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.

When young guys do super intense bicep curls they're not used to, their muscle scans show changes that start right away, get worse over a week, and can still be seen two months later.

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.

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.

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.