Noninvasive estimation of the maximal lactate steady state in trained cyclists.

Abstract

The purposes of this study were to estimate noninvasively the maximal lactate steady state (MLSS) in trained cyclists on a windload simulator with a velocity based technique and to determine whether the HR at MLSS (HR(MLSS)) elicited a similar blood lactate concentration (BLC) during field testing. To determine and verify MLSS, 10 male cyclists performed five to seven laboratory trials on separate days, including a VO2max test; a 5-km time trial (TT); and two or more 30-min trials at specific percentages of each subject's average 5-km TT speed (AVS5km). Mean+/-SD for the following variables were obtained at MLSS: velocity was 90.3+/-2.7% of the AVS5km, BLC was 5.4+/-1.6 mM, RPE was 15+/-2.1, VO2 was 80+/-6.3% of VO2max, and HR was 167+/-9.5 beats x min(-1), which was 88+/-3.8% of the mean maximum HR. Field tests included three laps of an 8-km road circuit at HR(MLSS) +/-3 beats x min(-1) and one lap at maximum sustainable velocity (a road TT). There were no significant differences in BLC, HR, and RPE between the three steady-state road laps and the lab MLSS trial. There was also good agreement between the road and lab MLSS velocity/TT velocity ratios. Our data suggest that 5-km TT cycling velocity, as measured on a windload simulator, may be used to estimate MLSS and the HR at MLSS for training purposes.