Abstract
Muscle strength (MS) is an important component of soccer player's physical fitness. It is theorized that MS positively influence level of physical performance and reduce risk of musculoskeletal injuries. However, evidence of how MS impact soccer team's success is lacking, especially at professional league.
PURPOSE: To determine the effect of MS on team performance success in male professional soccer league.
METHODS: Cross-sectional study design with one hundred thirty-five male soccer players of the highest Czech league were classified according to team's final league ranking into groups: (A) 1st-4th ranking (n = 45), (B) 5th-12th ranking (n = 49) and (C) 12th-16th (n = 41). Isokinetic MS was tested by the Cybex Humac Norm dynamometer. Peak torque (PT) of knee extensors (KE) and knee flexors (KF) were evaluated in three (60,180,300 °.s-1) angular velocities (AV) for dominant (DL) and non-dominant leg (NL). Multilevel analyses of variances (MANOVA), Bonferroni post hoc test, and partial eta square (ηp2) were used for statistical assessment.
RESULTS: MANOVA showed a significant effect of MS on team's performance success (λ = 0.86, F4,1584 = 31.33; p < 0.01, ηp2 = 0.07). Post-hoc analyses revealed Group A had significantly (p < 0.05) greater muscle strength of KN in DL at all AV compared to B and C group, but differences between B and C was not statistically different (60°.s-1: A = 3.19 +- 0.45 N.s.kg-1, B = 2.87 +- 0.31 N.s.kg-1, C = 2.90 +- 0.29 N.s.kg-1, 180°.s-1: A = 2.28 +- 0.31 N.s.kg-1, B = 2.02 +- 0.22 N.s.kg-1, C = 2.06 +- 0.22 N.s.kg-1 and 300°.s-1: A = 1.69 +- 0.23 N.s.kg-1, B = 1.49 +- 0.18 N.s.kg-1, C = 1.53 +- 0.21 N.s.kg-1). Similar results were found when compared PT in NL (60°.s-1: A = 3.21 +- 0.0.40 N.s.kg-1, B = 2.97 +- 0.29 N.s.kg-1, C = 2.94 +- 0.31 N.s.kg-1, 180°.s-1: A = 2.27 +- 0.29 N.s.kg-1, B = 2.05 +- 0.21 N.s.kg-1, C = 2.13 +- 0.24 N.s.kg-1 and 300°.s-1: A = 1.69 +- 0.23 N.s.kg-1, B = 1.50 +- 0.18 N.s.kg-1, C = 1.56 +- 0.0.20 N.s.kg-1). Conversely, when comparing PT of KF only one significant difference was found among A vs. C group at highest AV (300°.s-1) and DL (A = 1.09 +- 0.18 N.s.kg-1, C = 0.96 +- 0.14 N.s.kg-1).
CONCLUSION: The current findings indicate that team's finishing within the top four had greater MS of KEs than players whose team's finished at lower ranks. This evidence may be valuable to discuss team's success in male professional soccer league.