Purpose: The relationship between six descriptors of lactate increase, peak VO2, Wpeak, and 1-h cycling performance were compared in 24 trained, female cyclists (peak VO(2) = 48.11 +/- 6.32 mLxkg(-1)xmin(-1).
Methods: The six descriptors of lactate increase were: 1) lactate threshold (LT; the power output at which plasma lactate concentration begins to increase above the resting level during an incremental exercise test), 2) LT(1) the power output at which plasma lactate increases by 1 mM or more), 3) LT(D) (the lactate threshold calculated by the D-max method), 4) LT(MOD) (the lactate threshold calculated by a modified D-max method), 5) L4 (the power output at which plasma lactate reaches a concentration of 4 mmolxL(-1), and 6) LT(LOG) (the power output at which plasma lactate concentration begins to increase when the log ([La(-1]) is plotted against the log (power output). Subjects first completed a peak VO(2) test on a cycle ergometer. Finger-tip capillary blood was sampled within 30 s of the end of each 3-min stage for analysis of plasma lactate. Endurance performance was assessed 7 d later using a 1-h cycle test (OHT) in which subjects were directed to achieve the highest possible average power output.
Results: The mean power output (W) for the OHT (+/- SD) was 183.01 +/- 18.88, and for each lactate variable was:LT (138.54 +/- 46.61), LT(1) (179.17 +/- 27.25), LT(log) (143.97 +/- 45.74), L4 (198.09 +/- 33.84), LT(D) (178.79 +/- 24.07), LT(MOD)(212.28 +/- 31.75). Average power output during the OHT was more strongly correlated with all plasma lactate parameters (0.61<r<0.84) and W(peak) (r = 0.81) than with peak VO(2) (r = 0.55). The six lactate parameters were strongly correlated with each other (0.54<r<0.91) and of six lactate parameters, LT(D) correlated best with endurance performance (r = 0.84).
Conclusions: It was concluded that plasma lactate parameters and W(peak) provide better indices of endurance performance than peak VO(2) and that, of the six descriptors of lactate increase measured in this study, LT(D) is most strongly related to 1-h cycling performance in trained, female cyclists.