The effect of a soft active back support exosuit on trunk motion and thoracolumbar spine loading during squat and stoop lifts

Abstract

Back support exosuits aim to reduce tissue demands and thereby risk of injury and pain. However, biomechanical analyses of soft active exosuit designs have been limited. The objective of this study was to evaluate the effect of a soft active back support exosuit on trunk motion and thoracolumbar spine loading in participants performing stoop and squat lifts of 6 and 10 kg crates, using participant-specific musculoskeletal models. The exosuit did not change overall trunk motion but affected lumbo-pelvic motion slightly, and reduced peak compressive and shear vertebral loads at some levels, although shear increased slightly at others. This study indicates that soft active exosuits have limited kinematic effects during lifting, and can reduce spinal loading depending on the vertebral level. These results support the hypothesis that a soft exosuit can assist without limiting trunk movement or negatively impacting skeletal loading and have implications for future design and ergonomic intervention efforts.

Practitioner Summary

Back support exosuits have the potential to reduce musculoskeletal workplace injuries. We examined and modelled the impact of a soft active exosuit on spine motion and loading. The exosuit generally reduced vertebral loading and did not inhibit trunk motion. Results of this study support future research to examine the exosuit as an ergonomic intervention.

Keywords:

• Musculoskeletal modelling
• lifting
• exosuit
• lift technique

Acknowledgements

The study team would like to acknowledge Sarah Sullivan from the Wyss Institute Clinical Research Team for her contributions to the study protocol and data use agreement making this study possible, and all study participants. We acknowledge Chen Mo, DrPH, for advice in planning the statistical analysis.

Disclosure statement

C.J.W. and J.C. are inventors of at least one patent application describing the exosuit components described in the paper that have been filed with the U.S. Patent Office by Harvard University. Harvard University has entered into a licencing agreement with Verve Inc., in which C.J.W., and J.C. have an equity interest and C.J.W. has a board position. All other authors report no conflict of interest.

Additional information

Funding

This work was supported by the Department of Defense [CDMRP W81XWH-20-1-0608 and CDMRP W81XWH-20-1-0609], and the National Institute of Health [1UH2AR076731-01].