Muscle deoxygenation and neural drive to the muscle during repeated sprint cycling

Med Sci Sports Exerc. 2007 Feb;39(2):268-74. doi: 10.1249/01.mss.0000251775.46460.cb.

Abstract

Purpose: To investigate muscle deoxygenation and neural drive-related changes during repeated cycling sprints in a fatiguing context.

Methods: Nine healthy male subjects performed a repeated-sprint test (consisting of 10 x 6-s maximal sprints interspaced by 30 s of recovery). Oxygen uptake was measured breath-by-breath; muscle deoxygenation of the vastus lateralis was assessed continuously using the near-infrared spectroscopy technique. Surface electromyograms (RMS) of both vastus lateralis and biceps femoris were also recorded. Furthermore, before and after the repeated-sprint test, the percentage of muscle activation by voluntary drive (twitch-interpolated method) was measured during a maximal voluntary contraction.

Results and discussion: Consistent with previous research, our data showed a significant power decrement during repeated-sprint exercise. There was also a progressive muscle deoxygenation, but our data showed that the ability of the subjects to use available O2 throughout the entire repeated-sprint test was well preserved. Our data displayed a significant decrement in the RMS activity during the acceleration phase of each sprint across the repeated-sprint exercise. Moreover, decrement in motor drive was confirmed after exercise by a significant decrease in both percentage of voluntary activation and RMS/M-wave ratio during a maximal voluntary contraction.

Conclusion: In this experimental design, our findings suggest that the ability to repeat short-duration (6 s) sprints was associated with the occurrence of both peripheral and central fatigue.

MeSH terms

  • Adult
  • Anaerobic Threshold / physiology*
  • Bicycling / physiology*
  • Electromyography
  • Exercise / physiology*
  • Humans
  • Male
  • Muscle Contraction / physiology*
  • Muscle Fatigue / physiology
  • Muscle, Skeletal / innervation*
  • Muscle, Skeletal / physiology
  • Oxygen Consumption / physiology
  • Prospective Studies
  • Spectroscopy, Near-Infrared