KPBS (San Diego)
June 27, 2023
Mechanical engineer George Youssef has a strong interest in biomechanics, how the body’s joints and limbs perform physical tasks. That means he spends a lot of time thinking about sports.
He’s a professor at San Diego State University and when the school got into the NCAA men’s basketball final he was interviewed about the mechanics of a jump shot.
But he’s not a coach. His goal is to create sports equipment that helps athletes perform and be protected.
“Our approach is how we can make a better shoe that the players can work with,” Youssef said. “Or how can we make better materials that (can) be a liner for a football helmet to reduce concussions.”
Youssef has spent years trying to soften the blow of competitive sports by creating a new foam product. It will pad the inside of a football helmet to prevent concussions.
Injuries that come with sports are often the result of impact and that’s especially true of football. He said a protective helmet needs to do two things.
“You want to reduce the impact, or the force amplitude. You want to reduce that as much as possible. And you want to spread it (out) on time, as long as possible,” he said. “Then you want the body to react naturally to the incoming load.”
And keep that load below a safety threshold.
When Youssef says a helmet needs to slow the force of the impact, imagine being hit by a fast moving car compared to a slow one. He said the speed reduction achieved by a protective helmet is measured in milliseconds.
“Without the protection it’s about three milliseconds. With our foam it’s about 15 milliseconds. So that’s a significant increase in the time,” he said.
Youssef is not testing his helmet foam on a football field.
In his Experimental Mechanics Laboratory he has tools, such as a shock tube, that subject foam samples to various impacts and sensors that mimic the human brain determine how dangerous the impact is when it’s mitigated by the foam.
The material his lab has created includes several kinds of foam and joins them together.
“This foam sheet I’m holding in my hand has three different layers adhered together and we’ll actually have different densities for each of the layers,” said Mark Smeets, a lab assistant and doctorate student at SDSU.
The density of the foam changes as the force of the impact travels through the material.
Eventually, Youssef said he wants to partner with a company that makes football helmets, to see if concussions are reduced as players’ heads collide with ground or other helmets.
Some folks say football is too dangerous, and people simply should not play it. Youssef’s response: It’s hard to stop people from doing the things they like.
“Our job as engineers is to actually provide a safe way for them to enjoy whatever sport or activity they are trying to perform,” Youssef said.