Metabolic recovery in professional road cyclists: a 31P-MRS study.
OBJECTIVE
Aerobic training of professional road cyclists is linked to tremendous aerobic capacities that have never been clearly related to what occur in skeletal muscles submitted to a specific exercise. The aim of the present study was to examine specifically metabolic recovery after an incremental cycling exercise performed until exhaustion in professional road cyclists as compared with moderately trained subjects and so using 31P- MRS.


METHODS
Subjects performed a progressive cycling exercise on a cycloergometer until exhaustion, then they were positioned back in the magnet (delay lower than 45 s) for recovery scanning. 31P spectra of thigh muscles were time averaged in 2-s blocks at rest and for 15 min throughout the recovery period.


RESULTS
For a significantly more intense exercise (477 +/- 28 vs 334 +/- 24 W in controls; P < 0.001), professional road cyclists displayed similar end-of-exercise extrapolated pH values (6.43 +/- 0.16 vs. 6.34 +/- 0.05 in controls) and a significantly higher PCr concentration (20.1 +/- 0.8 vs. 13.3 +/- 0.5 mM in controls, P < 0.001). The pH recovery kinetics provided the evidence of metabolic adaptations related to a specific training in professional cyclists with a significantly faster rate (P < 0.01) of pH return toward basal values (32.8 +/- 18.9 vs 10.8 +/- 6.7 mM x min(-1)). On the contrary, no significant difference was measured for the PCr recovery kinetics. At rest, PDE concentration was significantly higher in professional cyclists (2.50 +/- 0.80 vs 1.76 +/- 0.42 mM), likely indicating a difference regarding fiber-type composition.


CONCLUSIONS
The present data demonstrated for the first time that the tremendous aerobic capacity in professional cyclists is linked to faster pH recovery kinetics after a specific cycling exercise.
Hug
François
F
Department of Sport Physiology, Faculty of Sport Sciences, IFR Marey, University of the Mediteranean (Aix-Marseille II), Marseille, France. francois_hug@hotmail.com
Bendahan
David
D
Le Fur
Yann
Y
Cozzone
Patrick J
PJ
Grélot
Laurent
L
D000222:Adaptation, Physiological; D000328:Adult; D001642:Bicycling / Q000502:physiology*; D016022:Case-Control Studies; D004734:Energy Metabolism / Q000502:physiology; D005080:Exercise Test; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D010725:Phosphocreatine / Q000378:metabolism*; D010759:Phosphorus Isotopes; D010807:Physical Endurance / Q000502:physiology; D012123:Pulmonary Ventilation / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology*
D010759:Phosphorus Isotopes; D010725:Phosphocreatine