REPRODUCIBILITY AND VALIDITY OF PHYSIOLOGICAL-PARAMETERS MEASURED IN CYCLISTS RIDING ON RACING BIKES PLACED ON A STATIONARY MAGNETIC BRAKE

The purpose of this study was: 1) To evaluate the reproducibility of p hysiological parameters measured during cycle exercise, and 2) To vali date the predictive capacity of physiological parameters related to en durance performance. Therefore, physiological variables were measured twice during cycling exercise in a group of seven cyclists. Each cycle exercise session was separated by one week and included progressive s ubmaximal cycling followed by a 5-km time trial. Two and three weeks l ater, endurance performance was evaluated by calculating average work output during a 50-km time trial (W-50km) To simulate cycle performanc e, the cyclists' private racing bikes were placed on a stationary magn etic brake. No differences were observed between paired physiological observations in the test-retest (P > 0.05). The coefficient of variati on (CV) was calculated from the differences between test-retest parame ters. CV for the maximal oxygen uptake (VO2max), average work output d uring the 5-km trial (W-5km), the calculated work intensity which incr eased the blood lactate concentration to 2 and 4 mmol/l (W-2mM and W-4 mM) and W-50km were 1.9, 2.7, 6.1, 5.9 and 6.3 %, respectively, while the 95 % confidence interval (CI) showing the expected range for varia tion in a retest was calculated to be 80 ml.min(-1), 9, 16, 18 and 18 W, respectively. Simple linear regression showed significant correlati ons between VO2max, W-5km, W-2mM, W-4mM and W-50km (r-values: range 0. 83 - 0.98, P < 0.01). In conclusion: 1) Physiological parameters can b e reproduced during an exercise test procedure in cyclists riding on r acing bikes placed on a stationary magnetic brake, and 2) The validity of VO2max, W-5km, W-2mM, and W-4mM as predictive parameters of endura nce was demonstrated.