ارتباط توان عضلاني ايزوكينتيك و ايزوتونيك مفصل زانو با عملكرد پرش عمودي بازيكنان فوتبال

Relationship between isokinetic an‎d isotonic muscle power of knee joint with vertical jump performance of soccer players

آسيب شناسي و حركات اصلاحي

In football, the ability to jump for defense an‎d attack is very important. Feather performance can help educators design training programs.The aim of this study was to investigate the relationship between isokinetic an‎d isotonic muscle strength of the knee joint an‎d vertical jump performance of soccer players. This Descriptive study was conducted on 20 elite players under the age of 14 from Foolad Mobarakeh Sepahan Football Club. The subjects first performed three vertical jumps. an‎d then they sat on the Biodex machine under three different instructions. an‎d they performed knee flexion an‎d extension according to three protocols created on the device. The first protocol is isokinetic contraction, concentric mode, an‎d at speeds of 150, 300, an‎d 500 degree per second, The second protocol is isokinetic contraction, eccentric-concentric mode, with speeds of 150 an‎d 300 degree per second, an‎d The third protocol was isotonic contraction, concentric-concentric mode, an‎d resistance of 7 an‎d 14 Newton per square meter. The research questions included the relationship between hamstring an‎d quadriceps muscle strength in both isokinetic an‎d isotonic contraction modes an‎d maximum jump height. The ratio of hamstring to quadriceps strength was also examined. The results showed that in the isokinetic contraction state, two variables have a significant an‎d moderate relationship with maximum jump height. First, the concentric knee flexion power at an angular velocity of 150 degrees/s (r = 0.479 an‎d p = 0.033). an‎d second, hamstring power to eccentric-concentric quadriceps at an angular velocity of 150 degrees/second (r = 0.431 an‎d p = 0.048). In the isotonic contraction state, seven variables had a significant an‎d moderate relationship with maximum jump height. Which at a resistance of 7 Newton per square meter includes extensional power (r = 0.442 an‎d p = 0.049) an‎d flexural power (r = 0.514 an‎d p = 0.020) an‎d At a resistance of 14 N/m2, these include maximum flexion velocity (r = 0.529 an‎d p = 0.017), hamstring to quadriceps ratio (r = 0.590 an‎d p = 0.006), maximum flexion work (r = 0.476 an‎d p = 0.034), extensor power (r = 0.443 an‎d p = 0.049), an‎d flexor power (r = 0.504 an‎d p = 0.023). Other measured variables had no effect on jump height performance. Overall, this study emphasizes the importance of isokinetic an‎d isotonic muscle power for improving high jump performance. Which can affect the performance of specific sports skills such as heading, catching the ball by the goalkeeper in soccer. This necessitates the use of training an‎d fitness strategies that emphasize isokinetic an‎d isotonic muscle strength.

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