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The evaluation of the effect of lifting belts on multijoint coordinated lifting performance has been limited. Thirteen subjects participated in two experiments: (a) fatiguing repetitive sagittal lifting and (b) asymmetric lifting. Both experiments were performed with and without the use of a common flexible lifting belt to determine the effect of belt use on the trunk and lower extremity motion and load sharing. During both tests, the use of the belt was observed to restrict the sagittal trunk range of motion and velocity, while the hip motion and velocity increased. Although one of the risk factors for acquisition of low back pain may be reduced while wearing the belt, the results also demonstrate a need for greater study of the consequences on the risk of injury to the other joints. More laboratory experiments and prospective epidemiological studies are needed before a conclusive recommendation could be made in favor of using the belt as a valid preventive measure.

Study Design: A repetitive lifting test in the sagittal plane was performed with a submaximal load at a maximal lifting rate to understand the effects of fatigue on kinematic and kinetic measures of performance., Objectives: To quantify the effect of fatigue during a highly repetitive lifting task, in terms of lifting force transmitted to the load, joint motion patterns, and internal joint load sharing., Summary of Background Data: Industrial surveillance and epidemiologic data suggest that repetitive lifting is a risk factor for low back pain. Previous studies examining the effect of fatigue have either been constrained to isolated trunk movement, or have not explored the internal load distribution and potential alteration in the loading patterns., Methods: Sixteen healthy male subjects performed repetitive lifting in the sagittal plane with a load equal to 25% of their maximal lifting capacity, at a maximal lifting rate. Changes in lifting performance were determined from the power transferred to the box, joint kinematics, and joint kinetics. Data from three cycles at the start and end of the exercise were tested for the effect of fatigue using repeated-measures analysis of variance., Results: Fatigue was documented by a reduction in average lifting force and hip and spine torque generation, whereas internal joint load sharing was relatively unchanged. The fatigue was associated with decreased knee and hip motion, and increased lumbar flexion. Decreased postural stability also was evident., Conclusions: The significant decrease in postural stability and force generation capability because of the repetitive lifting task indicated a higher risk of injury in the presence of unexpected perturbation. Multijoint coordinated lifting tasks provide a more realistic protocol to study neuromuscular fatigue.