Muscle Synergies During Repetitive Stoop Lifting With a Bioelectrically-Controlled Lumbar Support Exoskeleton.

Chun Kwang Tan,Kenji Suzuki,Hideki Kadone,Yoshiyuki Sankai,Kousei Miura,Tetsuya Abe,Masao Koda,Masashi Yamazaki

doi:10.3389/fnhum.2019.00142

Chun Kwang Tan, Kenji Suzuki + Show 6 more

Open Access

https://doi.org/10.3389/fnhum.2019.00142

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Abstract

Lower back problems are common in the world, which leads to the development of various lumbar support exoskeletons to alleviate this problem. In general, previous studies evaluating lumbar support devices quantified assistance by reporting the reduction in back muscle activity and perceived fatigue. However, despite the beneficial effects of such devices, the effects of using such exoskeletons on muscle coordination are not well-studied. In this study, we examined the short-term change in muscle coordination of subjects using a bioelectrically-controlled lumbar support exoskeleton in a fatiguing stoop lifting task with muscle synergy analysis. Results indicate that muscle coordination changes were dominated by changes in timing coefficients, with minimal change in muscle synergy vectors. Analysis on muscle coordination changes would be useful to design future generations of exoskeletons.

Highlights

Lower back problems are health issues encountered throughout the world, as the number of individuals with lower back pain globally is expected to increase substantially (Hoy et al, 2012)
Our current study aims to examine the effects of a lumbar support exoskeleton from the perspective of muscle coordination with muscle synergy analysis
Chvatal and Ting (2012) provided evidence in their results and cited a multitude of studies that strongly support the assumption that modifications in human walking can be attributed to variances in the recruitment of spatially-fixed muscle synergies

Summary

Introduction

Lower back problems are health issues encountered throughout the world, as the number of individuals with lower back pain globally is expected to increase substantially (Hoy et al, 2012). Even healthcare workers like nurses are affected and identified to be the most vulnerable to lower back pain (Yassi and Lockhart, 2013). The prevalence of this health problem has led to the development of various assistive exoskeletons for industrial purposes (de Looze et al, 2016). They found that such devices are shown to reduce back muscle activity during physical loading. Other versions of such devices have been developed for general use and caregivers, like the Hybrid Assistive Limb (HAL) for Lumbar Support (Hara and Sankai, 2010) and Smart Suit Lite (Imamura et al, 2011)

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