Insole Program in the Manufacturing Setting: Impact on Lower Extremity Muscle Activity

Hasbro Games in East Longmeadow, Massachusetts sought to evaluate the impact of their year-long companyinstituted footwear insole program after removing floor mats. The employees subjectively reported reduced aches and pains while standing and working on concrete factory floors with the insoles; but because there was no objective data to substantiate their responses, the actual mechanism influencing the reported reductions in aches and pains remained unknown. Hasbro and the American International College's physical therapy program collaboratively designed a study using electromyography (EMG) to investigate the potential difference in lower leg muscle activity with and without the insoles. Of the several employees who volunteered, 43 were randomly selected to participate in the EMG insole study. All participants reported standing or walking on concrete floors for 60 to 90 percent of their workday. Results of the EMG study disclosed a consistent reduction in lower leg muscle activity for both of the muscle groups using the company-issued polyurethane insoles compared with no insoles. There was a statistically significant reduction for peak and average Medial Gastrocnemius muscle activity and peak Tibialis Anterior with insole trials. While there was a reduction in average Tibialis Anterior muscle activity, the level was not statistically significant. Reducing lower leg muscle activity would have an accumulating beneficial effect for employees throughout daily, weekly, and annual work tasks. The greatest potential may be realized for those engaged in the utilities, transportation, hospitality, and service sectors of the economy.