Intensity Thresholds and Maximal Lactate Steady State in Small Muscle Group Exercise.

The aim of our study is to determine the first (LTP1 ) and the second (LTP2 ) lactate turn points during an incremental bicep curl test and to verify these turn points by ventilatory turn points (VT1 and VT2 ) and constant-load exercise tests. Twelve subjects performed a one-arm incremental bicep curl exercise (IET) after a one repetition maximum (1RM) test to calculate the step rate for the incremental exercise (1RM/45). Workload was increased every min at a rate of 30 reps/min until maximum. To verify LTPs, VT1 and VT2 were determined from spirometric data, and 30 min constant-load tests (CL) were performed at 5% Pmax below and above turn points. Peak load in IET was 5.3 ± 0.9 kg (Lamax : 2.20 ± 0.40 mmol·L-1 ; HRmax : 135 ± 15 b·min-1 ; VO2max : 1.15 ± 0.30 L·min-1 ). LTP1 was detected at 1.9 ± 0.6 kg (La: 0.86 ± 0.36 mmol·L-1 ; HR 90 ± 13 b·min-1 ; VO2 : 0.50 ± 0.05 L·min-1 ) and LTP2 at 3.8 ± 0.7 kg (La: 1.38 ± 0.37 mmol·L-1 ; 106 ± 10 b·min-1 ; VO2 : 0.62 ± 0.11 L·min-1 ). Constant-load tests showed a lactate steady-state in all tests except above LTP2 , with early termination after 16.5 ± 9.1 min. LTP1 and LTP2 could be determined in IET, which were not significantly different from VT1 /VT2 . Constant-load exercise validated the three-phase concept, and a steady-state was found at resting values below VT1 and in all other tests except above LTP2 . It is suggested that the three-phase model is also applicable to small muscle group exercise.