Three times in the past nine months a guy I've been intimate with has pulled a muscle while he was with me.
Here's the funny part. One guy strained his back while making out with me. We weren't even having sex, rough or otherwise.
Admittedly, the other two were injured in the throes of sex I'd characterize as fun. I still wouldn't call it rough though.
I'm a sadist. I'm pretty sure that fact is well documented already. However, I didn't engage in any S&M activities with any of these three guys. I didn't cane them or paddle them. Nothing.
From this I can state two pieces of advice, though it should be rather obvious, I'd think.
One, perhaps you should be in better shape if you want to hang with me. You can't be injuring yourself from playing with me unless you want to get redshirted.
Two, you should probably not tell a sadist like me that you hurt yourself getting frisky with me unless you fully comprehend how much I'm going to savor your pain and tease you mercilessly because of it.