Faculty Opinions recommendation of Opioid-mediated muscle afferents inhibit central motor drive and limit peripheral muscle fatigue development in humans.

Central motor drive to active muscles is believed to be reduced during numerous exercise tasks to prevent excessive peripheral fatigue development. The purpose of the present study was to use hypoxia to exacerbate physiological perturbations during a novel, intermittent exercise task and to explore the time-course and interplay between central and peripheral neuromuscular adjustments. On separate days, 14 healthy men performed four sets of 6 × 5 maximal-intensity, isokinetic leg extensions (1 repetition lasting ∼7 s) at 300°/s (15 and 100 s of passive rest between repetitions and sets, respectively) under normoxia (NM, fraction of inspired O2 0.21), moderate (MH, 0.14), and severe normobaric hypoxia (SH, 0.10). Neuromuscular assessments of the knee extensors were conducted before and immediately after each set. There was an interaction between time and condition on the mean peak torque produced during each set ( P < 0.05). RMS/M-wave activity of the rectus femoris decreased across the four sets of exercise, but there was no difference between conditions (8.3 ± 5.1% all conditions compounded, P > 0.05). Potentiated twitch torque decreased post set 1 in all conditions (all P < 0.05) with greater reductions following each set in SH compared with NM but not MH (end-exercise reductions 41.3 ± 3.0% vs. 28.0 ± 3.2%, P < 0.05 and 32.1 ± 3.3%, P > 0.05). In conclusion, severe hypoxia exacerbates both peripheral fatigue development and performance decrements during maximal, intermittent, dynamic leg extensions. In contrast to observations with other exercise modes, during exercise involving a single muscle group the attenuation of central motor drive does not appear to independently regulate the development of peripheral muscle fatigue.

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The slow component of pulmonary O2 uptake accompanies peripheral muscle fatigue during high-intensity exercise

Journal of Applied Physiology ◽

10.1152/japplphysiol.00249.2016 ◽

2016 ◽

Vol 121 (2) ◽

pp. 493-502 ◽

Cited By ~ 18

Author(s):

Daniel A. Keir ◽

David B. Copithorne ◽

Michael D. Hodgson ◽

Silvia Pogliaghi ◽

Charles L. Rice ◽

...

Keyword(s):

Muscle Fatigue ◽

High Frequency ◽

Lactate Threshold ◽

Slow Component ◽

Physiological Mechanism ◽

Progressive Increase ◽

Peripheral Muscle ◽

Fatigue Development ◽

The Difference ◽

Constant Power Output

During constant-power output (PO) exercise above lactate threshold (LT), pulmonary O2 uptake (V̇o2p) features a developing slow component (V̇o2pSC). This progressive increase in O2 cost of exercise is suggested to be related to the effects of muscle fatigue development. We hypothesized that peripheral muscle fatigue as assessed by contractile impairment would be associated with the V̇o2pSC. Eleven healthy men were recruited to perform four constant-PO tests at an intensity corresponding to ∼Δ60 (very heavy, VH) where Δ is 60% of the difference between LT and peak V̇o2p. The VH exercise was completed for each of 3, 8, 13, and 18 min (i.e., VH3, VH8, VH13, VH18) with each preceded by 3 min of cycling at 20 W. Peripheral muscle fatigue was assessed via pre- vs. postexercise measurements of quadriceps torque in response to brief trains of electrical stimulation delivered at low (10 Hz) and high (50 Hz) frequencies. During exercise, breath-by-breath V̇o2p was measured by mass spectrometry and volume turbine. The magnitude of V̇o2pSC increased ( P < 0.05) from 224 ± 81 ml/min at VH3 to 520 ± 119, 625 ± 134, and 678 ± 156 ml/min at VH8, VH13, and VH18, respectively. The ratio of the low-to-high frequency (10/50 Hz) response was reduced ( P < 0.05) at VH3 (−12 ± 9%) and further reduced ( P < 0.05) at VH8 (−25 ± 11%), VH13 (−42 ± 19%), and VH18 (−46 ± 16%), mirroring the temporal pattern of V̇o2pSC development. The reduction in 10/50 Hz ratio was correlated ( P < 0.001, r2 = 0.69) with V̇o2pSC amplitude. The temporal and quantitative association of decrements in muscle torque production and V̇o2pSC suggest a common physiological mechanism between skeletal muscle fatigue and loss of muscle efficiency.

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An electromyographic index for localized muscle fatigue

Journal of Applied Physiology ◽

10.1152/jappl.1977.43.4.750 ◽

1977 ◽

Vol 43 (4) ◽

pp. 750-754 ◽

Cited By ~ 216

Author(s):

L. Lindstrom ◽

R. Kadefors ◽

I. Petersen

Keyword(s):

Power Spectrum ◽

Muscle Fatigue ◽

Power Spectrum Analysis ◽

Muscle Action ◽

Localized Muscle Fatigue ◽

Fatigue Development ◽

Fatigued Muscle ◽

Muscle Action Potential ◽

Velocity Changes ◽

Objective Quantification

A new method for objective quantification of localized muscle fatigue is described. The method is based on power spectrum analysis of myoelectric signals obtained from the fatigued muscle. It permits real-time investigations and yields statistically based criteria for the occurrence of fatigue. The findings are interpreted in terms of muscle action potential conduction velocity changes and rate of the fatigue development.

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Plyometric Training Does Not Affect Central and Peripheral Muscle Fatigue Differently in Prepubertal Girls and Boys

Pediatric Exercise Science ◽

10.1123/pes.22.4.547 ◽

2010 ◽

Vol 22 (4) ◽

pp. 547-556 ◽

Cited By ~ 5

Author(s):

Albertas Skurvydas ◽

Marius Brazaitis

Keyword(s):

Muscle Fatigue ◽

Central Fatigue ◽

Quadriceps Muscle ◽

Voluntary Activation ◽

Peripheral Fatigue ◽

Plyometric Training ◽

Peripheral Muscle ◽

Before And After ◽

Voluntary Contractions ◽

Prepubertal Girls

The aim of the study was to evaluate the effect of plyometric training (PT) on central and peripheral (muscle) fatigue in prepubertal girls and boys. The boys (n = 13, age 10.3 ± 0.3 years) and girls (n = 13, age, 10.2 ± 0.3 years) performed continuous 2-min maximal voluntary contractions (MVCs) before and after 16 high-intensity PT sessions. PT comprised two training sessions per week of 30 jumps in each session with 20 s between jumps. The greatest effect of PT was on excitation–contraction coupling, (twitch force increased by 323% in boys and 21% in girls) and height of a counter–movement jump (increased by 37% in boys and 38% in girls). In contrast, the quadriceps voluntary activation index, central activation ratio, and MVC did not change significantly after PT. The thickness of the quadriceps muscle increased by 9% in boys and 14% in girls after PT. In conclusion, boys and girls demonstrated similar changes in indicators of central fatigue (50–60% decrease) and peripheral fatigue (45–55% decrease) after MVC before and after PT.

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Electrophysiologic evaluation of muscle fatigue development and recovery in late polio

Archives of Physical Medicine and Rehabilitation ◽

10.1016/s0003-9993(00)90109-6 ◽

2000 ◽

Vol 81 (6) ◽

pp. 770-776 ◽

Cited By ~ 10

Author(s):

Katharina Stibrant Sunnerhagen ◽

Ulrika Carlsson ◽

Arne Sandberg ◽

Erik Stålberg ◽

Marita Hedberg ◽

...

Keyword(s):

Muscle Fatigue ◽

Fatigue Development

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Effects of String Stiffness on Muscle Fatigue After a Simulated Tennis Match

Journal of Applied Biomechanics ◽

10.1123/jab.2013-0065 ◽

2014 ◽

Vol 30 (3) ◽

pp. 401-406 ◽

Cited By ~ 2

Author(s):

Jean Bernard Fabre ◽

Vincent Martin ◽

Gil Borelli ◽

Jean Theurel ◽

Laurent Grélot

Keyword(s):

Resonant Frequency ◽

Muscle Fatigue ◽

Ball Speed ◽

Tennis Players ◽

High Stiffness ◽

Fatigue Development ◽

Low Stiffness ◽

Exercise Muscle ◽

Forearm Muscle ◽

Tennis Match

We tested the influence of string stiffness on the occurrence of forearm muscle fatigue during a tennis match. Sixteen tennis players performed two prolonged simulated tennis matches with low-stiffness or high-stiffness string. Before and immediately after exercise, muscle fatigability was evaluated on the forearm muscles during a maximal intermittent gripping task. Groundstroke ball speeds and the profile of acceleration of the racquet frame at collision were recorded during each match. The peak-to-peak amplitude of acceleration and the resonant frequency of the frame were significantly greater with high- (5060 ± 1892 m/s2and 204 ± 29 Hz, respectively) than with low-stiffness string (4704 ± 1671 m/s2and 191 ± 16 Hz, respectively). The maximal and the averaged gripping forces developed during the gripping task were significantly reduced after the tennis match with high- (−15 ± 14%, and −22 ± 14%, respectively), but not with low-stiffness string. The decrease of ball speed during the simulated matches tended to be greater with high- than with low-stiffness string (P= .06). Hence, playing tennis with high-stiffness string promotes forearm muscle fatigue development, which could partly contribute to the groundstroke ball speed decrement during the game.

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