The Effect of Back Belt on Maximum Displacement and Center of Pressure Velocity in Different Lifting Styles

Mechanical loading is said to be an important factor in the development of low back pain (LBP). One of the main concerns in manual material handling (MMH) tasks is lifting loads, as this activity is present in most jobs. Despite the controversy about their effectiveness, belts are used in industry as either protective or assistive devices in manual load handling. The present investigation aimed to determine whether a commonly used back belt could improve maximum center of pressure displacement (COPMD) and center of pressure velocity (COPV) as the balance parameters during each of three common styles of lifting (squat, semi-squat, stoop). Twenty healthy female subjects participated in this study who were selected by nonprobability convenience sampling. The participants stood barefoot on the force plate. They lifted a box, weighting 4.53 kg (10 pound). The subjects were instructed to bend their knees (squat) or their lumbar (stoop) or both their knees and lumbar (semi-squat), to grasp the box handles, and to lift the load to the level of greater trochanter height. Half of the subjects performed the 3 trials with wearing belt at first try and the other half performed the trials without wearing the belt at first try. The mean of maximum displacement and velocity showed that there was a trend of increase in these variables in all 3 styles of lifting (squat, semi-squat and stoop) after wearing belt. One-way ANOVA with repeated measures results for COPMD and COPV showed that ‘Belt condition’ significantly affected the dependent variables. Wearing belt may decrease stability caused by increased COPMD and COPV.