University of Puget Sound student helps baseball players refine their pitching technique

Kevin Covarrubias ’23 hopes to continue studying biomechanics after graduating with his bachelor’s degree in exercise science from Puget Sound.

Twenty cameras on the motion-capture rig track the movements of 45 markers on each athlete’s body as they complete the assessment.

A lot of research has already been done on elbow and shoulder injuries, but Covarrubias noticed a gap in the existing literature when it comes to how other parts of the body are under stress during a pitch as ball speed increases. Using the tools in the lab at Driveline, Covarrubias can measure the rotational energies at work in each athlete’s pelvis and torso to see how each of those body segments contribute to pitch velocity. The data is clear: higher rotational kinetic energy values in the pelvis and torso were associated with faster pitches. Now, the next steps will be identifying strategies to keep those high velocities while limiting the torque that could lead to an injury.

“It was kind of amazing to see those first peak torso rotational velocity values,” Covarrubias says. “We were measuring values of over 1,000 degrees per second, which is insane, but it makes sense, because it’s all happening so fast. The whole pitch sequence only lasts 200 or 300 milliseconds. To get those high-velocity fastballs, you have to rotate your body in the blink of an eye.”

Athlete stands at Driveline Baseball, readying for motion capture filming

Reflective markers are placed with adhesive at precise anatomical landmarks, including each of the joints involved in throwing the pitch, to capture the most informative data. Here, a research subject stands with arms outstretched and feet shoulder-width apart while the camera system is calibrated.

Covarrubias is a senior exercise science major at University of Puget Sound, where he’s also getting minors in mathematics and biophysics, and participates in the Honors Program. He started his internship at Driveline in fall 2021, learning how to operate the lab’s motion-capture equipment, collect and clean data from athletes, and how to process that information. He was so intrigued by the process that he applied for another internship, for summer 2022, and collaborated with his faculty advisor to design a research project that would allow him to use the vast amount of data he was already collecting to learn something new.

Screenshot of Driveline Baseball motion capture

Using data from the motion-capture cameras, Covarrubias analyzes body movements using a three-dimensional digital representation of the athlete.

“Mixing the research with my internship has been a really great opportunity. I’ve learned a lot from my advisor, [Associate Professor of Exercise Science] Michael Pohl, and from the staff at Driveline, who all have practical sports science experience to draw from.”

After completing his degree this year, Covarrubias is hoping to travel to Europe with the Fulbright program before applying for grad school. He plans to continue pursuing his passion for sports and biomechanics, and eventually work for a company like Driveline to help athletes reach their peak performance.

“I’ve always been active and I’ve had a lot of sports injuries: concussions and sprains, for which I needed to do physical therapy. All that led me to want to study exercise science at Puget Sound,” Covarrubias says. “I want to teach athletes how to recover from these types of injuries and prevent future injuries so they can keep playing.”

Until then, Covarrubias will continue sticking reflective markers to more baseball players, conducting more assessments, and helping athletes in search of a faster pitch.

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