You've probably heard about baseball pitchers "throwing their arm out." It's a common overuse injury, and typically involves damage to their elbow's ulnar collateral ligament (UCL). In order to help avoid such injuries, and to assist pitchers in assessing their performance, biomechanics tech company Motus Global is introducing its Motus Sleeve.
The stretchable sleeve is worn on the pitcher's throwing forearm. Within a pouch on the elbow, it contains a 3D motion-sensing module – that module in turn consists of three accelerometers, three gyroscopes, flash memory, a Bluetooth transmitter, and a battery. It weighs 18 grams (0.6 oz), and can reportedly run for 8 hours on one charge.
Whether the athlete is training or playing in an actual game, the Sleeve automatically detects when a pitch is occurring. It responds by gathering data on metrics such as peak arm speed, peak wrist velocity, peak elbow velocity, peak varus (inward-turning) torque on the UCL, release point, elbow height at release, arm orientation at release, and forearm pronation at release.
Up to 450 throws' worth of that data can be stored on the flash memory for subsequent analysis, or it can be instantaneously transmitted to an app on a mobile device as far as 90 feet (27 m) away. That app can be used to analyze the pitcher's form, to monitor their performance and fatigue during a game in real time, and – using injury forecasting models – to determine if they're throwing with too much stress and volume over time.
Additionally, coaches using the app can monitor up to 200 players on one account.
The Motus Sleeve has already been tested on members of nine Major League Baseball teams, this September and October. Plans call for it to be made available to MLB and NCAA teams on a limited basis as of next February, with the rollout of a consumer version of the device scheduled to begin soon after. Pricing has yet to be determined.
The unrelated ShotTracker, incidentally, offers similar functionality for basketball players.