Muscle- and Mode-Specific Responses of the Forearm Flexors to Fatiguing, Concentric Muscle Actions

Hill, Ethan C.; Housh, Terry J.; Smith, Cory M.; Schmidt, Richard J.; Johnson, Glen O.

doi:10.3390/sports4040047

Cited by 10 publications

(9 citation statements)

References 58 publications

(73 reference statements)

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“…Furthermore, MMG amplitude and MMG mean power frequency values were greater at pretest, posttest, and recovery during the eccentric PT and concentric PT than MVIC muscle actions. These findings were also consistent with previous investigations [15,16] that have examined MMG responses for dynamic versus static muscle actions. In conjunction with previous investigations [15,16], the findings of the present study suggested that dynamic muscle actions may have resulted in greater intracellular and extracellular fluid turbulence, which caused greater muscle perturbations and increased the MMG values [4].…”

Section: Neuromuscular Responsessupporting

confidence: 92%

“…The fatigue-induced decreases in EMG mean power frequency from pretest to posttest for all three modes of muscle actions supported the fatiguing nature of the 50 repeated, submaximal, eccentric muscle actions. Specifically, fatiguing exercise has been associated with decreases in EMG mean power frequency that may reflect the effect of the accumulation of metabolic byproducts on muscle fiber action potential conduction velocity [15,16,18]. The increases in EMG mean power frequency at recovery may have reflected the clearance of metabolic byproducts or increases in muscle temperature [1].…”

Section: Neuromuscular Responsesmentioning

confidence: 99%

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Sex- and Mode-specific Responses to Eccentric Muscle Fatigue

et al. 2018

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The primary purpose of the present investigation was to examine sex-related differences as a result of fatiguing eccentric muscle actions on torque, muscle blood flow, electromyography, and mechanomyography. Eighteen men and 18 women performed peak torque trials prior to (pretest), immediately after (posttest), and 5-min after (recovery) completing 50 submaximal (60% of eccentric peak torque), eccentric, isokinetic (180°·s ) muscle actions of the elbow flexors. Electromyographic and mechanomyographic responses were simultaneously recorded from the biceps brachii muscle, and muscle blood flow was measured at pretest, posttest and recovery. There were sex- and mode-specific responses for torque, but there were no sex-specific muscle blood flow or neuromuscular responses. From pretest to posttest, torque decreased (80.0-88.2% of pretest) for both the men and women. At recovery concentric peak torque recovered to a greater extent in women (95.0% of pretest) than men (88.0% of pretest), while eccentric peak torque recovered to a greater extent in men (88.9% of pretest) than women (86.9% of pretest). The sex-specific torque responses were not associated with different motor control strategies or differences in the occlusion of muscle blood flow between the men and women. For both men and women, eccentric fatiguing exercise is manifested similarly during isometric muscle actions, but not during eccentric and concentric muscle actions.

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Section: Neuromuscular Responsessupporting

confidence: 92%

Section: Neuromuscular Responsesmentioning

confidence: 99%

Sex- and Mode-specific Responses to Eccentric Muscle Fatigue

et al. 2018

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“…For MVIC, however, the bilateral, unilateral right leg, and unilateral left leg fatiguing tasks resulted in non-significant PF in the exercising legs (decreases of approximately 14, 10, and 18%, respectively.) Previous studies (Byrne et al, 2001;Camic, 2011;Hill et al, 2016;Thompson et al, 2015) have reported conflicting evidence for quantifying PF from the PT and MVIC responses to various modes of fatiguing tasks. For example, Thompson et al, (2015) found that following a fatiguing, intermittent, isometric task, concentric PT recovered to the pre-fatigued level more quickly than did MVIC.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, the purpose of this study was to examine: 1) Mode-specific testing responses to isokinetic fatigue; 2) differences in PF between bilateral and unilateral leg extensions; and 3) the effects of fatiguing, unilateral, dynamic leg extensions on contralateral leg extension isokinetic PT and MVIC. Based on previous findings, it was hypothesized that there would be similar decreases in PT and MVIC following bilateral, as well as, unilateral muscle actions (Byrne et al, 2001;Camic, 2011;Hill et al, 2016), that unilateral muscle actions would result in greater decreases in PT and MVIC than bilateral muscle actions (Anders et al, 2020b;Matkowski et al, 2011;Rossman et al, 2012Rossman et al, , 2014 and that fatiguing, maximal, unilateral leg extensions would decrease contralateral PT and MVIC.…”

Section: Introductionmentioning

confidence: 99%

Ipsilateral and Contralateral Torque Responses to Bilateral and Unilateral Maximal, Fatiguing, Isokinetic Leg Extensions

Neltner

Anders

Keller

et al. 2020

IJKSS

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Background: Few studies have compared performance fatigability (PF) for bilateral versus unilateral isokinetic tasks. Objectives: The purpose of this study was to examine: Mode-specific testing responses to isokinetic fatigue, differences in PF between bilateral and unilateral leg extensions, and the effects of fatiguing, unilateral, dynamic leg extensions on contralateral isokinetic peak torque (PT) and maximal voluntary isometric contraction (MVIC). Methods: Eight men (mean ± SD: age= 22.5 ± 2.5 yr.) completed pre- and post-testing for PT and MVIC following 50 bilateral, unilateral right or left leg maximal, isokinetic leg extensions at 180°·s-1, on three separate days. Fatigue-induced decreases in PT and MVIC were used to quantify PF. The data were analyzed with a 4-way repeated measures ANOVA, follow up, and post-hoc analyses. Results: The results indicated that there were no differences (p > 0.05) in PF for the bilateral versus unilateral fatiguing tasks, decreases in PT (p < 0.001 - 0.016; d = 0.54 - 2.58) and MVIC (p < 0.001 - 0.006; η2p = 0.682 - 0.962) for the exercised legs during unilateral fatigue, and a contralateral increase (p = 0.007) in PT following the right leg fatiguing task. Conclusion: The results indicated that PT was more sensitive to fatiguing isokinetic tasks than was MVIC. In addition, there was a facilitation of PT in the contralateral leg following unilateral right leg fatigue. The differences in PT and MVIC testing may be attributable to the timing and/or relative contributions of peripheral and central fatigue.

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“…Li and Hong found when stroke patients took negative-heeled shoes during walking the sEMG amplitudes of GS and BF increased, accompanied by greater knee flexion [ 14 ]. Other studies reported that it was the GS but not the BF that exhibited reduced sEMG amplitude and frequency with decreased knee motion in post-stroke gait [ 15 , 16 ]. These studies inspired us that to further examine the amplitude and frequency information underlying the sEMG signals of the involved muscles would help better understand the causes and solutions of stiff-knee gait in post-stroke patients.…”

Section: Introductionmentioning

confidence: 99%

Associations between lower-limb muscle activation and knee flexion in post-stroke individuals: A study on the stance-to-swing phases of gait

Wang

Yue

et al. 2017

PLoS ONE

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Reduced knee flexion is a leading feature of post-stroke gait, but the causes have not been well understood. The purpose of this study was to investigate the relationship between the knee flexion and the lower-limb muscle activation within the stance-to-swing phases of gait cycle in the post-stroke hemiplegic patients. Ten stroke patients and 10 age- and gender-matched healthy subjects participated in the experiment. The lower-limb kinematic signals and the surface electromyography (sEMG) signals of the left and right rectus femoris (RF), biceps femoris (BF) and lateral gastrocnemius (GS) were recorded during walking. The angle range (AR) of knee flexion, the root mean square (RMS) and the mean frequency (MNF) of sEMG signals were calculated from the terminal stance (TSt) to the initial swing (ISw) phases of gait cycle. Stroke patients showed lower bilateral AR of knee flexion and lower RMS of GS on the paretic side, but higher MNF of RF on the non-paretic side compared with the controls. Within the stroke patients, significant differences were found between their paretic and non-paretic limbs in the AR of knee flexion, as well as in the RMS and MNF of GS (p < 0.05). Regression analysis showed that the RMS of BF, MNF of BF and MNF of GS explained 82.1% of variations in AR of knee flexion on paretic side (r2 = 0.821). But the RMS and MNF of all the muscles (including the RF, GS and BF) could explain 65.6% of AR of knee flexion variations on the non-paretic side (r2 = 0.656), and 45.2% of variations for the healthy subjects (r2 = 0.452). The reduced knee flexion during gait was associated with altered magnitude and frequency of muscle contractions and with simplified muscle synergy in the post-stroke hemiplegic patients. Identifying the muscles that are responsible for knee stiffness may facilitate improvement of rehabilitation strategy for post-stroke gait.

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Muscle- and Mode-Specific Responses of the Forearm Flexors to Fatiguing, Concentric Muscle Actions

Cited by 10 publications

References 58 publications

Sex- and Mode-specific Responses to Eccentric Muscle Fatigue

Sex- and Mode-specific Responses to Eccentric Muscle Fatigue

Ipsilateral and Contralateral Torque Responses to Bilateral and Unilateral Maximal, Fatiguing, Isokinetic Leg Extensions

Associations between lower-limb muscle activation and knee flexion in post-stroke individuals: A study on the stance-to-swing phases of gait

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