The plank is the go-to isometric core exercise — a braced front hold that teaches you to keep a stiff, neutral spine under load. Here's how to do it with good form, the muscles it works, the mistakes to avoid, and how to program it.
The plank is an isometric anti-extension hold that primarily works the deep core (transverse abdominis and rectus abdominis), with the obliques, glutes and shoulders stabilizing the position. You hold your body in a straight line on your forearms and toes, resisting the urge to let your hips sag toward the floor. It's one of the simplest ways to build core stability that carries over to squats, deadlifts and everyday movement, and it needs no equipment.
The plank is an isometric hold, so nothing moves — the muscles work to keep your spine and pelvis from changing position. The deep abdominal wall does most of the work, assisted by the obliques and glutes, while the shoulders and back stabilize you off the floor.
| Role | Muscles | What they do in the hold |
|---|---|---|
| Primary mover | Transverse abdominis, rectus abdominis | Resist spinal extension and keep the trunk rigid |
| Assisting | Obliques | Prevent the torso from twisting or side-bending |
| Assisting | Glutes | Hold the pelvis in a neutral, slightly tucked position |
| Stabilizers | Shoulders, upper back, quads | Support your bodyweight and keep the line straight |
Step-by-step form for the forearm plank. Focus on tension, not time — a strict short hold beats a sloppy long one.
If you want to train the same anti-extension pattern with a different emphasis or difficulty, these are the common swaps:
The plank fits at the end of almost any session, or as part of a core circuit. General starting points:
| Goal | Sets × hold | Notes |
|---|---|---|
| Core strength | 3 × 20–45 s | Strict form, full tension; add difficulty when the top of the range feels easy |
| Endurance | 2–3 × 45–60 s | Longer holds, still clean; regress to knees before form breaks down |
| Frequency | 2–4× / week | Recovers fast; progress by adding time, a harder lever, or a weight plate on the back |
Building visible abs is a two-part job: planks and other core work build the muscle, but whether you can see it depends on your body-fat level and nutrition — abs are built in the kitchen too. See cutting and nutrition for lifting for that side of it.
Log every plank hold — the duration and how many sets — in LiftHero, and it charts your progression so you can see your holds getting longer or your difficulty climbing over the weeks. You can slot the plank into a core circuit, add a rest-timer between holds, and save it into a routine so it's ready the next time you train. LiftHero records what you log; it doesn't diagnose your form.
It's an isometric anti-extension hold that mainly works the deep core, especially the transverse abdominis and rectus abdominis, along with the obliques. The glutes, shoulders and back stabilize the position.
Quality beats duration. For most people, holds of 20 to 60 seconds with strict form are plenty. Once you can hold a clean minute, it's usually more useful to add difficulty than to keep extending the time.
Planks build core strength and can develop the abdominal muscles, but visible abs also depend on body-fat level and nutrition — abs are built in the kitchen too. Training the muscle and managing body fat both matter.
Usually the hips are sagging and the spine is extending. Tuck the pelvis, squeeze the glutes and abs, and shorten the hold if needed so you can keep a neutral spine.
The plank recovers quickly, so 2 to 4 sessions per week works well. A few strict holds per session, progressed by adding time or difficulty, is enough for most lifters.
Track your planks, watch your holds get longer, and run a real program — free on iOS.
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This guide is educational and not medical advice. Consult a qualified coach or medical professional before starting or changing a training program.
By Meitar Lazimi, founder of LiftHero · Last updated July 9, 2026.