Document Type : Original Articles


Department of Sport Injuries and Corrective Exercises, Faculty of Physical Education and Sport Sciences, University of Guilan, Rasht, Iran


Background: increased knee valgus, decreased knee flexion and poor landing pattern are contributing risk factors for anterior cruciate ligament (ACL) injuries in young soccer players. This study aimed to investigate the effect of the Prevent Injury and Enhance Performance (PEP) program on knee valgus and knee flexion angles and Landing Error Scoring System (LESS) test scores in young male soccer players with poor landing mechanics.
Methods: The present study was quasi-experimental. 47 soccer players with poor landing mechanics were purposefully recruited and they were randomly assigned to the intervention group (n=23 players, age= 12.69±0.70 years, height= 1.53±0.06 m, weight= 49.91±6.76 kg) and control group (n=24 players, age= 12.55±0.64 years, height= 1.51±0.08 m, weight= 51.25±7.73 kg). Knee Valgus angle, Knee flexion angle and LESS test scores were measured at the baseline and the end of the study. The intervention group used the PEP program as a warm-up for 8 weeks while the control group performed its routine warm-up during this time. ANCOVA and paired-sample t-test were used to evaluate changes.
Results: The results obtained in the intervention group showed there was a significant reduction in knee valgus angle (p=0.001) and there were significant enhancements in knee flexion angle (p=0.003) and LESS test scores (p=0.001) but there were no significant differences in the control group in knee valgus and knee flexion angles (p>0.05) except for LESS test scores (p=0.001). Moreover, the outcome showed significant differences between groups in knee valgus angle (p=0.001), knee flexion angle (p=0.025) and LESS test scores (p=0.001).
Conclusion: This study demonstrated that PEP program was effective in reducing dynamic knee valgus angles, increasing knee flexion angles and improving LESS test scores in young soccer players. Thus, it seems that this program can reduce the risk of ACL injuries in young male soccer players.