A Study on the Effect of Isometric Quadriceps Activation and Vastus Medialis Obliquus Strengthening in Decreasing Q-Angle among Young Females

Females are more prone for lateral displacement of patella than males due to increased Q-angle (15–18°) in them compared to males (12–15°). In a normal state, lateral displacement is prevented by geometry of the joint and by the passive stabilizers. Even though contraction of the quadriceps tends to displace the patella laterally, vastus medialis oblique (VMO) acts medially and posteriorly as much as it acts proximally, and so its tension helps in resisting the Q angle effect. There are two procedures in common practice to reduce Q-angle and thereby to prevent lateral displacement of patella– either through vastus medialis oblique (VMO) strengthening or by isometric quadriceps activation (quadriceps muscle strengthening). We wanted to compare the effects of isometric quadriceps activation and VMO strengthening in reducing Q angle in a group of young females.METHODSA non-randomized, two group, pre-test, post-test assessment of Q-angle was done. Twenty healthy females of 18-20 age group were selected and randomly divided into two groups. Isometric quadriceps activation and VMO strengthening was done for 4 weeks. Q-angles were measured before and after the strengthening exercise using a long arm goniometer.RESULTSThe mean q angle before treatment was 21. (minimum 20 and maximum 23). While after the treatment, q angles were significantly reduced in both the groups and mean q angle was 16.3.CONCLUSIONSBoth the isometric quadriceps activation and VMO strengthening reduced Q-angle significantly and there was no significant difference between the two procedures. Results of this study help the physiotherapist in choosing the exercise for the management of patellofemoral pain and lateral displacement of patella.

Influence of knee extension in sitting position with hip adduction on surface EMG of quadriceps muscles in patients with patellofemoral pain syndrome / 医用生物力学

Objective To investigate the possible effect of fully knee extension in sitting position with or without hip adduction on quadriceps imbalance in patients with patellofemoral pain syndrome (PFPS) by using surface electromyography (sEMG). Methods sEMG signals of vastus lateralis (VL) and vastus medialis oblique (VMO) muscles from 30 patients with PFPS as PFPS group and 30 healthy subjects as control group were collected, during their fully knee extension in sitting position with or without hip adduction. All the EMG data were then analyzed by extracting time domain indexes, namely, the root mean square (RMS) and integrated EMG (IEMG), to compare the balanced relationship between VL and VMO muscles. Results In PFPS group, there were no significant differences in VL time domain indexes during knee extension in sitting position with or without hip adduction, while statistical differences were found in VMO time domain indexes, and values of RMS and IEMG of VMO were higher under hip adduction, which indicated that the VMO muscle recruitment was strengthened. Conclusions Fully knee extension in sitting position with hip adduction can promote EMG activities of VMO muscles in patients with PFPS, which will help to balance the VL and VMO muscles.

Effect of double-leg semi-squats with hip adduction on the vastus medialis oblique of patients with patellofemoral pain syndrome / 中华物理医学与康复杂志

Objective To investigate the possible effect of performing double-leg semi-squats with hip adduction on the imbalance between vastus lateralis (VL) and vastus medialis oblique (VMO) muscles of patients with patellofemoral pain syndrome (PFPS).Methods Thirty patients with PFPS were selected to be in the study group,matched with 30 healthy subjects who were enrolled as the control group.Electromyography was used to record VL and VMO activities while the subjects performed double-leg semi-squats (DSs) and double-leg semi-squats with hip adduction (DSs-HA).Results In the study group,when performing DSs,the average RMS was (103.31 ± 44.54) μV and the IEMG was (8.02 ±3.45) μVs for VL.For VMO the RMS was (85.02 ±41.19) μV and the IEMG was (6.72 ±3.20) μVs.The differences in the time domain indexes (RMS,IEMG) between VL and VMO were both significant during DSs (P ＜ 0.05).There was no significant differences during DSs-HA (P ＞ 0.05).The time domain indexes (RMS,IEMG) of VMO were significantly different in both the DSs and DSs-HA (P ＜ 0.05).Conclusions Stronger sEMG signals were seen from the VMO in the double-leg semi-squats with hip adduction than without hip adduction,which indicates that more selective VMO activation can be obtained in the exercise with hip adduction to help balance the VL and VMO.

Activity of the Quadriceps during Semisquat and Squat Exercises with Isometric Hip Adduction and Abduction in Young Healthy Persons

OBJECTIVE: To determine the effects of isometric hip adduction and abduction on the activity of vastus medialis obliquus (VMO) and vastus lateralis (VL) during semisquat and squat exercise. METHOD: Thirty healthy male subjects without history of knee pain were recruited. Subjects performed a traditional exercise combined with hip adduction and abduction during semisquat and squat exercise. A total of 3 repetitions lasting 6 seconds each were executed following two-minute intervals. The EMG signals were collected from VMO and VL of the dominant leg. The data were normalized to the maximal isometric voluntary contraction of VMO and VL at 90degrees of knee flexion using isokinetic dynamometer and analysed in terms of their RMS values. RESULTS: The activity of both VMO and VL was significantly greater during both semisquat and squat exercise with hip adduction and abduction than without hip adduction and abduction. The VMO/VL ratio was significantly greater. The squat exercise produced significantly greater VMO and VL activity than the semisquat exercise, regardless of hip position. However, there were no significant differences in VMO/VL ratio between semisquat and squat exercise. CONCLUSION: Combining isometric hip adduction using theraband during semisquat exercise produced higher VMO/ VL ratio through more selective VMO activation and could be easy and effective rehabilitation program in patellofemoral pain syndrome.

Electromyographic Analysis of Muscle Activities of Knee Joint in Patients with Patellofemoral Pain Syndrome / 中国康复理论与实践

@#Objective To analyze electromyographic (EMG) activities of vastus medialis obliquus (VMO) and vastus lateralis (VL) in patients with patellofemoral pain syndrome (PFPS) before and after an exercise program.Methods 26 subjects with PFPS were randomly divided into the EMG biofeedback plus exercise group (group A) and exercise only group (group B) with 13 cases in each group. All patients in two groups were trained with family exercise program, but the patients of the group A used a EMG biofeedback while training. The relative activities of VMO and VL of all patients in two groups were assessed with the EMG apparatus for a continuous 6 hours period before and 8 weeks after training. At the same time the intensity of the knee pain was also assessed.Results There was no statistics difference in VMO/VL EMG ratio of the group B ( P>0.05), whereas the group A had significantly higher VMO/VL EMG ratio ( P<0.05).Conclusion The EMG biofeedback apparatus used in home exercise program of PFPS patients can improve the recruitment of VMO.