The Electromyographic Feedback and Feedforward Activity of Selected Lower Extremity Muscles During Toe-in Landing in Female Athletes

Background: Positioning the legs in performing spike technique significantly contributes to the development and prevention of lower limb injuries. The present study aimed to evaluate and compare the feedback and feedforward activaties of selected lower limb muscles during triple jump spike with and without toe-in landing in female volleyball players. Methods: In this controlled-laboratory study, 15 female elite volleyball players performed triple spike in toe-in and neutral positions. The electrical activity of tibialis anterior, proneus longus, gastrocenemius, vastus medialis, vastus lateralis, semitendinosus, and biceps femoris muscles was recorded using a 16-channel surface electromyography device (Baya Med Company). The Dependent Samples t-test was applied to analyze the obtained data at the 95% confidence level. Results: In toe-in landing, the semitendinosus muscle  activity (P=0.040) significantly decreased in the feedforward phase. Besides, in the feedback phase, there were significant increases in tibialis anterior (P=0.039) and proneus longus (P=0.043). Eventually, a significant decrease was observed in the medial gastrocenemius (P=0.042) and biceps femoris muscle (P=0.047) activities. Conclusion: Decreased biceps femoris muscle activity during the feedback phase with the toe-in position may be associated with the decreased supportive effect of hamstring muscle, increased anterior knee shear force, and subsequently anterior cruciate ligament injury. Increased activity of leg and ankle muscles may also increase the odds of muscular fatigue and subsequent ankle sprain during toe-in landing.