# Crunch with Legs on Stability Ball

A floor crunch with your lower legs resting on top of a stability ball and hands behind your head. Trains the abs, with the obliques assisting, while the raised legs keep your hips still.

- Beginner · Isolation
- Equipment: Stability ball
- HD video: https://media.seto.fit/exercises/crunch-legs-on-stability-ball/video/male.mp4
- HTML: https://seto.fit/exercises/crunch-with-legs-on-stability-ball/

## Muscles worked

- Abs: 9/10
- Obliques: 5/10

## How to do the Crunch with Legs on Stability Ball

1. Lie on your back, lower legs resting on the ball.
2. Hands behind your head, elbows out to the sides.
3. Curl your shoulder blades off the floor, legs still.
4. Lower your shoulders slowly back to the floor.

### Full technique — 6 steps

1. Lie on your back with your hips and knees bent to about 90 degrees.
2. Rest the backs of your lower legs on top of a stability ball.
3. Place your hands lightly behind your head with elbows pointing out to the sides.
4. Exhale and curl your head, neck, and shoulder blades up off the floor.
5. Keep your legs and the ball still as your ribs move toward your pelvis.
6. Lower your shoulders back to the floor under control, then repeat.

## Common mistakes

- Pulling the head with hands
- Swinging the torso with momentum
- Letting the ball roll away
- Dropping into the next rep

## Form cues

- Curl ribs toward pelvis
- Hands stay by head
- Keep chin neutral
- Exhale on the curl
- Keep the ball still

## How much to do

- **Strength**: 2–3 sets of 10–15 reps · rest 1 min · 2–3 reps in reserve · lower 2 s, pause 1 s, lift 1 s
- **Muscle growth** (good fit): 3–4 sets of 12–20 reps · rest 1 min · 2–3 reps in reserve · lower 2 s, pause 1 s, lift 2 s
- **Endurance** (best fit): 2–3 sets of 20–30 reps · rest 45 s · 3–4 reps in reserve · lower 1 s, lift 2 s

Reps in reserve: how many more you could still do when you end the set.

## Substitutes by equipment

Same muscles, same movement — pick the version you have the gear for.

- **Dumbbells**: [Dumbbell Decline Sit-Up](https://seto.fit/exercises/dumbbell-decline-sit-up/), [Dumbbell Straight Arm Crunch](https://seto.fit/exercises/dumbbell-straight-arm-crunch/)
- **Resistance bands**: [Lying Resistance Band Crunch](https://seto.fit/exercises/lying-resistance-band-crunch/), [Lying Resistance Band Knee Tuck](https://seto.fit/exercises/lying-resistance-band-knee-tuck/)
- **Medicine ball**: [Medicine Ball Toe Touch Crunch](https://seto.fit/exercises/medicine-ball-toe-touch-crunch/), [Medicine Ball Straight Arm Crunch](https://seto.fit/exercises/medicine-ball-straight-arm-crunch/)
- **Suspension trainer**: [Suspension Trainer Hanging Knee Raise](https://seto.fit/exercises/suspension-trainer-hanging-knee-raise/), [Suspension Trainer Hanging Leg Raise](https://seto.fit/exercises/suspension-trainer-hanging-leg-raise/)

## Where to start and where to go next

Same muscles, same movement. Too hard for now — step down; once it gets easy — step up.

- **This exercise: Crunch with Legs on Stability Ball — 15% of bodyweight**
- Harder: [Reverse Crunch](https://seto.fit/exercises/reverse-crunch/) — 25% of bodyweight
- Harder: [Ab Wheel Pass Crunch](https://seto.fit/exercises/ab-wheel-crunch/) — 30% of bodyweight

## Quick answers

### What muscles does the Crunch with Legs on Stability Ball work?

Primary: Abs 9/10. Also works: Obliques 5/10.

### When should I do the Crunch with Legs on Stability Ball in a workout?

Finisher. Goes last, once the heavy work is done. ≈ 5 min with rest.

### How many sets and reps of the Crunch with Legs on Stability Ball?

Strength: 2–3 sets of 10–15 reps, rest 1 min, 2–3 reps in reserve. Muscle growth: 3–4 sets of 12–20 reps, rest 1 min, 2–3 reps in reserve. Endurance: 2–3 sets of 20–30 reps, rest 45 s, 3–4 reps in reserve.

### What can I do instead of the Crunch with Legs on Stability Ball?

Dumbbells: Dumbbell Decline Sit-Up, Dumbbell Straight Arm Crunch. Resistance bands: Lying Resistance Band Crunch, Lying Resistance Band Knee Tuck. Medicine ball: Medicine Ball Toe Touch Crunch, Medicine Ball Straight Arm Crunch. Suspension trainer: Suspension Trainer Hanging Knee Raise, Suspension Trainer Hanging Leg Raise.

### What is a harder version of the Crunch with Legs on Stability Ball?

Reverse Crunch (25% of bodyweight), Ab Wheel Pass Crunch (30% of bodyweight).

How we rate exercises: https://seto.fit/guides/methodology/

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