A forearm plank on a ball is a plank hold with your forearms resting on top of an exercise ball instead of on the floor. You kneel behind the ball, set your forearms on it with your hands together, then straighten your legs so you balance on your toes with your body in one line from head to heels. The ball wants to roll, so your stomach muscles and the muscle that holds your shoulder blades against your ribs (serratus anterior) have to work to keep it still. It is usually a step up from a steady plank on the floor.

How to do the forearm plank on a ball

Kneel behind a stability ball on a mat. Lean forward and rest both forearms on top of the ball, elbows under your shoulders and hands loosely clasped.
Tighten your stomach gently and press your forearms down into the ball, so your shoulder blades stay flat on your back instead of sinking together.
Straighten your legs behind you, one at a time if that feels steadier, until you are up on your toes with your feet about hip width apart.
Hold your body in a straight line from your head through your hips to your heels, eyes on the ball, and keep breathing.
When the time is up, or your hips start to drop, lower your knees to the mat and rest.

What you should feel

Steady, hard work across your stomach, with your shoulders and the muscles around your shoulder blades busy keeping the ball still. Your lower back should feel held and supported, never strained.

Common mistakes

Letting the hips sag, which moves the load into your lower back.
Pushing the hips up high to make the hold easier.
Letting the ball roll forward so the elbows end up well in front of the shoulders.
Holding your breath once the ball starts to wobble.

How often

Many programs start with 2 to 4 holds of 15 to 30 seconds, with a short rest between them, a few days a week. Your physio will adjust this.

Stop and check with your physio if

Pain in your lower back that grows as you hold.
Shoulder pain, or a sense that a shoulder is about to slip out.
Chest pain or pressure, dizziness or feeling faint, a racing or irregular heartbeat, or being far more out of breath than the effort should cause.
The shoulder feels as if it has slipped out of place, looks a different shape or suddenly locks so you cannot move the arm, or your hand turns cold, pale or blue. Go to an emergency department straight away, without driving yourself, and do not try to put the shoulder back in yourself.

From the clinic

The video starts with the woman kneeling, forearms on the ball, before she straightens her legs. That kneeling position makes a good first version: hold a straight line from your knees to your head until it feels solid, then move onto your toes. If the ball still feels too lively, build the base with a plank or kneeling plank on the floor. Once this hold is easy, stir the pot adds small circles with the ball.

Choose an anti-burst exercise ball, pump it up firm and set it on a non-slip surface with space around you in case it rolls away. Your shoulders carry much of your weight on a moving surface here, so after shoulder surgery, a dislocation or a broken arm, check with your physio before you lean on the ball. If you have had surgery on your spine, chest or heart in recent months, get the go-ahead from your surgical team or physio first.

Holding a plank on a ball puts heavy load through the stomach wall. If you are pregnant, have had abdominal surgery or have a hernia, ask your physio or doctor before you try a forearm plank on a ball. If you have recently given birth, including by cesarean section, or you have a gap down the middle of your stomach muscles (diastasis recti), ask your physio, midwife or doctor first. If a ridge or bulge appears down the middle of your stomach during the hold, stop and tell your physio.

If you have high blood pressure, breathe steadily through every hold and never hold your breath. With a heart condition or high blood pressure, check with your doctor before you start. If chest pain, pressure or tightness does not ease quickly when you rest, spreads to your arm, neck, jaw, stomach or back, or comes with sweating, feeling sick, feeling light-headed or being short of breath, call emergency services straight away, as this can be a heart attack. If it eases quickly and none of these happen, get medical advice the same day, and do not exercise again until you have been checked. If you faint while exercising, call emergency services, even if you feel fine again quickly.

Written and checked by the PocketPhysio editorial team. Last updated 2026-09-28.

This page is general education, not a diagnosis or a personal treatment plan. If you have pain, an injury or a health condition, see a physiotherapist or doctor before starting new exercises.

Forearm plank on a ball