what is the rectangle on the back of rugby shirts

The rectangle on the back of modern rugby shirts is usually a GPS tracking pod. It helps coaches monitor player movement, speed, distance covered, and workload during matches and training.

What it does

• Tracks running distance and sprinting.
• Measures player workload and positioning.
• Often includes other sensors, not just GPS, such as heart-rate or motion data.

Why it sits there

That spot between the shoulder blades is practical because it keeps the device centered and secure while players are running, tackling, and falling. The casing is designed to stay in place and reduce the chance of injury or interference.

Simple example

If you notice a small raised rectangle on a Springbok or other pro jersey, it is usually the housing for performance tech rather than a design detail.

TL;DR

It’s a performance-tracking unit , not a pocket or decoration.