Thread by @KarlZelik

One of the most common questions I hear is: could occupational #exoskeletons cause muscle atrophy/loss? Interestingly I’ve never heard anyone ask: when workers develop overuse injuries (& miss work for days, end up immobilized for weeks, or leave) does it cause muscle atrophy?
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I’m far more concerned about the latter scenario, which we know occurs regularly. Based on current scientific evidence, given the modest unloading provided by most #exoskeletons & #exosuits, & given the strenuous jobs done by industrial users, atrophy seems unlikely (imho).
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Relevant excerpt from Krogh-Maden et al. in the Journal of Applied Physiology:
“...most literature suggests that reduced muscle loading must be drastic, such as limb immobilization or bed rest, to observe muscle atrophy."
physiology.org/doi/full/10.11…
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Also here’s a great figure from a publication on skeletal muscle properties. It shows that far too little or far too much muscle activation can lead to atrophy. But for a large intermediate range of activations muscles maintained their mass (i.e. did not atrophy).
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Individuals in physically demanding jobs often work 8 to 10+ hour shifts, in addition to physical activities they do at home. Many are already over-exerting themselves (over-stimulating/activating muscles) on a daily basis.
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Hypothetically, if we were to map the physical demands of these jobs onto that muscle mass vs activation figure, then I'd expect to be in the middle or over towards the right side of the plot…
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...maybe even on the right-hand descending portion of curve for some workers/jobs, which suggests that occupational #exoskeletons & #exosuits that unload muscles might actually lead to increased muscle mass (hypertrophy) and prevent atrophy.
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While I understand why people ask "could exoskeletons cause muscle atrophy?", I believe we should also be asking the opposite: "could #exoskeletons prevent/reduce muscle atrophy?" E.g. by reducing injuries & missed work, or empowering an aging workforce.
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For those who haven't worn an exoskeleton yet… it's not like being bedridden, immobilized or launched into space for a prolonged time. The vast majority simply provide partial assistance during physically onerous tasks; for example making a heavy object feel less heavy.
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It may initially seem counterintuitive, but scientifically it seems completely plausible (and I'd say probable) for occupational #exoskeletons & #exosuits to combat rather than induce muscle atrophy in the long run, in a variety of circumstances and applications.
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#Exoskeletons are an emerging field & we are excited to learn more about longitudinal effects on users as more devices become adopted into industry, and are viable to use/study over months and years.
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In the meantime, its valuable to remember that these technologies are built upon & benefit from a wealth of knowledge from fields like musculoskeletal #biomechanics, material science & #ergonomics, which provide insight on what to expect from exos & other assistive tech.
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Hope these thoughts are helpful in broadening and balancing the conversation around #exoskeletons and #exosuits, and their effects on musculoskeletal health. Exciting times ahead for the field!!
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Update: this Twitter thread turned into a Forbes article thanks to @ExoskeletonRep
forbes.com/sites/borislav…
#exoskeleton #exosuit #supersuit #biomechanics #WearableTech #wearables