from high-density surface EMG recordings. For a subgroup of participants, motor units were matched during control and cognitive challenge trials, so the same motor unit was analyzed across conditions. Reduced force steadiness was associated with greater oscillations in the synaptic input to motor units during both control and cognitive challenge trials ( r = 0.45-0.47, P < 0.01). Old adults and young women showed greater oscillations in the common synaptic input to motor units and decreased force steadiness when the cognitive challenge was imposed, but young men showed no change across conditions (session × age × sex, P < 0.05). Oscillations in the common synaptic input to motor units is a potential mechanism for altered force steadiness when a cognitive challenge is imposed during low-force contractions in young women and old adults. NEW & NOTEWORTHY We found that oscillations in the common synaptic input to motor units were associated with a reduction in force steadiness when a cognitive challenge was imposed during low-force contractions of the elbow flexor muscles in young women and old men and women but not young men. Age- and sex-related muscle weakness was associated with these changes.
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Affiliation(s)
- Hugo M Pereira
- Department of Health and Exercise Science, University of Oklahoma , Norman, Oklahoma
| | | | - Kevin G Keenan
- Department of Kinesiology, University of Wisconsin-Milwaukee , Milwaukee, Wisconsin
| | - Francesco Negro
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia , Brescia , Italy
| | - Dario Farina
- Department of Bioengineering, Imperial College London, Royal School of Mines , London , United Kingdom
| | | | - Kristy A Nielson
- Department of Psychology, Marquette University , Milwaukee, Wisconsin
| | - Sandra K Hunter
- Department of Physical Therapy, Marquette University , Milwaukee, Wisconsin
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31
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Gardiner PF, Ljubicic V. Special issue on nervous system and exercise. Appl Physiol Nutr Metab 2018; 43:v. [PMID: 30380929 DOI: 10.1139/apnm-2018-0393] [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]
Affiliation(s)
- Phillip F Gardiner
- a Spinal Cord Research Center, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Vladimir Ljubicic
- b Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
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