The effect of back belt use on isometric lifting force and fatigue of the lumbar paraspinal muscles.

STUDY DESIGN

A repeated measures multivariate design to assess the effect of back belts on isometric lifting force and lumbar paraspinal muscle fatigue.

OBJECTIVE

To determine the efficacy of lumbar back belts in minimizing a loss in isometric force production and fatigue of lumbar paraspinal muscles.

SUMMARY OF BACKGROUND DATA

Increased prevalence of back belts in industry and lack of scientific evidence supporting them suggested additional research was needed. There has been no conclusive research to substantiate manufacturer claims that use of belts reduces fatigue of lumbar paraspinals.

METHODS

Twenty-four subjects, 13 men and 11 women, were tested twice: once with and once without a belt. All subjects performed a dynamic lifting task at a rate of 10 lifts per minute for 20 minutes. Surface electromyograms from the lumbar paraspinals and isometric force measurements were recorded during a static maximal isometric lift at 0, 10, and 20 minutes. Load during the dynamic task was determined as 20% of initial maximum isometric force. Electromyographic data were used to detect changes in median power spectral frequencies. Muscular fatigue was indicated by a reduction in median power spectral frequency values or a decrease in isometric force-generating capacity.

RESULTS

Multivariate and univariate analyses suggest that there is no effect on lumbar paraspinal muscle fatigue or isometric lifting force production as a result of back belt use.

CONCLUSIONS

These findings do not support the use of back belts for the purpose of minimizing either lumbar paraspinal muscle fatigue or a loss in isometric lifting force production.