Knee joint stability estimation by hamstring/ quadriceps femoris muscles torque ratios in range of movements in male and female athletes

Aim. The aim of our investigation is to determine the hamstring/ quadriceps femoris (H/Q) muscles torque ratios in the concentric/ concentric (C/C) and eccentric/ concentric (E/C) contractions in different angular positions of the knee range of movements (ROM). Methods. Fifteen female and 13 male athletes participated in the investigation. The muscles were tested by the dynamometer system "REV-9000" (Technogym) in isokinetic movements at the angular velocity of 90°/s. The ROM in the knee joint was from 10° in extension to 90° in flexion. The torques are detected at the ROM with the step of 10° in the C/C and in the EH/CQ contractions. The t - test for paired data groups was employed to determine differences between characteristics in the C/C and E/C contractions. The Student t - test for unequal groups was used to estimate the muscles torques ratios sex differences. Results. The ratio of the EH/CQ torques is significantly higher than in the C/C contractions only in the extended (30°) and flexed knee positions (70° and 80°). It can be explained by the eccentric H contractions only in the extreme positions of the ROM in sport movements. The H/Q torques ratios in the C/C contractions are greater for males in comparison with the females. The differences between genders are significant in the middle part of the ROM and flexed knee joint (ROM angles 50°, 60° and 70°). The muscles torques ratios in the EH/CQ contractions are none significantly greater for males than for females in all angles in the ROM. Conclusion. The investigation proves the role of eccentric hamstring muscles action in the knee joint stability providing during the movements in the extreme positions of the range of movements, and greater knee joint stability during movements in males than in females.