Influence of Relative Adiposity on Static Back Extensor Muscle Endurance in Apparently Healthy Adults

Few studies have sought to gain insight into the determinants of endurance capacity of the back extensor muscles. This study investigated the influence of body fat on the endurance of the back extensor muscles using different measures of adiposity in apparently healthy Nigerian adults. Three hundred and seventy-six consecutive adults aged 38.9 ± 13.5 years participated in the study. The participants performed the Biering-Sørensen test of static muscular endurance, and their height, weight and percentage body fat (PBF) were measured using standard procedures. Body mass index (BMI), lean body mass and body fat mass were calculated. Descriptive statistics of mean and standard deviation, ANOVA and multiple regression analysis were used. The a level was set at 0.05. A significant difference (p = 0.000) was found in the isometric holding time (IHT) of the underweight (131.04 ± 49.61 seconds), normal (125.52 ± 46.3 seconds), overweight (85.61 ± 37.24 seconds) and obese (73.02 ± 41.67 seconds) categories using the BMI definition. Significant differences (p = 0.000) were found in the IHT among the lean, acceptable, moderately overweight and overweight categories for males and females using the PBF classification. After controlling for age, sex and other anthropometric factors, BMI was significantly associated (p = 0.000) with IHT, accounting for approximately 40% of the variability in back muscle endurance; PBF was significantly associated (p = 0.000) with IHT for males and accounted for approximately 50% of the variability in males and females. Overweight and obesity are important factors in the aetiology of decreased back extensor muscle endurance. Approaches to reduce decreased back muscle endurance and the risk of low back pain may include prevention of overweight and obesity.