Objective: The gluteus medius (GM) is a strong abductor and medial rotator of the thigh, and plays an important role in stabilizing the pelvis and controlling the knees during athletic activities.Weakness in the GM can have adverse effects onperformance and increase the risk of lower extremityinjuries. The aim of this study was to validate a newtraining device by comparing the activation of theGM when performing a squat with and without thedevice. Methods: Thirty-two female athletes (mean age 20 ± 3) performed body weight squats on and offthe device, while surface electromyography wasrecorded bilaterally on the GM. Results: All testsubjects were able to perform the squat and toactivate the GM. The activation of the GM was significantly higher when using the new device than when performing squats on the floor (Z=-4.9,P<0.001). Correlation tests between a complete sequence of three squats and one selected repetition revealed that activation was consistent throughout theexercise (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: The newly developed training device increases muscle activity in the GM during squats. Moreover, the results showed thatsquatting on the device activates the left and rightside of the body equally, and that the GM was activated during the whole hip flexion exercise. This information and the new training device can be usedin training programs to improve stabilization of the pelvis and lower extremities during dynamic exercises.