Effects of a passive shoulder exoskeleton on muscle activity among Danish slaughterhouse workers.

AIM

To evaluate the effect of a shoulder exoskeleton on muscle activity and to compare the effect with a lifting glove among slaughterhouse workers in occupational settings.

MATERIALS AND METHODS

We conducted a crossover study of 26 workers measured during two work days with and without the use of a passive shoulder exoskeleton and a lifting glove at a Danish slaughterhouse. Electromyography sensors were placed bilateral on 5 shoulder muscles. The 10th, 50th, and 90th percentiles of muscle activity normalized by maximal voluntary contractions were measured and analyzed using mixed effect models.

RESULTS

For the 50th percentiles of the agonist muscles, the exoskeleton reduced muscle activity bilaterally for deltoid anterior with up to 29.47%, deltoid middle with 10.22%, and upper trapezius with 22.21%. The lifting glove only reduced muscle activity for right deltoid anterior (36.59%) and upper trapezius (7.11%), but generally increased left muscle activity with up to 15.58%.

DISCUSSION

The exoskeleton showed larger reductions in muscle activity compared to the lifting glove.