Emg Characteristics Of Elite Trampoline Athletes’ Feet On Impact

PURPOSE: Evaluate the effects of ankle taping, general trampoline shoes, and three different modified trampoline shoes and how they affect trampoline techniques during back tuck jumping. METHODS: Eighteen athletes (13 men and 5 women; age M = 22.83 years old, SD = 4.06, height M = 167 cm, SD = 7.19 cm and weight = M 57.78 kg, SD = 6.29 kg) from the Chinese National Trampoline Team at the Beijing National Trampoline Sport Base who had no major injuries or surgery during the last year. Trigno EMG System was used to measure the EMG signals of bilateral Rectus Femoris, Medial Hamstring, Tibialis Anterior, Lateral Gastrocnemius, and Peroneus Longus while doing a whole set of jumping. The “initial contact” (IC) where from 300 ms to the first or fifth metatarsal head initially makes contact with the trampoline surface. The “full press” (FP) where the calcaneus has the maximum pressure on the net. The “rebounce” (RE) where the fifth metatarsal head is exiting the trampoline surface. Five trampoline shoes were tested, 8-shaped, with insoles, combo (8-shaped/insoles), regular shoes with ankles taped, and regular trampoline shoes. Athletes performed five sets of trampoline jumps with randomly worn shoes. Each muscle’s iEMG (%MVC*ms) and three different time periods were analyzed. RESULTS: The EMG activity increased significantly for Rectus Femoris when wearing 8-shaped and combo shoes. Medial Hamstring had the least EMG activity when wearing combo shoes. EMG values for right dominate leg’s Medial Hamstring increased when wearing 8-shaped shoes during full contact period. EMG values for Tibia Anterior decreased on the right dominate leg when wearing 8-shaped shoes during IC period. EMG values for Peroneus Longus increased during the RB might be due to athletes’ unfamiliarity with insoles. CONCLUSIONS: Wearing the 8-shaped shoe increased right leg Rectus Femoris, Medial Hamstring, and Tibialis aterior EMG activity during IC time and the FP time. This might enable an athlete to increase wanted power to the feet’s impact on the net which results in a higher rebounce. Right Lateral Gastrocnemius EMG activity decreased during RE time when using 8-shaped shoes which enables the athlete to use the rebound energy from the net better. Interviews with the athletes support the EMG findings that 8-shaped trampoline shoes increase performance.