Reliability of a Field and Laboratory Test of Repeated Sprint Ability

The purpose of this study was to assess the reliability of a fi eld and a laboratory test of repeated sprint ability (RSA). Twelve adolescent boys (15.3 ± 0.3 years) completed fi ve trials of both a fi eld RSA test (7 × 30 m sprints) and a laboratory RSA test (7 × 5 s sprints) performed on a nonmotorized treadmill. Mean coeffi cients of variation (CV) calculated across all trials were < 2.7% for fi eld sprint times, and, in the laboratory, < 2.9% for velocity and < 8.4% for power output. Fatigue indices (FI) calculated from data in both environments exhibited mean CVs > 23%. The inconsistency in the FIs resulted from the mathematical procedures used in the FI calculation methods. Based on the reliability scores, it was concluded that results obtained from measured performance variables in the fi eld and laboratory, and not calculated FIs, should be used to report RSA.