Comparison of Isometric Strength between the Preferred and Non-Preferred Leg of Iran Professional Men Soccer Players

Kicking and cutting skills in soccer are clearly unilateral, require asymmetrical motor patterns and lead to the development of asymmetrical adaptations in the musculoskeletal function of the lower limbs. So, the purpose of this study was to compare isometric strength of knee muscles between the preferred and non-preferred leg in youth men professional soccer players. In total 36 young men soccer players (Mean ±SD; age: 18.7 ± 1.6 y, weight: 73.1±6.4 kg, height: 181.3±5.5 cm) with at least 5 years soccer experience from two professional clubs volunteered to participate in this study. The isometric quadriceps and hamstring torques measured at 30°, 60° and 90° of knee extension and flexion by Biodex System 3. T-test and one way ANOVA was used for analysing the data. Results of this study showed that preferred leg had significantly higher peak torque in knee flexors than non-preferred leg torque at 3 angels (P<0.05). Although non-preferred leg had more peak torque in knee extensors than preferred leg but the differences between them was not significant at three angles. There were significance differences in the peak torque of quadriceps muscles of preferred leg in three angles (P<0.05). The non-preferred leg knee extensors peak torque increased significantly as angles degree increased (P<0.05). With increasing degree of knee angles from 30 to 90 in preferred leg hamstring strength also decreased (P<0.05). Level of peak torque of hamstring in non-preferred similar to preferred leg at 30 degree was highest and at 90 degree was lowest (P<0.05). About 88.9% of soccer players had significance musculoskeletal deficits. It can be concluded that playing soccer and use more of one side of body led to musculoskeletal asymmetry. Therefore, it is suggested that soccer players use of training to strengthening both sides of the body.