The regular fit means you can move freely without fabric bunching up anywhere.
Kishigo 9110-9111 High-Performance Microfiber T-Shirt
The regular fit here is all about simplicity and comfort for any activity.
Kishigo Mens 100% Polyester High Performance Microfiber T-Shirt – 9110-9111
A nice touch is having this in S, M, L, XL, 2XL, 3XL, 4XL, or 5XL.