Document Type : Original article
Department of Sport Injuries and Corrective Exercises, Faculty of Sport Sciences & Health, Shahid Beheshti University, Tehran, Iran
shahid beheshti university
Background and Aims: ACL injury is one of the most common and serious injuries of the knee joint, which include about 80% of all knee ligament surgeries. Studies have shown that a significant percentage of this injury (70%) occurs non-traumatically and usually during movements such as deceleration, landing or side cutting. Studies have shown that focus instructions improve performance. The aim of this study was to investigate the acute effect of focus instructions on the kinetic variables associated with ACL injury
Materials and Methods: In this research, 24 young football players from the two clubs of Tehran Premier League were randomly divided into two groups: external focus attention (n=12), internal focus attention (n =12). First, dynamic postural stability index (DPSI), peak of vertical, anterior-posterior and medio-lateral GRF and rate of loading during the jump-landing movement from a 30 cm platform were calculated from GRF which was recorded using a force plate with a sampling frequency of 1000 HZ. Then, the internal and external focus instructions were taught to the participants and the two groups were tested again to examine the changes. Statistical methods of repeated measure ANOVA, paired t-test and independent t-test were used to evaluate the changes
Results: The results showed significant changes in the vertical GRF and rate of loading variables in both groups of internal and external focus attention (P≤0.05). No significant difference was observed in the DPSI, anterior-posterior and medio-lateral GRF
Conclusion: The results of this study showed that acute instructions of both internal and external focus attention can improve landing mechanics and landing-related kinetic variables. It seems that the external focus instructions have been able to increase the motor control of the limb, lead to a further reduction of vertical GRF and the load of applied to the lower limb in compared to the instructions of internal focus and thus reduce the risk of ACL injury.
Keywords: ACL injury prevention, single leg jump-landing, attention focus, kinetics