Effect of Warm-up on Blood Lactate Kinetics and Supra-maximal Cycling Performance

Abstract

The involvement of a raised blood lactate induced by warm-up prior to performance is unclear and the effects of warm-up on blood lactate kinetics have not been examined. PURPOSE: To examine the effect of different intensity warm-up on blood lactate kinetics and supra-maximal cycling performance. METHODS: 11 trained male cyclists cycled to exhaustion for 1 min at a load of 0.075 x body mass (kg) preceded by one of three warm-up protocols in random order: (WE) Easy −6 min at 40% peak aerobic power (PAP); (WM) Moderate −5 min at 40% PAP + 1 min at 80% PAP; (WH) Hard −5 min at 40% PAP + 1 min at 110% PAP - each followed by 10 min seated recovery. Blood lactate kinetics of the warm-up and performance test were analysed using a biexponential model which predicted extravascal lactate generation (A), lactate invasion (k1) and evasion (k2) to/from the blood and required the blood lactate concentration (BLC) immediately prior to exercise (BLCpre). RESULTS: There was a difference between BLCpre in each protocol (WE 1.16±0.32; WM 1.98±0.27;WH 4.19±0.88 mmol·l-1, p<0.001). WH reduced the net amount of lactate released (δBLC), calculated by deducting BLCpre from the peak BLC achieved following completion of the performance test (WE 11.56±1.55; WM 10.44±1.85; WH 9.20±1.21 mmol·l-1; p<0.02). However there was no effect upon anaerobic lactate contribution to energy as A was unaffected by the warm-ups (WE 14.91±1.88; WM 14.45±2.48; WH 13.88±1.86 mmol·l-1, p>0.05). The apparent blunted blood lactate response was due to a slower k1 in WH (WE 0.47±0.12; WM 0.42±0.06; WH 0.36±0.06min-1, p<0.01) and thus a delayed time to reach a peak (WE 5.69±0.70; WM 6.04±0.74; WH 7.19±0.90 min, p<0.01). Despite a reduced ability to remove lactate and protons from the muscle compartment mean power was not affected by the warm-up protocols (WE 516±28; WM 521±26; WH 526±34 W, p>0.05). CONCLUSIONS: The intensity of active warm-ups did not affect supra-maximal cycling performance. The apparent blunted blood lactate response was not due to a reduced reliance upon anaerobic lactate metabolism but to a slower invasion of lactate into the blood. Care must be taken when implying that a blunted δBLC indicates a reduced reliance on anaerobic metabolism as BLC kinetics may indicate otherwise.