COMPARISON BETWEEN INDIVIDUAL ANAEROBIC THRESHOLD AND VENTILATORY THRESHOLD DETERMINED IN CYCLISTS

Abstract

PURPOSE The purpose of the present study was to investigate the relationships between physiological variables related to Individual Anaerobic Threshold (IAT) and Ventilatory Threshold (VT) in cyclists. METHODS 8 cyclists (national level) performed two incremental tests on cycle ergometer (initial load of 50 W and 50 W increments at each 3 min stage until exhaustion) to determine the IAT and VT. Ventilatory parameters were monitored on a breath-by-breath basis, and blood lactate was measured at the end of each stage and during post exercise recovery period. The lactate kinetics during the test and post-exercise recovery was used for IAT identification. VT was determined in duplicate and detected visually by a secondary rise in pulmonary minute ventilation and ventilatory equivalent for oxygen, and a marked rise in ventilatory equivalent for carbon dioxide (VE/VCO2). The power output (W), VO2 (ml·kg−1·min−1) and heart rate (bpm) related to IAT and VT were identified. RESULTS No differences were observed (P > 0.05) and a high correlation was verified between the VO2 (48.1 ± 3.7 vs 48.0 ± 3.8 ml·kg·min−1; r = 0.90; p < 0.01), power output (246.9 ± 33.9 vs 256.3 ± 32.0 W; r = 0.84; p < 0.01) and heart rate (171.3 ± 12.0 vs 173.8 ± 9.2 bpm; r = 0.97; p < 0.01) corresponding to IAT and VT respectively. CONCLUSION The VT identification by considering a marked rise on the VE/VCO2 reflects the same phenomenon as IAT. However, other studies must be done in order to verify if the maximal lactate steady state can be observed at exercise intensities (W) related to VT identified by this method. This would bring important implications for training prescription. Supported by CAPES/CNPq