Muscles worked
Abs, lower back, shoulders, glutes.
Why plank works
Unlike a crunch, which moves the spine, a plank trains your core to resist movement — bracing against gravity trying to pull your hips down or up. That "anti-extension" strength is closer to what your core actually does in daily life and in most other exercises, which is why coaches treat it as a foundational stability drill rather than just an ab exercise.
How to do plank
- Place your forearms on the floor, elbows under your shoulders.
- Extend your legs back, toes on the floor.
- Form a straight line from head to heels.
- Brace your abs and squeeze your glutes.
- Hold, breathing steadily.
Form tips
- Imagine pulling your elbows toward your toes.
- Keep your hips level with your shoulders.
- Quality over time — a solid 30 seconds beats a sloppy 2 minutes.
Common mistakes
- Hips sagging toward the floor.
- Hips piking up too high.
- Holding your breath.
Who should modify or avoid this
If you have wrist pain, drop to your forearms (as described here) rather than a straight-arm plank. Anyone with lower-back pain should keep holds short and stop immediately if the low back — rather than the abs — starts to ache, since that usually signals the hips are sagging.
Sets and reps
3 holds of 20–45 seconds. Build time gradually.
Variations & progressions
- Easier: plank on your knees or hands elevated.
- Harder: longer holds, shoulder taps, or plank reaches.
- Try side planks for the obliques.
Looking for a full routine? Try our beginner bodyweight workout.