Fatigue-related Changes in Lifting Performance with Obesity
Ghesmaty Sangachin, Mahboobeh
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Despite the rising prevalence of obesity, little is known about its moderating effects on injury risk factors, such as fatigue, in occupational settings. This study investigated the effect of obesity, fatigue and their interaction on lifting performance of 14 participants, 7 obese (mean BMI: 33.2 kg m -2 ) and 7 non-obese (mean BMI: 22.2 kg m -2 ) subjects. To induce fatigue, subjects performed repetitive lifting tasks for 1 hour at 120% of their maximum acceptable weight of lift. Generalized linear mixed models were fit to posture and acceleration data. The obese group bent to a ∼10° lower peak trunk sagittal flexion angle, had 17% lower RMS jerk and took 0.8 seconds longer per lift. Post-fatigue, the obese group increased their trunk transverse and extension accelerations while the non-obese maintained theirs. These changes combined with their greater upper body mass may put individuals who are obese at higher risk of injury while lifting when fatigued.