Repeated sprint protocols (running and dribbling) : reproducibility and variation by competitive level

Abstract

Soccer is a complex sport, requiring the repetition of many actions, and several tests are currently being used to assess the physical prowess of players. Repeated sprint ability (RSA) has been shown to be an important factor for determining success in soccer. Sprinting and dribbling on the same course are partly related, although the skill of dribbling is more complex than that of sprinting. The purpose of this study was to develop a repeated dribbling ability (RDA) test for young soccer players. Reproducibility of test and variability by competitive level were considered. The sample consisted of 67 young male soccer players (16.11±0.59 years) who were measured in RSA and RDA protocols within the following competitive level groups and according to the structure of Portuguese youth soccer under-17: local level (n=34) and national level (n=37). Pearson product-moment correlation coefficient was used to measure the linear correlation between different variables. The t-student was used to compare the means between different groups. The smallest worthwhile difference was set at Cohen’s effect size of 0.2 and 0.5. Cohen’s d effect sizes (ES) and thresholds (0.2, 0.6, 1.2, 2.0, 4.0 for trivial, small, moderate, large, very large and extremely large) were also used to compare the magnitude of the differences in anthropometrical characteristics and physical performance. Analysis of RDA reproducibility confirmed the future usefulness of the test (reliability coefficients: mean time = 0.83 total time = 0.83 and ideal time = 0.85). This study reinforces that RSA protocols associate better with competitive level group. Moreover, standard for smallest worthwhile differences between performance levels within these groups of youth players could assist the coach. Keywords: youth soccer, sport skill, dribble performance, short-term maximal effort, field-testing.