Relationship between static and dynamic balance abilities in Italian professional and youth league soccer players

Objectives: To assess the existence of correlations between static and dynamic balance abilities in young and professional elite soccer players. Design: Cross-sectional. Participants: Fifty-one elite players who regularly compete at national level divided into two groups: Professional (age 18e34, n ¼ 20) and Under 15e17 (age 14e16, n ¼ 31). Main outcome measures: Dynamic balance was assessed for the case of a single-leg landing task by means of vertical time to stabilization (TTS) and postural sway calculated on the basis of center-of-pressure (COP) trajectories (sway area, COP displacements in antero-posterior and medio-lateral direction, COP path length). The same parameters were also measured for a 20 s one-legged stance to assess static balance abilities. Results: No significant correlations were found between static and dynamic balance parameters except for TTS and COP displacements in the antero-posterior direction (r = 0.29, p = 0.003). Professional players are characterized by lower TTS in comparison with youth leagues players (0.767 vs. 1.188 s for the dominant limb, p < 0.001) and exhibit reduced sway area (of 34e40%, p < 0.05) for both conditions tested. Conclusion: The assessment of balance in soccer players should be performed with both dynamic and static tests, considering that the postural control performances in the two cases are not related.