Obesity effect on isometric strength of the trunk extensors

Trunk muscle strength could contribute to overexertion and falls related back injuries. With obesity, greater trunk extensor muscle is expected to overcome the additional mass especially those accumulated in the abdomen area. The objective of this study was to investigate the extent of obesity effect on maximum trunk extensor muscles' capacity. 33 females and 35 males in three age-matched groups of normal weight, overweight, and obese completed four replications of three repeated maximum voluntary isometric contractions (MVICs) of trunk extensor muscles. Obesity impairment was evident in the strength per kilogram body mass (BM) and fat-free mass (FFM). FFM and age explained 60% of the variability of the trunk strength. The findings of this study suggest an inferior performance with obesity in complex tasks requiring high intensity strengths.