What do you get when you cross a jumping jack with a plank? A plank jack. This awesome dynamic core move is as intense as it sounds, as you tighten your stabilizer muscles to lock your body in as you jump in and out with your legs. But what are the benefits of a plank jack and what would happen if I added 100 plank jacks to my workout routine for a week?
If you want to get more bang for your buck on your abs workout, the plank jack is a great move to try because it works your abs and shoulders at the same time. As you jump in and out with your legs, your shoulders hold your body in a plank, which means you’re working on your shoulder strength and challenging your abs in this move.
As a reminder, 100 reps of anything is a lot, and what works for me may not be right for you and your body. If you’re new to plank jacks, or if you’re returning to training after an injury, it’s a good idea to have a personal trainer check your form before adding reps to make sure you’re using proper form. moves.
How to make a plank jack
To do a plank jack, start in a plank position, with your arms outstretched, hands under your shoulders, feet together, your body forming a straight line from the crown of your head to the heels of your feet.
Keep your core engaged by thinking about sucking your navel into your spine. Jump to the side with both feet, as you would for a jumping jack. If you a eating yoga, point your feet at the edges of the mat. Jump your feet back in quickly and continue to jump your feet in and out, keeping your core engaged.
Read more on how to do a plank jackthe benefits of shelf jacks and the modifications you can try here.
I Did Plank Jacks Every Day For A Week — Here’s What Happened
Are plank jacks the secret to a stronger core? I set out to find out more. This is what I learned:
My core had to work super hard during this move
There’s no doubt about it: 100 reps of plank jacks was a lot. On the first day, I decided the best way to make this move more bearable was to break up the reps, so I did four sets of 25 plank jacks. This helped me focus on my form throughout the movement – it’s important to engage your core muscles the entire time to avoid straining your lower back.
Planks and plank variations, including the plank jack, activate all core muscles. Including the rectus abdominis (the outer “six-pack” muscles), the transverse abdominis (the deeper core muscles), and the obliques. They also work the hips and back. Far from being just an aesthetic goal, a strong core can help improve your balance and posture, as well as relieve lower back pain.
I felt it in my shoulders
I didn’t expect to feel this exercise in my shoulders as much as I did, but by day three’s reps I had to drop to my elbows for the plank jacks. As a runner, I don’t spend much time training my upper body, and this challenge reminded me that I definitely had some work to do.
I also found this exercise more of a cardio blast than usual planks or side shelves. Equivalent to Mountain climbers, the plank jacks increased my heart rate as I jumped my legs in and out. They’re also much less impactful than, say, burpees or high knees, so this is definitely a move I’ll be adding to my warmups in the future.
I traded some modifications
I added this challenge to my routine in week four of marathon training, and after a particularly grueling 13-mile run, doing 100 plank jacks felt like a step too far for my tired muscles. Instead, I swapped the jacks for plank jack toe tapers, tapping one foot to the side of my exercise mat and then the other, instead of jumping. I actually noticed that it took longer to complete the toe taps, which made my core work just as hard. This was a good reminder that rest days are important, but also that you should always listen to your body and adjust exercises if necessary.
Another day I decided to up the ante and put one of the best resistance bands on my thighs to add some resistance to my plank jacks. This made me feel the exercise more in my legs and I had to work harder to keep my pelvis stable.
I will do this again in the future
Of course, a week of plank jacks hasn’t visibly changed my core — visible abs are the result of low body fat percentage, not endless plank jacks or sit-ups (here’s how to calculate your body fat percentage and why it matters). That said, I really enjoyed this challenge and will definitely add plank jacks to my warmups in the future, just not 700.
Looking for more workout inspiration? This is what happened when I added a plank to my morning routine for a week and when I did planks every day. Also check out this gym workout, which uses just four exercises to build full-body strength.