Gluteus Medius and Minimus Muscle Structure, Strength, and Function in Healthy Adults: Brief Report

This article describes gluteus medius and minimus muscle thickness and hip abductor strength and function in healthy adults and explores the relationships between muscle thickness and function. Gluteus medius and minimus muscle thickness (B-mode ultrasound), isometric hip abductor strength (Biodex dynamometer), and lower extremity function (timed Trendelenburg test, Five-Times-Sit-to-Stand Test [FTSST], and lateral step-down test) were measured in healthy adults using a cross-sectional study design. A total of 22 subjects were included: 10 men and 12 women, mean age 25.2 (SD 3.1) years, mean BMI 22.9 (SD 3.5) kilograms per metre squared. Muscle thickness of the gluteals was a mean 3.88 (SD 0.13) centimetres, and mean hip abductor peak torque was 111 (SD 43) newton-metres. FTSST mean time was 5.3 (SD 0.2) seconds, and median scores were 2.0 points for lateral step-down and 90 seconds for timed Trendelenburg. No significant relationships were found between gluteal muscle thickness and functional tests (rs=-0.28 to 0.37, ps=0.09-0.80) or strength (r=-0.24, p=0.28). Although hip abductors are key pelvic stabilizers for functional movements, gluteal muscle thickness was not associated with strength or function. This may be a result of agonist muscle activity, leading to an inability to isolate the gluteals, and to the ceiling effects of the functional tests.