A New Training Device To Optimize Muscle Activation Of The Gluteus Medius During Progressive Hip Flexion

Abstract: Abstract Background: The Gluteus Medius (GM) muscle has an important role in stabilizing the pelvis and controlling the knees during athletic activities. Weakness in the GM can affect performance negatively and increase the risk of lower extremity (LE) injuries. During functional activities different parts of the muscle becomes activated depending on the degree of hip flexion. However, many GM strength exercises only train the GM in one fixed degree of hip flexion. Purpose: The purpose of the present study was to develop and validate a new training device designed to increase the muscle activation of the GM during progressive hip flexion in squats. Methods: The new device was developed to offer resistance training against hip abduction during squats. To be able to validate the new device in activating the GM, 32 female athletes (mean age 20 ± 3) with various athletic backgrounds was included in the study. All subjects performed squats on and off the device while surface electromyographical (SEMG) activity was recorded from GM on both sides of the body. Results: All test subjects were able to perform the squat and to activate the GM. When the squats were performed on the new device the muscle activation in GM was significantly higher compared to bodyweight squats (Z=-4.9, p < 0.001). Correlation tests between a complete sequence of five squats and one selected repetition revealed that activation was consistent throughout the exercise, (right GM: rs = 0.93, p < 0.001, left GM: rp = 0.92, p < 0.001) . No differences in activation were found between the right and left GM when squatting on the device. Conclusion: This study showed that the newly developed training device increased the muscle activity in GM during squats. Moreover, the results showed that squatting on the device activates the left and right side of the body equally and that the GM was activated during the whole exercise, under ongoing hip flexion. This information could be used to develop new training methods with the aim to improve stabilization of the pelvis and lower extremities during functional activities.