I did plank ski jumps every day for a week — and my abs still haven’t forgiven me

Plank ski jumps, or planks skiers, are not for the faint of heart. They’re a plank variation like no other, and do a seriously good job when it comes to hitting most of the major muscle groups in your midsection.

But how do you do plank ski jumps, what are the benefits, and what happens to your abs if you do them every day for a week? To find out more, we unrolled our yoga mat and got to work.

Let’s start by taking a look at the plank ski jump. The good news is, you don’t need to travel to the slopes to practice this one — instead, it gets its name from the lateral ski jump exercise, which targets the glutes, quads, and hamstrings. However this time, you’re jumping your legs while you’re in the plank position, forcing your core to work hard to stabilize your body as you move your legs from side to side.

As with all ab exercises, if you’re completely new to them, or you’re returning to workouts following an injury or pregnancy, it’s a good idea to check with a personal trainer before diving straight in. This is a more advanced plank variation, and if you’re a beginner, you might want to start with bodyweight planks to build your core strength.

How to do a plank ski jump

Let’s start by taking a look at how to do a plank ski jump, or plank skier.

Start in a high plank position, with your wrists stacked underneath your shoulders, and your core engaged. Think about sucking your belly button in towards your spine.
With your legs together, jump your feet up and to the left of your body, use your abs to lift your legs and kick them out to the side.
From here, jump your legs back to the middle, so you’re back in your high plank position, then jump them to the right side of your body.
If you want to up the ante, jump from left to right, without bringing your legs back to the middle.

I did plank ski jumps every day for a week — here’s what happened

Ready to find out what happened when I added this brutal ab move to my workouts for a week?

This one worked my core, hard

On day one of this challenge, I started out with all the enthusiasm I usually bring to these week-long challenges. Here on the Tom’s Guide fitness desk, we love nothing more than a weird and wonderful work challenge, and I’ve tried them all — from 100 dead bugs a day, to plank jacks.

For the first couple of days, I opted for 20 reps on each side, jumping back to a high plank in between each direction change. I found my core had to work really hard to keep my body stable, and I opted to do 10 reps on each side, then take a break to ensure I was moving with the correct form, and not letting my back arch. As with all plank variations, it’s important to keep squeezing your core to prevent any arching in your lower back.

Planks, and plank variations, including the plank jack, active all of the core muscles. Including the rectus abdominis (the outer ‘six-pack’ muscles), the transverse abdominis (the deeper core muscles), and the obliques. They also work into the hips and back.

It got my heart rate up

Unlike the traditional plank, which left my abs shaking but heart rate relatively steady, this one got my heart rate up thanks to the jumping element of the move. On days when I was heading out the door for a run, I used this as a warm-up to get my abs firing beforehand, helping me think about running with a better posture.

As part of the week-long challenge, I tried to add a couple of extra reps each day to keep making things a little harder. On day four, I switched things up and removed the middle part of the skier, jumping my legs from my left elbow, to my right. This was definitely harder, and I had to think about kicking my legs up and back towards my glutes to get them high enough to switch sides.

My shoulders worked almost as hard as my abs

I wasn’t expecting to feel this exercise in my shoulders as much as I did, but this was a real reminder I need to work on my shoulder strength, especially after a day hunched over my laptop (I’m sure you can relate). Part of the challenge of this move is to not let your body rock back and forth as you jump your legs from side to side — your torso and arms should be still throughout.

Of course, a week of plank ski jumps didn’t visibly change my core — visible ab muscles are the result of a 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 be adding plank jacks to my warm-ups in the future, just not so many of them!