During physical exercise, compression inside sports bras changes depending on material properties, leading to insufficient breast support. The purpose of this study was to explore how 3D body scanning can be used to capture females’ breast area measurements change, when wearing compression sports bras before and after a running activity. A commercial seamless sports bra style in size medium and medium level compression, was tested before and after eleven subjects ran in place for five minutes. Seventeen slice measurements taken with [TC]² NX-16 3D body scanner at 0.25 inchesintervals between underbust and armpit levels were collected and compared. Results showed a significant decrease of overall compression of 0.08 inches between before and after run conditions, and the distribution of the reduction was larger below maximum breast circumference level, confirming upwards shift of breast tissue. This study provides knowledge to be used for improving the design of sports bras as compression garments.