Reliability and Validity of the 30-15 Intermittent Field Test With and Without a Soccer Ball.

Objective : The purpose of this study was to examine the reliability and validity of the 30-15 Intermittent Field Test (30-15 IFT ) with and without a ball. Methods : Twenty-four collegiate female soccer players (19.46 ± 1.22 years; 167.01 ± 7.23 cm; 60.95 ± 7.84 kg) performed 1 trial of the Yo-Yo Intermittent Recovery (YYIR) test, 3 trials of the 30-15 IFT , and 3 trials of the 30-15 IFT with a ball (30-15 IFT-B ), separated by a minimum 48 hours. Maximal intermittent running velocity (V IFT ), heart rate at exhaustion (HR peak ), and rating of perceived exertion (RPE) were collected. Results : Intraclass correlation coefficients (ICCs) between trials demonstrated good reliability during the 30-15 IFT in V IFT (ICC = 0.88) and HR peak (ICC = 0.89), in addition to the 30-15 IFT-B V IFT (ICC = 0.83) and HR peak (ICC = 0.87). V IFT was significantly reduced in 30-15 IFT-B (15.82 km h -1 ) compared to 30-15 IFT (17.52 km h -1 ; p < .001), regardless of trial. HR and RPE were significantly greater in 30-15 IFT compared to 30-15 IFT-B ( p < .05). Estimated maximal oxygen consumption (VO 2 max) YYIR and estimated VO 2 max of 30-15 IFT and 30-15 IFT-B was very strongly ( r = 0.82) and strongly ( r = 0.68) correlated. Conclusion : The 30-15 IFT is considered valid and reliable and the 30-15 IFT-B was reliable in female soccer players.