THE RELATIONSHIP BETWEEN PLASMA LACTATE PARAMETERS, W-PEAK AND 1-H CYCLING PERFORMANCE IN WOMEN

Purpose: The relationship between six descriptors of lactate increase, peak (V) over dot O-2,W-peak, and 1-h cycling performance were compar ed in 24 trained, female cyclists (peak (V) over dot O-2 = 48.11 +/- 6 .32 mL . kg(-1) . min(-1)). Methods: The six descriptors of lactate in crease were: 1) lactate threshold (LT; the power output at which plasm a lactate concentration begins to increase above the resting level dur ing an incremental exercise test), 2) LT1 (the power output at which p lasma lactate increases by 1 mM or more), 3) LTD (the lactate threshol d calculated by the D-max method), 4) LTMOD (the lactate threshold cal culated by a modified D-max method), 5) L4 (the power output at which plasma lactate reaches a concentration of 4 mmol-L-1), and 6) LTLOG (t he power output at which plasma lactate concentration begins to increa se when the log([La-]) is plotted against the log (power output)). Sub jects first completed a peak (V) over dot O-2 test on a cycle ergomete r. Finger-tip capillary blood was sampled within 30 s of the end of ea ch 3-min stage for analysis of plasma lactate. Endurance performance w as assessed 7 d later using a 1-h cycle test (OHT) in which subjects w ere directed to achieve the highest possible average power output. Res ults: 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), LT1 (17 9.17 +/- 27.25), LTLOG (143.97 +/- 45.74), L4 (198.09 +/- 33.84), LTD (178.79 +/- 24.07), LTMOD (212.28 +/- 31.75). Average power output dur ing the OHT was more strongly correlated with all plasma lactate param eters (0.61 < r < 0.84) and W-peak (r = 0.81) than with peak (V) over dot O-2 (r = 0.55). The six lactate parameters were strongly correlate d with each other (0.54 < r < 0.91) and of the six lactate parameters, LTD correlated best with endurance performance (r = 0.84). Conclusion s: It was concluded that plasma lactate parameters and W-peak provide better indices of endurance performance than peak (V) over dot O-2 and that, of the six descriptors of lactate increase measured in this stu dy, LTD is most strongly related to 1-h cycling performance in trained , female cyclists.