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Hirono T, Watanabe K. Muscle Fiber Conduction Velocity During Electrically Stimulated Contraction at Various Joint Angles, During Joint Movements, and During Voluntary Contractions. J Appl Biomech 2023; 39:446-450. [PMID: 37678832 DOI: 10.1123/jab.2023-0004] [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: 01/06/2023] [Revised: 06/29/2023] [Accepted: 08/02/2023] [Indexed: 09/09/2023]
Abstract
Muscle fiber conduction velocity (MFCV) can be affected by muscle fiber geometry at different joint angles and during joint movements. This study aimed to investigate MFCV during electrically evoked contraction at different joint angles, during joint movements, and during voluntary contractions. Sixteen healthy young men participated. A stimulation electrode was attached on the innervation zone of the vastus lateralis, and a linear electrode array was attached on the vastus lateralis. Under a static condition, electrically evoked electromyography signals were recorded at knee joint angles set every 15° between 0° and 105°. Under a passive movement condition, signals were recorded during knee extension and flexion passively. Under a voluntary contraction condition, signals were recorded while performing 30% or 60% of maximum voluntary contraction. MFCV was calculated using cross-correlation coefficients. Under the static condition, there were no differences in MFCV among various joint angles. Under the passive movement condition, MFCV was significantly greater during high velocity or shortening. Under the voluntary contraction condition, MFCV was significantly greater during high-intensity voluntary contraction and with a shortened muscle length. Joint angles do not influence MFCV markedly during relaxation, but it is possible to overestimate MFCV during movement or voluntary contraction.
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Affiliation(s)
- Tetsuya Hirono
- Laboratory of Neuromuscular Biomechanics, School of Health and Sport Science, Chukyo University, Toyota,Japan
- Research Fellow of Japan Society for the Promotion of Science, Tokyo,Japan
| | - Kohei Watanabe
- Laboratory of Neuromuscular Biomechanics, School of Health and Sport Science, Chukyo University, Toyota,Japan
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2
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Nuzzo JL, Pinto MD, Nosaka K. Overview of muscle fatigue differences between maximal eccentric and concentric resistance exercise. Scand J Med Sci Sports 2023; 33:1901-1915. [PMID: 37269142 DOI: 10.1111/sms.14419] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/15/2023] [Accepted: 05/22/2023] [Indexed: 06/04/2023]
Abstract
Since the 1970s, researchers have studied a potential difference in muscle fatigue (acute strength loss) between maximal eccentric (ECCmax ) and concentric (CONmax ) resistance exercise. However, a clear answer to whether such a difference exists has not been established. Therefore, the aim of our paper was to overview methods and results of studies that compared acute changes in muscle strength after bouts of ECCmax and CONmax resistance exercise. We identified 30 relevant studies. Participants were typically healthy men aged 20-40 years. Exercise usually consisted of 40-100 isokinetic ECCmax and CONmax repetitions of the knee extensors or elbow flexors. Both ECCmax and CONmax exercise caused significant strength loss, which plateaued and rarely exceeded 60% of baseline, suggesting strength preservation. In upper-body muscles, strength loss at the end of ECCmax (31.4 ± 20.4%) and CONmax (33.6 ± 17.5%) exercise was similar, whereas in lower-body muscles, strength loss was less after ECCmax (13.3 ± 12.2%) than CONmax (39.7 ± 13.3%) exercise. Muscle architecture and daily use of lower-body muscles likely protects lower-body muscles from strength loss during ECCmax exercise. We also reviewed seven studies on muscle fatigue during coupled ECCmax -CONmax exercise and found similar strength loss in the ECC and CON phases. We also found evidence from three studies that more ECC than CON repetitions can be completed at equal relative loads. These results indicate that muscle fatigue may manifest differently between ECCmax and CONmax resistance exercise. An implication of the results is that prescriptions of ECC resistance exercise for lower-body muscles should account for greater fatigue resilience of these muscles compared to upper-body muscles.
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Affiliation(s)
- James L Nuzzo
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia
| | - Matheus D Pinto
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia
| | - Kazunori Nosaka
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia
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3
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Jones EJ, Guo Y, Martinez‐Valdes E, Negro F, Stashuk DW, Atherton PJ, Phillips BE, Piasecki M. Acute adaptation of central and peripheral motor unit features to exercise-induced fatigue differs with concentric and eccentric loading. Exp Physiol 2023; 108:827-837. [PMID: 37018481 PMCID: PMC10988466 DOI: 10.1113/ep091058] [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: 12/01/2022] [Accepted: 03/14/2023] [Indexed: 04/07/2023]
Abstract
NEW FINDINGS What is the central question of this study? Conflicting evidence exists on motor unit (MU) firing rate in response to exercise-induced fatigue, possibly due to the contraction modality used: Do MU properties adapt similarly following concentric and eccentric loading? What is the main finding and its importance? MU firing rate increased following eccentric loading only despite a decline in absolute force. Force steadiness deteriorated following both loading methods. Central and peripheral MU features are altered in a contraction type-dependant manner, which is an important consideration for training interventions. ABSTRACT Force output of muscle is partly mediated by the adjustment of motor unit (MU) firing rate (FR). Disparities in MU features in response to fatigue may be influenced by contraction type, as concentric (CON) and eccentric (ECC) contractions demand variable amounts of neural input, which alters the response to fatigue. This study aimed to determine the effects of fatigue following CON and ECC loading on MU features of the vastus lateralis (VL). High-density surface (HD-sEMG) and intramuscular (iEMG) electromyography were used to record MU potentials (MUPs) from bilateral VLs of 12 young volunteers (six females) during sustained isometric contractions at 25% and 40% of the maximum voluntary contraction (MVC), before and after completing CON and ECC weighted stepping exercise. Multi-level mixed effects linear regression models were performed with significance assumed as P < 0.05. MVC decreased in both CON and ECC legs post-exercise (P < 0.0001), as did force steadiness at both 25% and 40% MVC (P < 0.004). MU FR increased in ECC at both contraction levels (P < 0.001) but did not change in CON. FR variability increased in both legs at 25% and 40% MVC following fatigue (P < 0.01). From iEMG measures at 25% MVC, MUP shape did not change (P > 0.1) but neuromuscular junction transmission instability increased in both legs (P < 0.04), and markers of fibre membrane excitability increased following CON only (P = 0.018). These data demonstrate that central and peripheral MU features are altered following exercise-induced fatigue and differ according to exercise modality. This is important when considering interventional strategies targeting MU function.
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Affiliation(s)
- Eleanor J. Jones
- Centre of Metabolism, Ageing and Physiology (COMAP), MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research CentreUniversity of NottinghamNottinghamUK
| | - Yuxiao Guo
- Centre of Metabolism, Ageing and Physiology (COMAP), MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research CentreUniversity of NottinghamNottinghamUK
| | - Eduardo Martinez‐Valdes
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental SciencesUniversity of BirminghamBirminghamUK
| | - Francesco Negro
- Department of Clinical and Experimental SciencesUniversità degli Studi di BresciaBresciaItaly
| | - Daniel W. Stashuk
- Department of Systems Design EngineeringUniversity of WaterlooWaterlooOntarioCanada
| | - Philip J. Atherton
- Centre of Metabolism, Ageing and Physiology (COMAP), MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research CentreUniversity of NottinghamNottinghamUK
| | - Bethan E. Phillips
- Centre of Metabolism, Ageing and Physiology (COMAP), MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research CentreUniversity of NottinghamNottinghamUK
| | - Mathew Piasecki
- Centre of Metabolism, Ageing and Physiology (COMAP), MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research CentreUniversity of NottinghamNottinghamUK
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4
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Nuzzo JL, Pinto MD, Nosaka K. Muscle fatigue during maximal eccentric-only, concentric-only, and eccentric-concentric bicep curl exercise with automated drop setting. Scand J Med Sci Sports 2023; 33:857-871. [PMID: 36752667 DOI: 10.1111/sms.14330] [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: 11/11/2022] [Revised: 01/23/2023] [Accepted: 02/03/2023] [Indexed: 02/09/2023]
Abstract
Connected adaptive resistance exercise (CARE) machines are new technology purported to adjust resistance exercise loads in response to muscle fatigue. The present study examined muscle fatigue (strength loss, fatigue perceptions) during maximal eccentric-only (ECCmax -only), concentric-only (CONmax -only), and coupled ECC-CON (ECCmax -CONmax ) bicep curl exercise on a CARE machine. Eleven men and nine women completed the three protocols in separate sessions and in random order. All protocols included 4 sets of 20 maximal effort muscle contractions. Strength loss was calculated as Set 4 set end load minus Set 1 highest load. The CARE machine's algorithm adjusted resistances automatically, permitting continued maximal effort repetitions without stopping. Consequently, all protocols caused substantial fatigue. Women were most susceptible to strength loss from exercise that included maximal efforts in the ECC phase, whereas men were most susceptible to strength loss from exercise that included maximal efforts in the CON phase. With ECCmax -only exercise, ECC strength loss (mean ± SD) was similar between men (55.9 ± 14.1%) and women (56.4 ± 10.8%). However, with CONmax -only exercise, men and women experienced 55.6 ± 6.2% and 35.3 ± 8.7% CON strength loss, respectively. With ECCmax -CONmax exercise, men experienced greater ECC (62.9 ± 7.7%) and CON (77.0 ± 5.3%) strength loss than women (ECC: 48.5 ± 15.7%, CON: 66.2 ± 12.1%). Heightened perceptions of fatigue and pain of the exercised limb were reported after all protocols. Women generally reported more biceps pain than men. The results illustrate CARE technology delivers ECC-only and accentuated ECC exercise feasibly. Acute responses to repeated maximal effort bicep curl exercise with such technology might differ between men and women depending on muscle contraction type.
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Affiliation(s)
- James L Nuzzo
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
| | - Matheus D Pinto
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
| | - Kazunori Nosaka
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
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Xu Y, Wang K, Jin Y, Qiu F, Yao Y, Xu L. Influence of electrode configuration on muscle-fiber-conduction-velocity estimation using surface electromyography. IEEE Trans Biomed Eng 2022; 69:2414-2422. [PMID: 35077351 DOI: 10.1109/tbme.2022.3145038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Muscle fiber conduction velocity (MFCV) is an important myoelectric parameter and can be estimated by analyzing surface electromyography (EMG). Among many factors, electrode configuration plays a key role on MFCV estimation. Most studies adopt bipolar configuration (BC) for CV estimation. However, a thorough understanding of the underlying mechanism is lacking, confusing the design of the most appropriate EMG measurement setup for CV estimation. The aim of this study is therefore to systematically investigate the influence of electrode configuration on MFCV estimation. METHODS Four possible configurations are considered, including BC, monopolar configuration (MC), common average reference (CAR), and a special monopolar configuration (SMC) using a fix channel on the active muscle as reference. For each configuration, mathematic models computing the time delay between adjacent channels are derived and evaluated by dedicated simulation as well as real EMG measurements. MFCV was calculated using the maximum likelihood algorithm with and without channel normalization. RESULTS The simulation results are in line with the mathematical models. The CVs estimated from the real EMG with and without normalization are 4.30.7 and 7.23.7 m/s, 5.71.3 and 20.44.7 m/s, 9.03.4 and 20.69.8 m/s, and 5.52.5 and 5.52.4 m/s for BC, MC, SMC, and CAR, respectively. CONCLUSION Our results show normalized BC to produce the most accurate CV estimation, in line with the mathematical models and the simulation results. SIGNIFICANCE These findings enable a better understanding of the influence of electrode configuration on MFCV estimation, providing useful information for EMG measurement setup design aiming at MFCV studies.
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Cabral HV, Meiburger KM, de Oliveira LF, Vieira TM. Changes in supramaximal M-wave amplitude at different regions of biceps brachii following eccentric exercise of the elbow flexors. Eur J Appl Physiol 2020; 121:307-318. [PMID: 33070208 DOI: 10.1007/s00421-020-04520-4] [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: 12/20/2019] [Accepted: 10/01/2020] [Indexed: 11/30/2022]
Abstract
PURPOSE Previous evidence from surface electromyograms (EMGs) suggests that exercise-induced muscle damage (EIMD) may manifest unevenly within the muscle. Here we investigated whether these regional changes were indeed associated with EIMD or if they were attributed to spurious factors often affecting EMGs. METHODS Ten healthy male subjects performed 3 × 10 eccentric elbow flexions. Maximal voluntary contraction (MVC), muscle soreness and ultrasound images from biceps brachii distal and proximal regions were measured immediately before (baseline) and during each of the following 4 days after the exercise. Moreover, 64 monopolar surface EMGs were detected while 10 supramaximal pulses were applied to the musculocutaneous nerve. The innervation zone (IZ), the number of electrodes detecting largest M-waves and their centroid longitudinal coordinates were assessed to characterize the spatial distribution of the M-waves amplitude. RESULTS The MVC torque decreased (~ 25%; P < 0.001) while the perceived muscle soreness scale increased (~ 4 cm; 0 cm for no soreness and 10 cm for highest imaginable soreness; P < 0.005) across days. The echo intensity of the ultrasound images increased at 48 h (71%), 72 h (95%) and 96 h (112%) for both muscle regions (P < 0.005), while no differences between regions were observed (P = 0.136). The IZ location did not change (P = 0.283). The number of channels detecting the greatest M-waves significantly decreased (up to 10.7%; P < 0.027) and the centroid longitudinal coordinate shifted distally at 24, 48 and 72 h after EIMD (P < 0.041). CONCLUSION EIMD consistently changed supramaximal M-waves that were detected mainly proximally from the biceps brachii, suggesting that EIMD takes place locally within the biceps brachii.
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Affiliation(s)
- Hélio V Cabral
- Biomechanics Laboratory, Biomedical Engineering Program (COPPE), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
| | - Kristen M Meiburger
- Biolab, Department of Electronics and Telecommunications, Politecnico di Torino, Turin, Italy.,PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - Liliam F de Oliveira
- Biomechanics Laboratory, Biomedical Engineering Program (COPPE), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Physical Education and Sports School (EEFD), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Taian M Vieira
- PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy.,Laboratory for Engineering of the Neuromuscular System (LISiN), Department of Electronics and Telecommunications, Politecnico di Torino, Turin, Italy
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Krenn MJ, Vargas Luna JL, Mayr W, Stokic DS. Bipolar transcutaneous spinal stimulation evokes short-latency reflex responses in human lower limbs alike standard unipolar electrode configuration. J Neurophysiol 2020; 124:1072-1082. [PMID: 32845202 DOI: 10.1152/jn.00433.2020] [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: 12/15/2022] Open
Abstract
Noninvasive electrical stimulation targeting the posterior lumbosacral roots has been applied recently in reflexes studies and as a neuromodulation intervention for modifying spinal cord circuitry after an injury. Here, we characterized short-latency responses evoked by four bipolar electrode configurations placed longitudinally over the spinal column at different vertebral levels from L1 to T9. They were compared with the responses evoked by the standard unipolar (aka monopolar) electrode configuration (cathode at T11/12, anode over the abdominal wall). Short-latency responses were recorded in the rectus femoris, medial hamstrings, tibialis anterior, and soleus muscles, bilaterally, in 11 neurologically intact participants. The response recruitment characteristics (maximal amplitude, motor threshold) and amplitude-matched onset latencies and paired-pulse suppression (35-ms interstimulus interval) were assessed with 1-ms current-controlled pulses at intensities up to 100 mA. The results showed that short-latency responses can be elicited with all bipolar electrode configurations. However, only with the cathode at T11/12 and the anode 10 cm cranially (∼T9), the maximum response amplitudes were statistical equivalent (P < 0.05) in the medial hamstrings, tibialis anterior, and soleus but not the rectus femoris, whereas motor thresholds were not significantly different across all muscles. The onset latency and paired-pulse suppression were also not significantly different across the tested electrode configurations, thereby confirming the reflex nature of the bipolar short-latency responses. We conclude that the bipolar configuration (cathode T11/12, anode ∼T9) produces reflex responses that are ostensibly similar to those evoked by the standard unipolar configuration. This provides an alternative approach for neuromodulation intervention.NEW & NOTEWORTHY Transcutaneous spinal stimulation with the identified bipolar electrode configuration may offer several advantages for neuromodulation interventions over commonly used unipolar configurations: there are no associated abdominal contractions, which improves the participant's comfort; additional dermatomes are not stimulated as when the anode is over the abdominal wall or iliac crest, which may have unwanted effects; and, due to a more localized electrical field, the bipolar configuration offers the possibility of targeting cord segments more selectively.
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Affiliation(s)
- Matthias J Krenn
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi.,Center for Neuroscience and Neurological Recovery, Methodist Rehabilitation Center, Jackson, Mississippi
| | - Jose L Vargas Luna
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Winfried Mayr
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Dobrivoje S Stokic
- Center for Neuroscience and Neurological Recovery, Methodist Rehabilitation Center, Jackson, Mississippi
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Stožer A, Vodopivc P, Križančić Bombek L. Pathophysiology of exercise-induced muscle damage and its structural, functional, metabolic, and clinical consequences. Physiol Res 2020; 69:565-598. [PMID: 32672048 DOI: 10.33549/physiolres.934371] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Extreme or unaccustomed eccentric exercise can cause exercise-induced muscle damage, characterized by structural changes involving sarcomere, cytoskeletal, and membrane damage, with an increased permeability of sarcolemma for proteins. From a functional point of view, disrupted force transmission, altered calcium homeostasis, disruption of excitation-contraction coupling, as well as metabolic changes bring about loss of strength. Importantly, the trauma also invokes an inflammatory response and clinically presents itself by swelling, decreased range of motion, increased passive tension, soreness, and a transient decrease in insulin sensitivity. While being damaging and influencing heavily the ability to perform repeated bouts of exercise, changes produced by exercise-induced muscle damage seem to play a crucial role in myofibrillar adaptation. Additionally, eccentric exercise yields greater hypertrophy than isometric or concentric contractions and requires less in terms of metabolic energy and cardiovascular stress, making it especially suitable for the elderly and people with chronic diseases. This review focuses on our current knowledge of the mechanisms underlying exercise-induced muscle damage, their dependence on genetic background, as well as their consequences at the structural, functional, metabolic, and clinical level. A comprehensive understanding of these is a prerequisite for proper inclusion of eccentric training in health promotion, rehabilitation, and performance enhancement.
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Affiliation(s)
- A Stožer
- Institute of Physiology, Faculty of Medicine, University of Maribor, Slovenia.
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Watanabe K, Sakai T, Kato S, Hashizume N, Horii N, Yoshikawa M, Hasegawa N, Iemitsu K, Tsuji K, Uchida M, Kanamori M, Iemitsu M. Conduction Velocity of Muscle Action Potential of Knee Extensor Muscle During Evoked and Voluntary Contractions After Exhaustive Leg Pedaling Exercise. Front Physiol 2020; 11:546. [PMID: 32536878 PMCID: PMC7267216 DOI: 10.3389/fphys.2020.00546] [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: 11/12/2019] [Accepted: 04/30/2020] [Indexed: 11/13/2022] Open
Abstract
Purpose Muscle fiber conduction velocity (CV) has been developed to estimate neuromuscular fatigue and measured during voluntary (VC) and electrically evoked (EC) contractions. Since CV during VC and EC reflect different physiological phenomena, the two parameters would show inconsistent changes under the conditions of neuromuscular fatigue. We investigated the time-course changes of CV during EC and VC after fatiguing exercise. Methods In 14 young males, maximal voluntary contraction (MVC) of knee extensor muscles, CV during electrical stimulation (CV-EC) and MVC (CV-VC) were measured before and immediately, 30 min, 60 min, 120 min, and 24 h after exhaustive leg pedaling exercise. Results CV-EC significantly increased immediately after the fatiguing exercise (p < 0.05) and had a significant negative correlation with MVC in merged data from all time-periods (r = -0.511, p < 0.001). CV-VC significantly decreased 30, 60, and 120 min after the fatiguing exercise (p < 0.05) and did not show any correlations with MVC (p > 0.05). Conclusion These results suggest that CV during EC and VC exhibits different time-course changes, and that CV during EC may be appropriate to estimate the degree of neuromuscular fatigue after fatiguing pedaling exercise.
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Affiliation(s)
- Kohei Watanabe
- Laboratory of Neuromuscular Biomechanics, School of International Liberal Studies, Chukyo University, Nagoya, Japan
| | - Taiki Sakai
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Japan
| | - Shosaku Kato
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Japan
| | - Natsuka Hashizume
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Japan
| | - Naoki Horii
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Japan.,Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | - Maki Yoshikawa
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Japan
| | - Natsuki Hasegawa
- Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, Japan
| | - Keiko Iemitsu
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Japan
| | - Katsunori Tsuji
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Japan
| | - Masakata Uchida
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Japan
| | - Masao Kanamori
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Japan
| | - Motoyuki Iemitsu
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Japan
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Latella C, Goodwill AM, Muthalib M, Hendy AM, Major B, Nosaka K, Teo WP. Effects of eccentric versus concentric contractions of the biceps brachii on intracortical inhibition and facilitation. Scand J Med Sci Sports 2018; 29:369-379. [DOI: 10.1111/sms.13334] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 10/28/2018] [Indexed: 12/30/2022]
Affiliation(s)
- Christopher Latella
- Centre for Exercise and Sports Science Research (CESSR), School of Medical and Health Sciences; Edith Cowan University; Joondalup Western Australia Australia
| | - Alicia M. Goodwill
- Centre for Research and Development in Learning (CRADLE); Nanyang Technological University; Singapore
| | - Makii Muthalib
- Silverline Research; Brisbane Queensland Australia
- Cognitive Neuroscience Unit (CNU), School of Psychology; Deakin University, Deakin University; Geelong Victoria Australia
| | - Ashlee M. Hendy
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences; Deakin University; Geelong Victoria Australia
| | - Brendan Major
- Cognitive Neuroscience Unit (CNU), School of Psychology; Deakin University, Deakin University; Geelong Victoria Australia
| | - Kazunori Nosaka
- Centre for Exercise and Sports Science Research (CESSR), School of Medical and Health Sciences; Edith Cowan University; Joondalup Western Australia Australia
| | - Wei-Peng Teo
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences; Deakin University; Geelong Victoria Australia
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Nasrabadi R, Izanloo Z, Sharifnezad A, Hamedinia MR, Hedayatpour N. Muscle fiber conduction velocity of the vastus medilais and lateralis muscle after eccentric exercise induced-muscle damage. J Electromyogr Kinesiol 2018; 43:118-126. [PMID: 30273919 DOI: 10.1016/j.jelekin.2018.06.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 06/06/2018] [Accepted: 06/15/2018] [Indexed: 10/28/2022] Open
Abstract
Change in muscle fiber conduction velocity (MFCV) has been reported after eccentric exercise induces muscle fiber damage, most likely due to a change in membrane permeability of the injured fiber. The extent of damage to the muscle fiber depends on the morphological and architectural characteristics of the muscle fibers. Morphological and architectural characteristics of the VMO muscle fibers are different from VL muscle. Thus, it is expected that eccentric exercise of quadriceps muscle results in a non-uniform fiber damage within the VMO and VL muscle and, as a consequence, non-uniform changes in membrane excitability and conduction velocity. The aim of the study was to investigate MFCV of the VMO and VL muscles before and 24 h after eccentric exercise. Multichannel surface EMG signals were concurrently recorded from the right VMO and VL muscles of 15 healthy men during sustained isometric contractions at 50% of the maximal force. Maximal voluntary force significantly reduced after eccentric exercise with respect to the pre-exercise condition (P < 0.0001). MFCV decreased over time during the sustained contractions at faster rates when assessed 24 h after exercise (VMO = -26.1; VL = -20.1) with respect to the pre-exercise condition (VMO = -9.1; VL = -13.7, P < 0.0001). Moreover, VMO showed a greater rate of reduction in MFCV over sustained contraction (26.1 ± 10.7%) in comparison with VL muscle (20.1 ± 8.5%, P < 0.025) 24 h after eccentric exercise. The result indicates that eccentric exercise contributes to a larger reduction in MFCV within the VMO muscle as compared to the VL muscle. This may abolish the ability of VMO to counteract the lateral pull of the VL muscle during knee extension, thereby leaving the knee complex more vulnerable to injury.
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Affiliation(s)
- Razieh Nasrabadi
- Department of Sports Sciences, Islamic Azad University of Bojnourd, Iran
| | - Zahra Izanloo
- Center for Biomechanics and Motor Control (BMC), Department of Sports Sciences, University of Bojnord, Bojnord, Iran
| | - Ali Sharifnezad
- Department of Sports Biomechanics, Sports Sciences Research Institute of Iran, Iran
| | | | - Nosratollah Hedayatpour
- Center for Biomechanics and Motor Control (BMC), Department of Sports Sciences, University of Bojnord, Bojnord, Iran.
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12
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Garnier YM, Lepers R, Dubau Q, Pageaux B, Paizis C. Neuromuscular and perceptual responses to moderate-intensity incline, level and decline treadmill exercise. Eur J Appl Physiol 2018; 118:2039-2053. [DOI: 10.1007/s00421-018-3934-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 07/05/2018] [Indexed: 11/28/2022]
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13
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Hight RE, Beck TW, Bemben DA, Black CD. Adaptations in antagonist co-activation: Role in the repeated-bout effect. PLoS One 2017; 12:e0189323. [PMID: 29216288 PMCID: PMC5720767 DOI: 10.1371/journal.pone.0189323] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/22/2017] [Indexed: 11/23/2022] Open
Abstract
Eccentric exercise results in an adaptation which attenuates muscle damage from subsequent exercise—termed the “repeated-bout effect (RBE).” Purpose: Study examined antagonist co-activation and motor-unit recruitment strategy, assessed via dEMG, concomitant to the RBE. Methods: Nine participants performed 5 sub-maximal isometric trapezoid (ramp-up, hold, ramp-down) contractions at force levels corresponding to 50% and 80% of maximal isometric strength (MVC). Surface EMG signals of the biceps brachii were decomposed into individual motor-unit action potential trains. The relationship between mean firing rate (MFR) of each motor-unit and its recruitment threshold (RT) was examined using linear regression. Eccentric exercise was then performed until biceps brachii MVC had decreased by ~40%. Surface EMG of the biceps and triceps were collected during eccentric exercise. MVC, range-of-motion (ROM), and delayed onset muscle soreness (DOMS) were measured 24-hours, 72-hours, and 1-week following eccentric exercise. Three weeks later all procedures were repeated. Results: Changes in MVC (-32±14% vs -25±10%; p = 0.034), ROM (-11% vs 6%; p = 0.01), and DOMS (31.0±19mm vs 19±12mm; p = 0.015) were attenuated following the second bout of exercise. Triceps EMG was reduced (16.8±9.5% vs. 12.6±7.2%; p = 0.03) during the second bout of eccentric exercise. The slope (-0.60±0.13 vs -0.70±0.18; p = 0.029) and y-intercept (46.5±8.3 vs 53.3±8.8; p = 0.020) of the MFR vs. RT relationship was altered during contractions at 80% of MVC prior to the second bout of eccentric exercise. No changes were observed at 50% of MVC. Conclusion: A reduction in antagonist co-activation during the second bout of eccentric exercise suggests less total force was required to move an identical external load. This finding is supported by the increased negative slope coefficient and an increased y-intercept of the linear relationship between RT and MFR.
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Affiliation(s)
- Robert E. Hight
- Department of Health and Exercise Science, University of Oklahoma, Norman, Oklahoma, United States of America
| | - Travis W. Beck
- Department of Health and Exercise Science, University of Oklahoma, Norman, Oklahoma, United States of America
| | - Debra A. Bemben
- Department of Health and Exercise Science, University of Oklahoma, Norman, Oklahoma, United States of America
| | - Christopher D. Black
- Department of Health and Exercise Science, University of Oklahoma, Norman, Oklahoma, United States of America
- * E-mail:
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Boccia G, Dardanello D, Tarperi C, Rosso V, Festa L, La Torre A, Pellegrini B, Schena F, Rainoldi A. Decrease of muscle fiber conduction velocity correlates with strength loss after an endurance run. Physiol Meas 2017; 38:233-240. [PMID: 28099172 DOI: 10.1088/1361-6579/aa5139] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Monitoring surface electromyographic (EMG) signals can provide useful insights for characterizing muscle fatigue, which is defined as an exercise-induced strength loss. This experiment investigated the muscle fiber conduction velocity (CV) changes induced by an endurance run. The day before and immediately after a half-marathon run (21.097 km) 11 amateur runners performed maximum voluntary contractions (MVCs) of knee extensor muscles. During the MVC, multichannel EMG was recorded from the vastus lateralis and EMG amplitude and CV were calculated. After the run, knee extensors showed a decreased strength (-13 ± 9%, p = 0.001) together with a reduction in EMG amplitude (-13 ± 10%, p = 0.003) and in CV (-6 ± 8%, p = 0.032). Knee extensor strength loss positively correlated with vastus lateralis CV differences (r = 0.76, p = 0.006). Thus, the exercises-induced muscle fatigue was associated not only with a decrease in EMG amplitude, but also with a reduction in CV. This finding suggests that muscle fibers with higher CV (i.e. those with greater fiber size) were the most impaired during strength production after an endurance run.
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Affiliation(s)
- Gennaro Boccia
- CeRiSM Research Center 'Sport, Mountain, and Health', via del Ben 5/b, Rovereto, (TN) 38068, Italy. Department of Medical Sciences, Motor Science Research Center, School of Exercise & Sport Sciences, SUISM, University of Turin, 12, piazza Bernini, Torino 10143, Italy
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15
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Kouzaki K, Kobayashi M, Nakamura KI, Ohta K, Nakazato K. Repeated bouts of fast eccentric contraction produce sciatic nerve damage in rats. Muscle Nerve 2016; 54:936-942. [PMID: 26994356 DOI: 10.1002/mus.25110] [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: 08/31/2015] [Revised: 03/08/2016] [Accepted: 03/16/2016] [Indexed: 11/08/2022]
Abstract
INTRODUCTION We evaluated sciatic nerve impairment after eccentric contractions (ECs) in rat triceps surae. METHODS Wistar rats were randomly assigned to different joint angular velocity: 180°/s (FAST), 30°/s (SLOW), or nontreated control (CNT). FAST and SLOW groups were subjected to multiple (1-4) bouts of 20 (5 reps, 4 sets) ECs. Nerve conduction velocity (NCV) and isometric tetanic ankle torque were measured 24 h after each ECs bout. We also assessed nerve morphology. RESULTS After 4 ECs bouts, NCVs and isometric torque in the FAST group were significantly lower than those in the CNT (NCV: 42%, torque: 66%; P < 0.05). After 4 bouts, average nerve diameter was significantly smaller in the FAST group [2.39 ± 0.20 μm vs. 2.69 ± 0.20 μm (CNT) and 2.93 ± 0.24 μm (SLOW); P < 0.05] than that in other two groups. CONCLUSIONS Chronic ECs with high angular velocity induce serious nerve damage. Muscle Nerve 54: 936-942, 2016.
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Affiliation(s)
- Karina Kouzaki
- Graduate School of Health and Sport Science, Nippon Sport Science University, 7-1-1, Fukasawa, Setagaya, Tokyo, 158-8508, Japan.
| | - Masatoshi Kobayashi
- Graduate School of Health and Sport Science, Nippon Sport Science University, 7-1-1, Fukasawa, Setagaya, Tokyo, 158-8508, Japan
| | - Kei-Ichiro Nakamura
- Division of Microscopic and Developmental Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, Fukuoka, 830-0011, Japan
| | - Keisuke Ohta
- Division of Microscopic and Developmental Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, Fukuoka, 830-0011, Japan
| | - Koichi Nakazato
- Graduate School of Health and Sport Science, Nippon Sport Science University, 7-1-1, Fukasawa, Setagaya, Tokyo, 158-8508, Japan
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LÓPEZ JOSÉRAFAEL, MIJARES ALFREDO, KOLSTER JUAN, HENRÍQUEZ-OLGUÍN CARLOS, ZHANG RUI, ALTAMIRANO FRANCISCO, ADAMS JOSÉANTONIO. Whole Body Periodic Acceleration Improves Muscle Recovery after Eccentric Exercise. Med Sci Sports Exerc 2016; 48:1485-94. [DOI: 10.1249/mss.0000000000000932] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Satkunskienė D, Stasiulis A, Zaičenkovienė K, Sakalauskaitė R, Rauktys D. Effect of Muscle-Damaging Eccentric Exercise on Running Kinematics and Economy for Running at Different Intensities. J Strength Cond Res 2016; 29:2404-11. [PMID: 25774624 DOI: 10.1519/jsc.0000000000000908] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The objective of this study was to explore the changes in running kinematics and economy during running at different intensities 1 and 24 hours after a muscle-damaging bench-stepping exercise. Healthy, physically active adult women were recruited for this study. The subjects' running kinematics, heart rate, gas exchange, minute ventilation, and perceived exertion were continuously recorded during the increasing-intensity running test on a treadmill for different testing conditions: a control condition and 1 and 24 hours after the bench-stepping exercise test. Two muscle damage markers, muscle soreness and blood creatine kinase (CK) activity, were measured before and 24 hours after the stepping exercise. Muscle soreness and blood CK activity were significantly altered (exact p ≤ 0.05, Monte Carlo test) 24 hours after the bench-stepping exercise. The stride length, stride frequency, and support time at different running intensities did not change. Twenty-four hours after the previous step exercise, ankle dorsiflexion in the support phase was significantly higher during severe-intensity running, the range of knee flexion at the stance phase was significantly lower during moderate-intensity running, and knee flexion at the end of the amortization phase was significantly lower during heavy-intensity running compared with the control values (exact p ≤ 0.05, Monte Carlo test). The running economy at moderate and heavy intensities, maximum ventilation, and maximum heart rate did not change. We conclude that, given moderate soreness in the calf muscles 24 hours after eccentric exercise, the running kinematics are slightly but significantly changed without a detectable effect on running economy.
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Affiliation(s)
- Danguolė Satkunskienė
- 1Institute of Sport Science and Innovations; 2Department of Applied Biology and Rehabilitation; and 3Department of Coaching Science, Lithuanian Sports University, Kaunas, Lithuania
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18
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Increases in M-wave latency of biceps brachii after elbow flexor eccentric contractions in women. Eur J Appl Physiol 2016; 116:939-46. [PMID: 26994769 DOI: 10.1007/s00421-016-3358-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 03/12/2016] [Indexed: 12/13/2022]
Abstract
PURPOSE Eccentric contractions (ECCs) induce muscle damage that is indicated by prolonged loss of muscle function and delayed onset muscle soreness. It is possible that ECCs affect motor nerves, and this may contribute to the prolonged decreases in force generating capability. The present study investigated the hypothesis that M-wave latency of biceps brachii would be increased after maximal elbow flexor ECCs resulting in prolonged loss of muscle strength. METHODS Fifteen women performed exercise consisting of 60 maximal ECCs of the elbow flexors using their non-dominant arm. M-wave latency was assessed by the time taken from electrical stimulation applied to the Erb's point to the onset of M-wave of the biceps brachii before, immediately after, and 1-4 days after exercise. Maximal voluntary isometric contraction (MVC) torque, range of motion (ROM) and muscle soreness using a numerical rating scale were also assessed before and after exercise. RESULTS Prolonged decreases in MVC torque (1-4 days post-exercise: -54 to -15 %) and ROM (1-2 days: -32 to -22 %), and increased muscle soreness (peak: 4.2 out of 10) were evident after exercise (p < 0.05). The M-wave latency increased (p < 0.01) from 5.8 ± 1.0 ms before exercise to 6.5 ± 1.7 ms at 1 day and 7.2 ± 1.5 ms at 2 days after exercise for the exercised arm only. No significant changes in M-wave amplitude were evident after exercise. CONCLUSION The increased M-wave latency did not fully explain the prolonged decreases in MVC torque after eccentric exercise, but may indicate reversible motor nerve impairment.
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Semmler JG. Motor unit activity after eccentric exercise and muscle damage in humans. Acta Physiol (Oxf) 2014; 210:754-67. [PMID: 24761463 DOI: 10.1111/apha.12232] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It is well known that unaccustomed eccentric exercise leads to muscle damage and soreness, which can produce long-lasting effects on muscle function. How this muscle damage influences muscle activation is poorly understood. The purpose of this brief review is to highlight the effect of eccentric exercise on the activation of muscle by the nervous system, by examining the change in motor unit activity obtained from surface electromyography (EMG) and intramuscular recordings. Previous research shows that eccentric exercise produces unusual changes in the EMG–force relation that influences motor performance during isometric, shortening and lengthening muscle contractions and during fatiguing tasks. When examining the effect of eccentric exercise at the single motor unit level, there are substantial changes in recruitment thresholds, discharge rates, motor unit conduction velocities and synchronization, which can last for up to 1 week after eccentric exercise. Examining the time course of these changes suggests that the increased submaximal EMG after eccentric exercise most likely occurs through a decrease in motor unit conduction velocity and an increase in motor unit activity related to antagonist muscle coactivation and low-frequency fatigue. Furthermore, there is a commonly held view that eccentric exercise produces preferential damage to high-threshold motor units, but the evidence for this in humans is limited. Further research is needed to establish whether there is preferential damage to high-threshold motor units after eccentric exercise in humans, preferably by linking changes in motor unit activity with estimates of motor unit size using selective intramuscular recording techniques.
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Affiliation(s)
- J. G. Semmler
- Discipline of Physiology; School of Medical Sciences; The University of Adelaide; Adelaide SA Australia
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Cadore EL, González-Izal M, Pallarés JG, Rodriguez-Falces J, Häkkinen K, Kraemer WJ, Pinto RS, Izquierdo M. Muscle conduction velocity, strength, neural activity, and morphological changes after eccentric and concentric training. Scand J Med Sci Sports 2014; 24:e343-52. [PMID: 24833263 DOI: 10.1111/sms.12186] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2014] [Indexed: 11/27/2022]
Abstract
This study compared the effects of concentric and eccentric training on neuromuscular adaptations in young subjects. Twenty-two men and women were assigned to one of two groups: concentric (CON, n = 11) and eccentric (ECC, n = 11) training. Training consisted of 6 weeks of isokinetic exercise, performed twice weekly, starting with two sets of eight repetitions, and progressing to five sets of 10 repetitions. Subjects were tested in strength variables [concentric, eccentric, and isometric peak torque (PT), and rate of force development (RFD)], muscle conduction velocity (CV), neuromuscular activity, vastus lateralis (VL) muscle thickness, and echo intensity as determined by ultrasonography. There were similar increases in the concentric and eccentric PTs in both the CON and ECC groups (P < 0.01), but only the ECC group showed an increase in isometric PT (P < 0.001). Similarly, both groups exhibited increased VL muscle thickness, CV, and RFD, and reduced VL echo intensity (P < 0.05). Significant correlations were observed among the relative changes in the neuromuscular outcomes and training variables (e.g., total work, average PT) (r = 0.68-0.75, P < 0.05). The results showed that both training types similarly improved dynamic PT, CV, RFD, and muscle thickness and quality during the early weeks of training.
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Affiliation(s)
- E L Cadore
- Department of Health Sciences, Public University of Navarre, Tudela, Navarre, Spain
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Qi Z, Zhai X, Ding S. How to explain exercise-induced phenotype from molecular data: rethink and reconstruction based on AMPK and mTOR signaling. SPRINGERPLUS 2013; 2:693. [PMID: 24404437 PMCID: PMC3879393 DOI: 10.1186/2193-1801-2-693] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 12/17/2013] [Indexed: 12/25/2022]
Abstract
During endurance and resistance exercise training, AMPK and mTOR signaling were known as selective pathways implicating the differentiation of exercise-induced phenotype in skeletal muscle. Among the previous studies, however, the differences in exercise protocol, the individuality and the genetic heterogeneity within species make it difficult to reach a consistent conclusion in the roles of AMPK and mTOR signaling. In this review, we aim not to reanalyze the previous articles and present the research progress of AMPK and mTOR signaling in exercise, but to propose an abstract general hypothesis for exercise-induced phenotype. Generally, exercise- induced skeletal muscle phenotype is independent of one and a few genes, proteins and signaling pathways. Convergent adaptation will better summarize the specificity of skeletal muscle phenotype in response to a single mode of exercise. Backward adaptation will open a new concept to illustrate the process of exercise-induced adaptation, such as mitochondrial quality control and muscle mass homeostasis.
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Affiliation(s)
- Zhengtang Qi
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention, Ministry of Education, East China Normal University, Shanghai, 200241 China ; College of Physical Education and Health, East China Normal University, Shanghai, 200241 China
| | - Xiaofeng Zhai
- Department of Traditional Chinese Medicine, Changhai Hospital, Shanghai, 200438 China
| | - Shuzhe Ding
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention, Ministry of Education, East China Normal University, Shanghai, 200241 China ; College of Physical Education and Health, East China Normal University, Shanghai, 200241 China
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Moir GL, Erny KF, Davis SE, Guers JJ, Witmer CA. The development of a repetition-load scheme for the eccentric-only bench press exercise. J Hum Kinet 2013; 38:23-31. [PMID: 24235981 PMCID: PMC3827748 DOI: 10.2478/hukin-2013-0042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The purpose of the present study was to develop a repetition-load scheme for the eccentric-only bench press exercise. Nine resistance trained men (age: 21.6 ± 1.0 years; 1-repetition maximum [RM] bench press: 137.7 ± 30.4 kg) attended four testing sessions during a four week period. During the first session each subject's 1-RM bench press load utilizing the stretch-shortening cycle was determined. During the remaining sessions they performed eccentric-only repetitions to failure using supra-maximal loads equivalent to 110%, 120% and 130% of their 1-RM value with a constant cadence (30 reps·min(-1)). Force plates and a three dimensional motion analysis system were used during these final three sessions in order to evaluate kinematic and kinetic variables. More repetitions were completed during the 110% 1-RM condition compared to the 130% 1-RM condition (p=0.01). Mean total work (p=0.046) as well as vertical force (p=0.049), vertical work (p=0.017), and vertical power output (p=0.05) were significantly greater during the 130% 1-RM condition compared to the 110% 1-RM condition. A linear function was fitted to the number of repetitions completed under each load condition that allowed the determination of the maximum number of repetitions that could be completed under other supra-maximal loads. This linear function predicted an eccentric-only 1-RM in the bench press with a load equivalent to 164.8% 1-RM, producing a load of 227.0 ± 50.0 kg. The repetition-load scheme presented here should provide a starting point for researchers to investigate the kinematic, kinetic and metabolic responses to eccentric-only bench press workouts.
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Affiliation(s)
- Gavin L. Moir
- Exercise Science Department, East Stroudsburg University, East Stroudsburg, PA, USA
| | - Kyle F. Erny
- Exercise Science Department, East Stroudsburg University, East Stroudsburg, PA, USA
| | - Shala E. Davis
- Exercise Science Department, East Stroudsburg University, East Stroudsburg, PA, USA
| | - John J. Guers
- Exercise Science Department, East Stroudsburg University, East Stroudsburg, PA, USA
| | - Chad A. Witmer
- Exercise Science Department, East Stroudsburg University, East Stroudsburg, PA, USA
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Gonzalez-Izal M, Cadore EL, Izquierdo M. Muscle conduction velocity, surface electromyography variables, and echo intensity during concentric and eccentric fatigue. Muscle Nerve 2013; 49:389-97. [DOI: 10.1002/mus.23926] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Miriam Gonzalez-Izal
- Department of Health Sciences; Public University of Navarre; Campus de Tudela Avenida de Tarazona s/n 31500 Tudela, Navarre Spain
| | - Eduardo Lusa Cadore
- Department of Health Sciences; Public University of Navarre; Campus de Tudela Avenida de Tarazona s/n 31500 Tudela, Navarre Spain
| | - Mikel Izquierdo
- Department of Health Sciences; Public University of Navarre; Campus de Tudela Avenida de Tarazona s/n 31500 Tudela, Navarre Spain
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Feasibility study of detecting surface electromyograms in severely obese patients. J Electromyogr Kinesiol 2013; 23:285-95. [DOI: 10.1016/j.jelekin.2012.09.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 09/09/2012] [Accepted: 09/24/2012] [Indexed: 12/14/2022] Open
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Adaptations at the Shoulder of the Throwing Athlete and Implications for the Clinician. TECHNIQUES IN SHOULDER AND ELBOW SURGERY 2012. [DOI: 10.1097/bte.0b013e31823fe84f] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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