Skip to content
ascend.
Exercise guide

Crunch - Legs On Exercise Ball

How to do the Crunch - Legs On Exercise Ball with correct form, the muscles it works, and where it fits a training plan you actually stick to.

IsolationBody OnlyBeginnerPull
Primary muscles

Abs

Secondary

Equipment

Body Only

Step by step

How to do the Crunch - Legs On Exercise Ball

  1. 1

    Lie flat on your back with your feet resting on an exercise ball and your knees bent at a 90 degree angle.

  2. 2

    Place your feet three to four inches apart and point your toes inward so they touch.

  3. 3

    Place your hands lightly on either side of your head keeping your elbows in. Tip: Don't lock your fingers behind your head.

  4. 4

    Push the small of your back down in the floor in order to better isolate your abdominal muscles. This will be your starting position.

  5. 5

    Begin to roll your shoulders off the floor and continue to push down as hard as you can with your lower back. Your shoulders should come up off the floor only about four inches, and your lower back should remain on the floor. Breathe out as you execute this portion of the movement. Squeeze your abdominals hard at the top of the contraction and hold for a second. Tip: Focus on a slow, controlled movement. Refrain from using momentum at any time.

  6. 6

    Slowly go back down to the starting position as you inhale.

  7. 7

    Repeat for the recommended amount of repetitions.

In Ascend

Log it, see it on your body.

Every Crunch - Legs On Exercise Ball set you log feeds Ascend's anatomy heatmap — so your abs volume is visible at a glance — and counts toward your bodyweight-strength tier.

Related

More abs exercises

Ascend Club

The climb is free. The Club is how you go further.

Core tracking is free forever. Club unlocks the coach, the competition, and the depth — for the price of one protein-shake a month.

AI Coach

Your own coach character

Pick Rae, June or Atlas — a coach that reads your last 90 days and proposes the next move. Free gets nudges; Club gets the full conversation.

Leagues

Mountain leagues, worldwide

Get ranked against climbers everywhere — every muscle tiered by bodyweight strength. Promote, demote, and prove it weekly.

Challenges

Weekly + monthly challenges

Fresh goals that keep the streak interesting — solo or with your crew. Something to chase beyond your own numbers.

Analytics

Deep analytics + PR projections

See exactly when you'll hit your next PR and bodyweight goal — 4, 8, 12 weeks out. The trajectory, not just today's number.

Crews

Unlimited crews

Run as many crews as you want — squads, family, gym friends. Shared summits, cheers, and a feed that keeps everyone climbing.

Themes & more

Themes, higher AI limits, full export

Aurora, Volcanic and Summit themes. More AI chat headroom. And CSV + JSON export of everything, anytime — your data stays yours.

See Club plans

14-day free trial · no card · cancel anytime · founder pricing locked forever.