Background: Drywall installation has an injury rate four times that of the construction industry average. Workers are exposed to hazards related to slips, falls, and falling objects, in addition to the large and awkward loads they must carry. Drywall sheets can weigh more than 100 lb. and contribute to disabling musculoskeletal injuries of the shoulders and back.
Objective: In this study, an unpowered lift assist device was developed to manage the load of a drywall sheet during the installation process.
Methods: In order to measure the effect of the lift assist device, a laboratory study with 10 healthy male participants performing two lifts, lifting from ground to erect and lifting from erect to ceiling, with and without the help of the device, was performed. These lifts were chosen to simulate a drywall installer's frequent lifting motions. Participants were fitted with electromyography (EMG) on the erector spinae, latissimus dorsi, rectus abdominus, and external oblique muscles to measure activation. Mean, peak, and effort data for the lifting exercises were extracted and compared to the unassisted lift.
Results: The lift assist device resulted in a reduction in mean EMG signal of 69% average over both lifts and muscle groups. Peak EMG and effort (i.e., area under the curve) were reduced by 78% and 75%, respectively.
Conclusions: These data demonstrate the effectiveness of the device in reducing compressive back loads during drywall installation, which warrants future development.
Keywords: Drywall lifting; back injury; back pain; construction; occupational injuries.