Ever done a push-up and felt your hips hit the floor and your arms barely bend? We’ve been there.

A push-up is a total-body functional movement that’s great for increasing strength. It has the added benefit of engaging your core and lower body.

Since it’s a bodyweight exercise, it can be done just about anywhere — with a ton of variations to liven things up.

So whether you’ve been unsuccessful in the past or just want to fine-tune your form, here are the details you’ll need to master for a perfect push-up.

1. Start in a high plank position

To get into a plank, place hands firmly on the floor, directly under shoulders. Ground toes into the floor to stabilize your lower half.

Brace core (tighten abs as if preparing to take a punch), engage glutes and hamstrings, and flatten your back so your entire body is neutral and straight.

2. Lower your body

Keep back flat and eyes focused about 3 feet in front of you. Maintain a neutral neck and lower your body until chest grazes the floor.

Don’t let your butt dip or stick out at any point during the move — your body should stay in a straight line from head to toe.

Draw shoulder blades back and down, keeping elbows tucked close to your body (don’t “T” your arms).

3. Push back up

Keeping core engaged, exhale as you push back to starting position. Pro tip: Imagine you’re screwing your hands into the floor as you push back up. Repeat for 10–20 reps or as many as you can do with good form.

Once you’ve nailed the form, mix it up with one of these 82 push-up variations.

The fix

Sure, push-ups are known for strengthening your pecs, shoulders, and triceps, but they’re actually a total-body move.

You’ll want to engage your lower body. Focus on tightening your glutes and legs to keep your lower back from arching or sagging during the move.

And instead of letting your hips flop to the floor, press your chest to the floor first, keeping hips in the same plane as shoulders.

Concentrating on form and reps can make it easy to forget one of the most important parts of working out: breathing.

The fix

Don’t hold your breath. It sounds simple, but you’d be surprised how often people forget. Inhale on the way down and exhale on the way up.

The fix

Letting those arms pop out to 90 degrees can be really tough on your shoulders. Instead of forming a T with your arms and body, keep your elbows tucked closer, at a 20- to 40-degree angle to your torso.

Having sloppy form will make for a less effective exercise that targets fewer muscles. A common example of this is pushing back up before your chest gets anywhere near the floor.

The fix

The key here is quality over quantity. Make sure each push-up reaches a full range of motion. You’ll want to get your chest as close to the floor as feels comfortable and fully extend your elbows at the top.

If you can’t complete a rep with your chest down low, modify the exercise by bringing your knees to the floor. Once you master that, go back to a push-up with lifted knees.

The fix

If you’ve ever had neck pain while doing a push-up, chances are you’re not holding your neck in a neutral position.

If you don’t have the strength to lower your chest to the floor yet, it’s common to strain your neck so your forehead lowers first. You can fix this by picking a point on the floor a few feet in front of you to stare at.

If you still feel yourself twisting your neck into a strange angle, bring your knees down to the floor until your form improves.

The fix

It might feel easier (at first) to shift your weight back during a push-up. But not stacking your wrists directly under your shoulders compromises your form and takes the work out of your chest.

To fix this, shift your body forward slightly so your shoulders sit directly on top of your wrists before performing the first step.

Special thanks to Ben Wegman, trainer at Fhitting Room in NYC, for demonstrating these moves.