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 (Tm) 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 +/- 0.2 degrees C AW and C, respectively).

Results: Active warm-up significantly increased the concentration of acetylcarnitine from 4.5 +/- 1.5 mmol x kg(-1) dry muscle (dm)(-1) at rest to 9.4 +/- 1.6 mmol x kg dm(-1) before the onset of exercise. There was no change in acetylcarnitine 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, 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 between trials immediately before the onset of exercise(m)