Purpose: Strengthening of the VMO has been suggested as a treatment technique for the PFPS, as the weakness of this component of the quadriceps is one of the reasons of the mal alignment of the patella. Therefore, attempts have been made selectively to strengthen the VMO.Materials and Methods: We chose three common therapeutic exercises for the PFPS in the open kinetic chain.The EMG activity of the VMO and VL were evaluated in the dominant lower limb, during three training programs in three experimental groups and a control group. Eight healthy women volunteers, aged from 20-30 years(X=24.94, SD=I.97), were studied in each group (Total= 32 subjects). The characteristics of training programs were as follows: The first experimental group: quadriceps setting with dorsiflexion of the foot (30 times per day, three times per week, lasting 4 weeks). The second experimental group: SLR with lateral rotation of the femur (according to Delorm-Watkins training program, three times per week, lasting 4 weeks). The third experimental group: terminal extension of the knee (0-30 degrees) with medial rotation of tibia in the special splint for the isometric contraction of quadriceps (according to Delorm-Watkins training program, three times per week, lasting 4 weeks). The control group. The EMG activity of VMO and VL muscles were recorded as the pre-test, mid-test, and post-test for 12 seconds and the average rectified value (ARV) of the power spectrum of the EMG signal was used to evaluate the muscles" activities.Results: Statistical analysis showed that in the first group, the ARV of the VMO was increased in the I2th session compared to the 6th session. The ARV of the VL had no significant difference during the training sessions. In the second group, the ARV of the VMO and VL had no significant difference during the training sessions. In the third group, the ARV of the VMO showed a significant increase between the 12th and 6th sessions and the 12th and 1st sessions. In addition, the VMO: VL IEMG ratio, in the second and third groups was increased significantly between the 12th and 1st sessions.Conclusions: The results suggest that the VMO can be selectively strengthened by performing the SLR with the LR of the femur and the SAQ with the MR of the tibia.

Background and Aims: In patients with lateral patellofemoral compression syndrome, the vastus medialis muscle is weaker than the vastus lateralis muscle. The purpose of the present study was to investigate the effect of an exercise protocol focusing on vastus medialis activation on the electrical activity and cross-sectional areas of the vastus medialis and vastus lateralis muscles. Materials and Methods: In the current study, 30 females with lateral patellofemoral compression syndrome, aged 25. 4± 5. 7, were selected and randomly divided into two groups. The experimental group participated in isokinetic knee extension exercises at terminal 30° extension arc with maximal external rotation of the leg for eight weeks. The control group did not participate in any regular exercise. Before and after the intervention, the cross sectional areas and electrical activities of the vastus medialis and vastus lateralis muscles were measured using ultrasonography and electromyography. Data were analyzed running independent and paired t-tests at the significance level of P<0. 05. Results: There were no significant differences in any of the variables between the two groups before intervention (P<0. 05). But after the intervention, the vastus medialis/vastus lateralis activity and cross-sectional area ratio in the experimental group were found to be significantly higher than those of the control group (P<0. 001). Conclusion: According to the results, using isokinetic knee extension exercises can selectively strengthen the vastus medialis muscle and reduce the imbalance between vastus medialis and lateralis muscles in patients with lateral patellofemoral compression syndrome.

Background: In Genu-valgum tibiofemoral angle increases above its normal value of 6°. This disorder causes difficulty in walking and sport activities in short-.term. But in long-term, because of increased force on lateral compartment of the knee, osteoarthritic changes of the lateral side of the knee and ligamentous laxity of medial side of knee could happen. In the past, osteotomies have been done on lateral side of distal femur for correction of Genuvalgum. We are suggesting a medial approach, posterior to vastus medialis with close-wedge osteotomy from medial side as an alternative approach for correction of genovalgum. Method: A Clinical trial study of 20 lower limbs operated between 1988 to 2002. Results: 20 lower limbs were operated with this technique. The mean age was 23.2, 14 patients were female and 2 male. 10 limbs were left and the other 10 were right side. Mean valgus angle was 14.75° preoperatively and 3° postoperatively the mean follow-up period was 628 days (Minimum 50 and maximum 1111 days). At follow-up, the range of knee motion in all limbs was normal. There was no infection postoperatively, quadriceps force was 5/5 in 18 and 4/5 in two limbs. Functional improvement was observed in 15 cases and all 16 patients had full satisfaction from the appearance of the limbs.

Background and Aim: It is believed that dysfunction of the quadriceps muscle can be considered as one of the cause of patellofemoral pain syndrome with great emphasis placed on vastus medialis oblique and vastus lateralis muscles imbalance. The purpose of this study was to compare the EMG activity ratio of vastus medialis oblique: vastus lateralis muscles in athletes with and without patellofemoral pain syndrome.Materials and Methods: 12 athletes with Patellofemoral pain syndrome (age 23.23±3.70 year, height 179±7.00 cm, and weight 73.86±12.00kg) and 12 healthy male athletes (age 23.45±3.17 year, height 177±4.00 cm, and weight 68.84±8.53 kg) Participated in a quasi-experimental study. Numerical Pain Rating scale was used to assess the pain. EMG activity of vastus medialis oblique and vastus lateralis muscles during dynamic postural perturbation were collected using a 16- channel EMG System. To data wasanalysed by Independent-t test at the significance level was set as P£0.05.Results: The mean vastus medialis oblique: vastus lateralis EMG activity ratio in athletes with patellofemoral pain syndrome were less than control group. No significant difference was observed in the vastus medialis oblique: vastus lateralis EMG activity ratio between two groups during forward perturbation (p=0.56) and backward perturbation (p=0.52).Conclusion: Our findings suggest that vastus medialis oblique: vastus lateralis ratio was not differe between athletes with and without patellofemoral pain syndrome in postural dynamic perturbation and it is likely that long-term pain cause’s muscular balance reactions adaptation in athletes with patellofemoral pain syndrome. The results of this study would be useful for therapists to identify changes in motor control strategies and in a rehabilitation program design for athletes with patellofemoral pain syndrome.