T-shirt promotion

I have helped my Personal trainer with some t-shirt designs. This is the latest one and I though, why not share it here. This is a shirt that will be given to his customers that will be competing and this image will be used as a small promotion for his instagram. Software used is Blender and Photoshop.
I found it really hard to make good looking t-shirt material for a render like this. If someone have god tips or know good tutorials on that, please share!

Peace out! :cool:

Very professional! They look great!