Methods of exercise intensity and lactataemia determination of lactate minimum test in rats

Abstract

The lactate minimum test (LMT) is a useful protocol for determining the intensity corresponding to the maximal lactate steady state. Nevertheless, different methods to determine LMT variables are found in the literature. The aim of this study was to analyse three different methods for determining the effort intensity (LMTi) and lactataemia (LMTLAC) corresponding to LMT. We subjected seventeen rats to LMT in a swimming ergometer, following three steps: (1) acidosis induction phase; (2) recovery of nine minutes; and (3) incremental swimming intensity phase. We determined the LMTi and LMTLAC using three methods: visual inspection (VI - non-mathematic), second order polynomial function (fPOLY - mathematic) and spline function (fSPL - mathematic). Results showed no significant differences between the LMTi or LMTLAC values determined using VI (5.32+0.50% bw and 5.62+0.78 mM, respectively), fPOLY (5.31+0.53% bw and 5.64+0.72 mM, respectively) and fSPL (5.32+0.54% bw and 5.59+0.76 mM, respectively). We found significant correlations between the three methods (P<0.05). We concluded that the determination of the intensity and lactataemia corresponding to LMT are not influenced by mathematic or non-mathematic methods in swimming sedentary rats.