Purpose The aim of the study was to compare the level of isokinetic strength of knee extensors (KE) and flexors (KF) and ratio of knee flexors (H) vs. extensors (Q) muscle strength of the dominant lower limb in two professional soccer teams of differing performance level. Material and method The tested groups consisted of professional soccer players of the highest league in the Czech Republic (n = 40 players).
The players were divided into two groups according to the score in the overall table. The first group was composed of players who were placed in the second place in overall table (n = 22) and the second team consisted of players whose team were third bottom (n = 18).
Maximum peak muscle torque of KE and KF and their mutual ratio (H:Q) were assessed during concentric contraction at different velocities by means of an isokinetic dynamometer. Results The results of the study did not show any significant differences between the tested groups in the level of KE and KF strength (p}0.05).
Contraction velocity indicated significant influence on the level of KE and KF strength (p}0.05). Contraction velocity did not significantly effect ipsilateral ratio between H and Q thigh muscles (p}0.05).
Similarly, no significant difference was found in this ratio between both tested groups (p}0.05). Values of H:Q ratio that indicate an increased predisposition to injury were found in four players.
Discussions and conclusions The results of the study suggest that, in the case of professional players of the same league level (regardless of score in the table), the level of indicators of thigh muscle isokinetic strength is comparable.