Which laboratory variable is related with time trial performance time in the Tour de France?

OBJECTIVE To investigate the relationship between several physiological variables that can be easily obtained during cycle ergometer gradual testing (for example, peak power output (W(peak)), Vo(2max), or ventilatory threshold (VT)) and actual (>50 km) time trials (TT) time performance during the Tour de France. METHODS We collected data in professional cyclists from the first TT of the 1998 Tour de France (TT1, 58 km distance; n = 6 cyclists) and the first (TT2, 56.5 km; n = 5) and second TT of the 1999 Tour de France (TT3, 57 km; n = 5). RESULTS A negative relationship was found between power output (W) at VT (VT(Watt)) and TT final time (s) in TT1 (r = -0.864; p = 0.026; standard error of estimate (SEE) of 73 s; and 95% confidence limits (95% CL) -0.98; -0.18), TT2 (r = -0.77; p = 0.27; SEE of 139 s; and 95% CL -0.98; 0.35), and TT3 (r = -0.923; p = 0.025; SEE of 94 s; and 95% CL -1.00; -0.22). CONCLUSIONS Actual performance in long TT during the Tour de France (>50 km distance, performed after at least 1-2 weeks of continuous competition), in which some cumulative fatigue inevitably occurs, is related, at least in part, to the power output that elicits the VT. No other routine physiological variable (for example, Vo(2max) or W(peak)) is related to performance in this type of event.