COMPARISON OF A SIMULATED 16.1-KM TIME TRIAL, VO(2)MAX AND RELATED FACTORS IN CYCLISTS WITH DIFFERENT VENTILATORY THRESHOLDS

Differences in cycling performance have been observed in cyclists with similar VO(2)max values yet different lactate thresholds. The purpose of the current study was to compare a simulated 16.1-km cycling time trial, VO(2)max and related factors in cyclists who significantly vari ed in ventilatory threshold. From an original group of 18 category III or IV cyclists, two groups of 6 cyclists were formed based on ventila tory threshold values as high (77 +/- 4 % of VO(2)max - Group H) or lo w (68 +/- 2.8 % - Group L). VO(2)max and a 16.1-km time trial were com pleted on a Velodyne trainer. No significant difference (p greater tha n or equal to 0.05) was noted between groups in VO(2)max (Group H 4.00 +/- 0.28 l. min(-1), Group L 4.15 +/- 0.67 l.min(-1)), however signif icant differences (p less than or equal to 0.05) were found in ventila tory threshold and time trial scores. Group H completed the time trial in 16.29 +/- 2.08 min while Group L averaged 20.93 +/- 3.03 min. Grou p H completed the time trial 28% more quickly by working at a signific antly higher percentage of VO(2)max, a higher power output and a faste r pedal rate than Group L. From a battery of physiologic and body comp osition parameters, the ventilatory threshold expressed as VO2 (l.min( -1)) was the best predictor (r = -0.76) of time trial performance in t he 12 cyclists. The findings of this study indicate that the ventilato ry threshold was superior to VO(2)max in discerning performance differ ences in a 16.1-km cycling time trial, and was the best predictor of t he simulated time trial performance.