Exercise Ball Windmill
The exercise ball windmill is a rotational core exercise that targets the obliques by lowering the legs side to side while holding an exercise ball. The added weight and instability increase the demand on the obliques, lower back, and deep core stabilizers.
How to do it
- Lie on your back with your arms extended out to the sides and an exercise ball held between your feet.
- Lift your legs to a 90-degree angle, squeezing the ball between your feet.
- Slowly lower your legs to one side toward the ground, rotating at the hips.
- Return to the center and lower to the opposite side.
- Continue alternating sides for the desired number of repetitions.
Form cues
- Squeeze the ball firmly between your feet
- Keep your arms flat on the floor for support
- Lower your legs slowly under control
- Stop before your lower back lifts off the mat
Breathing: Inhale as you lower your legs to the side, and exhale as you use your core to return to the center.
Common mistakes
- Using momentum to swing legs up and down, which reduces oblique activation and strains the lower back
- Letting the opposite shoulder lift off the floor, which decreases the stretch and rotation on the core
- Dropping the legs too fast, which makes it hard to control the weight of the ball
Muscles worked
Primary: obliques. Secondary: lower back, glutes, core.
Suggested sets & reps
Get fitter
3 sets × 10 reps per side, rest 60 s
Lose weight
3 sets × 10–12 reps per side, rest 60 s
Build muscle
3 sets × 8–10 reps per side, rest 90 s
Easier, harder & alternatives
Make it easier
Make it harder
Take care if…
- If you feel lower back discomfort, ease off and reduce your range of motion or choose a gentler core exercise.
General educational guidance, not medical advice. Stop on sharp pain and check with a qualified professional if unsure.
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Start free →Frequently asked questions
What should I do if I feel this in my lower back?
If you feel strain in your lower back, your range of motion is likely too large. Do not lower your legs as far to the floor, and keep your core braced tightly.
How often can I do the exercise ball windmill?
You can include this exercise 2 to 3 times per week as part of your core or full-body routine, allowing at least a day of rest between sessions.
What size exercise ball should I use?
A standard smaller medicine ball or a small stability ball that you can comfortably grip between your feet works best for this movement.