Major League Baseball has approved the use of a biometric monitor that can be worn by players during games.

The device is the first of its kind approved by any of the major American sports leagues to be worn during competition. They are manufactured by a company called WHOOP.

The device can be worn on various parts of the body, and it measures sleep, recovery and strain. Thanks to the 100 megabytes of data a day that is gathered, it allows a player and a team to monitor the current state of an athlete's body heading into a game.