The plank is the go-to core-stability exercise — it trains your abs to resist movement, which is exactly what they do in real life and in every big lift.
FormTwin gives you a living 3D twin of your anatomy. Tap any muscle to see how to train it, and watch the muscles you work light up as you log your sessions.
Get FormTwin — free on the App StoreThe plank primarily works the deep abs (including the transverse abdominis) and obliques, which brace to keep your spine stable, along with the glutes and shoulders that hold the position.
Planks build core strength and stability, but visible abs come from low body fat. Planks are a great core builder — pair them with nutrition to actually see the muscle.
Quality beats duration. A hard, fully-braced 20–40 seconds is more useful than a sloppy two-minute hold. Progress by adding tension or harder variations, not just time.
This guide is general fitness information, not medical advice. Muscle involvement varies with form, grip and individual anatomy. Consult a professional before starting a new program.