The safety and productivity of workers engaged in materials handling has been a topic of interest to industrial engineers and ergonomists for some time. One of the fundamental questions that has generated considerable research is that of how to define and measure material handling capacity. The potential role of human muscle power and the resultant capacity to exert power on an external load as a measure of materials handling capacity is explored. Aside from applied literature in the exercise and sports science disciplines supporting this notion, a more theoretical basis is provided by the muscle physiology and morphology literature. The further empirical investigation of power as a means of defining materials handling capacity is supported.