A BOSU lunge is a forward lunge where your front foot lands on the domed side of a BOSU ball, a half ball balance trainer with a flat base. The dome gives and tilts under the foot, so the front leg has to lower you and keep you steady at the same time. It is a late-stage exercise, usually added once an ordinary lunge on the floor is easy and well controlled.

How to do the bosu lunge

Set the BOSU dome side up on a non-slip floor, about one long stride in front of you, next to a counter, wall rail or sturdy chair back you can reach.
Stand tall with your hands on your hips, as in the video, or with one hand on your support.
Step forward and place the whole front foot in the middle of the dome. Let the wobble settle before you go down.
Bend both knees and lower straight down, letting the back knee drop toward the floor. In the video he goes to about a right angle at both knees, but a shallow lunge is the place to start. Keep the front knee in line with your second toe and your back upright.
Push through the front foot to step back to standing behind the BOSU.
Finish all the reps on one leg, then change sides if both legs are in your program.

What you should feel

Work in the front of the thigh and the buttock of the front leg, with lots of small corrections at that ankle and knee as the dome shifts.

Common mistakes

Setting up with nothing to hold, or on a rug.
Putting the foot near the edge of the dome, where it tips the most.
The front knee wobbling inward as you lower.
Dropping so fast that the back knee hits the floor.

How often

Many programs start with 1 to 2 sets of 5 to 8 shallow lunges on each leg, holding a support at first, and add depth as control improves. Your physio will adjust this.

Stop and check with your physio if

You feel dizzy, lightheaded, faint or sick, or the room seems to spin. Hold your support, sit down and get medical advice the same day before you practice again. If you faint, it does not settle within a few minutes of sitting still, your vision suddenly blurs or goes double, or you cannot stand or walk steadily, call emergency services.
Sharp pain in the knee, hip or ankle, or the front knee buckles.
Your ankle rolls on the dome.
You wobble so much that only a hard grab on your support stops a fall. Step back off the dome and rest.

From the clinic

He lunges with nothing to hold in the video, but keep a counter, rail or sturdy chair within arm's reach every time, and hold it as you step on and off. Wear flat shoes that fit well and grip the floor, not socks, tights or bare feet. If you have fallen in the past year, feel unsteady on your feet, take medicines that can make you dizzy or have osteoporosis, ask your doctor or physio before you train on a BOSU, and practice when someone else is at home. If you are pregnant, check with your midwife or physio before you start.

A sudden loss of balance is different. Call emergency services straight away for any sign of a stroke, even if it goes away: sudden dizziness with unsteadiness or falling over, a face that droops on one side, an arm you cannot lift or keep up, slurred or muddled speech, weakness or numbness on one side of your body or face, sudden blurred vision, double vision or loss of sight, or a sudden severe headache.

Build up to it in stages. A steady forward lunge on the floor comes first, then the balance pad lunge or the BOSU squat. The back knee does not have to reach the floor, so stop short if a low kneel is sore.

If you have had a hip replacement, get the go-ahead from your surgeon or physio before you try the BOSU lunge. Some operations limit this kind of work for the first months, so the timing depends on your surgery. After a knee fracture or knee surgery, including a knee replacement, follow your surgeon's or physio's plan, and start this exercise only when they have cleared you. After an ankle fracture or ankle surgery, follow your surgeon's or physio's weight-bearing plan, and start this exercise only when they have cleared you.

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.

Bosu lunge