The Effect of PNF Stretching and Lower Extremity Strengthening Programs on Knee Joint Range of Before and After Local Fatigue of the Quadriceps Muscle in Male Athletes with Patellofemoral Pain Syndrome

Purpose:Patellofemoral pain syndrome (PFPS) leads to a decrease in the range of motion and strength of the knee muscles. The aim of this study was to investigate the effect of PNF stretching exercises and lower extremity strengthening on knee range of motion and quadriceps muscle strength before and after local quadriceps fatigue in male athletes with PFPS.Methods:24 male athletes (20-30 years age range) with PFPS from Tehran were randomly divided into two equal groups of PNF stretching exercises and strengthening exercises. Two groups trained for 8 weeks, 3 sessions a week for 60 minutes. The range of motion of the knee and the strength of the quadriceps were measured before and after each training session (at each testing session and after harvesting) using a digital electro goniometer (accuracy: 0/1 degrees) and Biodex isokinetic dynamometer. The data were analyzed using ANOVA with a significance level of P<0/05.Results:The exercise program significantly improved the range of knee motion in the extension movement (ES=0/75 and P<0/05). A significant difference was observed between the measurements before and after the test (ES=0/75). The range of knee motion in the extension movement increased by 16% in the stretching group and 11% in the strengthening group after 8 weeks. Additionally, the exercise program significantly increased the strength of quadriceps muscles (ES=0/65 and P<0/05). The comparison and post-test showed a significant difference (ES=0/75). After 8 weeks, quadriceps strength increased by 19% in the stretching group and 12% in the strengthening group. Conclusion:Both training programs were exercises, but PNF stretching exercises were better than strengthening exercises in improving knee range of motion and knee strength in athletes with PFPS. Future researches should examine the effectiveness of these interventions in female athletes.