Polynomial adjustment as a new technique for determination of lactate minimum velocity with blood sampling reduction

Abstract

The purpose of this study was to analyze the possibility of identifying the lactate minimum velocity (LM) and estimating the maximal lactate steady state intensity (MLSS) by applying a polynomial function to just three stages of the LM test. Seventeen physically active males (24.1 ± 4.0 years; 23.8 ±2.2kg.m2(-1) BMI; 11.7 ± 3.8% body fat) performed: 1) a 1600m time trial (1600mV); 2) a 150m sprint to induce hyperlactatemia, and then an incremental test (InT) consisting of 6 x 800m at intensities of 78, 81, 84, 87, 90 and 93% of 1600mV; 3) 2 to 3 sessions of constant 30 min running tests to identify MLSS. Blood lactate [lac] was determined by an electrochemical method (YSI - 2700 SELECT). The LM was identifi ed visually (LMv) as well by applying polynomial function to the [lac] responses at all 6 stages (LMp), to the 1st, 3rd and 5th stages (LMp135), to the 1st, 3rd and 6th stages (LMp136) and to the 1st, 4th and 6th stages (LMp146) of InT. The ANOVA detected no differences between the velocities (m.min-1) identified by LMv (196.0 ± 17.8) LMp (198.0 ± 17.6), LMp135 (197.7 ± 17.6), LMp136 (200.0 ± 17.2), LMp146 (199,7 ± 18,1) and MLSS (198.7 ±16.6) (p>0.05), with a high correlation among each other (p<0.01). The polynomial function identifi ed LM even when applied to just 3 stages of the incremental test, enabling for prediction of MLSS intensity with a reduced number of blood samples being collected during testing.