Crunch - Legs On Exercise Ball

Crunch - Legs On Exercise Ball is a beginner-level isolation in the strength category that primarily works the abs. It is performed with bodyweight.

How to do it

1. 1Lie flat on your back with your feet resting on an exercise ball and your knees bent at a 90 degree angle.
2. 2Place your feet three to four inches apart and point your toes inward so they touch.
3. 3Place your hands lightly on either side of your head keeping your elbows in. Tip: Don't lock your fingers behind your head.
4. 4Push the small of your back down in the floor in order to better isolate your abdominal muscles. This will be your starting position.
5. 5Begin 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. 6Slowly go back down to the starting position as you inhale.
7. 7Repeat for the recommended amount of repetitions.

Muscles worked

Primary muscles in filled badges, secondary in grey. Tap for more exercises per muscle.

Tips and common mistakes

• •Focus on the muscle contraction and control the eccentric (lowering) phase.
• •Add load only once you complete all reps with good form — progressive overload.
• •Initiate the pull from the target muscle rather than jerking with body momentum.
• •Prioritize full range of motion over heavy weight with partial reps.

Sets and reps

For hypertrophy: 3–4 sets × 8–12 reps with 1–2 reps in reserve (RPE 7–9) and 1–2 minutes rest. For strength: 3–5 × 4–6 with longer rest.