A Q&A with Biomechanical Engineer Karl Zelik
Spotlight articles shine a light on designers we admire. Our founder and principal designer Rebeccah Pailes-Friedman has met many wonderful industry experts as an educator and career designer, and in our Spotlight interviews we ask them about their work and their journey. In this interview we spoke with biomechanical engineer and Vanderbilt University professor Karl Zelik.
In addition to being a professor, Karl is the co-founder and co-director of the Center for Rehabilitation Engineering and Assistive Technology at Vanderbilt, a research center dedicated to improving health, mobility and independence for those with physical disabilities and to enhancing human performance and well-being through advances in movement science and assistive technology. He is also the co-founder and chief scientist of the exosuit company HeroWear. He’s on the board of a nonprofit called the American Bionics Project, which aims to accelerate the development and adoption of revolutionary technologies for people with lower limb disabilities, and he does biomechanics and assistive technology consulting in industry. In short, he knows what he’s talking about. We met Karl while working with HeroWear on the first Apex exosuit, and we’ve followed his work and his social media with interest ever since. His ability to translate technical information for stakeholders of all stripes makes him an ideal person to talk to about engineering. We asked him about what drew him to the biomechanics and mobility space, how he integrates comfort into his projects, and what he sees in the future of assistive technology.
Q: You are one of the principal investigators at Vanderbilt’s Center for Rehabilitation Engineering and Assistive Technology, we are honored to have worked with you on a few projects. For those who might not be familiar, could you explain what biomechanical engineering is?
A: The field of biomechanics really just means that we’re applying the laws of physics to biological systems like animals or humans. We use biomechanics to understand human movement and to understand nature. We also use it to design better tools, better equipment, and to pretty much design everything in our environment to work better with the human body: to keep us healthy, to help improve our performance, to help improve our well-being and the things that we can do in society. Biomechanics has a hand in almost everything you interact with, from the shoes you wear to the seats that you sit on to pretty much every tool and toy that you encounter in your daily life.
Q: How did you get into this field, and how did health and mobility become your area of specialization? What is your origin story?
A: I am the second oldest of four boys in my family. I was very into sports when I was young. I was also incredibly reckless with my body. As a kid, I got a lot of broken bones. I got a lot of stitches, mostly doing stupid things. I was always testing the limits of the human body, of my own body. I was fortunate in college to discover biomechanical engineering, which was a much safer way to test the limits of the human body. I got really interested—I’d say hooked—on researching and developing assistive technologies. Those are technologies that could help keep us safe, that could help protect or repair broken bodies and keep us physically active and doing the things that we love. So I’ve been hooked on this field of exoskeletons and prosthetics for nearly 2 decades.
Q: Could you share an example of an impactful innovation that your lab has generated?
A: I’ve been doing research and development in the field of biomechanics and assistive technologies for the last 17 years. We’ve worked on everything from prosthetic limbs to exoskeletons to wearable sensor technologies.
To date, the most impactful innovation has been the work we’ve done around back exosuits. These were initially developed and researched and validated at our lab at Vanderbilt University, where we also developed a lot of the underlying patent innovations. We then spun off a private company called HeroWear, which manufactures and sells these exosuits. You all [at Interwoven] have been an integral part of that process.
Our mission is to help save the backs of hard-working men and women in all sorts of physical industries like logistics, manufacturing, military, and many others. Our current exosuit, the HeroWear Apex 2, is now used by thousands of workers around the globe. It’s essentially a three pound suit that takes 50 to more than 100 pounds of strain off the back of a worker every time they bend to lift. It’s having a big impact in terms of reducing the strain people feel on their body, reducing the wear and tear, and helping people be able to do their jobs without sacrificing their bodies or sacrificing their long-term health. It’s helping people to go home at the end of the day and have more energy and do the things that they enjoy, it’s helping reduce injuries in the workplace, and it’s helping workers stay healthy and productive. That is something that’s been really rewarding to see, and Interwoven has played a critical role in helping take the fundamental science that we developed at Vanderbilt and translate that into a product that can work in the real world; that can scale across different industries and different organizations.
Q: What impact do you see assistive technology having on the future of healthcare?
A: Assistive technology has a long history of impact within the healthcare space, from prosthetic limbs to braces to wheelchairs and in many other assistive devices and tools. It feels like we are entering a new era. The next generation of healthcare assistive technology is on the horizon. Robotic exoskeletons for people who are paralyzed just received Medicare reimbursement codes this year, 10 years after they received FDA approval. This was a massive milestone that just happened earlier this year, a watershed moment for the assistive technology field in healthcare. I think this is an example of the type of next generation technologies that are on the horizon.
There’s a ton of excitement right now about new assistive technologies, to help—first and foremost—patients, but also to help the clinicians and the caregivers. The truth is that there’s also a lot of hype right now, and there’s a ton of work ahead. I’m optimistic about the long term impact of these emerging technologies and the impact that they’re going to have on people’s lives, particularly for folks who are dealing with disabilities or diseases or injuries.
Q: You have mentioned appreciating the conversation around comfort in wearable technology. How do you approach integrating comfort into the assistive technologies you’re working on in the lab?
A: Designing for comfort has been a great lesson for me, especially over the last five years. I’ve spent my entire professional career as an engineer and a scientist. As engineers, we’re drawn to the technical side of design. We love technical requirements. We love going deep on biomechanical engineering. And sometimes we’re overly drawn to buzzwords like robotics and AI. But as someone who is developing a technology that is meant to be worn, and as someone who wants that technology not just to be tested in a laboratory but actually to be used daily by people, I’ve gained a deep appreciation for the importance of comfort and user experience. In fact, none of the technical capabilities matter with wearable tech if a person isn’t willing to wear the thing that you’ve designed.
I have a much deeper and more nuanced appreciation for comfort now than I did 10 years ago, certainly more than I did as a graduate student or postdoc or early professor. The approach that we take now when we’re designing things is to spend a lot more time on the front end with end users early in the design process to really understand their needs. And then we apply a user-centric, iterative design process that requires us to build both technical requirements and what we call user stories, or sometimes personas. This forces us to design solutions that are both effective and practical.
One common mistake in the assistive technology field—that I’ve seen widely in academia and also in the commercialization sector:—is overly focusing on optimizing effectiveness but not simultaneously designing for practicalities. Those practicalities are exemplified by questions like: Is the device comfortable? Physically, thermally, and psychosocially? Does it get in the way or interfere with movement? Is it going to be accessible and affordable to your intended end user? Will it fit people of different body shapes and sizes? These are such critical questions, and the mistake developers often make is not having those front-of-mind and included in the early iterative design process. It’s not something you can just tack on later. I think there are more people now embracing the importance of comfort and practicality but the field of assistive technology still has a ways to go in fully embracing that.
Q: Could you tell us about a project that you are working on now?
A: For the first five years as a professor at Vanderbilt, our lab was largely focused on lower limb prosthetics. Then, for the next five years, we were focused on these occupational exosuits, which led to spinning out HeroWear. We did a lot of the underlying research and developed a lot of the patented technologies underlying the exosuit, but then that project moved out into the real world and it became a separate business and an area of growth independent of the academic research.
In the last year or so, we’ve shifted our focus to remote patient monitoring as part of a 5-year project funded by the National Institutes of Health. Our goal is to use wearable sensor technologies to monitor patients after they’ve had surgery, to try to understand how to ensure that they quickly and fully recover. We’re using sensors that are embedded in shoes—with custom algorithms that we develop using biomechanics and machine learning—to non-invasively monitor musculoskeletal loading. We’re using this new sensor capability to look at individuals after they’ve had a specific type of lower-limb bone fracture surgery to better understand their healing and recovery process and try to elevate the standard of care. We hope to impact the long-term health outcomes of these patients, which unfortunately aren’t great for this population. This work is ongoing.
What’s exciting is that we’ve come up with a unique new way of monitoring the force that’s experienced on a person’s shank bone, the tibia bone, which is practical and effective to use outside the research lab and in daily life. We are now exploring how to use this new capability with patients who have had to undergo surgery to repair a badly fractured tibia bone. As they are recovering, we have algorithms that can—without implanting anything in their body—estimate how much force they’re putting on their bone. The loading of the bone plays a key role in stimulating tissue recovery and it helps the bone heal itself after the surgery. Monitoring bone loading in daily life may serve as a sort of biomarker to understand if patients are on the path to recovery or if we may need to alert their clinician that they need to change their rehab exercises or perform more physical activity to better stimulate biological healing processes.
Q: Where do you get your inspiration for new research?
A: When I was a graduate student, all of my research inspiration—the specific projects I was working on, the specific questions I was trying to answer—came from the academic community, from reading the scientific literature, from attending scientific conferences and understanding the gaps in the field. At the time, when I was a trainee, I also worked with a professor, who helped to set the research agenda and the priorities.
As I have gotten later into my career, where I source research ideas has really shifted. Now, probably only a third of what I work on are problems directly out of the scientific literature or derived from academic researchers in the field.
I’d say another third of my research ideas come from spending a lot more time with assistive technology end users and others outside of academia. That might be clinical patients, it might be medical doctors, it might be safety professionals, or it might be workers in different environments. So I am now drawing a lot more from industry and clinical perspectives, and from end user perspectives.
Then the last third of research ideas is honestly just from my daily life. Biomechanics is everywhere and there are opportunities all around for assistive technology to positively impact our lives. An example is the origins of the back exosuit. I wasn’t originally thinking about the massive problem of back pain and injury in physical jobs like warehousing and manufacturing, although perhaps I should have been. I got interested in back exosuits because I was a parent to young children and, like many parents, I was experiencing some back pain. I started thinking, Is there a way to develop a wearable device that would fit into my daily life and also provide me with back relief? The back exoskeletons that existed at the time were all too heavy, bulky, cumbersome, and costly to fit into my life. It got me thinking about how to keep the biomechanical effectiveness of these devices, but make them more practical, form-fitting, and comfortable. Soft, elastic back exosuits turned out to be a remarkably elegant and effective solution—if you can get the details right, which is where we focused a lot of our research and development efforts for several years.
Q: You are incredibly prolific; researching and writing, teaching, working in industry, and maintaining a significant social media presence. What strategies do you find useful for playing so many roles, keeping so many balls in the air? Please tell us your secret!
A: I mean, I think my secret is that I probably don’t do this juggling act as well as I should. I drop balls all the time. I’m lucky to work with amazing teams and people who are patient and forgiving. I’m lucky to live with an amazing family who is patient and forgiving when I don’t get the balance right. Throughout my career it’s been a continuous area of improvement, and I don’t feel like I have it figured out. I’m actively trying to find ways to be able to focus on a smaller number of priorities. Unfortunately, in academia, we have a tendency to spread ourselves too thin.
Q: You are known for translating tech out of the lab, and you do a great job of making technical information accessible for students and non-experts. What are some strategies you use to do that translating?
A: As researchers, we spend a lot of time going really deep in our fields and trying to help generate new knowledge. Part of our responsibility is figuring out, How do we communicate this information to stakeholders? How do we share this information with different groups?
I’ve come to appreciate that science communication to broad audiences is an important component of my job as a professor and, like any other component, we have to practice it. I’ve spent a lot of time trying to explain and simplify difficult concepts and trying to understand who the audience is, and what they may or may not need. I’m not always successful, in fact, I’ve probably come up with a lot of terrible analogies! But science communication has been a priority for me, and I’ve practiced it like any other skill. I’ve gotten better at understanding different audiences. What motivates them? What interests them? What causes their eyes to light up or for them to ask follow-on questions? How can I take technical content and pull out the key part that they need to know? Often it’s the 80/20 rule. What gets them most of the way there in understanding the concept without me geeking out on every little detail or boring them to sleep.
Every time I present, I’m tailoring the content to a specific audience. I’ve been fortunate over time to present to almost every conceivable audience, from very young children to high school age children to college students to experts in our scientific field to safety leaders to government officials to military leaders to boards of large organizations. And each person, whether you’re talking to somebody in safety or to someone who’s an operations or to someone in finance or to someone who’s aspiring to be a scientist, is interested in different aspects of a topic.
Exoskeleton are a great example because they’re such a fun, engaging topic, everyone is interested. I’ve even spent time with Hollywood producers and talked about these types of topics. I think the more time you get to spend with diverse groups of people talking about a similar topic, the better you get at explaining things. It’s natural now for me to be able to tailor the content, the message, and how technical or detailed it needs to be for a certain group. I would attribute that to a lot of practice, probably a lot of failure, and experimenting with different descriptions and analogies. Being in the field for 17 years I’ve talked to a lot of different people about biomechanics and assistive technology.
One of our objectives at the university is also to do science and engineering outreach. We bring students from kindergarten through 12th grade into the lab and show them some of the research and technology we use. We do everything from maker fairs to lab tours to having a big outreach event every year where we have an open house and invite anybody to come and check out the prosthetics and exoskeletons in the motion analysis lab. Sometimes we go out to local schools in the community and do outreach events. A lot of our outreach is about trying to share some of the cool things that kids can do with math and science, planting that seed. These have also been formative experiences for me, as well as other members of our lab, to practice and hone our science communication skills.
Q: What’s in your future?
A: For the next couple of years, I’m excited to go deeper into this space of wearable sensors and remote patient monitoring that I described earlier, and to continue supporting HeroWear during a period of significant growth.
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