what is in the back of the rugby shirts

The lump or box on the back of rugby shirts is a GPS tracking device. This device is used by coaches to track a variety of biometric data, such as the distance covered, speed, and heart rate of players during training and matches. The GPS pod is designed to sustain collisions and is cleverly positioned in a sleeve in the back of the rugby jersey. The device is kept in place between the shoulder blades in something called a "Bro," which works in much the same way as a female athletes sports bra. The data provided by the GPS tracking device can help both professional and amateur rugby players to improve their performance.