Muscle coordination changes during intermittent cycling sprints.
Maximal muscle power is reported to decrease during explosive cyclical exercises owing to metabolic disturbances, muscle damage, and adjustments in the efferent neural command. The aim of the present study was to analyze the influence of inter-muscle coordination in fatigue occurrence during 10 intermittent 6-s cycling sprints, with 30-s recovery through electromyographic activity (EMG). Results showed a decrease in peak power output with sprint repetitions (sprint 1 versus sprint 10: -11%, P<0.01) without any significant modifications in the integrated EMG. The timing between the knee extensor and the flexor EMG activation onsets was reduced in sprint 10 (sprint 1 versus sprint 10: -90.2 ms, P<0.05), owing to an earlier antagonist activation with fatigue occurrence. In conclusion, the maximal power output, developed during intermittent cycling sprints of short duration, decreased possibly due to the inability of muscles to maintain maximal force. This reduction in maximal power output occurred in parallel to changes in the muscle coordination pattern after fatigue.
Billaut
François
F
Laboratoire Ergonomie Sportive et Performance -- EA 3162, Université du Sud Toulon-Var, Avenue de l'Université, BP 132, 83957 La Garde Cedex, France. billaut@univ-tln.fr
Basset
Fabien A
FA
Falgairette
Guy
G
D000328:Adult; D004576:Electromyography; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D013997:Time Factors