The need to establish a reliable test to detect changes in performance is essential. The knowledge of the reliability of a test is essential so that it is interpretable and to reduce unreliable measurement procedures, which will lead to results that cannot be replicated. Also, if a test is unreliable it will attenuate the relationship between variables thus making the discovery of existing relations more difficult. Protocols which measure a set amount of distance or work to perform in the shortest possible time have been found most reliable and have therefore been used for monitoring the enhancement of sporting performance. However, these performance tests have not been previously reported in young cyclists. Therefore, the purpose of the study was to measure the reliability of a performance test in well-trained adolescent cyclists. Method Eight male and one female cyclist (mean age 15.7 ±0.7 y) participated in the study. Prior to the performance tests lactate threshold (LT) and peak VO2 were assessed on the same day using an SRM cycle ergometer. The performance test was repeated on three separate days and consisted of 30 minutes of steady state (SS) cycling at 80 % of individual LT with the work rate independent from the pedalling rate. Immediately after the SS cycling a time trial (TT) started with the cyclists having to complete a fixed amount of work as fast as possible. The performance measure was the time to complete the target amount of work, which was calculated adapted from the formula of Jeukendrup et al, (1996): target work (J) = 25% Delta . 1800, where 1800 is the time in s 25% Delta = WLT + 25(Wmax predicted . WLT) (WLT = power output (W) at LT; Wmax predicted = predicted maximal power output, from linear regression analysis, with VO2 as the dependent variable and power output as the predictor). The only feedback the cyclists received during the TT was the work performed and the work to finish, which the cyclists could see from a computer screen. Reliability was assessed using a variety of methods including the coefficient of variation (CV) as the [(SD/ mean)*100] for each participant, intraclass correlation coefficients and typical error (SD of the difference in mean /.2) expressed as a CV (%). Results The mean (SD) body mass and stature of the group were 66.2 ±5.4 kg and 175.9 ±7.6 cm respectively. The mean peak VO2, % peak VO2 @ LT and blood lactate @ LT were 58.1 ±2.5 mL.kg-1.min-1, 69 ±6 % and 2.1 ±0.2 mmol.L-1 respectively. The group mean times for the TT were TT1 1889 ±306, TT2 1857 ±283 and TT3 1953 ±279 s respectively. Individual CV varied from 0.25 to 10 %. The intraclass correlation coefficients for TT1/2 and 2/3 were r = 0.78 and 0.93 (p<0.05). The typical errors, expressed as a CV % on the log transformed performance times, were 7.3 and 3.7 % for TT1/2 and TT2/3 respectively. Discussion/Conclusion To the best of our knowledge reliability studies in performance tests of adolescent cyclists have not been published. The main findings of this study demonstrate that the reliability for performance time is higher in trials 2 and 3 in comparison to trial 1. The largest individual CVs were observed between the first and the second trial. The change in performance times across trials is likely to represent a practice effect because of the novelty of the task. The differences in CV and SD between the three TTs indicate that trial two and three were more reliable than TT 1, suggesting a habituation trial is needed. To enhance the validity of the experimental design we suggest that in adolescent cyclists familiarisation of at least one practice trial should be undertaken when undertaking novel performance protocols. It is concluded that the present performance test used to assess cycling performance is reliable in young cyclists with lower variation between trials 2 and 3. These data will be useful to other investigators interested in monitoring change of performance or the effects on performance in interventionist trials.
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