Relationships between speed, power, and endurance in youth soccer players

Soccer is a sport with an intermittent nature, and it includes both low- and high-intensity actions. In soccer, anaerobic and aerobic capacities play a key role in the performance and are therefore crucial determinants. Important actions that players need to be able to perform include sprints, jumps, tackles, change of directions, and accelerations. In order to test soccer performance, multiple field tests have been invented for their easy access and implementation during in-season and off-season. The purpose of the study was to examine the relationship between speed, power, and endurance in youth male and female soccer players and determine whether endurance performance can be predicted from sprinting and/or vertical jump ability. A total of 154 youth soccer players from the highest competition level in Finland in the Under-15 and Under-17 age groups were included in the retrospective analysis for this study. Participants consisted of both males (n = 81) and females (n = 73). The experimental design for this study highlights the importance of the relationship between linear speed, power and endurance. Testing was done in Eerikkilä Sport Facilities and testing battery included countermovement jump, Yo-Yo intermittent endurance test level 2, linear speed (5m, 10m, 30m) and the repeated sprint ability tests. Adequate resting times were held between all the tests. There were significant differences between males and females in all test variables (p < 0.001). In males, moderate correlations were observed between the YYIETL2 and the 30m (r = 0.313; P = 0.004), 5m (r = 0.347; P = 0.002), and 10m sprints (r = 0.305; P = 0.006). Moderate correlations were found between RSATotal and the 30m (r = 0.426; P < 0.001) and 5m (r = 0.360; P < 0.001). Among females, moderate correlations were observed between the YYIETL2 and the 30m (r = 0.394; P < 0.001), 10m (r = 0.325; P = 0.005), and 5m sprints (r = 0.307; P = 0.008). Large correlations were observed between RSATotal and the 10m (r = 0.579; P < 0.001) and 5m (r = 0.501; P < 0.001) sprints with a very large correlation between RSATotal and the 30m sprint (r = 0.719; P < 0.001). Similarly, very large correlation was found between RSAAverage and the 30m sprint (r = 0.705; P < 0.001). This current study showed that sprint speed was moderately related to soccer-specific endurance performance in both female and male youth soccer players. Female players showed from large to very large correlations between sprint speed and RSA. This information could be used when the focus is to enhance RSA by increasing sprint speed. However, caution should be used when comparing the results with different populations as the test results may vary between players regarding sex and age group