Whether lifting, pushing, or pulling, manual handling of materials produces stress on the musculoskeletal system, leading to hundreds of thousands of worker injuries annually. The Bureau of Labor Statistics consistently reports sprains, strains, and tears as the most prevalent injury type, resulting in days away from work.
Body mechanics training and back belts have historically been common responses to the problem. However, literature reviews and case-control studies have shown both to be ineffective at impacting injury rates. Injury prevention efforts focused on influencing body mechanics through the use of training and back belts should be redirected toward the approach that has long been validated as effective in the literature—the redesign of high-risk tasks.
Curious to see examples of task redesign and to learn more on this topic? Check out ICW Group’s webinar, Sprains and Strains: Why Your Prevention Efforts Aren’t Working!
What you need to know about back belts
A widely cited study sought to measure the impact of a robust training program for US postal distribution center workers. An intervention group of over 2,500 workers received two initial hour-and-a-half-long, hands-on training sessions conducted by physical therapists. In addition, refresher sessions were administered throughout the duration of the study. Five-and-a-half years after the program’s implementation, there was no statistically significant difference between the intervention group’s rate of low back injury and that of the control group of workers who did not participate in the training program.
Both back belts and body mechanics training share a common goal – to encourage workers to maintain a straight back while lifting. There is evidence that back belts can be successful at reducing back bending and yet they still fail to reduce rates of injury. This leads one to question the premise behind these interventions. Namely, back bending during lifting results in a significantly higher risk of injury.
Despite the conventional wisdom, the evidence challenges this assumption. A 2016 study used vertebral implants to measure the compressive forces on the spine for participants asked to lift items using both squat and stoop postures. The researchers found that the spinal loads did not substantially differ between the two techniques. A second study produced similar results when the participants were positioned over the item being lifted but found that squat lifting actually resulted in higher compressive force on the spine when lifting with the feet positioned behind the item. The researchers note that a likely explanation is the fact that, in some situations, squat lifting leads to a greater horizontal distance between the lower back and the item being lifted. Squat lifting can also prompt workers to stand further from an item to allow it to clear the knees as they bend forward. In light of the evidence, it is recommended that workers be encouraged to assume the posture that is most comfortable for them.
