Vastus medialis oblique: vastus lateralis EMG activity ratio during postural perturbations in athletes with and without patellofemoral pain syndrome

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.
12 athletes with Patellofemoral pain syndrome (age 23.23±3.70 year, height 179±7.00 cm, and weight 73.86±12.00 kg) 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 was analysed by Independent-t test at the significance level was set as P≤0.05.
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=0.568) and backward perturbation (p=0.521).
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.