When UM-Dearborn Assistant Professor of Mechanical Engineering Amanda Esquivel began planning her recent study comparing head acceleration among boys and girls lacrosse players, she knew one of her first challenges would involve a basic engineering problem. Unlike their male counterparts, female lacrosse players do not wear helmets. So he quickly ruled out using the helmet-based sensing systems already developed to study football players’ head impacts.
Instead, she bought a headband system that the athletes could strap on with their protective goggles—which sounds like a pretty simple setup. But when another sensor was used, which hadn’t been put into the research service in this way before, her team had to validate it properly so they could get the kind of data they were after.
“When you put a sensor in a helmet or a headband, what you’re really measuring is what’s going on in the helmet or the headband — not what’s going on in the middle of the head,” Esquivel said.
To solve that problem, they first fitted a crash test dummy head with the headband mounted sensors as well as a second set of sensors in the center of the head. The team then subjected the dummy to all sorts of influences. Finally, using a bit of mathematical modelling, they correlated the information from the two sensors – so the data coming from the outside would be a reasonable stand-in for the inside.
Even then, Esquivel says this type of modeling isn’t “perfect.” And she is quick to point out that even when you have gone to all the trouble of validating the sensors and collecting data on real athletes, you still only manage to lay a few bricks in the wall researchers hope to eventually to take. That, of course, determines the effects of such impacts on our brain, and ultimately, establishing some prescriptive thresholds for athletes.
Such is the nature of sports injury research today, that many big conclusions may be decades away and breakthroughs are more likely to happen cumulatively in small chunks rather than big, dramatic steps. However, wearable sensors could be a field-changing innovation. Compared to football, which has a research body that includes 20 years now, Esquivel says helmetless sports, women’s sports and youth sports are an underexplored territory, and the new technology could enable researchers to tackle all kinds of significant questions . “The important thing to remember is that even if we could draw conclusions from what we’ve learned from 20 years of studying adult male footballers, it still doesn’t necessarily tell us everything what we need, say. soccer players or women’s lacrosse players — or kids who play the same sports.”
In addition to expanding studies in other sports, the wearable technology could help researchers explore a wider range of sports injuries. For example, one of Esquivel’s most recent projects is a collaboration with UM Mechanical Engineering Research Professor James Ashton-Miller, who is studying one of the most common catastrophic knee injuries in sports. Until now, she says, ACL tears are often assumed to be an acute injury, caused by a single serious incident that damages the ligament. But in research with cadavers, Ashton-Miller showed that cumulative loading on a ligament can sometimes lead to ACL tears.
Now, Esquivel and Ashton-Miller are preparing a study that would use the wearable sensor system to examine the same questions on live athletes. “You can only extrapolate what you see on shore to what you see in living people, because the body is constantly repairing itself,” says Esquivel. “But if we were to see a similar phenomenon, our goal would be to figure out what would be a dangerous loading cycle for ACL, and maybe even identify actions or movements that specifically contribute to these types of loads .”
If, through this new study, they were able to reach conclusions about that, it could ultimately be used as the basis for an early warning system that gives athletes the opportunity to rest and receive compensation; or it may simply help coaches and trainers minimize movements in practice that can cause ACL overuse injuries.
Such progress, says Esquivel, would still be a few steps away. But in a field where the main conclusions are drawn from one small study at a time, each step, by its very nature, counts as a step in the right direction.
Source: UM-Dearborn
