Hate crunches? Expert PT recommends this 1-minute 'wonder' exercise for better deep core strength and cardio fitness

I won’t lie - since having three children, my pelvic floor has never quite been strong enough to withstand extended bouts of jumping, so when I heard about the benefits of the jack plank exercise, it was music to my ears.

Not only would I be challenging my core and pelvic stability (all the more important as I head towards perimenopause), but I’d also benefit from the cardio element in this "dynamic variation of the traditional plank, which combines core stability with cardiovascular work", as Rowan Clift, training and nutrition specialist at AI-based fitness and lifestyle coaching app Freeletics, says.

The jack plank is a compound movement, Clift explains, that challenges your core, coordination, endurance, and full-body control. Taking a deep breath, I was ready to give this wonder exercise a go.

What is the jack plank exercise?

The jack plank exercise is a hybrid between a plank and a jumping jack, says Clift. "You maintain a strong plank position while jumping your feet in and out," he explains. "It's often used in functional workouts to elevate your heart rate while building strength and stability through the midsection."

While the name might sound off-putting and there's no doubt this is a more advanced exercise, the jack plank is simple when you get the hang of it, but you need to make sure you can do a traditional plank first.

Much like the side plank or the reverse plank, this exercise is also one of many plank variations you can do to liven up your core workout routine or use as a finisher after a strength or Pilates workout.

How to do the jack plank exercise

• Start in a high plank position with your hands directly under your shoulders and your body in a straight line.
• Engage your core, then jump your feet wide out to the side.
• Return to the centre, just like a jumping jack.
• Keep your hips steady and your back flat, making sure your hips don’t move up too high.
• Move at a slow, controlled pace.
• Repeat the exercise as many times as you can, aiming for a full minute as a beginner.

Expert tip: Edwina Jenner, an expert PT and women's fitness specialist who demonstrates the move above, suggests trying "to imagine you are a surfboard with straight legs, a straight spine, and straight arms" to get the flat position you need for the jack plank.

How to make the jack plank exercise easier

If you find the jack plank exercise too difficult right now, don't give up. “Slow the move right down by stepping your feet out one at a time instead,” says Jenner.

By taking the jumping out of the movement, you're removing some of the pressure on your key core and stabilising muscles, such as the abdominals and obliques, as well as easing tension on your shoulders.

Benefits of the jack plank

1. It's a full-body exercise

The jack plank is what's known as a compound exercise, meaning it works multiple muscles at once. "Although its primary focus is the core, this is absolutely a full-body exercise,” says Clift.

"You’ll be working your core to stabilise your torso and prevent excessive movement. Your shoulder and chest are heavily engaged to keep your upper body steady, while your lower back muscles assist in maintaining spinal alignment. The jumping action also provides a dynamic strength and endurance challenge for the lower body," he says.

2. It's efficient

Not many of us have time to spend hours in the gym or doing workouts at home, and adding the jack plank to your workout can shorten this time even more, expert PT Clift suggests.

“It challenges strength, stability, endurance, and cardiovascular conditioning at the same time," he says, taking away the need for a long workout featuring lots of different exercises.

3. The jack plank targets the deep core

Most core exercises will strengthen the core muscles. The clue is in the name, after all. The jack plank exercise is one of only a few that target the deep core, explains Jenner.

“It targets your deep core muscles, including the transverse abdominis and obliques," says Jenner, along with muscles in the pelvic floor. "These are essential for posture, balance, and injury prevention, and they become more compromised as we age."

Looking for more deep core exercises? Leg raises and pelvic tilts are two of the others.

4. Jack planks boost cardiovascular fitness

When you think of exercises for the heart, activities such as walking, running, and cycling probably come to mind. However, many resistance exercises can offer that "quick cardio boost", says Jenner, without you having to step foot on the treadmill or outside.

"Each time you jump your feet out, your heart rate increases, making it an excellent hybrid move that trains muscular endurance and cardiovascular fitness," she says

What muscles does the jack plank work?

• Core muscles: namely, the rectus dominus, transverse abdominis, and obliques.
• Deltoids and pectorals: in other words, your shoulders and chest muscles will be maintaining stability through the upper body and working against gravity.
• Leg muscles: including glutes, quadriceps, and hamstrings, making the jack plank one of the best glute exercises and quadricep exercises you can do.
• Adductors: these are the inner thigh muscles, and they’re notoriously overlooked in most training regimes, as they can be tricky to recruit. Responsible for drawing the leg into the midline of the body, you'll recruit them when jumping inwards during a jack plank.
• Abductors: working in opposition to the adductors, the abductors are located within the hip joint and work to move the legs away from the midline of the body. They also help stabilise the hip and pelvis region.