The lactate and ventilatory thresholds in resistance training.

PURPOSE

This study was designed to identify the lactate threshold (LT) and first ventilatory threshold (VT ) in a graded resistance half-squat test and determine whether both thresholds are produced at the same workload. A further goal was to compare the visual inspection and algorithm adjustment methods of detecting both thresholds during graded resistance exercise.

METHODS

Twenty-four young men completed two test sessions 48 h apart; (i) the one-repetition maximum (1RM) was determined, (ii) an incremental load test was performed to locate LT and VT . VT was calculated in three different ways based on pulmonary ventilation, the ventilatory equivalent of oxygen or the end-tidal oxygen pressure (as VT -VE, VT -VE·VO2-1 or VT -PetO respectively).

RESULTS

LT and VT were located at the same intensity of exercise during the incremental load test. Using the algorithm method, the LT and VT -VE were estimated at 24·8 ± 4·8% 1RM (50·6 ± 10·5 kg) and 23·7 ± 4·8% 1RM (48·4 ± 10·0 kg), respectively; the difference between the two values being non-significant (P = 0·127). In addition, positive correlation was observed between the two thresholds (r = 0·761; P<0·001; intraclass correlation coefficient (ICC) (0·864). The visual inspection and algorithm adjustment methods provided similar LT and VT values (r > 0·796; ICC > 0·885).

CONCLUSIONS

The LT and VT were readily located during the incremental load half-squat test at similar workloads using both the visual inspection and algorithm adjustment methods. Both thresholds served to define two physiological stages (I, II) corresponding to the zones described for endurance exercise. Thus, both LT and VT could be used to prescribe the same intensity of resistance half-squat exercise.