Modeling of maximum endurance time for one-handed carrying tasks

The objective of this study was to establish models to predict maximum endurance time (MET) for one-handed carrying tasks. A one-handed carrying experiment, under three loads and two walking speeds, was performed. The participant carried a dumbbell on the side using either dominant or nondominant hand. His or her arm was straight-down. The MET values were collected. Both power and exponential functions were adopted in establishing simplified MET models considering the relative force (f_MVC) applied. The simplified models were further expanded to full models where body weight and walking speed were also included. It was found that the power models provided better estimates than the exponential models when the f_MVC was lower than approximately 0.17 for both the simplified and full models. Considering the effects of the walking speed, the full models are recommended when the f_MVC is 0.3 or lower.