Does team lifting increase the variability in peak lumbar compression in ironworkers?

Ironworkers frequently perform heavy lifting tasks in teams of two or four workers. Team lifting could potentially lead to a higher variation in peak lumbar compression forces than lifts performed by one worker, resulting in higher maximal peak lumbar compression forces. This study compared single-worker lifts (25-kg, iron bar) to two-worker lifts (50-kg, two iron bars) and to four-worker lifts (100-kg, iron lattice). Inverse dynamics was used to calculate peak lumbar compression forces. To assess the variability in peak lumbar loading, all three lifting tasks were performed six times. Results showed that the variability in peak lumbar loading was somewhat higher in the team lifts compared to the single-worker lifts. However, despite this increased variability, team lifts did not result in larger maximum peak lumbar compression forces. Therefore, it was concluded that, from a biomechanical point of view, team lifting does not result in an additional risk for low back complaints in ironworkers.