How to Do Crunches
Start and end of one clean rep of Crunches.
Quick facts
| Primary muscle | Core |
|---|---|
| Secondary muscles | — |
| Equipment | Bodyweight |
| Category | Strength |
How to perform Crunches
- Lie flat on your back with your feet flat on the ground, or resting on a bench with your knees bent at a 90 degree angle. If you are resting your feet on a bench, place them three to four inches apart and point your toes inward so they touch.
- Now place your hands lightly on either side of your head keeping your elbows in. Tip: Don't lock your fingers behind your head.
- While pushing the small of your back down in the floor to better isolate your abdominal muscles, begin to roll your shoulders off the floor.
- Continue to push down as hard as you can with your lower back as you contract your abdominals and exhale. Your shoulders should come up off the floor only about four inches, and your lower back should remain on the floor. At the top of the movement, contract your abdominals hard and keep the contraction for a second. Tip: Focus on slow, controlled movement - don't cheat yourself by using momentum.
- After the one second contraction, begin to come down slowly again 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.
- Stop a rep or two short of failure on most sets to keep form clean and recover faster.
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 Crunches work?
Crunches is a focused movement that primarily works the core.
What equipment do I need for Crunches?
None — Crunches is a bodyweight movement, so you only need your bodyweight and a little space.
How many sets and reps should I do for Crunches?
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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