Postural performance and strategy in the unipedal stance of soccer players at different levels of competition.

CONTEXT: Sport training enhances the ability to use somatosensory and otolithic information, which improves postural capabilities. Postural changes are different according to the sport practiced, but few authors have analyzed subjects' postural performances to discriminate the expertise level among highly skilled athletes within a specific discipline. OBJECTIVE: To compare the postural performance and the postural strategy between soccer players at different levels of competition (national and regional). DESIGN: Repeated measures with 1 between-groups factor (level of competition: national or regional) and 1 within-groups factor (vision: eyes open or eyes closed). Dependent variables were center-of-pressure surface area and velocity; total spectral energy; and percentage of low-, medium-, and high-frequency band. SETTING: Sports performance laboratory. PATIENTS OR OTHER PARTICIPANTS: Fifteen national male soccer players (age = 24 +/- 3 years, height = 179 +/- 5 cm, mass = 72 +/- 3 kg) and 15 regional male soccer players (age = 23 +/- 3 years, height = 174 +/- 4 cm, mass = 68 +/- 5 kg) participated in the study. INTERVENTION(S): The subjects performed posturographic tests with eyes open and closed. MAIN OUTCOME MEASURE(S): While subjects performed static and dynamic posturographic tests, we measured the center of foot pressure on a force platform. Spatiotemporal center-of-pressure measurements were used to evaluate the postural performance, and a frequency analysis of the center-of-pressure excursions (fast Fourier transform) was conducted to estimate the postural strategy. RESULTS: Within a laboratory task, national soccer players produced better postural performances than regional players and had a different postural strategy. The national players were more stable than the regional players and used proprioception and vision information differently. CONCLUSIONS: In the test conditions specific to playing soccer, level of playing experience influenced postural control performance measures and strategies.