Estimate of the 3,5 MMOL.L-¹ lactate threshold by maximal and submaximal variables during treadmill incremental test

Resumen

In predictive models, there is a lack of studies that have associated maximal and submaximal variables to attain lactate threshold (LT). Therefore, the purpose of this paper was to investigate the possibility for predicting 3.5 mmol.l-1 LT velocity (V3.5) using maximal and submaximal variables. The heart rate (HR) corresponding to 12 km.h-1 velocity (HR12), the peak heart rate (HRPEAK), the velocity corresponding to HR of 170 bpm (V170) and the peak velocity (VPEAK) were the independent variables used. Forty-six runners underwent to progressive test with initial velocity between 6 and 10.8 km.h-1, and increments of 1.2 km.h-1 every three minutes. The subjects were randomly assigned to validation group (n= 30) or cross-validation group (n= 16). Multiple regression analysis (Enter selection) resulted in the following predictive equation (p< 0.05): V3.5 (km.h-1)= -3.650 + (1.042 x VPEAK), with SEE= 1.2 km.h-1 (7.7%) and R²= 0.74. There were no significant differences between measured and predicted V3.5 values in validation group (r= 0.86) or in cross-validation group (r= 0.79). Entering the variables HR12, HRPEAK or V170 did not increase model accuracy. From these results, it is suggested that the use of VPEAK accurately predict 3.5 mmol.l-1 LT velocity.