5 Killer Isometric Abs Exercises to Work Your Core

Strengthening your core is one of the best ways to build a foundation for a healthy body.

In particular, isometric abs exercises can provide your core with new challenges that will break up the monotony of your traditional core workouts.

“Anyone can do isometric ab exercises,” says Austin Kallai, NASM-certified fitness and group exercise instructor. “And, it’s like a sneak attack on your core because [it] oftentimes doesn’t seem like an abs exercise at first.”

Plus, they work postural muscles in the same way they function in everyday life and some sports — to decelerate and resist movement.

We rounded up some of the best isometric abs exercises to strengthen your core. Add them into your next workout routine for a solid burn!

1. Planks

The most basic isometric abs exercise is a plank. It comes in many variations, all of which work your body in slightly different ways.

Forearm plank

Place your forearms on the ground with your elbows directly underneath your shoulders. Your forearms should be parallel and your palms down.
Step your feet back so your legs are extended straight behind you, and balance on the balls of your feet.
Form a straight line from your head to heels: Engage your core and squeeze your glutes to avoid arching your low back or sticking your hips up in the air.
Press through your shoulders to dome your upper back instead of sinking down into your shoulder blades.
Hold for 30 seconds to a minute.

High plank

Assume a push-up position with your hands placed under your shoulders, arms straight, and your feet together.
Squeeze your glutes and brace your core (imagine someone is about to punch you in the gut) to lock your body into a straight line from head to heels.
Hold for 30 seconds to a minute.
Engage your core and glutes to keep your body stable. Your body should be straight from your head to your hips to your heels.
Hold for 30 seconds to a minute, and then rest before you repeat.

Side plank

Set up in a high-plank position.
Shift your weight onto the outside edge of your right foot and into your right hand. Rotate your hips and shoulders so they’re square to the side.
Stack your left foot on top of your right, and lift your left arm toward the ceiling, so your shoulders are stacked on top of each other.
Engage your core and glutes to keep your body stable. Your body should be straight from your head to your hips to your heels.
Hold for 30 seconds to a minute, and then rest before you repeat.
Repeat on the other side for an equal amount of time and reps.

There are also many variations to the side plank. Here are a few options:

Lower to your forearm for a forearm side plank.
Lift your top leg.
Place your top hand on your top hip.

2. Bear Hold

This is another isometric abs exercise that involves being on all fours. The variation of position will really make your abs work!

Set up in a tabletop position with your hands under your shoulders and your knees under your hips. Your head should be neutral relative to your spine.
Make sure your low back is flat, your neck lengthened, and your abs are engaged.
Tuck your toes and press your hands into the floor to lift your knees a couple inches off the floor.
Squeeze your core and hold, remembering to breathe evenly.
Hold for 30 seconds to a minute.

3. Hollow Body Hold

This exercise can be extremely challenging, but it’s very simple to adjust it to match your very own fitness level.

Lie down on your back with your arms and legs extended straight up to the ceiling.
Engage your abs and press your low back down to the floor, and lift your shoulders off the ground.
Slowly lower your arms and legs toward the floor, keeping your core engaged and your lower back on the floor.
If your low back comes off the floor, you’ve gone too far, so lift your legs and arms just a bit until it reconnects.
Hold this position while squeezing your abs and pressing your low back to the floor. Rest, and then repeat.

4. Warrior III

This posture will strengthen your core, and it’ll also fire up your glutes and legs!

- Start in a standing position with your feet hips-width apart and your arms by your sides.
- Shift your weight onto your right leg and lift your left knee up slightly toward your chest, being sure to keep your hips even.
- Shift your weight forward and lower your chest as you extend your left leg behind you. Your feet should be flexed with your toes pointing to the floor. Keep your body in a straight line as you try to get your upper body and back leg parallel to the floor.

Adjust your hips so that your pelvis is parallel with the floor. Your right leg should be as straight as possible.
To help with your balance, you can keep your arms by the sides of your legs, bring them in a prayer position in front of your chest, or extend them straight out in front of you.
Hold up to 30 seconds. Reverse the move to return to standing, and repeat on the other side.

5. Boat Pose

A common core exercise in yoga classes, boat pose is another isometric exercise that’s sure to get your abs shaking.

Start in a seated position with your knees bent and feet on the floor in front of you. Place your hands on your hamstrings behind your knees.
Lean back, lifting your feet off the floor and balancing on your sitting bones. Keep your spine straight. Point your toes.
Straighten your legs slightly so your shins are parallel to the floor. Release your grip on your thighs and reach your arms forward, palms facing one another. This is your basic boat pose.
If you want more of a challenge, straighten your legs so they form a 45-degree angle with the floor.
Hold up to 30 seconds.