Changes of Pedaling Technique and Muscle Coordination during an Exhaustive Exercise

Abstract : Purpose: Alterations of the mechanical patterns during an exhaustive pedaling exercise have been previously shown. We designed the present study to test the hypothesis that these alterations in the biomechanics of pedaling, which occur during exhaustive exercise, are linked to changes in the activity patterns of lower limb muscles. Methods: Ten well-trained cyclists were tested during a limited time to exhaustion, performing 80% of maximal power tolerated. Pedal force components were measured continuously using instrumented pedals and were synchronized with surface EMG signals measured in 10 lower limb muscles. Results: The results confirmed most of the alterations of the mechanical patterns previously described in the literature. The magnitude of the root mean squared of the EMG during the complete cycle (RMS cycle) for tibialis anterior and gastrocnemius medialis decreased significantly (P G 0.05) from 85% and 75% of T lim , respectively. A higher RMS cycle was obtained for gluteus maximus (P G 0.01) and biceps femoris (P G 0.05) from 75% of T lim. The k values that resulted from the cross-correlation technique indicated that the activities of six muscles (gastrocnemius medialis, gastrocnemius lateralis, tibialis anterior, vastus lateralis, vastus medialis, and rectus femoris) were shifted forward in the cycle at the end of the exercise. Conclusions: The large increases in activity for gluteus maximus and biceps femoris, which are in accordance with the increase in force production during the propulsive phase, could be considered as instinctive coordination strategies that compensate for potential fatigue and loss of force of the knee extensors (i.e., vastus lateralis and vastus medialis) by a higher moment of the hip extensors.
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Soumis le : vendredi 13 juillet 2018 - 16:09:13
Dernière modification le : mardi 17 septembre 2019 - 11:02:02

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Sylvain Dorel, Jean-Marc Drouet, Antoine Couturier, Yvan Champoux, François Hug. Changes of Pedaling Technique and Muscle Coordination during an Exhaustive Exercise. Medicine and Science in Sports and Exercise, American College of Sports Medicine (ACSM), 2009, 41 (6), pp.1277 - 1286. ⟨10.1249/MSS.0b013e31819825f8⟩. ⟨hal-01838813⟩

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