First-stance phase force contributions to acceleration sprint performance in semi-professional soccer players

Background: Sprint running is a key determinant of player performance in soccer that is typically assessed and monitored using temporal methods. Purpose: The aim of this study was to examine the relationship between ground reaction force kinetics at the first step and sprint running performance in soccer players in order to enhance the development of training and assessment methods. Methods: Nineteen semi-professional soccer players participated (mean ± s: age 21.1 ± 1.9 years, body mass 79.4 ± 7.3 kg and stature 1.79 ± 0.06 m). The participants completed 20 m acceleration sprint runs as timing gates recorded split times between 0–5, 5–10, 10–15, 15–20 and 0–20 m. A force plate captured vertical, anteroposterior and mediolateral ground reaction force data (1000 Hz) of the first right foot strike stance phase. Results: Ground reaction force metrics, including peak anteroposterior propulsive force (r = 0.66 to 0.751; P =.000 to.002), peak vertical ground reaction force (r = 0.456 to 0.464; P =.045 to.05), average medial-lateral/anteroposterior orientation angle (r = −0.463; P =.023), and average anteroposterior/vertical orientation angle (r = −0.44; P =.03) were correlated with one or all split times between 0–5 m, 5–10 m, 10–15 m, 15–20 m and 0–20 m. Conclusions: Acceleration sprint running in soccer requires minimised mediolateral and increased anteroposterior loading in the stance phase. Multi-component ground reaction force measures of the first step in acceleration sprint runs are important for developing performance assessments, and understanding force application techniques employed by soccer players. .