Estimation of the lactate threshold using bioelectrical impedance spectroscopy: a new noninvasive method.

Bioelectrical Impedance Spectroscopy (BIS) is a noninvasive technology with potential application to study exercise physiology as body composition and estimation of maximal oxygen uptake. The aim of the study was to compare the power at lactate threshold (WLT) obtained using blood lactate concentration (BLC) with the power at lactate threshold from BIS (WBT). Fifty physical education students, 35 men and 15 women (age: 24.1 +/- 5.5 years; height: 168.6 +/- 24.6 cm; weight: 70.1 +/- 9.8 kg), undergoing incremental cycle ergometer test (ICET) have participated of the study. Significant correlations (p<0.05) for Pearson coefficient were found between the two methods (r = 0.96) and standard error of estimate (SEE)=5.6 W. The mean value showed 66.7+/- 20.3 W and 66.7+/- 21.1 W between the invasive technique (WLT) and noninvasive technique (WBT), respectively. The results of this study suggest that BIS, when applied with the ICET, is a valid method to estimate the power at LT.