I've been programming and lifting weights for years now, and I can attest to how well they work together. The two times I'm most excited to code are consistently (1) when it's late and I know I should be sleeping, and (2) immediately after finishing a good workout at the gym. Interestingly, I got off to a similar start with both activities:
"I don't know about this, I've always been pretty small guy. I'm not just a weightlifter." "Dude, shut up and come with us."
"I don't know about this, I've always just done design stuff. I'm not really a back-end guy." "Dude, shut up and read this PHP guide."
Easily two of the most transformative conversations I've ever had.