In today’s world, player safety is one of the terms that is always in the news. The NFL put new concussion protocols in place this season, and the NBA did the same in 2011. But what exactly is a concussion? The Center for Disease Control defines it as follows:
A concussion is a type of traumatic brain injury, or TBI, caused by a bump, blow, or jolt to the head that can change the way your brain normally works. Concussions can also occur from a blow to the body that causes the head to move rapidly back and forth. Even a “ding,” “getting your bell rung,” or what seems to be mild bump or blow to the head can be serious.
Concussions are an even bigger issue in youth sports, as damage to the brain while it is still developing can have last negative impacts. So, as this issue becomes more important, technology has developed and expanded to help the medical and sports professions evaluate concussions and concussion recovery better.
Dr. Lloyd Smith of Washington State University has come up with technology to simulate ball-human impacts for two different types of softballs. After doing simulations, Smith and his research partners found that the two different types of softballs widely used in competition have very different impacts when striking someone in the head.
Dr. Smith uses a modal called Total Human Model for Safety (Thums) that describes the 50th-percentile male. This means that physically, the model is an average human male.
“The Thums model is a computer model of a 50th percentile male. It was developed by Toyota to study automobile safety. Automotive companies will now model car crashes before they build a car and perform the safety crashes that we sometimes see on video.”
Dr. Smith thinks this technology can be applied to many other sports and could perhaps revolutionize the way concussions and their impacts are monitored.
For more information, check out the Q&A below.
How did you initially come up with the idea to undertake this type of research?
We have been working for a number of years to develop a numerical model to predict bat performance. We have found that modeling the bat is relatively easy, while the ball is a significant challenge. The most challenging part of describing the ball is accurately describing the amount of energy is dissipates and its sensitivity to high displacement rates. We have recently made significant progress in the accuracy of our ball model. At the same time we became aware of human models that others have developed, and decided to combine our model of the ball with existing models of the body to study injury and the effect of ball design.
Can you describe (in layman’s terms) the technology required to make a project like this possible?
I’ll focus on the ball, since that is our contribution. The first step is experimental data. We perform instrumented impact tests of the ball hitting different rigid surfaces (flat plates and cylinders). We also cut the ball open and perform tests to understand the impact response of the material. Once we understand the material, we build a computer model of the ball and compare that model to our experimental tests of the ball. Softballs are ideal for this kind of work, because their center is solid polyurethane and are fairly easy to make material test samples out of. Surprisingly baseballs have similar response, but it is challenging to figure out the response of yarn. So instead we modify our softball model until it matches the response of a baseball.
Do you plan to design a 50th percentile female to test the softball on instead of the male model?
There are other human models of different sized male and females. We intend to include these models in our work as we expand our capabilities.
What do you think causes the stark differences between the two types of softballs used?
Softballs and baseballs can be designed to have different hardness and different elasticity. Balls used for t-ball, for instance, are much softer than major league balls. The polyurethane used to make softballs can be greatly manipulated. We know generally that making a ball softer will lessen the impact, but until this research we could not quantify the effect. This is important to know, because if you make the ball too soft, it stays deformed after impact and will knuckle in unpredictable ways. This could possibly increase injury to fielders. Thus there is a balance in how soft a ball should be made.
Do you plan to apply this technology and theory to test concussions or head injuries in other sports?
Yes, there are many sports this work can be applied to including ice and field hockey, cricket, and lacrosse. The techniques we have developed for softball and baseball apply directly.
In your opinion, what is the significance of this study?
I think we will only see more examples like this where we are able to better simulate complex situations that are relevant to our society. This a nice example where industry (thums) and academia (our ball model) can work together to help make a fun sport more enjoyable.
Is it possible to make this technology for real humans (i.e. to measure player impact via some device on a football uniform)?
Yes. We can measure displacements and accelerations on the outside of our model and compare it with direct measures on the outside of an athlete. We can also measure displacements and accelerations on the inside of the athlete using our model, which we can’t do on real people. That is one of the real insights to be gained from approaches like this.