Selective Training Of The Vastus Medialis And Vastus Lateralis Using Emg Biofeedback

Twenty-one subjects suffering from various knee problems of a neuromuscular nature were randomly divided into a treatment (N = 10) and a control (N = 11) group. Their clinical picture presented with conditions such as patella dislocation and subluxation, patella alta, lateral tracking syndrome, and chondromalacia, with symptoms such as pain, swelling, tenderness, VMO atrophy, locking, and limited ROM. In an attempt to investigate whether selective training of the vastus medialis (VM) and the vastus lateralis (VL) with the use of EMG biofeedback is possible, treatment group subjects were provided with EMG biofeedback, whereas control group subjects were placed in a no-treatment treatment waiting condition. All subjects were evaluated during baseline, treatment, and one month follow-up on five exercise conditions that are characteristic for adversely influencing the patellofemoral mechanism: knee extensions, knee extensions with resistance, deep knee bends, deep knee bends with the affected leg only, and taking a step on a stool with the affected leg. The averages of the difference in the recorded EMG values of these two muscles served as indicators of change, and these data were treated statistically. Multivariate analyses of variance showed that the treatment effect was significant for the treatment group but there was no change in the control group. Consequently, the control group was provided with treatment as well, and multivariate analysis of variance testing revealed that, following treatment, subjects in this group improved as much as those in the original treatment group and that the treatment effect remained until the follow-up evaluation for all subjects. The clinical picture of all subjects improved markedly, closely following progress in their ability to selectively coordinate the activity of these two muscles