Determining what should be taught during lift-training instruction

Abstract

Every year many workers who perform manual materials handling tasks receive training on lifting techniques. The goal of these training programs is to reduce the biomechanical loads experienced by the spine, thereby reducing the potential for low back injury. The purpose of this article was to determine the effectiveness of specific lifting techniques used in the training of 955 material handling workers at 14 grocery, retail, and beverage distribution centers in controlling the three-dimensional spine moments experienced during simulated work tasks. Each subject underwent up to five one-on-one training sessions with a coach over a 12 month period (time = 0, 1 month, 3 months, 6 months, and 9 months) while instrumented with the LiftTrainer TM biofeedback system. This PC-based system quantified the tri-axial moments at L5/S1 as trainees lifted and provided the coach with real-time audio feedback and post-lift charting to quantify progress. The coach used the objective data in guiding the trainee towards behaviors that reduced one or more of the directional moments. Within each training session, several different techniques were usually suggested by the coach. At the completion of the session each trainee was rated on a 4-point scale as to how well each of the techniques was adopted. These scales became the independent variables in three multiple regression analyses used to determine which techniques account for the within session change in the moment values and which could best be used to predict performance at the end of a session. Results indicated that trainees should be taught to slide boxes close prior to lifting, move the box and body together, initiate the lift by shifting the gaze upward, and think strategically about the lifting task in order to reduce the forward bending moments. Twisting moments were reduced by keeping the box close, moving the feet, and moving the box and body together. The lowest side-bending moments occurred with smoother lifts and the use of body english during load placement.