Effect of active warm-up on metabolism prior to and during intense dynamic exercise

Purpose: This study investigated whether active warm-up (AW) would increase muscle acetylcarnitine concentration before exercise, thereby reducing the reliance on nonoxidative ATP production during subsequent high-intensity exercise. Methods: Six female subjects performed a 30-s sprint at 120% of their maximal power output on an electronically braked cycle ergometer 5 min after undertaking an active warm-up. To exclude any effect of muscle temperature (T-m) on metabolism, AW was compared with control (C), which involved passively heating the muscle to the same temperature as that achieved by active warm-up (37.1 +/- 0.3 vs 37.2 +/- 0.2degreesC AW and C, respectively). Results: Active warm-up significantly increased the concentration of acetylcarnitine from 4.5 +/- 1.5 mmol.kg dry muscle (dm)(-1) at rest to 9.4 +/- 1.6 mmol.kg dm(-1) before the onset of exercise. There was no change in acety1carnitine concentration in C. During exercise the accumulation of muscle lactate was significantly less in AW compared with C (21.9 +/- 3.8 vs 34.3 +/- 2.3 mmol.kg dm(-1), respectively). Conclusion: The main finding of this study was that there was less accumulation of blood and muscle lactate during intense dynamic exercise preceded by active warm-up, which could not be accounted for by a difference in T-m between trials immediately before the onset of exercise.