Effect of Prior Mental or Physical Fatigue on the Biomechanical Response During a Lifting Task

Abstract

Repetitive lifting is a requirement in many occupations and often leads to prevalent and costly back injuries. What is unknown is how fatigue, whether mental or physical, occurring before the primary lifting task impacts the biomechanical response during the task. Study participants completed three lifting tasks with prior mental fatigue (Stroop test), prior physical fatigue (running on a treadmill), or no prior fatigue. Electromyography (EMG) was used to measure muscle activity and fatigue, and Borg’s Rating of Perceived Exertion (RPE) was also assessed. Muscle activation data and RPE data indicated that both prior mental and physical fatigue increases muscle activation and perceived exertion.