Abstract
The purpose of research was to compare strength parameters of lower limbs (knee extensors and flexors) and their asymmetries (bilateral and unilateral) in elite and sub-elite professional soccer players.The screened sample was composed of two professional soccer teams. The first team (Team 1 - elite professional players, n = 28, age = 24.31 +- 4.79 years) was a leader of the first Czech league the second team (Team 2 - sub-elite professional players, n = 24, age = 26.19 +- 3.67 years) was a leader of the second Czech league.
Maximum peak torque (PT) and derived parameters (bilateral ratio [Q:Q and H:H] and unilateral ratio [H:Q]) were evaluated using Cybex isokinetic dynamometer at three angular velocities (60, 180, 300 o.s-1) for the dominant (DL) and non-dominant leg (NL) during the knee flexion (KF) and extension (KE) in concentric contraction.The factor of P (performance) revealed a significant effect on the level of isokinetic strength of lower limbs in soccer players (F(1.596) = 91.74, p 0.05, η2 = 0.01). The factor of the tested muscle group (KE, KF) showed a significant effect on the compared bilateral differences (F(1.288) = 11.13, p < 0.01, η2 = 0.04).
Post-hoc tests also showed significantly higher (p < 0.01) values of the bilateral deficit in KF compared to KE. A significant effect was also found in the unilateral ratio of the lower limbs (H:Q) on the basis of comparison of the performance criterion (F(1.288) = 15.51, p < 0.01, η2 = 0.05) and angular velocity of movement (F(2.288) = 5.56, p < 0.01, η2 = 0.04).The results of the study suggest that more than 50 % of players have at least one strength asymmetry regardless of their performance level.
Elite professional players have greater muscular strength of KE and KF, especially at higher angular velocity.