Innovation on the Mat

By Alex Piazza
apiazza@umich.edu

Emma McLean tumbled from one corner of the mat to the other, ending her floor exercise with a high double backflip in the pike position.

The University of Michigan gymnast had performed this routine thousands of times, but when she landed, a sharp pain shot up her heel.

“It felt like I went right through the floor, kind of like I landed on concrete,” said McLean, a junior kinesiology major.

X-rays and an MRI revealed the Big Ten Conference champion bruised the soft tissue in her left heel—an injury that sidelined McLean for a couple weeks. She practiced with a standard heel cup to prevent further injury, but it was thick and uncomfortable.

Michigan Athletics then turned to Professor Ellen Arruda, who partnered with U-M engineering technician Andrea Poli to create a custom heel cup using thin, lightweight materials that reduce force and dissipate energy when McLean lands on her feet.

McLean worked closely with Arruda and Poli to customize the geometry of the cushion for both the injured and healthy parts of her foot. Using her new heel cup, McLean was able to compete in the Big Ten Championship in Illinois.

“The heel cup they were working with was just too compliant,” said Arruda, the Maria Comninou Collegiate Professor of Mechanical Engineering. “It would essentially bottom out if she did a flip and landed on the hard surface. We instead use materials that have damping capacity to take some of that energy and dissipate it away from her heel.”

The custom heel cup is partly the result of a university initiative that brings researchers, Michigan Athletics and industry partners together to optimize physical performance and health for people of all ages and abilities. Launched in 2016, the U-M Exercise and Sport Science Initiative (ESSI) draws on expertise from across campus to interface, prioritize and conduct sport and exercise-related research and innovation.

“Heel injuries are pretty common in gymnastics simply due to the fact that there is no footwear, and the competition mats can be pretty hard,” said Lisa Hass, senior associate athletic trainer for U-M women’s gymnastics. “You cannot be tentative in this sport—you have to go for it and be really aggressive. This new heel cup allows gymnasts to do exactly that, and for that reason, it’s a real game changer.”

This scenario is nothing new for Arruda and Poli, who last spring partnered with the U-M baseball team to create a specialized batting glove for infielder Ako Thomas so that he could return to play after suffering a broken bone in his hand.

They fashioned composite padding in the shape of a donut, which they sewed into Thomas’ batting glove. The glove helped reduce force and dissipate energy when Thomas’ bat made contact with a baseball. And the unique shape provided padding around Thomas’ surgery scar, without covering the incision, in order to reduce any discomfort.

“The glove really helps because it prevents the knob of the bat from digging into my hand, like it normally would,” said Thomas, who last season led the conference in batting average and on-base percentage. “It makes a huge difference, not only when I’m batting, but on defense, too. There were times (last) season when the ball took a bad hop and hit the padded area of my glove, and it didn’t even hurt.”

Using materials similar to those found in McLean’s heel cup and Thomas’ batting glove, Arruda and her colleagues also are working to create a football helmet that would effectively dissipate the energy sustained after hits, thus reducing brain injury.

And since its inception, ESSI has funded U-M research projects that range in scope from measuring the effects of physical activity on brain aging to examining the influence of sleep on athletic performance. As science and technology create a host of new opportunities to transform the world of exercise and sport, U-M researchers will continue to partner with Michigan Athletics to optimize the health and performance of student-athletes.

“There is enormous room for potential in this field, and by building closer relationships between the research arm and athletics, ESSI plays a critical role in the future of exercise and sport science,” said Arruda, who co-directs ESSI with U-M Professor Ron Zernicke.