Prolonged depression of knee ‐extensor torque complexity following eccentric exercise

New FindingsWhat is the central question of this study?Does eccentric exercise leading to prolonged knee ‐extensor torque depression also result in a prolonged loss of knee‐extensor torque complexity?What is the main finding and its importance?The recovery of the loss of torque complexity after eccentric exercise took 24  h, whereas after acute muscle fatigue it took 10 min. The depression of torque complexity after eccentric exercise was prolonged.AbstractNeuromuscular fatigue reduces the temporal structure, or complexity, of muscle torque output. Exercise ‐induced muscle damage reduces muscle torque output for considerably longer than high‐intensity fatiguing contractions. We hypothesized that muscle‐damaging eccentric exercise would lead to a persistent decrease in torque complexity, whereas fatiguing exercise would not. Ten healthy participan ts performed five isometric contractions (6 s contraction, 4 s rest) at 50% maximal voluntary contraction (MVC) before, immediately after and 10, 30 and 60 min and 24 h after eccentric (muscle‐damaging) and isometric (fatiguing) exercise. These contractions were also repeated 48 h and 1 week after eccentric exercise. Torque and surface EMG signals were sampled throughout each test. Complexity and fractal scaling were quantified using approximate entropy (ApEn) and the detrended fluctuation analysis α exponent (DFA α). Global, central and peripheral perturbations were quantified using MVCs with femoral nerve stim...

Source: Experimental Physiology - November 28, 2018 Category: Physiology Authors: Jamie Pethick, Katherine Whiteaway, Samantha L. Winter, Mark Burnley Tags: RESEARCH PAPER Source Type: research