How to Do Crunch - Legs On Exercise Ball
Start and end of one clean rep of Crunch - Legs On Exercise Ball.
Quick facts
| Primary muscle | Core |
|---|---|
| Secondary muscles | — |
| Equipment | Bodyweight |
| Category | Strength |
How to perform Crunch - Legs On Exercise Ball
- Lie flat on your back with your feet resting on an exercise ball and your knees bent at a 90 degree angle.
- Place your feet three to four inches apart and point your toes inward so they touch.
- Place your hands lightly on either side of your head keeping your elbows in. Tip: Don't lock your fingers behind your head.
- Push the small of your back down in the floor in order to better isolate your abdominal muscles. This will be your starting position.
- 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.
- Slowly go back down to the starting position as you inhale.
- Repeat for the recommended amount of repetitions.
Muscles worked
- Core (primary): braces the trunk and resists twisting to protect the spine.
Sets & reps by goal
| Goal | Sets × reps | Load | Rest |
|---|---|---|---|
| Strength | 3–5 × 3–5 | Heavy (~85%+) | 2–3 min |
| Hypertrophy | 3–4 × 8–12 | Moderate (~65–75%) | 60–90 s |
| Endurance | 2–3 × 15–20 | Lighter (~50–60%) | 30–45 s |
Bodyweight movement: once you own the top of a rep range, progress by slowing the tempo, pausing at the hardest point, or moving to a harder variation instead of adding load.
Form tips
- Brace as if about to take a light punch and breathe shallowly — don't hold your breath for the whole set.
- Own the largest range you can control with clean form before you chase extra reps.
- Treat every rep the same — a repeatable setup and bar path is what lets you add weight safely over time.
- Breathe out on the effort and in on the return, keeping one steady rhythm across the set.
Common mistakes
- Cranking with the hip flexors or neck instead of moving from the trunk.
- Cutting the range short to squeeze out extra reps instead of owning each full one.
- Chasing weight jumps before the current load feels solid on every rep.
Frequently asked questions
What muscles does Crunch - Legs On Exercise Ball work?
Crunch - Legs On Exercise Ball is a focused movement that primarily works the core.
What equipment do I need for Crunch - Legs On Exercise Ball?
None — Crunch - Legs On Exercise Ball is a bodyweight movement, so you only need your bodyweight and a little space.
How many sets and reps should I do for Crunch - Legs On Exercise Ball?
It depends on your goal: about 3–5 sets of 3–5 heavy reps for strength, 3–4 sets of 8–12 for muscle growth, or 2–3 sets of 15–20 for endurance. Bodyweight movement: once you own the top of a rep range, progress by slowing the tempo, pausing at the hardest point, or moving to a harder variation instead of adding load.
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