Major League Soccer has been an early adopter of new technology with the help of Adidas, and the San Jose Earthquakes are just one of the league's teams to give it a try. Players have small sensors made by Adidas placed into pockets in their undershirts. The sensors then send real-time data to the coaching staff's iPad.
"We get some instant feedback on the field in terms of certain metrics that we feel are important like heart rate. Working at the upper limit of our heart rate that we want to be in and also during our rest we know when they are down at a reasonable level when we can train again," said Mark Watson, head coach of the Earthquakes.
Read More American soccer's continued expansion gamble
Watson said the data are helpful in gauging levels of exhaustion both in practice and during games. The data complied are particularly useful in determining when a player has adequately recovered from an injury, and is suitable to play again, he said.
The data have also forced him to rethink the team's whole process regarding practice, and have made the team and coaching staff more responsive to individual health circumstances.