1. Knee extensor fatigue developed during high-intensity exercise limits lower-limb power production.
- Author
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O'bryan, Steven J., Billaut, François, Taylor, Janet L., and Rouffet, David M.
- Subjects
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STATISTICAL correlation , *CYCLING , *ELECTROMYOGRAPHY , *FATIGUE (Physiology) , *KNEE , *HAMSTRING muscle , *CALF muscles , *GLUTEAL muscles , *EXERCISE intensity , *RECTUS femoris muscles - Abstract
We investigated the association between changes in vastii electromyography (EMG) and knee extensor fatigue during high-intensity cycling, and the subsequent effect on lower-limb power and intermuscular coordination during all-out cycling. On two separate days, participants completed 30-s all-out cycling or 10-min of high-intensity cycling followed by 30-s all-out cycling. EMG for gluteus maximus (GMAX), rectus femoris (RF), vastii (VAS), hamstrings (HAM) and gastrocnemius (GAS); co-activation for GMAX/RF, VAS/HAM and VAS/GAS; isometric maximal voluntary force (IMVF) and resting twitch (RT) of the knee extensors were measured. VAS EMG increases during high-intensity cycling (6% to 14%, P < 0.05) were negatively correlated (r = −0.791, P < 0.05) with knee extensor IMVF decreases (−2% to−36%, P < 0.05) following the exercise. Knee extensor IMVF decreases were positively correlated (r = 0.757, P < 0.05) with all-out cycling power reductions (0% to −27%, P < 0.05). VAS/GAS co-activation did not change (P > 0.05) during all-out cycling while VAS and GAS EMG decreased. Larger increase in VAS EMG during high-intensity cycling was associated with greater knee extensor fatigue and larger power reduction during all-out cycling. High VAS/GAS co-activation potentially limited power reduction induced by knee extensor fatigue during all-out cycling. [ABSTRACT FROM PUBLISHER]
- Published
- 2018
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