Intermittent Endurance and Repeated Sprint Ability in Soccer Players

The ability to perform high-intensity intermittent exercise (i.e., Yo-Yo Intermittent Recovery Test Yo-Yo IR1) and to repeat sprints with relatively short recovery times (i.e., 20- to 30-seconds, relatively short time interval repeated sprint ability (RSA)) has been shown to be relevant fitness variables in soccer. However, though they potentially share common features, it is not known whether these 2 abilities are associated. The aim of this study was to examine the relationships between Yo-Yo IR1 and RSA performances in elite soccer players. Twenty-three soccer players (age 19 ± 1 years, height 181 ± 5.7 cm, body mass 73.2 ± 4.1 kg, %body fat 11 ± 2.4) performed the Yo-Yo IR1 and a test for RSA (7 × 30 m with 25-second recovery). Results were 2,289 ± 409 m, 31.21 ± 1.13 seconds, and 4 ± 2.1% for Yo-Yo IR1, total sprint time, and sprint decrement, respectively. Yo-Yo IR1 showed a significant and moderate relationship with sprint decrement (r² = -0.44, p = 0.04). Splitting the sample into Best and Worst Yo-Yo IR1 performers according to median score (2,320 m), the Best group showed lower RSA total time (30.69 ± 0.99 vs. 31.79 ± 1.06, p < 0.05) and speed decrement (2.90 ± 0.86 vs. 5.09 ± 2.42, p < 0.01) compared to the Worst group. Sprint-time deterioration over 30 m occurred earlier (from the second sprint on) in the Yo-YoWorst compared with in the Yo-YoBest group (from the fourth sprint on, p < 0.001). Intermittent high-intensity endurance is poorly associated with RSA performance (r² = 0.19). Consequently, coaches and strength and conditioning professionals should consider both Yo-Yo IR1 and RSA in their testing batteries. A Yo-Yo IR1 performance ≥2,320 m could be considered as a reasonable indicator of physical fitness in elite soccer. Relatively short time interval test protocols similar to the present study should consist of at least 5 sprint bouts.