This article evaluates the effectiveness of two interventions: a self-leveling pallet carousel designed to position the loads vertically and horizontally at origin, and an adjustable cart designed to raise loads vertically at destination to reduce spine loads.

Low back disorders among workers in manual material handling industries are very prevalent and have been linked to manual palletizing operations. Evidence into the effectiveness of ergonomic interventions is limited, with no research that investigates interventions with adjustable load location.

Thirteen males experienced in manual material handling participated in simulated order selecting tasks where spine loads were quantified for each intervention condition: carousel to traditional cart, pallet to traditional cart, pallet to adjustable cart, and carousel to adjustable cart.

The results showed that combining both devices results in reduction in spine compression (61%), anterior-posterior shear (72%), and lateral shear (63%) compared to traditional palletizing conditions. Individually, the carousel was responsible for the greatest reductions, but the lowest values were typically achieved by combining the adjustable cart and carousel.

The combination of the interventions (self-leveling carousel and adjustable cart) was most effective in reducing the spine loads when compared to the traditional pallet-cart condition. The individual interventions also reduced the loads compared to the traditional condition.

With de-palletizing/palletizing tasks being a major source of low back injuries, the combination of self-leveling carousel and adjustable cart has been found to be effective in reducing the peak spine loading as compared to traditional pallet on floor and nonadjustable flat cart conditions.