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Courtesy: Loyola University Medical Center

The MTw Kit, an updated version of the XBus Kit, is a motion tracking system that can monitor skeletal motions. Here, the team at Loyola University Medical Center demonstrates how the kit works in a lab setting.

New technology throws curve at pitching injuries

by Lorenzo Patrick
Apr 25, 2013

XBus Testing

Loyola University Medical Center

Dr. Michael Conti Mica (right) fits volunteer Patrick Strotman (left) with the XBus wrist monitor as Dr. Dane Salazar (middle) observes.

Matt Gelfand was a starting pitcher from of West Essex High School in New Jersey in 2003. The slender left-hander looked to build on his success at the University of New Hampshire in what he initially thought would be a starting role.

His shoulder had other plans.

“At the time I thought it was just fatigue,” he said. “I had become a reliever because I couldn't go more than a few innings without feeling pain. My coach thought it was a rotator cuff, and eventually I just had to stop.”

Gelfand, 27, now a graduate student at Northwestern University, recently discovered he tore his labrum shoulder tendon. He attributes this to a deterioration in his throwing mechanics. “My delivery got lower to manage the pain. I think it was due to the amount of innings I pitched in high school, and me pitching three-quarters of the year in college.”

Pitchers, such as Gelfand, have a new weapon in the battle against shoulder injuries. A new 3-D motion detection system could help identify mechanical breakdowns in pitchers, Loyola University researchers are reporting.

The XBus Kit, manufactured by Xsens in Enschede, Netherlands, is a portable system, requiring only a laptop to operate. Competing systems based on the use of cameras or electromagnetic imaging are limited to indoor use because of their size.

The Loyola study, published in the journal Musculoskeletal Surgery, examined the relationship between the humerus (upper arm bone) and scapula (shoulder bone) in a pitcher's throwing motion. In a well-rested pitcher, the two bones move together and limit the strain on shoulder muscles. Their combined movement, called the scapulo-humeral rhythm, diminishes once a pitcher tires and could lead to shoulder injuries.

“It's very difficult with the naked eye to pick this [motion] up,” said Dr. Pietro Tonino, co-author of the study and a sports medicine surgeon at Loyola University Medical Center in Maywood. The XBus system uses 3-D gyroscopes, magnetometers and accelerometers to measure the motion.

In the study, 13 college pitchers were tracked at three different points to measure their scapulo-humeral rhythm: before pitching, after 60 pitches, and after 24 hours rest. Two pitchers, or 15.5 percent of the field, showed similar movement throughout all three sessions. The largest group had five pitchers, or 38.5 percent of participants, which showed fatigue after 60 pitches, but made a full recovery after 24 hours. Another group of three, or 23 percent, showed fatigue, but made a partial recovery after their day of rest. The final group of three did not recover after their resting period and was at greatest risk for shoulder injury.

The system should prevent most, but not all, shoulder injuries because of the abnormality of the pitcher's throwing motion, said Tonino.


The study mirrored a growing trend at the major league level towards using motion capture technology in evaluating a player's injury risk. Some experts questioned how much the research would translate to the major leagues, as past studies using collegiate pitchers haven't been historically great indicators. They said the price tag, which starts at $6,000 and could go up to $20,000 or more, to be used for pitchers, may limit this technology to professional teams.

Gelfand hopes the new technology can eventually help younger pitchers avoid his fate. “If you just ignore the problem, it's going to persist,” he said. “The best way to address it is when you first feel discomfort, not just pitch through it.”