Plank
Also known as: Front plank
An isometric hold that trains the core to resist extension and stay rigid.
What it is
An isometric exercise where you hold a straight-body position on your forearms and toes. It trains the core's main job — resisting movement (here, anti-extension) to keep the spine stable — rather than crunching.
Muscles worked
Primary: Core (rectus abdominis, deep core). Secondary: Shoulders, Glutes.
How to perform it
- Set your forearms on the floor under your shoulders, legs extended behind you on your toes.
- Form a straight line from head to heels, tucking the pelvis slightly so the lower back doesn't sag.
- Brace the abs and squeeze the glutes, keeping the neck neutral.
- Hold for time, breathing steadily, and stop when your form starts to break.
Common form faults
- Hips sagging toward the floor. Tuck the pelvis and squeeze the glutes and abs to keep a straight line; shorten the hold if you can't hold position.
- Hips piking up into an easy tent shape. Bring the hips down in line with the shoulders and heels so the core actually works.
Programming
Train quality over marathon holds — once you can hold a solid position for around 45–60 seconds, add difficulty (weight, longer lever, reaching) rather than just chasing minutes.
Variations & substitutions
Frequently asked questions
- How long should I hold a plank?
- Long holds have diminishing returns. Once you can hold a strong, straight position for around a minute, it's more useful to make it harder — add weight, extend the lever, or add reaching movements — than to keep extending the time.
- Why do I feel it in my lower back?
- That usually means the hips are sagging and the back is taking over. Tuck the pelvis, squeeze the glutes and abs, and shorten the hold until you can keep a flat, braced line.
Written and reviewed by Mathew Beale — MSc Biotechnology, University of Reading.
Last reviewed: