Reliability of Performance Outputs and Formulas Related with Fatigue Index in 10 x 20 m Repeated Sprint Test

Abstract

Objective: Repeated sprint test (RST) is commonly used in sports disciplines which include repeated sprints, such as team and racquet sports to evaluate the performance. The purpose of this study was to determine the test-retest reliability coefficients of performance outputs and fatigue index that was calculated from seven different equations in 10x20 m RST protocol with 30 s passive rest between sprints. Materials and Methods: 15 male sport school students (Age:22.9±2.7 years; Height:178.0 ± 7.9 cm; Weight: 77.9 ± 11.5 kg) voluntarily participated in this study. 10x20 m RST protocol was applied twice with 48 hours intervals after a standard warmup. Total sprint time (TST), fastest sprint time (FST), slowest sprint time (SST) and fatigue index that were calculated by seven different equations were determined after both RST. The dependent sample t-test was used to determine the differences between repeated measurements. Intraclass-correlation coefficient (ICC), typical error (TE) and typical error as a coefficient of variation (TE_CV) were calculated for test-retest reliability. Results: The mean scores of TST, FST, SST and fatigue index which were calculated by seven equations were not significantly different between repeated measurements (p>0.05). The test-retest ICC for TST, FST, and SST was moderate (0.763, 0.541 and 0.544 respectively). In addition, the test-retest ICC was moderate for fatigue index which were calculated from seven different equations during repeated measurements (0.429-0.767). The TE fatigue scores varied within a wide range of 0.97-3.98%. It was also observed that TE_CV changed in a very wide range for all equations (43.5- 214.6%). Conclusion: The findings of this study showed that the test-retest reliability of performance variables obtained from 10x20 m RST was high except fatigue scores. This protocol can be used to monitor training and observation of trial effects during studies. The low reliability of fatigue scores requires careful evaluation of the results.