Often, the simplest exercises seem the hardest. Calisthenic movements like the pushup and pullup are notoriously difficult, even for many people who can throw around a barbell like no one’s business. There’s just something about moving one’s own bodyweight that gets real tricky.

That said, if you can’t do a proper push-up, you’re definitely not alone. Luckily, there’s no shortage of ways to fix pushup form — here are the six most common pushup mistakes and how to fix them.

Your Spine Hyperextends

If your spine hyperextends then your core isn’t strong enough for standard pushups.

The goal in a push up is to maintain a rigid body with an imaginary line from your head to your toes, says Miriam Alicea, NASM CPT, NASM CES and MYXfitness coach.

“When the spine collapses or hyperextends, it’s usually not a result of upper body strength,” she says. “Instead, it’s usually due to insufficient core strength and the ability to stabilize the lumbopelvic region and keep it neutral throughout the motion.”