The Effects of Performing Bridge Exercise and Hip Thrust Exercise using Various Knee Joint Angles on Trunk and Lower Body Muscle Activation in Healthy Subjects

Objective: This study aimed to identify the effects of assuming different knee angles and hip abduction during bridge exercise and hip thrust exercise on lower body muscle activity. Design: Cross-sectional study Methods: Thirty-three healthy adults (18 men and 15 women) were instructed to perform the bridge and hip thrust exercises while randomly assuming 120°, 90° and 60° of knee flexion and 0° and 30° of hip abduction. EMG data (%maximum voluntary isometric contraction) were recorded three times from the erector spinae (ES), gluteus maximus (GM) and biceps femoris (BF) muscles of participant's dominant side and the mean values were analyzed. Results: The results showed that, during the hip thrust compared to the bridge exercise, there was significantly greater gluteus maximus muscle activity in all hip conditions while the biceps femoris activity was significantly less, and the erector spinae muscle activity was significantly greater with 30° of hip abduction (p<0.05). With all exercises, the erector spinae and the biceps femoris exhibited significantly greater muscle activity with 60° of knee flexion compared to 90° and 120° of knee flexion (p<0.05), and significantly greater muscle activity with 90° compared to 120° of knee flexion (p<0.05). In the case of the gluteus maximus, greater muscle activity was exhibited with 120° compared to 60° of knee flexion with all hip abduction conditions (p<0.05). Conclusions: It was effective for muscle activation of main agonists such as the gluteus maximus and erector spinae during thrust exercise, and the change in knee flexion angle was effective for muscle activation of the gluteus maximus. Therefore, it is considered that this study can be used as a selective indicator of the target movement angle during hip strengthening exercise for specific muscles.