HeroWear Apex Science Overview
10 Things We Know
Science is in our veins. Pioneering research on this exosuit technology started in 2015 at a leading biomechanics laboratory at Vanderbilt University. HeroWear spun out from this lab a few years later after multiple prototypes, successful experiments, peer-reviewed publications, and patents on the core technology. And the scientific studies haven’t stopped since.
The Apex is one of the most heavily researched and scientifically validated exoskeletons in the world. And the results are unequivocal. There have been over a dozen academic research studies on the Apex (and the prototypes that led to it) from institutions like:
- Auburn University
- Vanderbilt University
- Iowa State University
- University of Wyoming
- Arizona State University
- Pennsylvania State University
- Georgia Institute of Technology
- Berlin University of Applied Sciences and Technology
And there have been dozens of industry field studies completed using the Apex, conducted by HeroWear as well as independently run trials by organizations like:
- DHL (logistics)
- Cargill (manufacturing)
- SAIF (insurance company)
- Construction Scotland Innovation Centre
Here are 10 things we know about the Apex from university and industry studies. And just as importantly, there’s a brief summary of the consistent and converging results from rigorous studies in labs and workplaces around the world, which underpin how and why we know these things.
1) Apex reduces the strain on back muscles
Back muscle strain reduction has been proven repeatedly. Vanderbilt University studies measured back muscle activity reductions of 14-43% and muscle fatigue reductions of 29-47% when wearing an exosuit during different bending and lifting tasks (Lamers 2018, 2020). Independent validation studies from Iowa State University (Vathing 2022) and the University of Wyoming (Gorsic 2021) found similar, corroborating evidence. Our published field studies with international logistics and retail companies also confirmed similar back muscle activity reductions when workers wore exosuits (Yandell 2020). Industry-led trials have further solidified the scientific evidence of back strain relief. For instance, SAIF, an Oregon-based insurance company, independently conducted trials with several of its policyholders and after multiple weeks of use reported a 73% reduction in low back discomfort at work when wearing the Apex.
Note: The ability to biomechanically and substantially reduce back muscle strain during bending and lifting is one of the main differentiators of exosuits versus traditional back belts, which have not proven to be effective. To learn more about the science of how human augmentation exosuits like the Apex differ from back belts, check out the Knowledge Base on the HeroWear website.
Apex reduces compression force on spinal discs
2) The Apex reduces compression force on spinal discs.
Multiple studies based on electromyography (muscle activity), musculoskeletal modeling, force-instrumented devices, human biomechanics, and ergonomics experiments have shown that exosuits like the Apex reduce spine compression force during bending and lifting. For instance, a Vanderbilt University study (Lamers 2018) estimated a 5-10% reduction in spine compression force when wearing an exosuit. A Queen’s University study (Abdoli-Eramaki 2007) provided similar, corroborating evidence and includes an extended discussion of the biomechanical principles. Several newer studies have provided further evidence confirming spinal disc offloading (e.g., Lamers 2021, Yun 2021). The simplest explanation of how it works: the leverage provided by the exosuit acts like an artificial set of back muscles. But if you want the more detailed biomechanical explanation of how the exosuit’s moment arm about the spine provides a larger mechanical advantage and why this reduces both muscle and spine forces–along with a visual analogy to give you a better intuition–then check out the “How does the HeroWear Apex work?” video on the HeroWear YouTube channel.
3) The Apex reduces muscle fatigue & increases endurance.
Laboratory and field studies have each found evidence of less back muscle fatigue and more user endurance when wearing an exosuit. A Vanderbilt study (Lamers 2020) used the frequency content of back muscle activity to monitor the fatigue state of the muscles, and found that an exosuit reduced back muscle fatigue rate by an average of 29-47% during sustained bending. Another Vanderbilt field study on heavy lifting found that most U.S. Army Soldiers increased their endurance by 25-75% when wearing an exosuit for repetitive lifting. An independent validation study by the University of Wyoming concluded that their empirical results on 20 participants “confirm that the HeroWear Apex could reduce muscle demand and fatigue” (Gorsic 2021). In one industry-led study, Cargill reported its workers’ effort to lift at work decreased by about 25% when wearing the Apex. Field study data compiled by HeroWear from 154 workers wearing the Apex in their daily work, across various industries, found similar reductions in lifting effort of 20-30%. Likewise, in Apex trials completed by the Construction Scotland Innovation Centre, the results suggested reduced downtime and reduced fatigue of workers during typical construction tasks (CSIC 2022).
4) The Apex reduces bodily discomfort on the back as well as legs and shoulders.
HeroWear has conducted dozens of field studies in which workers use the Apex daily in their jobs. Survey data about bodily discomfort are collected before the Apex is introduced (baseline) and after weeks of Apex use. Workers consistently report less work-related discomfort in their lower and upper backs, shoulders, knees, hips and thighs. Field study data from 154 Apex users across different industries indicates, on average, 35% reductions in low back discomfort and 40% reduction in knee discomfort. Similar results have been replicated in independently-run field studies. For instance, in a multi-week field study conducted independently by SAIF (insurance company) workers reported a 73% reduction in low back discomfort when wearing the Apex.
5) The Apex reduces overexertion injury risk factors
Two converging lines of evidence indicate that the Apex reduces work-related musculoskeletal disorder risks. First, ergonomic assessment tools provide quantitative insight on how much injury risks are reduced by an intervention, such as the Apex exosuit, that alleviates peak forces on the lower back. In one material handling study using an ergonomics assessment tool called Exo-LiFFT, the Apex was estimated to reduce back injury incidence by 20–60% (Zelik 2022). Second, reductions in bodily discomfort (see #4 above) are a leading indicator of reduced injury risk due to overexertion. Multi-year data from large-scale studies on thousands of users will be needed in the future to definitively corroborate and quantify the exosuit effects on injury incidence, but existing evidence is promising; it shows reductions in multiple risk factors and suggests that considerable work-related musculoskeletal injury reduction is anticipated for workers wearing exosuits like the Apex.
6) The Apex makes lifting easier
The Apex not only provides an assistive torque about the back, but also about the hips, which makes lifting easier. In one peer-reviewed field study on logistics and retail workers, >90% of the workers reported that the exosuit made lifting feel easier (Yandell 2020). In a Vanderbilt-led study with the U.S. Army, 100% of Soldiers reported that they were satisfied with the lifting assistance (Slaughter & Rodzak, In Review). In another study at the University of Wyoming, participants completed a wide range of lifting and lowering tasks, and reported that every task was mildly or moderately easier to perform while wearing the Apex (Gorsic 2021). All these published studies are further corroborated by HeroWear field studies data on 154 daily users of the Apex. These workers reported an average of 26% reduction in effort for a typical lift and 32% reduction in effort required for their heaviest lifts. An independent field study conducted by SAIF insurance company found similar numbers: 29% reduction in overall perceived effort and 32% reduction in effort required for the heaviest lifts (SAIF 2022).
7) The Apex is comfortable for daily work
Before we ever created the Apex, we spent a couple of years researching how and where to apply exosuit forces comfortably to the body. We published the first ever scientific peer-reviewed study characterizing the comfort limits of exosuit forces applied to different parts of the body (Yandell 2020B). And we were the first to comprehensively characterize human-exosuit interface dynamics during the transmission of mechanical power from an exosuit to a user (Yandell 2019). Based on these pioneering scientific studies, we then created prototypes of the Apex and completed further user comfort testing. In a peer-reviewed field study on logistics and retail workers, >90% of the workers reported that the Apex prototype was comfortable to wear (Yandell 2020). These findings were used to finalize the Apex product and ensure it could comfortably assist men and women of different sizes and shapes. In a recent Vanderbilt-led study, 82% of Soldiers reported that they were satisfied with the comfort of an exosuit prototype (developed for the U.S. Army) and the remaining 18% were neutral in their opinion of comfort (Slaughter & Rodzak, In Review). HeroWear has observed similar outcomes across dozens of field studies: when properly fit, the vast majority of users find the Apex to be comfortable to wear for their daily work.
8) The Apex doesn’t increase muscle demands on other parts of the body
Although the Apex reduces back muscle activity, it does not do so at the expense of increasing muscle demands on other parts of the body. Independent studies by Iowa State University, Vanderbilt University, and the University of Wyoming all found that abdominal muscle activity does not increase when wearing the Apex (Lamers 2020, Gorsic 2021, Vathing 2022). The energy stored in the Apex’s elastic bands comes from gravity, not from the user’s abdominal muscles having to work harder. The University of Wyoming study also concluded that when wearing the Apex “no adverse effects on other muscles or during non-lifting tasks were noted.” Similarly, a recent study at Arizona State University found that the Apex had no adverse effects on walking stability (balance), regardless of whether the exosuit was in assistance or non-assistance mode (Yu 2022). Collectively, these studies provide strong converging evidence that the Apex does not interfere with or increase demands on other muscles or body parts. This conclusion is further bolstered by HeroWear field data (N=154) showing reductions in discomfort across a wide range of body parts (see #4 above).
9) The Apex fits into work & is well-accepted by workers
Because of its form factor and design, the Apex has repeatedly been found to fit well into different work environments and to be well-accepted by diverse users. In our peer-reviewed field study with international logistics and retail companies, 100% of workers reported that the exosuit could fit into their daily work without interfering with other aspects of their job (Yandell 2020). An independent field study by Pennsylvania State University found the Apex fit well into work at a foundry (Slavin 2021). A series of field studies led by SAIF insurance company concluded that the Apex was a good fit for jobs involving prolonged bending or ground-level work, heavy or repetitive lifting, both at work and at home. However, they cautioned that the Apex may not work with all PPE or other worn gear, so this compatibility needs to be checked beforehand. Finally, based on HeroWear-led field studies (N=154), 85% of Apex users have reported being able to perform all job tasks while wearing the exosuit.
10) The Apex is preferred over rigid exoskeletons in various jobs & industries
In the last 5 years, the occupational exoskeleton field has come to the collective realization that the biggest barriers to adoption are not related to physical assistance, but rather to comfort and movement interference. While rigid exoskeletons and soft exosuits have each repeatedly been proven to provide back relief and musculoskeletal offloading (Kermavnar 2020; Lamers 2021; Schwartz 2021), it is now evident in the scientific literature and in industry feedback that soft exosuits like the Apex are perceived by most users to be more comfortable and less restrictive to movement. A Pennsylvania State University study found this when comparing the Apex to a rigid exoskeleton for use in a foundry. The study concluded the “Apex suit fits Benton’s process much better [than the rigid exoskeleton]” and one of the main reasons cited was because the Apex was more flexible to move in (Slavin 2021). In a separate study conducted by the Berlin University of Applied Sciences and Technology, the Apex was tested on agriculture workers and compared to an exoskeleton built from semi-rigid rods (Frixen 2022). This study found that the Apex had better usability and acceptance amongst users, and one of the main reasons cited was because the Apex was more comfortable and because its modular design could be better adapted to fit the different body proportions of users.
Multiple thought leaders in the exoskeleton field have also made public statements about soft exosuits, like the Apex, generally being preferred over rigid exoskeletons due to comfort and movement interference differences. For instance, in a recent keynote presentation on occupational exoskeletons (CRE-MSD UW 2022), Dr. Maury Nussbaum, a leading ergonomics researcher on exoskeletons from Virginia Tech remarked, “I also think the future is soft. We do lots of demos for people in different occupational sectors (construction, mining, etc.) and a clear message I hear is that [for] these exosuits that are mainly soft materials, people are much more receptive to them… [they’re] much more comfortable over time.”
These remarks are consistent with the feedback we hear from our own Apex field studies. Many Apex clients either trialed rigid exoskeletons before contacting us, or performed head-to-head comparisons of multiple exoskeletons before selecting the Apex as their preferred exosuit.
If you have additional questions about the science behind the Apex, or need access to some of the publications, please contact us. We’re proud of the rigorous research underlying this back-relieving technology. We’re deeply involved in science ourselves and in supporting others conducting independent research. And we’re always happy to discuss and share the current state of exosuit science.
Footnote: HeroWear field study data are from 154 workers at companies in various industries, including logistics, manufacturing, retail, and construction. These represent a subset of data that HeroWear has collected from workers. Data shared here are only from companies that opted for their workers’ data to be included. Survey results are only included for workers who used the Apex for a minimum of 2 weeks at work, and typical usage ranged from 2-10 weeks prior to survey completion. To avoid biasing the results, HeroWear did not pay any companies to participate. Companies purchased the Apexes used in each field study, and workers were not compensated in any way for their feedback. Workers completed written surveys at their workplace, then sent them to HeroWear for deidentification and compilation of the results.