Effects of specific warm-up at various intensities on energy metabolism during subsequent exercise

BACKGROUND: To investigate the effects of specific warm-up at various intensities on energy metabolism during subsequent intense exercise. METHODS: Experimental design: specific warm-up was consisted of 3 sets of wrist flexions for 5 min, with each set followed by a 3-min rest. The intensity of specific warm-up was set at 20%, 30% or 40% of maximal voluntary contraction (MVC). The subjects then performed a set of wrist flexions at 60% MVC for 4 min as the criterion exercise. For the control experiment, criterion exercise was done without specific warm-up. Participants: Five healthy volunteers. Measurements: using phosphorus-31 magnetic resonance spectroscopy, spectra were obtained from the wrist flexor muscles to determine the ratio of inorganic phosphate to phosphocreatine (Pi/PCr) and intracellular pH. RESULTS: The Pi/PCr during the criterion exercise after specific warm-up at any intensity was not significantly different from that without specific warm-up. The intracellular pH during the criterion exercise after specific warm-up at 30% or 40% MVC was significantly higher than that without specific warm-up. CONCLUSIONS: These results indicate that mild warm-up exercise could inhibit the development of intracellular acidosis during subsequent intense exercise.