Obesity-related differences in muscular capacity during sustained isometric exertions

Over one-third of the world adult population is overweight or obese, and the prevalence continues to increase. Obesity is a risk factor for injury, and the growing prevalence may be associated with increases in the future incidence and cost of injuries. In this study, we examined obesity-related differences in muscular capacity during sustained isometric exertions involving hand grip, shoulder flexion, and trunk extension. Thirty-six young individuals who were obese or not obese (aged 18–29) completed these exertions at fixed levels of absolute loads involving low-moderate levels of effort. Individuals who were obese had an overall ∼20% higher absolute strength, but ∼20% lower relative strength. These differences were most evident in the hand grip and shoulder exertions. Parameters of fitted exponential relationships between endurance time and task demands (as a percentage of strength) were similar in both groups. Perceptual and performance responses were also consistent between groups. Accordingly, we conclude that obesity may not substantially influence muscular capacity for these tasks.

► Absolute strengths for upper extremity and torso exertions increase with obesity.
► In contrast, relative strength for these tasks is decreased with obesity.
► Endurance time vs. effort level was not substantially affected by obesity.
► Obesity did not influence motor performance during sustained endurance tasks.
► Future work should assess obesity-related differences in more complex situations.