Up until the 2024 college football season, a quarterback might be looking to the sidelines and relying on a sound, a sequence of hand motions, or a large sign with logos and symbols on it to get play information. This year, the rules have changed. Players no longer need to rely on these cues to decide which plays come next thanks to the NCAA’s approval of coach-to-player communication for FBS, or football bowl subdivision, teams.

MSU quarterback Aidan Chiles wears an insert in the earhole of his helmet to help him hear play calls clearly through coach-to-player communication. Credit: Nick Schrader, Michigan State University.

Used in the NFL for 12 years now, coach-to-player communication involves inserting a device into a helmet so play calls can be heard clearly. One defensive player and one offensive player on the field for each team is allowed to wear the communication device, denoted with a bright green “C2P” sticker on the back of the helmet.

While this change is an exciting one, it comes with its own set of challenges. Among them: making sure players can hear play calls over the crowd noise of tens of thousands of fans.

“We wanted our student-athletes to be able to get the call from their coach on the sideline with minimal interference,” said Andrew Kolpacki, head football equipment manager at Michigan State University.

To do this, the football team turned to Tamara Reid Bush, a professor of mechanical engineering and biomedical engineering at MSU. Bush worked with her team of students in the Biomechanical Design Research Lab to develop 3D-printed plastic inserts that can snap in and out of the earholes of football helmets and reduce the noise players hear.

“We created a few different prototypes that we showed to the MSU football team. They tried them out, gave us some feedback, and we refined them again,” Bush said. “And then we came up with a winning product that they eventually used in games.”

Players who wear coach-to-player communication devices have a bright green “C2P” sticker on the back of their helmets. Credit: Nick Schrader, Michigan State University.

Rylie DuBois, a second-year biosystems engineering student, was the lead designer on the project. She created prototypes for the helmet inserts using a computer-aided drafting, or CAD, program. In each instance, it was crucial that the insert snapped tightly into the helmet and stayed put under pressure to reduce the chances of it popping out when a player is tackled.

“A little bit of pressure won’t knock them out,” DuBois said. “And this was designed on purpose so that it was easier to keep the inserts inside of the helmet even after heavy hits.”

“A load that’s applied or movement — that’s right in our lab’s wheelhouse,” Bush said. “The football helmet is a biomechanics problem: we needed to design a component that fills the hole, yet doesn’t stick out too far so it’s not going to catch on anything else or pop out during a tackle.”

Designing the inserts was a deceptively difficult task, as the size and shape of earholes vary depending on helmet size and brand, prompting the need for a lot of small adjustments.

Different helmet brands and sizes require different inserts. Credit: Nick Schrader, Michigan State University.

“There’s multiple different helmet manufacturers that our team uses to outfit our student-athletes. For every different helmet and size there’s a different ear hole cover that is needed,” Kolpacki said. “The College of Engineering did a lot of work to make sure these covers fit perfectly inside the earholes of each helmet brand and size.”

DuBois and Bush are both football season ticket holders — and when they spotted quarterback Aidan Chiles on a jumbotron wearing the inserts during a game this fall, they were elated.

“Once I saw it, I was so excited. I told everyone around me, like, ‘I designed those!’” DuBois said. “My parents called me, and they emailed me and texted me pictures of the inserts on their TV screens. It was very cool.”

Bush took pictures of the inserts on the jumbotron and later showed the students in her lab, who were just as excited as she was to see their work in action.

“This project really encapsules two of the most rewarding aspects of our work in the lab,” Bush said. “The first is being able to help people and see them use things that we’ve designed or created. The second is to see the excitement with the students in the fact that they can be involved with a process like this and explore creativity and innovation, and then see it being used in the end.”

The helmet inserts were designed to snap in and out of earholes and stay put during heavy hits. Credit: Nick Schrader, Michigan State University.

DuBois said designing the helmet inserts helped her hone the skills needed for her future career as a biomechanical engineer.

“I worked on my project management skills, my technical skills, communication skills and also solved a problem that deals with biomechanical issues,” she said. “This experience has allowed me to be more confident in the skills I learned in my engineering classes, as well as working with graduate students who have been there and know how the design process works.”

Bush, who in the past collaborated with the MSU basketball team to design a hand brace for former player Nick Ward, said collaborations between engineering and athletics are fruitful for both parties — and she’s looking forward to more in the future.

“MSU football has unique problems that they’ve identified but might not have all the solutions to those problems. As engineers, we’re trained to solve problems: seeing firsthand what the challenges are then coming up with innovative solutions and executing them,” Bush said. “That’s part of the education process. Our students are working on projects that matter and are being used right away.”