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How New Baseball Tech Helps Japan’s Pitchers Avoid Career-Ending Injuries

Hal Foster iQ Contributor
Baseball team jogging

Injuries may cut short many athletes’ dreams, but in Japan, a new medical technology is enabling young players to keep their baseball dreams alive.

When Satoshi Kurita was in high school, he dreamed of pitching in the Japanese big leagues. He was good, a star. But just as he was becoming a professional, he injured his throwing arm. He was never able to recover.

For several years, the left-handed pitcher tried to regain his form, speed and accuracy, but nothing worked. The worst part, he said, was the constant pain whenever he pitched.

Wanting to stay close to the sport he loved, he hung up his cleats and became a trainer and physical therapist.

“Today, my goal is finding a way to keep injuries from ending the dreams of these young players,” said Kurita, now 52 and coaching youth on the brink of making it to the big time.

Baseball coach talks to players

Recently Kurita learned about a breakthrough baseball tech tool: a motion-evaluation system that promises to help both improve pitchers’ performance and prevent them from suffering career-ending injuries.

Created by Tokyo-based start-up PrimeSap, one of the tool’s key components is sensors that record the body motions of athletes. The other is a tiny but powerful Intel Edison module that analyses the sensor data and produces graphics that identify any jerky motions athletes need to overcome.


Identifying Athlete Stress

A jerky motion, which shows up as a spike in an otherwise smooth line representing a sports activity on the graphic, signals stress on a shoulder, elbow, wrist, knee, ankle, tendon or ligament.

“The most important factor in whether there is a pitching injury is how the joints rotate around the bones’ axes when a ball is thrown,” said Mikihiko Watanabe, an orthopedic doctor and surgeon who is PrimeSap’s chief medical officer.

The smoother the rotation, the smaller the chance of injury, he explained.

PrimeSap founders Takeshi Kimura and Tetsuya Aoyama,

In addition to Watanabe, PrimeSap’s founders include CEO Takeshi Kimura, whose business experience includes healthcare consulting, and chief technology officer Tetsuya Aoyama, who created the software for the motion evaluation system.

Doctors, sports trainers, physical therapists and other exercise professionals can analyze the graphics in PrimeSap’s system to recommend changes to the way a pitcher throws.

workbench with tools

How PrimeSap Works

To create plastic holders for the sensors, PrimeSap used 3D printers. These holders allow the sensors to be placed in any location on an athlete’s body that needs to be analyzed.

“With a pitcher, for example, the sensors are at the wrist, upper arm, shoulder and lower back,” Kimura said. “There is also one on the ground the pitcher is throwing from.”

PrimeSap fitted to arm

Together, the sensors show whether a pitcher’s form is smooth – which indicates all moving parts are working together – or whether there is jerkiness that signals stress.

PrimeSap uses an Intel Edison module to evaluate the information the sensors collect, while embedding the same technology inside a baseball to record its velocity and spin when thrown. The Edison works due to its compact size; the module is just an inch and a half long.

primesap baseball tech with Intel Edison

PrimeSap uses the information from the Edison-embedded baseball, along with the body motion data, to paint a complete picture of the relationship between the pitcher’s body and the ball.

On a recent day at a baseball field along Tokyo’s Tama River, Kurita combined the PrimeSap system with his knowledge of baseball physiology to give 14-year-old pitcher Jay Tamura pointers on his form.

pitcher throwing

One of the top players in the Meguro West Little League team, Tamura has a blazing fastball, a devastating change-up and other pitching weapons that – barring an injury – could give him a shot at the major leagues.

Kurita put sensor-containing plastic holders on Tamura’s upper arm, elbow and wrist, then watched him throw. After a couple of pitches, he showed Tamura the pitching motion he thought would produce the best results while minimizing the chances of injury.

Refining a Pitcher’s Throw

Too many coaches teach pitchers to throw overhand because they believe it produces the most velocity, Watanabe said.

But overhand pitching, he said, which is characterized by a hard downward motion that sends the ball on a trajectory just past the pitcher’s ear, is unnatural. The body is tilted when throwing overhand, making the shoulder, elbow and wrist more susceptible to injury.

baseball tech

By looking at PrimeSap’s motion evaluation graphics, Kurita can tell if the pitch was good or bad, based on the amount of motion stress put on the shoulder than there should have been.

The trainer’s goal is to find the smoothest, most natural way for a pitcher to throw, then help the athlete refine that form to achieve the best performance. It could be a three-quarter arm motion, in which the ball is a foot away from the pitcher’s ear when thrown, something between three-quarter and overhand, or even a sidearm throw.

The graphics also help explain proper pitching form in a language that Little Leaguers can understand.

PrimeSap has also developed systems for boxing and swimming, and will have skiing and sprinting versions before the end of 2016.

While Kurita wishes the technology had been around when he had been pitching, he’s thankful it is allowing him to help another generation achieve its dreams.


Editor’s Note: In this Experience Amazing series, iQ explores how computer technology inside is enabling incredible experiences outside. We look at how computer technology powers new experiences and discoveries in science, the maker movement, fashion, sports and entertainment. To learn more about the tech behind these stories, visit Experience Amazing.

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