Predicting Maximal Lactate Steady State from Carminatti's Shuttle Run Test in Soccer Players

The objective of the present study was to determine the validity of Carminatti's shuttle run incremental test-T-Car derived parameters in estimating the maximal lactate steady state determined in shuttle run format. Eighteen soccer players performed a T-Car test, and several trials to determine the maximal lactate steady state. From T-Car were derived the heart rate deflection point, peak speed, maximal heart rate and parameters resulting from percentage of peak measures. The validity was accessed by Bland-Altman plots, linear regressions, and two one-sided tests of equivalence analysis. The results showed the speed at 80.4 % of T-Car peak speed, the heart rate deflection point and the 91.4 % of maximal heart rate were equivalent to maximal lactate steady state (Mean difference; +/- 90 % compatibility interval; - 0.8; +/- 1.5 %, - 0.4; +/- 1.1 %, and 0.0; +/- 2.7 %, respectively). Additionally, peak speed during the T-Car test was a stronger predictor of maximal lactate steady state (MLSS [km/h] = 2.57 + 0.65 x sPeak; r = 0.82 [90 % CI; 0.62-0.92], standard error of the estimate = 3.6 %; 90 % CI x / divided by 1.4). Therefore, soccer players can use the T-Car derived parameters as a noninvasive and practical alternative to estimate the specific maximal lactate steady state for soccer.