Stability Ball Knee Tucks: A Killer Core Exercise

Stability Ball Knee Tucks: A Killer Core Exercise

If you’re looking for a killer core workout that challenges your balance and gets every abdominal muscle engaged, look no further than your stability ball. One of the best ways to use it: stability ball knee tucks — also known as a jackknife. (And once you’ve nailed this one, here are other stability ball exercises to master.)


How to Do Stability Ball Knee Tucks


Here’s a step-by-step guide on how to do stability ball knee tucks with perfect form.

Step 1: Find your high plank, with the ball under you.

  • The first trick to stability ball knee tucks is simply to find the starting position. This can be a bit of a challenge.
  • The easiest way to start is to place your belly on the stability ball and then walk your hands forward over the floor until the ball is underneath your shins and ankles.
  • Make sure your hands are directly beneath your shoulders for strong plank alignment, and press the top of your feet down into the ball for stability.

Step 2: Engage your core.

  • While you’re on the stability ball, your core is what’s keeping you in place.
  • Keep those abs tight so you don’t roll off the ball.
  • By engaging your core, you’re ensuring a strong, aligned plank position without dropping into your low back.

Step 3: Tuck your knees.

  • Now it’s time to do the work. Exhale as you draw your knees into your chest.
  • Engage your abs as your knees are pulled into your chest.

Step 4: Extend.

  • On your inhale, straighten your legs behind you, returning to your starting position.
  • Make sure your shoulders are still stacked on top of your wrists.

Step 5: Repeat.

  • Challenge yourself to start with 10 repetitions of the stability ball knee tucks.


Stability Ball Exercises - Jacknife

Muscles Worked With Stability Ball Knee Tucks

Stability ball knee tucks are a great way to target your abs, but abs aren’t the only muscles you’ll use.


The main muscles you’re working during stability ball knee tucks are your abs. This exercise targets your entire core, from your six-pack rectus abdominus to the side obliques to your underlying “corset” abs (the transverse abdominus). This is truly a full-ab exercise.

Hip Flexors

Your hip flexors, or psoas, support your abs and help to bring your knees to your chest. So if the front of your hips are feeling sore the next day, that’s totally normal.


While you’re holding a plank position, your shoulders are stabilizing your position—and, also important, they’re keeping you from face-planting.


stability ball knee tucks - pin image