Effects of dynamic stretches on Isokinetic hamstring and Quadriceps femoris muscle strength in elite female soccer players

This study investigated the effects of dynamic stretches on isokinetic hamstring (H) strength, quadriceps femoris (Q) strength, and the H/Q ratio in elite female soccer players. Fifteen elite female soccer players (age: 22.13±2.69; height: 164.53±7.57; weight: 57.8±7.86) participated in the study. The length of the lower extremity and the circumference of the thigh were measured for each subject. On different days, isokinetic muscle strength of the participants was measured twice using a Biodex dynamometer and concentric/concentric 60˚/s, 180˚/s and 300˚/s test protocols. Knee flexion-extension range of motion (ROM) was measured using goniometry at two different times. After a non-stretching warm-up, the peak torque (PT) of the H and Q muscles at 60˚/s, 180˚/s and 300˚/s were measured. The H/Q ratios were calculated for 60˚/s, 180˚/s and 300˚/s. In addition, the PT values for the latter were calculated after dynamic stretches for H and for Q. Comparisons between the H and Q measurements showed a significant difference between peak torques, H/Q ratios, and ROM (p<0.01). In conclusion, dynamic stretches have positive effects on muscle strength, H/Q ratios and ROM. Therefore, dynamic stretches may increase performance and reduce the risk of injury to athletes.Keywords: Quadriceps; Hamstrings; Muscles Isokinetic; Dynamic stretchesSouth African Journal for Research in Sport, Physical Education and Recreation, 2012, 34(2): 15-25