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. 2021 Jul 29;18(15):8062.
doi: 10.3390/ijerph18158062.

Effectiveness of Soft versus Rigid Back-Support Exoskeletons during a Lifting Task

Mathilde Schwartz  1   2 , Jean Theurel  1 , Kévin Desbrosses  1
Affiliations

Effectiveness of Soft versus Rigid Back-Support Exoskeletons during a Lifting Task

Mathilde Schwartz et al. Int J Environ Res Public Health. .

Abstract

This study investigated the influence of passive back-support exoskeletons (EXOBK) design, trunk sagittal inclination (TSI), and gender on the effectiveness of an exoskeleton to limit erector spinae muscle (ES) activation during a sagittal lifting/lowering task. Twenty-nine volunteers performed an experimental dynamic task with two exoskeletons (two different designs: soft (SUIT) and rigid (SKEL)), and without equipment (FREE). The ES activity was analyzed for eight parts of TSI, each corresponding to 25% of the range of motion (lifting: P1 to P4; lowering: P5 to P8). The impact of EXOBK on ES activity depended on the interaction between exoskeleton design and TSI. With SKEL, ES muscle activity significantly increased for P8 (+36.8%) and tended to decrease for P3 (-7.2%, p = 0.06), compared to FREE. SUIT resulted in lower ES muscle activity for P2 (-9.6%), P3 (-8.7%, p = 0.06), and P7 (-11.1%), in comparison with FREE. Gender did not influence the effect of either back-support exoskeletons on ES muscle activity. These results point to the need for particular attention with regard to (1) exoskeleton design (rigid versus soft) and to (2) the range of trunk motion, when selecting an EXOBK. In practice, the choice of a passive back-support exoskeleton, between rigid and soft design, requires an evaluation of human-exoskeleton interaction in real task conditions. The characterization of trunk kinematics and ranges of motion appears essential to identify the benefits and the negative effects to take into account with each exoskeleton design.

Keywords: EMG; handling task; low back pain; musculoskeletal disorders; occupational back-support exoskeleton; wearable assistive device; workload.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Experimental task performed. The range of motion of trunk sagittal inclination (TSI) was divided into four equal parts for the lifting action (A: low (P1) to high platform (P4)) and for the lowering action (B: high (P5) to low platform (P8)).
Figure 2
Figure 2
The two exoskeletons used; (A) soft back-support exoskeleton or exosuit (SUIT) (Corfor®-V2, Villemus, France), and (B) rigid back-support exoskeleton (SKEL) (Laevo®-V1, Deft, The Netherlands).
Figure 3
Figure 3
Averaged ES muscles activity (% RMSREF) and standard deviation in women (W) and men (M), with the use of the rigid exoskeleton (SKEL, gray), the exosuit (SUIT, black), and without equipment (FREE, white). *: significant differences between exoskeletons (p < 0.05). No interaction between exoskeleton and gender was reported.
Figure 4
Figure 4
Averaged trunk sagittal inclination (TSI, in °) and standard deviation for each TSI part (from P1 to P8) of the lifting/lowering task (LLT) with the rigid exoskeleton (SKEL, gray), the exosuit (SUIT, black), and without equipment (FREE, white). 0° = straight posture. *: significant differences between exoskeletons (p < 0.05).
Figure 5
Figure 5
Averaged ES muscle activity (% RMSREF) and standard deviation for each TSI part (from P1 to P8) with the rigid exoskeleton (SKEL, gray), the exosuit (SUIT, black), and without equipment (FREE, white). *: significant differences between exoskeletons (p < 0.05).
See this image and copyright information in PMC

References

    1. De Looze M.P., Bosch T., Krause F., Stadler K.S., O’Sullivan L.W. Exoskeletons for industrial application and their potential effects on physical work load. Ergonomics. 2016;59:671–681. doi: 10.1080/00140139.2015.1081988. - DOI - PubMed
    1. Theurel J., Desbrosses K. Occupational Exoskeletons: Overview of Their Benefits and Limitations in Preventing Work-Related Musculoskeletal Disorders. IISE Trans. Occup. Ergon. Hum. Factors. 2019:1–17. doi: 10.1080/24725838.2019.1638331. - DOI
    1. Kermavnar T., de Vries A.W., de Looze M.P., O’Sullivan L.W. Effects of industrial back-support exoskeletons on body loading and user experience: An updated systematic review. Ergonomics. 2021;64:685–711. doi: 10.1080/00140139.2020.1870162. - DOI - PubMed
    1. Frost D.M., Abdoli E.M., Stevenson J.M. PLAD (personal lift assistive device) stiffness affects the lumbar flexion/extension moment and the posterior chain EMG during symmetrical lifting tasks. J. Electromyogr. Kinesiol. Off. J. Int. Soc. Electrophysiol. Kinesiol. 2009;19:e403–e412. doi: 10.1016/j.jelekin.2008.12.002. - DOI - PubMed
    1. Ulrey B.L., Fathallah F.A. Effect of a personal weight transfer device on muscle activities and joint flexions in the stooped posture. J. Electromyogr. Kinesiol. Off. J. Int. Soc. Electrophysiol. Kinesiol. 2013;23:195–205. doi: 10.1016/j.jelekin.2012.08.014. - DOI - PubMed

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