Comparative Analysis of Hip Muscle Activation During Closed-Chain Rehabilitation Exercises in Runners

Background: Increased hip adduction and internal rotation during the early stance phase of running have been linked to an increased risk of lower extremity injury. Both the gluteus maximus (GMAX) and gluteus medius (GMED) eccentrically control these motions. GMAX and GMED activation levels during commonly used rehabilitation exercises requires further exploration. Hypothesis/Purpose: The purpose of this study was to compare peak surface electromyography (sEMG) amplitudes of GMAX and GMED between three closed-chain rehabilitation exercises: bilateral hip external rotation with resistance band (BER), forward lunge with resistance band (FL), and single-leg rotational squat (SLS). It was hypothesized that the FL would elicit greater peak amplitude in the GMAX and GMED than SLS and BER. Study Design: Descriptive, observational cohort study. Methods:Twenty-two healthy runners (14 male, 8 female) had sEMG electrodes placed bilaterally on GMAX and GMED. Participants completed three repetitions each of BER, FL, and SLS exercises with sEMG data normalized to the maximal amplitude recorded at each muscle during the running trial (% MRC). Seven inertial measurement units affixed to the lower extremity measured joint kinematics to enable the exercises to be split into eccentric and concentric phases respectively. Results: There were no significant differences between exercises during the eccentric phases with all peak amplitudes for GMAX and GMED being less than \u3c 30% MRC. Both the SLS (GMAX: 48.2 ± 45.2% MRC, p = 0.019; GMED: 39.3 ± 24.8% MRC, p \u3c .001) and FL (GMAX: 65.8 ± 58.9% MRC, p \u3c .001; GMED: 52.2 ± 34.9% MRC, p Level of Evidence: