THE WAY SOME guys train and eat, you’d swear they were trying to lose muscle, not build it. But, hey, maybe that’s what they want—and if you want to join them, you’re more than welcome.

So if you’re looking to lose some size—if you’re already so jacked that your biceps are tearing your sleeves, and your dream is to look skinny and weak—you can do what they do. Or maybe you’re doing it already and don’t even realize it.

The only way to find out for sure is by checking our list of the 10 worst workout mistakes—things you do that sabotage your progress and cost you muscle.

Recognize a mistake as part of your daily routine? We also came up with some quick and easy fixes you can use to correct these problems and get your gains back again.