The aim of this study was to evaluate the association between physiological variables related to physical fitness determined by continuous straight running on a treadmill (peak velocity on treadmill: PV TRE, maximum oxygen uptake: VO2max, minimum velocity needed to reach VO2max: vVO2max, and velocity at the anaerobic threshold: vAT) and intermittent running with directional changes (peak velocity: PV) and repeated sprint ability (RSA) in soccer players. Twenty-nine athletes (17.9 ± 1.0 years, 178.7 ± 5.2 cm, 73.6 ± 6.7 kg, and 11.1 ± 1.3% body fat) performed the following tests on different days: 1) incremental protocol on a treadmill to determine PV TRE, VO2max, vVO2max, and vAT; 2) incremental intermittent running test to determine PV, and 3) Bangsbo test to evaluate RSA and to determine the mean time (MT), fastest time (FT), and fatigue index (FI). Pearson's correlation coefficient was used and a level of significance of 5% was adopted. PV obtained in the intermittent running test showed a higher correlation with MT and FT of the RSA test (r = -0.70, p < 0.01; r = -0.51, p < 0.01, respectively) than vVO2max (r = -0.43, p < 0.05; r = -0.14 p > 0.05) and PV TRE (r = -0.42, p < 0.05; r =-0.14, p > 0.05) determined by straight running on a treadmill. In conclusion, the relationship between physical fitness and RSA depends on the type of protocol (continuous line running vs. intermittent with directional changes) and the aerobic index used (capacity vs. power).
Physical fitness; Repeated sprint ability; Soccer; Physiological variables
