Effects of Different Isokinetic Training Programs on Hamstring/Quadriceps Ratio and Proprioception in Patients with Patellofemoral Pain

OBJECTIVES: To determine the effects of different isokinetic training programs; eccentric training, concentric training and combined (concentric-eccentric) training on quadriceps and hamstring muscle strength functional ratio (H/Qfunc ) and knee proprioception in Patellofemoral Pain Syndrome (PFPS) patients. METHODS: Thirty patients with unilateral PFPS were randomly assigned to 3 groups: concentric (CON, n=10) (31.23±3.12 years), eccentric (ECC, n=10) (33.73±2.21 years) and combined (combined, n=10) (30.41±4.35 years). In accordance with the progression principle, the training program was divided into 3 mesoscycles, and the sets and angular speeds were increased in each mesocycle. All groups were treated for 8 weeks. To determine H/Qfunc, eccentric quadriceps and concentric hamstring peak torques were evaluated at 60°/sec with Biodex System 3 (Biodex® Corp., Shirley, NY, USA). 20° and 60° of knee flexion target angles were used to evaluate the knee proprioception. Peak torques and proprioception were evaluated before and 8-week after training. Repeated measure of ANOVA was used for the analysis. RESULTS: There was a significant difference in H/Qfunc between groups at 60°/sec (F= 9.048, p<0.001). The mean improvement difference in ECC and CON-ECC groups were better than CON group. Proprioception improvement was found significant after 8-weeks training for both on 20° (F=150.879 p<0.001) and 60° (F=247.561, p<0.001) of knee flexion. The mean improvement was similar for 20° (F=1.964, p=0.132) and 60° (F=0.493, p=0.711) of knee flexion between the groups. CONCLUSION: Isokinetic training with the emphasis on eccentric training of quadriceps muscle had a significant effect in H/Qfunc in PFPS patients. This is mostly based on the improvement in quadriceps eccentric peak torque and the improvement in balance between hamstring and quadriceps muscles. Eccentric and combined (concentric-eccentric) training is more appropriate model for strengthening compared to only concentric training.