Holding a high plank—as if you were at the top of a pushup—is a good core builder in itself. But you can work more muscles and burn calories if you’re familiar with jacks.
What is a plank jack? It’s a simple move that turns a static hold into a dynamic exercise that’s effective on its own, but also offers plenty of room for variation.
“The plank jack combines two classic exercises, giving you the core-sculpting benefits of the plank and the cardio and strength-building elements of the jumping jack,” says Trevor Thimay, CSCS, Beachbody’s senior director of fitness and nutrition content.
Plank Jack: Step-by-Step Instructions
- Start in a push-up position: feet together, body straight from head to heels, arms straight and in line but slightly wider than your shoulders. This position begins.
- Keeping your core engaged, jump your feet outward, and then return to the starting position without letting your hips drop, as if performing a horizontal jumping jack.
What muscles does the plank jack work?
The plank jack exercise is all about building stability while performing explosive movements.
This means working your core muscles, which must work together to keep you in proper alignment through the steps.
- Erector spine: These muscles run the length of your spine and help keep it straight.
- Transverse Abdomen: This sheet of muscle wraps horizontally around your lower abdomen and helps stabilize your spine.
- Rectus abdominis: Also known as the six-pack muscle, these anterior abdominal muscles are also essential for keeping your spine stable.
Also working the chest, shoulders and triceps in an isometric role. To make sure you’re working the right muscles, be sure to focus on your form, Thiem says.
“Don’t let your hips sg,” he said. “Keep your core and body straight from head to heels from start to finish.”
How to Make a Plank Jack Stronger
There are several ways to increase the intensity with your plank jack workout, including:
- Move with your arms instead of your hands.
- Do an “uneven plank,” placing one arm down and one palm on the floor.
- Add your plank jacks to a burpee set, performing them right after leg thrusts
- Jump your arms out to the side and back in unison with your legs.
How to make the plank jack easier
If you’re new to the plank jack, coming back from an injury, or just want to tone it down to work on your form, there are several ways to dial up the intensity while still getting a great workout for those core muscles.
- From a high plank position, jump your legs out to the side and hold for a few seconds, and then jump again and hold for a few more seconds. In short, slow down.
- Another way to make the plank jack easier is to move your legs out to your sides instead of jumping at the same time.
Plank jacks are a great way to add a dose of cardio and core work to any workout, and the wide array of variations helps keep them interesting — and effective.