How Different Physical Qualities Influence Repeated Sprint Ability Tests in Elite Youth Soccer Players?

The aim of this study was to examine the relationships between different repeated sprint ability (RSA) tests and to determine whether all RSA tests were related to the same physical qualities. Twenty-five young elite soccer players (age: 17.1 ± 0.9 years; body height: 172.5 ± 4.6 cm; body mass: 68.1 ± 3.9 kg) participated in this study. Participants completed five RSA tests (i.e., RSA 20 + 20, RSA-linear, RSARANDOM, RSA 15 + 15, and RSA-Curve), a linear sprint test (i.e., a 30-m linear sprint with split times recorded at the 5^th and the 10^th m ), a curve sprint test (CV_Best and CV_Worst), a change of direction (COD) test, and vertical jump tests (i.e., SJ, CMJ and DJ tests) during a training camp. The main results showed moderate relationships between RSA-RANDOM and RSA 20 + 20 (r = 0.410; p < 0.05) and between RSA-Linear and RSA 15 + 15 (r = 0.475; p < 0.05). In addition, negative relationships were observed between RSA-Curve and the other RSA tests. Additionally, the RSA-Linear test obtained moderate relationships with a 10-m sprint (r = 0.485; p < 0.05), CV_Best (r = 0.484; p < 0.05), CV_Worst (r = 0.410; p < 0.05) and the CMJ (r = 0.403; p < 0.05), and the RSA-RANDOM test with COD (RSA_total: r = 0.414; p < 0.05; RSA_best: r = 0.489; p < 0.05). These findings may help coaches and sports scientists optimize training and performance assessment by identifying the most suitable RSA test for specific variables. In addition, training focused on improving different physical qualities can positively impact RSA performance.