Hip and knee muscles co-activation ratio during hip-focused exercises: a multichannel surface electromyography study

This study aimed to evaluate the muscle activation ratio of hip and knee during hip-focused exercises. Eleven active university students performed 13 hip-focused exercises frequently used in the treatment of knee disorders. The average sEMG amplitude of tensor fasciae latae (TFL), gluteus medius (GMed), gluteus maximus (GMax), adductor longus (AL), vastus medialis (VM), vastus lateralis (VL), and GMed/AL, GMax/AL, and VL/VM ratios were determined. Repeated-measures analyses of variance were performed to determine if there were differences in muscle activation while performing each of the 13 exercises. Sidelying clam-shell had the highest GMax/AL ratio of all the exercises examined. The hip hike exercise (5.36) had the highest GMed/AL ratio. The VL/VM ratio ranged from 0.77 to 1.16. Based on these results, sidelying clam-shell had the highest GMax/AL ratio. The hip hike exercise had a higher GMed/AL ratio compared to other hip-focused exercises. Additionally, forward lunge, squat, and single-leg squat with resistance band around the knee had the highest activity VL/VM ratio among exercises.