The Effect of Extended Durations of Walking in Different Footwear on Measures of Muscle Activity

In 2010, nearly 3.1 million nonfatal workplace injuries and illnesses were reported among private industry employers resulting in an incidence rate of 3.5 cases per 100 full time workers, according to the Bureau of Labor Statistics. Of the fatal occupational injuries in 2010, 14% were attributed to falls. Forty-five percent of falls have been attributed to inappropriate footwear, and occupationally induced muscle fatigue has been identified as a contributing factor to falls. Different footwear types have been shown to effect muscle fatigue levels during walking and standing. In an occupational setting, workers generally endure relatively small workloads for extended durations. The puipose of this study was to examine the amount of muscle activation of the ankle musculature over an extended duration of walking and standing in two types of commonly worn occupational footwear. Fourteen healthy male adults with no history of orthopedic, musculoskeletal, cardiovascular, neurological or vestibular abnormalities completed the study. The experimental session included an extended duration of walking (4 hours) with muscle activation of the ankle musculature during a maximal voluntary contraction measured at 30 minute intervals. The footwear included work boots that met .ANSI standards and low top shoes. A minimum of 72 hours of rest between conditions was provided. Repeated measures analyses of variance determined there were no significant differences between the time points for footwear or the time-shoe interaction. Significance was found with shoe type with the low top shoe eliciting greater activation for both muscles. Shaft height of the shoe may have been the significant influencing factor affecting muscle activity of the lower extremities. The work boots with the higher shaft showed more potential for resisting fatigue over extended durations. The results of this study may be beneficial in the aid of efficient design of future footwear to be worn in occupational settings