WPSL players to use Movement Interactive’s Hiji bands. Are they effective?

With the recent announcement that the WPSL will be partnering with Movement Interactive, Soc Takes was interested in exploring the idea and science behind using accelerometer-based equipment for diagnosing concussive injuries.

The idea behind using accelerometers is fairly simple, at least in premise. It has to do with g-forces (gravitational forces). One g-force is what you’re experiencing right now — the rate at which you’re being “pulled” toward the toilet bowl on which you are currently seated as you read this. As you accelerate — or more importantly in our case, decelerate — you experience increasing g-forces. Think about the experience of being on a roller coaster; that feeling of suddenly accelerating, turning, twisting or stopping causes your body to experience being pushed or pulled. That sensation is caused by g-forces.

Let us take a hypothetical scenario. You decide to play some pickup soccer with Mr. Mark Calloway, better known as “The Undertaker.” During the match, you find yourself going up for a header against him. The Undertaker, in all of his seven-foot glory, barely has to jump for the header. You, with all of your effort, manage to merely make contact with his elbow.

Bang. Lights out. 

While you were jumping up to get to the ball, your body was in motion. When your head suddenly struck a massive tattooed elbow, that motion was unnaturally stopped. This sudden cessation of movement resulted in very strong decelerative g-forces to your head.

So, in premise, if we were able to measure those g-forces on your head, we might be able to ascertain whether or not you’ve experienced a brain injury. Stick a device such as an accelerometer that measures g-forces onto someone’s head, and we’re in business.

Simple, right?

* * *

Dr. Eric Luster comes across as someone you want to drink a beer with. In my conversation with him, he is relaxed and hopeful that his product will help athletes across the world. In spite of my pushback against accelerometer-based data (more on this later), Luster remains calm and answers questions succinctly and highlights the evidence-based methodologies that Movement Interactive has adopted via its scientific team, data collection and patented analytics.

The general idea came to him as he watched his son play tackle football approximately seven years ago. Luster remembers realizing a horrible event that occurred while Luster was working on his PhD in computer science. A young high school football player had died after continuing to play through an undiagnosed concussion. Years later, as his son played tackle football on the same field that a horrendous event had occurred, Luster was determined to prevent history from repeating itself.

This catalyzed Luster into beginning the framework for Movement Interactive.

“We first tried to develop a sensor in the football helmet, but we quickly switched to adding it to a headband. The way it works is, it tracks to about 200 g of force in terms of acceleration. It also has a gyroscope that works to track rotational forces. We use some of the same technologies that helped modernize the automobile industry in terms of airbags,” Luster says, adding that a recently completed study at Gateway Community College showed that wearing the headband did not interfere with players’ ability to head the ball.

“We were astonished that 100% of the athletes forgot they were wearing the device.”

As the founder of Movement Interactive, he has launched a product that he believes will revolutionize concussion prediction and head injury data collection. This product is called the Hiji band. And, the Women’s Premier Soccer League (WPSL) will be the first national league to adopt its usage.

During this summer, baseline physiological and behavioral recordings will be generated from WPSL players during training. These recordings will be used to help with concussion diagnosis during the season, whenever the league does return to play. Soc Takes understands the league is still considering the option of playing their fall season.

With the Hiji system, if a player receives an impact, the sensor will measure rotation and linear g-forces. Subsequently, based on a proprietary algorithm, a “head impact criteria” score is then generated. If that score crosses a threshold — also calculated based on the same proprietary algorithm — an alert is sent to athletic trainers and coaches. Medical personnel would then be the ones responsible for determining if the player is at risk for concussion.

So, it is meant to be suggestive — although based on real-time impact data, not a diagnostic tool. Luster agrees, “It is intended to help better measure and track cumulative head impacts so players and coaches can more accurately monitor player health status over time.”

* * *

The data on accelerometer-based concussive prediction and diagnosis is equivocal at best; and I use that word carefully. The data in the field is mired by poorly-controlled studies that show small effect sizes (if at all).

It is beyond question that your head experiences strong g-forces (some estimate these can be as high as 100 g) during a brain injury. However, there are significant caveats to this data. For one, there are various metrics — linear forces, angular forces, etc. — to consider, and they are often inconsistently defined and measured in these studies. For example, the g-forces experienced by your head and neck during an injury are different. Perhaps more importantly, the g-forces experienced by your head are different than those experienced by your brain because the latter sits suspended in a nice jelly-like substance inside your skull. Finally, much of the confirmatory studies are conducted using crash test dummies, even though it is widely accepted that using test dummies cannot accurately model brain injury outcomes. Luster confirms that the Hiji band and sensor confirmatory data was also generated using dummies.

Luster listens to my rant about the equivocal nature of these studies patiently, never interrupting. He says, “This is why we want to work closely with the league (WPSL). We want to develop solutions with the league that contribute more than hurt the sport. When folks say these things are not accurate, we are OK with that. Our aim is to detect that severe head impact that will save someone’s life and we are confident about achieving that.”

Soc Takes reached out to neuropathologist and TBI researcher Dr. Willie Stewart for comment on accelerometer-based TBI research. Stewart is the leader of the Glasgow Brain Injury Research Group (GBIRG) and is currently a clinical associate professor at the University of Glasgow. While it must be stated that Stewart was not commenting on Hiji band technology specifically, he remains very skeptical about the implementation of equipment using accelerometers. He said, “There is no accelerometer ‘number’ that identifies concussion or brain injury. This, despite many thousands of hours and studies across numerous sports. It’s a myth. And then there is the issue that data from accelerometers is pretty noisy and not terribly reliable.”

* * *

It has to be stated that none of the above criticisms applies to Hiji per se. It is entirely possible that Hiji band technology does have efficacy and predictive capabilities. However, currently, it is impossible for us to know as there is no published data. Which brings us to the final issue — Hiji is a black box. It is built on proprietary and/or patented designs and algorithms. That poses an additional challenge in determining the validity and reliability of the innovation.

Luster says the cost for the equipment will be borne by parents and/or teams. Each Hiji band retails at $249.99. Whether or not teams in the WPSL — already running on a small budget — will be willing to pay for these bands is unclear. WPSL communications director James Poling (see disclosure below) expects that “at least one or two clubs” will utilize the system.

According to Luster, the Hiji band will be used in concert with SCAT3 diagnosis, and he reiterates that ultimately it will be a medical professional — not the band — that will determine whether or not a player has been concussed.

However, in order to facilitate that, athletic trainers would need to go through intensive training on how to correctly analyze and interpret the data generated by the system. Both Luster and the WPSL believe that is an achievable goal.

Poling says that though COVID has delayed plans, the league expects to host informational seminars for athletic trainers in the future. Dr. Vytus Ringus, WPSL medical director, will be responsible for the development of these seminars and tracking any potential health-related benefits of the Hiji system.

* * *

Luster is optimistic about the future for Hiji. One of his ideas is to help coaches make decisions regarding their training modules. He agrees with some of the concerns stated by Stewart and the scientific literature at large. He says, “Several of our competitors have tried the approach of simply capturing g-force to identify a concussion. Our product combines acceleration and rotation (from gyroscope) for completing the calculations. In many cases, it has been found that a 10 g impact can be more harmful than a 20 g impact given location, duration and rotation of the head.”

“If we notice a trend that there is a team that shows higher injury scores during a certain time point, we can contact the coach and let them know that they may consider changing a particular drill, ” Luster says.

He hopes to gain buy-in from youth leagues in the future, with the goal of collecting and tracking data longitudinally; he hopes to track injury data for individuals across their youth and young adult careers.

Personally, I’d be interested in seeing that data. But, how valid, robust and usable it is remains as uncertain as it is potentially exciting. While MLS still continues to drag its feet on its concussion protocol, perhaps we should celebrate the WPSL for setting up this innovative collaboration. But, only time will tell.

Disclosure: James Poling has been a freelance contributor for Soc Takes in the past. There are, however, no current financial ties between Soc Takes and Poling, Movement Interactive or the WPSL.

Follow Nipun on Twitter: @NipunChopra7.

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