Curling couldn’t be more simple. You pick up a barbell or dumbbell, set your shoulders, and lift the weight up to your chin. Yet I see folks screw up this arm day favorite way too often, and, usually, the issues are more nuanced. Believe it or not, a shoddy curl can actually strain your back and elbows, so it’s important to treat even the most basic moves with respect.

If you’re making any of these five mistakes, you may need to rethink your curling approach.