Introduction: Different researches have shown that the reduction in knee flexion angle during functional tasks such as jump and landing is one of the most important factors that can make the anterior cruciate ligament vulnerable. Since the knee range of motion in the sagittal plane is directly related with ankle range of motion, the aim of this study was to investigate the predictive relationship among the ankle range of motion limitation and knee flexion angle and risk of anterior cruciate ligament injury in male athletes.
Methodology: 15 male athletes with ankle dorsiflexion limitation constituted the group with limitation and 15 male athletes without any dorsiflexion limitation constituted the healthy group. Universal Goniometer was used to measure the ankle range of motion. Knee flexion angle at the moment of foot ground contact during single leg jump-landing task was recorded by electrogoniometer. Independent t-test was used for comparing the knee flexion angle at the moment of foot ground contact, Pearson correlation test was used to check the linear relationship between two variables and logistic regression was used to examine the predictive relationship between two variables. The significance level for all statistical analyzes were smaller than 0.05.
Results: The results showed that athletes with ankle dorsiflexion limitation landed with more knee extension. There was a strong correlation between the limitation of ankle dorsiflexion with the knee flexion angle (r=0.84). The results of logistic regression test showed that athletes with dorsiflexion limitation, were 1.4 times more at risk of injury.
Discussion: Limitation of ankle dorsiflexion can predict the knee flexion angle at the time of landing and the risk of the anterior cruciate ligament injury greatly. Limitation of ankle dorsiflexion and consequently reduced knee flexion angle at the time of foot ground contact, can lead to abnormal ground reaction force imposed on the knee and can cause knee injury.