Pilates Bent Knee Fall Out: How to Do It and Muscles Worked

How to do the Bent Knee Fall Out

Lie on your back on a mat with your knees bent, feet flat on the floor, and your spine in a steady neutral position.

1. Rest your arms loosely by your sides and find a comfortable, neutral spine.
2. Engage your deep abdominal muscles without flattening your lower back into the mat.
3. Slowly let your right knee open out to the side, lowering it toward the floor.
4. Keep your left knee pointing straight up at the ceiling the entire time.
5. Stop opening the right knee the moment you feel your left hip start to lift or twist.
6. Pause briefly at the bottom of your comfortable range of motion.
7. Use your core to draw the right knee back to the starting position.
8. Repeat the movement on the other side.

• Breath. Teachers cue breathing differently, but a common pattern is to inhale as your knee opens to the side, and exhale as you draw it back to the center.
• Where you feel it. You should feel a deep, subtle effort in your lower abdomen and obliques to keep your pelvis level, along with a gentle stretch in your inner thigh. You should not feel any strain or pinching in your lower back.
• How many. 8 to 10 slow repetitions per side

Common mistakes

• Rocking the pelvis. Imagine a glass of water resting on your lower stomach and move only as far as you can without spilling it.
• Letting the stationary knee sway. Focus on pressing the foot of your non-moving leg firmly into the mat to help anchor that side.
• Flattening your lower back. Maintain your neutral spine by keeping a tiny, natural curve behind your lower back throughout the exercise.
• Moving too fast. Slow the pace down so you can actually feel your transversus abdominis working to control the weight of your leg.
• Forcing the knee to the floor. Only lower your knee as far as your hip flexibility and core control allow, rather than aiming for the ground.

Make it easier or harder

Easier

• Place your hands on your hip bones to give yourself physical feedback on whether your pelvis is moving.
• Make the movement much smaller, only opening the knee an inch or two.
• Rest a small folded towel under the moving knee's outer thigh to limit the range of motion.

Harder

• Perform the exercise with your feet lifted in a tabletop position.
• Straighten the non-moving leg out flat on the mat while the bending knee opens.

Who should be careful

• After the first trimester of pregnancy, many guidelines advise against long periods lying flat on the back. A side-lying or propped version is an alternative.

Related exercises

• Corkscrew Intermediate to advanced
• Single Leg Stretch Beginner to intermediate
• The Hundred Beginner to intermediate
• Chest Lift Beginner
• Quadruped Arm and Leg Reach Beginner

This exercise is part of our pages on Pilates for Back Pain, Pilates for Sciatica, Pilates for Diastasis Recti, Pilates for Hip Pain.

When to see a doctor or physical therapist

• Sharp or shooting pain deep inside the hip joint.
• A snapping sensation in the hip that causes discomfort.
• Lower back pain that worsens as the leg opens.
• Numbness or tingling traveling down your leg.

This page is general education, not a diagnosis or treatment plan. If you have a health condition, are pregnant or are recovering from an injury or surgery, check with your own clinician before trying new exercises.

How we put this page together. Exercise data (type, level, equipment and muscles) was compiled by our editors from the classical mat order in Joseph Pilates’ 1945 book and from commonly taught mat repertoire. Muscle lists are a general anatomy guide; cueing differs between teachers. Text drafted with AI assistance and checked by the Editorial Team. See our editorial policy. Last checked October 2026.