The effect of workplace based strengthening on low back injury rates: A case study in the strip mining industry.

The purpose of this study was to demonstrate the effect of a once a week exercise program focused specially at lumbar extensor strengthening. This is a comparative study where workers volunteered to exercise were compared to workers who did not exercise. Low back claims for one year were noted to document efficacy of the training program. Change in strength was also noted. There was a 54% to 104% increase in strength during a 20 week program. The incidence of back injuries in the exercise group was 52 injuries per 200,000 employee hours versus the industry average of 1.09 back injuries per 200,000 employee hours. The average incidence of injury for the previous nine years at the company participating in the program was 2.94 injuries per 200,000 employee hours. The injury incidence in the workers not exercising was 2.55 injuries for 200,000 employee hours. The average workers' compensation liability dropped from $14, 430.00 per month to $380.00 per month for the study year. The significant increase in strength associated with the exercise program correlated with the greatly reduced incidence of back claims.