I just had to stop and show off how my 15 1/4 inch biceps fill out this extra large sweat shirt! When I flex, the sleeves fill to their max, stretching the seams to their limits! I love seeing how I can fully fill out the sleeves of what's supposed to be a baggy sweatshirt! It's even pulling from around my back and under my armpits. Even why I try to cover up my muscles still want to bulge through my clothes!