Torn at the first motion under his arm

The shirt is chic and I wanted to keep it happy. The quality of workmanship is appears to be wertig in order and also the material. I call myself sometimes as a relatively sporty average European. The shirt in XXL (!) Spanned striking at the upper arms and chest, so at a stretching movement, the material (not the seams) is torn under the executive arm.
I have not tried it, but the exchange is thus reliably prevented. Shame ...