The clamshell exercise was employed to strengthen the GMed muscle (Boren et al., 2011 (link)). Four progressions were used to increasingly loading the GMed from 47% to 77% of its maximum voluntary isometric contraction. The written informed consent for publication was received from the participant in the figure (Fig. 3). Progressions 1 to 3 were performed in side-lying with the exercising leg on top, hips flexed 45 degrees, knees slightly flexed, and feet together. Progression 4 was performed with the hip in a fully extended position. All exercises in the progression were held for 5 sec and performed for 10 repetitions with a 10-sec rest between repetitions. The participants began with the exercise corresponding to their baseline muscle strength. The exercise was performed 5 days per week for 8 weeks.