After really intense arm exercises that strain the muscles, some people can get serious swelling that lasts over two weeks, spreads down to the hand because of gravity, and gets so big it shocks both the person and doctors who don’t expect it from just working out.

After a tough bicep workout, guys' arm muscles swell up a lot in just two days, then shrink below normal size and stay that way for over two months.

Doing certain types of hard arm exercises that lengthen the muscle while it's working can make your arms weaker and less flexible within a day.

When you lift weights for a long time, some muscles like your chest can grow bigger than they do right after a workout, but this doesn't happen with your arm muscles like biceps.

Some guys who do really intense bicep exercises can lose almost all their strength right after and take over a month and a half to fully recover — way longer than usual.

When people who don't normally lift weights do a tough arm exercise twice, four weeks apart, their biceps don't stretch as much the second time, even though they're trying just as hard.