Comparison of the gluteus medius strength between obese and eutrophic individuals: a cross-sectional study

Abstract

Background: The hip abductor muscles play an important role in stabilizing the pelvis during gait, with its main function being performed by the gluteus medius. Gluteus medius insufficiency is associated with biomechanical alterations and musculoskeletal disorders. Due to being overweight and a possible muscle mass decrease, maintaining the abductor muscular function can be a great challenge for the obese. However, it is still unclear whether the musculature of obese individuals manages to compensate for these alterations. Therefore, the aim of this study was to compare the gluteus medius strength between obese and normal weight individuals using a digital hand-held dynamometer.Methods: Twenty-five obese (BMI > 35 kg / m2) participated in the study, being matched in gender, age, and height with normal weight individuals. The gluteus medius strength was measured by a single examiner using a belt-stabilized hand-held digital dynamometer on the knee of individuals positioned in lateral decubitus. Three measurements were recorded with rest intervals, considering only the highest value measured for each limb for analysis. The difference between pairs was calculated and the data distribution pattern was assessed using the Shapiro-Wilk test (p < 0.05), and the matrices of the variables were standardized and analyzed using the principal component analysis (PCA).Results: For the strength variables (Newtons) on both sides, no statistical differences were detected between the groups (p > 0.05). However, statistical differences were detected in these variables between the groups (p < 0.05) when normalizing the measurements in relation to individuals' weights (Newtons / kilograms). The PCA indicates that both strength in absolute values and normalized by weight are reduced in obese individuals.Conclusions: These findings indicate that obese individuals have the same or lower strength (PCA) to move more mass, which may suggest a relative weakness that induces functional limitation.Trial registration: The study was approved by the UNIOESTE Human Research Ethics Committee (#1.180.202) in July 2015.