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

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.

[1]  D. Delpy,et al.  System for long-term measurement of cerebral blood and tissue oxygenation on newborn infants by near infra-red transillumination , 1988, Medical and Biological Engineering and Computing.

[2]  T D Noakes,et al.  Physiological models to understand exercise fatigue and the adaptations that predict or enhance athletic performance , 2000, Scandinavian journal of medicine & science in sports.

[3]  E. Coyle,et al.  Inertial-load method determines maximal cycling power in a single exercise bout. , 1997, Medicine and science in sports and exercise.

[4]  D. Paterson,et al.  Adaptation of pulmonary O2 uptake kinetics and muscle deoxygenation at the onset of heavy-intensity exercise in young and older adults. , 2005, Journal of applied physiology.

[5]  J. Duchateau,et al.  Muscle fatigue during concentric and eccentric contractions , 2000, Muscle & nerve.

[6]  S C Gandevia,et al.  Twitch interpolation of the elbow flexor muscles at high forces , 1998, Muscle & nerve.

[7]  Alain Belli,et al.  Muscle function during brief maximal exercise: accurate measurements on a friction-loaded cycle ergometer , 2004, European Journal of Applied Physiology and Occupational Physiology.

[8]  Eiji Okada,et al.  Influence of adipose tissue on muscle oxygenation measurement with an NIRS instrument , 1998, European Conference on Biomedical Optics.

[9]  R. Richardson,et al.  Skeletal muscle intracellular PO(2) assessed by myoglobin desaturation: response to graded exercise. , 2001, Journal of applied physiology.

[10]  Sébastien Racinais,et al.  Time of day influences the environmental effects on muscle force and contractility. , 2005, Medicine and science in sports and exercise.

[11]  J. Leigh,et al.  Myoglobin O2 desaturation during exercise. Evidence of limited O2 transport. , 1995, The Journal of clinical investigation.

[12]  D. Delpy,et al.  Quantification in tissue near–infrared spectroscopy , 1997 .

[13]  B. Saltin,et al.  Muscle oxygen kinetics at onset of intense dynamic exercise in humans. , 2000, American journal of physiology. Regulatory, integrative and comparative physiology.

[14]  M. Polkey,et al.  Effects of exhaustive incremental treadmill exercise on diaphragm and quadriceps motor potentials evoked by transcranial magnetic stimulation. , 2004, Journal of applied physiology.

[15]  B. Sjödin,et al.  Reduced oxygen availability during high intensity intermittent exercise impairs performance. , 1994, Acta physiologica Scandinavica.

[16]  Fabien A. Basset,et al.  Muscle coordination changes during intermittent cycling sprints , 2005, Neuroscience Letters.

[17]  S. Gandevia.  Spinal and supraspinal factors in human muscle fatigue. , 2001, Physiological reviews.

[18]  C. Willíams,et al.  Human muscle metabolism during intermittent maximal exercise. , 1993, Journal of applied physiology.

[19]  B. Wittenberg,et al.  Role of myoglobin in the oxygen supply to red skeletal muscle. , 1975, The Journal of biological chemistry.

[20]  A. Belli,et al.  Influence of fatigue on EMG/force ratio and cocontraction in cycling. , 2000, Medicine and science in sports and exercise.

[21]  G. Millet,et al.  Alterations of neuromuscular function after an ultramarathon. , 2002, Journal of applied physiology.

[22]  S C Gandevia,et al.  Reliability of measurements of muscle strength and voluntary activation using twitch interpolation , 1995, Muscle & nerve.

[23]  D. Downham,et al.  Superimposed single impulse and pulse train electrical stimulation: A quantitative assessment during submaximal isometric knee extension in young, healthy men , 1999, Muscle & nerve.

[24]  R. Richardson,et al.  Skeletal muscle phosphocreatine recovery in exercise-trained humans is dependent on O2 availability. , 1999, Journal of applied physiology.

[25]  H. Green,et al.  Mechanisms of muscle fatigue in intense exercise. , 1997, Journal of sports sciences.

[26]  D. Bishop,et al.  Muscle buffer capacity and aerobic fitness are associated with repeated-sprint ability in women , 2004, European Journal of Applied Physiology.

[27]  T D Noakes,et al.  1996 J.B. Wolffe Memorial Lecture. Challenging beliefs: ex Africa semper aliquid novi. , 1997, Medicine and science in sports and exercise.

[28]  Y. Ballay,et al.  Mechanisms contributing to knee extensor strength loss after prolonged running exercise. , 2003, Journal of applied physiology.