Paper #82 The relation between knee flexors and extensors in soccer players

Abstract

The balance between knee flexors and extensors can be very important in preventing overuse injuries. The extensors generate the knee extension power, and the flexors must act to decelerate the tibia during knee extension, that way absorbing the energy developed by the quadriceps muscle (Garret et al, 1984). If either the quadriceps is relatively stronger or the hamstrings are relatively weaker, a muscle lesion might happen. In athletes with a 10% difference between flexors and extensors, there is a probability of muscular and tendinous lesions( Safran et al, 1989). We also observe that athletes with flexors strength less than 60% of the quadriceps are more susceptible to lesions. Grace et al (1984) did not identify any relation between muscular imbalance and lesions in 172 American football college players. Our study has 2 objectives: determine the concentric flexion/extension tork in soccer athletes, to compare the agonist/antagonist relationship in different speeds. The sample was composed by 9 under 20 soccer players, with no history of previous lesions. The data were obtained with an evaluation with the equipment Cybex 2000, e treated statistically by the package STATISTICA 6.0. We used the Student t test to detect differences between flexors and extensors. The balance between knee flexors and extensors can be very important in preventing overuse injuries. The extensors generate the knee extension power, and the flexors must act to decelerate the tibia during knee extension, that way absorbing the energy developed by the quadriceps muscle (Garret et al, 1984). If either the quadriceps is relatively stronger or the hamstrings are relatively weaker, a muscle lesion might happen. In athletes with a 10% difference between flexors and extensors, there is a probability of muscular and tendinous lesions( Safran et al, 1989). We also observe that athletes with flexors strength less than 60% of the quadriceps are more susceptible to lesions. Grace et al (1984) did not identify any relation between muscular imbalance and lesions in 172 American football college players. Our study has 2 objectives: determine the concentric flexion/extension tork in soccer athletes, to compare the agonist/antagonist relationship in different speeds. The sample was composed by 9 under 20 soccer players, with no history of previous lesions. The data were obtained with an evaluation with the equipment Cybex 2000, e treated statistically by the package STATISTICA 6.0. We used the Student t test to detect differences between flexors and extensors.