Relationship between maximal exercise parameters and individual time trial performance in elite cyclists with physical disabilities
It is widely accepted that the ventilatory threshold (VT) is an important determinant of endurance performance. This study investigated whether the physiological responses during a 20km time trial (TT) in cyclists with physical disabilities (medium to high functional ability) relate to their VT and also to determine which variable(s) best predict their performances. Nine elite cyclists (19±2yrs; 170±10cm; 62±8kg; 53±8 ml.min-1.kg-1) participated in the study. Subjects performed a ramped exercise protocol (20W·min-1) to exhaustion and a self-paced, 20km TT on the Velotron cycle ergometer. Mean values for heart rate (HR) (181±8bpm) and %HR max (92±3.13%) for the 20km TT were not significantly different when compared to values at VT (HR: 180±8bpm, %HR max: 93±1.17). However, the mean power output (PO) during the TT (199±42W) was significantly lower (p<0.05) than the PO at the VT (250±65W). Peak power output (PPO) predicted 83% of the variance when performance was measured as 20km average watts and was the only significant variable, amongst all VT and maximal variables, included in the stepwise multiple regression model. These results suggest that the self-selected exercise intensity of cyclists with physical disabilities during a 20km TT and their VT is similar when exercise intensity is expressed as average HR and %HR max. Secondly, it has been shown for the first time that, similar to able-bodied cyclists, PPO at VT correlates best with TT performance in cyclists with disabilities.
Key words: Cycling; Ventilatory threshold; Time trial; Disabilities; Peak power output; Performance.