Background: Knee exercises are generally recommended following knee-related operations. Nevertheless, compliance in performing self-administered exercises is varying. The use of exergames may alter patient compliance. These computer games encourage the user to exercise. Exergames are not yet used much in orthopedic rehabilitation. The aim of this study was to analyze the influence of different seating positions in electromyography while performing knee exercises with the exergame GenuSport.
Material and methods: 72 healthy women and men were tested in 6 seating positions using an application-based knee-training device (KT). Positions were 1. user seated 90 upright with straight leg on KT, 2. 90 upright with leg exercising in external rotation on KT, 3. 90 upright with leg exercising in internal rotation on KT, 4. 90 upright with straight leg on 30mm elevated KT, 5. 45 upright with straight leg on KT and 6. 45 upright with straight leg on 30mm elevated KT. Electromyogram was recorded for biceps femoris, rectus femoris, semitendinosus, vastus medialis, adductor magnus and vastus lateralis.
Results: No significant difference was shown in position 2, 3 or 4 compared to position 1. In position 5 and 6, EMG reported significantly higher values compared to positions 1 to 4 (ischiocrural: 130% and quadriceps: 90%). The quadriceps was activated significantly less in position 6 compared to 5.
Conclusion: 1. Bedside-based knee extension exercises are most effective in a seated position of 45 trunk inclination. 2. A slightly more bent knee (KT elevation of 30mm) leads to a higher activation of the ischiocrural muscles.
Keywords: EMG; app-based rehabilitation; knee; muscle activity.