The 30-15 Intermittent Fitness Test: A Reliable, Valid, and Useful Tool to Assess Aerobic Capacity in Female Basketball Players

Purpose: The purpose of this study was to determine the reliability, validity, and usefulness of 30?15 Intermittent Fitness Test (30-15(IFT)) in female basketball players. Methods: Nineteen female basketball players (17.82 ? 1.94 yr, 175.4 ? 7.3 cm, 67.9 ? 7.7 kg) competing in the National Croatian League performed one trial of a continuous treadmill running test and two trials of the 30-15(IFT). The 30-15(IFT) involves 30-s runs across a 40-m course interspersed with 15 s of walking, with running speed increasing every 45 s. The continuous treadmill running test was used as the criterion for validation. Results: High to very high reliability across test?retest trials were observed for maximal oxygen uptake (VO(2)max) (CV = 4.9%, ICC = 0.85), the 30-15(IFT) end-running velocity (V-IFT) (CV = 6.0%, ICC = 0.85), and maximal heart rate (HRmax) (CV = 4.8%, ICC = 0.96). Criterion validity was supported for the 30-15(IFT) with strong to very strong relationships with VO(2)max (r =0.69), V-IFT (r =0.74), and HRmax (r =0.73) attained during the continuous treadmill running test. The typical error (TE) of the 30-15(IFT) was greater than the smallest worthwhile change for VO(2)max (1.16 > 0.42 ml/kg/min), V-IFT (0.56 > 0.20 km/h), and HRmax (2.15 > 1.89 bpm) adjudging usefulness of the test as marginal. The TE of 0.56 km/h (90% CI = 0.44?0.77 km/h) demonstrates changes in the performance of one to two stages (0.5?1.0 km/h) are meaningful. Conclusions: The 30-15(IFT) possesses acceptable reliability and validity to assess maximal aerobic fitness capacity in female basketball players. While the usefulness of the 30-15(IFT) was marginal, meaningful changes in performance consisted of only one to two stages. The present findings support the 30-15(IFT) as a practical testing option for basketball practitioners to assess fitness capacities in female players.