Side plank on knees: how to do it

The knees-down side plank is a beginner version of the side plank: you rest on one elbow and your bent knees and hold a straight line from knees to head, which works the muscles along the side of your trunk. It is a low-impact way to include some core work if you sit most of the day. It takes about 40 seconds.

It will not fix back pain on its own. Guidance on back pain generally recommends staying active and moving regularly, and gentle strengthening can be part of that.

General information, not medical advice. Move gently and stop if anything hurts.

How to do it

Lie on your side with your knees bent and your elbow under your shoulder.
Lift your hips so your body forms a line from knees to head.
Hold and breathe, then switch sides.

Dose: hold for 15 seconds on each side.

Tip: Keep your hips stacked and your neck in line with your spine.

Common mistakes

Letting your hips sag toward the floor. Stop the hold when this happens.
Rolling your hips forward or back. Keep them stacked.
Letting your head drop or crane. Keep your neck in line with your spine.
Holding your breath. Breathe normally during the hold.
Pushing into pain.

Easier options

Shorten the hold to 8 to 10 seconds per side.
Practise only the hip lift for a few reps before you hold.
Start with the forearm plank on knees and add this one later.

This matches the Side Plank (knees down) exercise in the Mo app.

When to stop and see a professional

Stop and speak to a doctor or physiotherapist if you notice:

numbness, tingling or weakness in a leg or foot
pain that shoots down a leg
pain that started after an accident, fall or other injury
problems controlling your bladder or bowels (seek emergency care)
pain that keeps getting worse, wakes you at night, or comes with fever or unexplained weight loss

If the movement causes sharp pain, stop and try the lying knee rock guide instead, or ask a professional.

Do this with Mo, a 5-minute guided routine app

Mo the sloth guides short daily posture, neck and back exercises, with gentle reminders and a pain check-in. Learn more about Mo.

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