Bent Knee Fall Out: Small Move, Big Benefits for Your Core and Hips

Emily the Physio
Mar 30
4 min read

Sometimes the smallest movements in Pilates pack the biggest punch, and the Bent Knee Fall Out is the perfect example. At first glance, it may look like a gentle, almost effortless exercise—barely a workout at all. But this subtle, controlled move is one of the best-kept secrets for building deep core stability, improving hip mobility, and developing the kind of body control that makes every Pilates move look polished and effortless.

Think of it as a quiet powerhouse. While one leg gently opens to the side, your core fires up behind the scenes, working overtime to stabilize your pelvis and keep everything balanced. The Bent Knee Fall Out is deceptively challenging, rewarding you with a stronger foundation, better posture, and hips that feel more mobile and free.

Ready to refine your core strength and connect with the deep stabilizers that often get overlooked? Let’s dive into the why, the how, and all the tips you need to perfect this Pilates classic.

What Is the Bent Knee Fall Out?

The Bent Knee Fall Out is a foundational Pilates exercise that targets your deep core muscles while encouraging hip mobility and pelvic control. It’s performed lying on your back, with knees bent and feet flat on the floor. From here, one knee gently “falls out” to the side while the other leg stays perfectly still.

The challenge? Keeping your pelvis completely stable as your leg moves. No tilting, no rocking—just pure core control and subtle, focused movement.

It may sound simple, but maintaining this stability requires your deep abdominals to work hard behind the scenes. It’s a move that builds strength and precision, two cornerstones of Pilates practice.

Muscles at Work in the Bent Knee Fall Out

Despite its subtle appearance, the Bent Knee Fall Out activates a wide range of muscles, making it a full-body stability challenge:

Transverse Abdominis (Deep Core): Your “corset” muscle fires up to keep your pelvis stable as the leg moves.
Pelvic Floor Muscles: These muscles work in harmony with your core to provide stability.
Hip Stabilizers (Gluteus Medius and Minimus): These small but mighty muscles on the sides of your hips keep the pelvis balanced.
Obliques: The internal and external obliques support rotational stability and prevent your body from tipping to the side.
Adductors (Inner Thighs): The leg returning to center engages the inner thigh muscles.

Together, these muscles create a symphony of control, balance, and precision.

How to Perform the Perfect Bent Knee Fall Out

Follow these steps to master this Pilates gem:

Start Position: Lie flat on your back with your knees bent, feet hip-width apart, and arms resting by your sides. Your spine should be in a neutral position, with a natural curve under your lower back.
Engage Your Core: Take a deep breath and gently draw your belly button toward your spine to activate your core.
Move with Control: Exhale as you slowly let one knee fall out to the side, keeping the movement small and controlled. Your pelvis and opposite leg should remain completely still.
Return to Center: Inhale as you gently bring the knee back to its starting position, using the inner thigh and core to control the return.
Switch Sides: Repeat on the opposite leg, alternating for 8–10 repetitions per side.

Remember: It’s all about quality, not quantity. Slow, controlled movements are the key to success.

Tips to Improve Your Form

The Bent Knee Fall Out is subtle but challenging. Here’s how to make every rep count:

Keep Your Pelvis Stable: Imagine balancing a glass of water on your pelvis—don’t let it tip! Your hips should stay level as the knee moves.
Small, Controlled Movement: The knee doesn’t need to drop far. Focus on control, not range of motion.
Engage Your Core First: Activate your transverse abdominis before moving your leg. Your core should feel like a strong, supportive brace.
Breathe Intentionally: Exhale as the knee falls out; inhale as it returns. Let your breath guide the movement.
Check Your Neck and Shoulders: Relax any tension in your upper body. Your shoulders and neck should stay soft and grounded.

Why the Bent Knee Fall Out Is a Must-Do Move

The Bent Knee Fall Out may not have the flashy appeal of a Roll-Up or Side Kick, but its benefits are undeniable:

Builds Deep Core Strength: It targets the transverse abdominis, essential for pelvic stability and proper movement mechanics.
Improves Hip Mobility: By gently moving the hip joint, the exercise helps release tightness and encourages better range of motion.
Refines Pelvic Stability: Keeping your pelvis still challenges your body to work as one strong, integrated unit.
Reduces Back Pain: Strengthening the deep core muscles provides better support for your spine and can alleviate lower back discomfort.
Improves Everyday Movement: From walking to lifting, a stable core makes everything feel smoother and more controlled.

Common Mistakes and How to Fix Them

Here are a few pitfalls to watch out for during the Bent Knee Fall Out:

Pelvis Tilting: If your pelvis rocks as the knee falls out, reduce the range of motion and focus on core engagement.
Overarching the Back: Maintain a neutral spine and avoid arching your lower back. Draw your abdominals in for support.
Moving Too Quickly: Slow down! The magic is in the control, not the speed.
Letting the Opposite Leg Move: Keep the non-moving leg completely still by anchoring your foot firmly into the mat.

Fun Facts About the Bent Knee Fall Out

A Foundation for Bigger Moves: Mastering this exercise improves core control for more advanced Pilates moves like leg circles and teasers.
It’s a Physical Therapist’s Favorite: The Bent Knee Fall Out is often prescribed to help build deep core strength and relieve lower back pain.
Small but Mighty: The subtle nature of the move forces your stabilizing muscles to work harder than you think.

Why We Love the Bent Knee Fall Out

The Bent Knee Fall Out reminds us that in Pilates, the smallest movements can yield the greatest rewards. It’s a quiet, meditative exercise that connects you deeply to your core while teaching the importance of control and precision.

Whether you’re a complete beginner or a seasoned Pilates enthusiast, this move is a must for building stability, strength, and body awareness.

So, roll out your mat, settle in, and let your breath guide the movement. One knee at a time, you’re laying the foundation for a stronger, more stable you.

Ready to explore more? Join us in class to discover how small steps lead to big changes. Let’s move, breathe, and strengthen together.