Do Exosuits Cause Muscle Atrophy, Deconditioning, or Weakness? Short Answer: No
There’s no evidence that exos have ever caused muscle deconditioning during real-world field use, and there’s no expectation that exos will weaken workers based on muscle physiology.
People sometimes ask if wearing an exosuit will make their muscles weaker over time. It’s an understandable question. Exoskeletons are a new technology, and when something assists the body, it’s natural to wonder if it could make users dependent.
But decades of research in muscle physiology and occupational biomechanics indicate that muscle atrophy (loss of muscle mass and strength) only happens under extreme conditions—such as being bedridden, having a limb in a cast, or living in zero gravity.
In contrast, exosuits like the HeroWear Apex 2 provide only partial assistance during certain physically demanding tasks. Workers still use their muscles throughout the day, both when wearing the suit and when not. The result is less fatigue and strain, not weaker muscles.
Here’s a breakdown of what is known from scientific studies, long-term field evaluations, and subject matter experts:
Muscle Physiology Perspective: Why Atrophy Happens and Why Exosuits Don’t Cause It
Muscle atrophy is caused by disuse—when a muscle goes unused or drastically underloaded for extended periods. Think of being in a cast after an injury, or confined to bed rest. In those cases, muscles shrink because they’re not being activated. In scientific terms, muscle atrophy occurs when reduced mechanical loading inadequately activates the mechanotransduction pathways that signal muscles to maintain and rebuild their strength.
By contrast, industrial exosuits work by reducing peak strain, not eliminating it. Exos typically reduce peak loads on targeted muscles and joints by about 10-40% during a subset of tasks, but the user’s muscles still perform the majority of the work. Exos simply help keep the body’s muscles and joints in a healthy, active range of effort.
As summarized in a peer-reviewed study in the Journal of Applied Physiology (Krogh-Madsen 2010): “Most literature suggests that reduced muscle loading must be drastic, such as limb immobilization or bed rest, to observe muscle atrophy.”
Hypothetically, if an exo took 80% of the load off of a muscle 100% of the time, then this would cause muscle atrophy. But this is akin to being put into a cast, or perhaps wearing a sci-fi Iron Man exoskeleton. However, this is incredibly far from the reality of modern exosuits like the HeroWear Apex 2.
During material handling, exos only take about 20-40% the load off back muscles and only during 5-20% of the day when people are bending and lifting (Geissinger 2020). This magnitude of offloading is far below the “disuse” threshold and simply is nowhere close to the conditions in scientific studies that have been observed to cause muscle atrophy. However, exos provide enough offloading to reduce muscle fatigue (Science Page 3) and ergonomic risks due to high musculoskeletal forces (Science Page 5).
This physiological perspective on exos aligns with how we think about other industrial tools (e.g. shovels, wrenches, lift tables, hand trucks, vacuum lifts, wheelbarrows) that also reduce musculoskeletal strain, but not enough to be fearful of muscle atrophy.
Interestingly, muscle physiology research has shown that both overuse and underuse can lead to weakness (Edgerton 2002):
Far too little muscle activity causes disuse atrophy. Far too much muscle activity also causes muscle atrophy—either because it impairs the tissue repair and recovery processes, or because it leads to a musculoskeletal injury that forces a drastic reduction in physical activity while a person recovers. Downtime—such as days away from work due to injury—can then quickly result in physical deconditioning. But for a large intermediate range of activations, muscles have been shown to maintain their mass and not atrophy—which further emphasizes why modest reductions in muscle activity amongst workers wearing exos in physical jobs with high rates of overexertion injury are not expected to experience muscle weakness or deconditioning effects.
To summarize and to put this muscle physiology research in perspective: worrying about real-world exosuits like the Apex 2 causing muscle weakness in physical workers is a bit like worrying that a runner who pares down from running 50 miles per week to running 40 miles per week will be at risk of muscle atrophy. A more apt analogy would be: imagine a warehouse worker who normally lifts 30-lb boxes 1,000 times every day, but then transitions to only lifting 20-lb boxes 1,000 times per day. There is no scientific evidence or practical rationale to suggest that this degree of muscle offloading would lead to weakness or atrophy.
Industry Insights: What the Long-Term Exo Research and Field Evidence Show
Long-term field trials and clinical monitoring with exos provide more corroboration: the evidence consistently shows no signs of muscle deconditioning amongst exo users.
Industry field studies have directly tested these questions about muscle strength. A few examples:
Toyota performed multi-year exo field tests from 2016-2019 that included periodic medical testing on exo users to determine if there was any observable loss of muscle strength. They found no decrease in muscle strength or conditioning, but they did see reductions in worker fatigue, injuries, and workers’ compensation claims (Barrero, EWTS 2020; Barrero Applied Ergonomics 2024)
A peer-reviewed study led by the BioRobotics Institute at Scuola Superiore Sant'Anna—in collaboration with other academic, clinical, and industry partners in Italy—monitored workers wearing occupational exos for six months (Parri 2025). Clinical evaluations included physiatrist visits, movement analysis, clinical questionnaires, and stability testing. They found no adverse clinical effects—in other words, no signs of muscle loss or deconditioning.
There is also indirect evidence from long-term, large-scale field studies that suggests muscle deconditioning does not result from exosuits like the Apex 2. For example:
A 2024 longitudinal injury study on warehouse workers measured improvements from 1 back injury every 27,000 hours worked historically to 0 back injuries over 281,000 hours when wearing Apex 2 exosuits. This dataset is equivalent to 140 full-time employees working for one year while regularly wearing exosuits. This dataset was estimated to encompass 50-60 million lifts by workers at four U.S. distribution centers from 3 companies. However, these workers did not wear exosuits 100% of time. Most workers wore the exosuits during 30-60% of their work shift, depending on their daily tasks and preferences. Nonetheless, back injuries dropped from 10.5 expected to zero. This injury reduction trend would not be expected if muscle deconditioning were happening—rather one would expect a decrease in back injuries while wearing the exosuit that was at least partially offset by an increase in back injuries during non-wear times. This was not observed. Instead, the results are consistent with the exosuit reducing the accumulation of tissue damage (wear-and-tear), even when only used intermittently.
The convergence of data from multiple, independent, long-term field evaluations further bolsters the physiological evidence that modern occupational exosuits do not cause muscle atrophy. If anything, they help users avoid the real pathways to weakness: injury, overexertion, and recovery-related downtime.
Expert Perspective
A number of subject-matter experts from academia, industry, and insurance have publicly shared their perspectives on this topic. Their conclusions echo the scientific and industry evidence overviewed above.
Dr. Carisa Harris, who directs the Center of Occupational and Environmental Health at the University of California Berkeley, acknowledged during an industry-focused podcast (Down With The Dig) that concerns about muscle atrophy are common amongst exoskeleton newcomers, noting:
“There have been some concerns about detraining or loss of strength if someone utilizes an exoskeleton”
However, she then shared her perspective based on her expertise in ergonomics and occupational health research:
“We’re just trying to augment someone’s existing physical capabilities and capacity, so assistance [from exos] is in the realm of 10-15% and it is certainly going to help reduce fatigue as a possibility, but we don’t see it actually providing so much assistance that it is going to decondition someone.”
Dr. Karl Zelik, a biomechanical engineering professor at Vanderbilt University and co-founder of HeroWear, further explained in a Forbes interview that:
“Based on current scientific evidence, given the modest unloading provided by most exo technologies and given the strenuous jobs done by industrial users, muscle weakness or atrophy seems unlikely.”
He added that: “For a large intermediate range of activations, muscles have been shown to maintain their mass and not atrophy. Exo technologies may actually help workers stay within this healthy intermediate range of musculoskeletal loading.”
He ultimately concluded that: “Although it may seem counterintuitive, scientifically it is completely plausible (and I'd say probable) for industrial exos to combat rather than induce muscle weakness in the long run, in a variety of industries, circumstances and applications.”
In closing, HeroWear is committed to continuing to accumulate data and to learn about the long-term impacts of exosuits on worker safety and well-being. However, there is already a lot that has been learned from rigorous research on muscle physiology to long-term exo deployments. From this current knowledge base, we can conclude that:
There is no evidence from the scientific literature or from industry field studies to indicate that exos are likely to decondition muscles or cause atrophy. Likewise, ergonomic and scientific experts familiar with exo technology have not found muscle weakening to be a credible, compelling, or realistic concern for modern exos. The fear of muscle weakness atrophy appears to be mostly rooted in science fiction, speculation, or fear of something new. Simply put: exosuits are not muscle disuse devices—they’re load-management tools. Exosuits don’t remove the need for a worker to use their muscles, they just make tough work more sustainable.