Bent-knee fall-out
Lying on your back with the knees bent, one knee lowers slowly out to the side and back while the pelvis stays still: a gentle trunk-control exercise from postnatal physiotherapy and Pilates. It trains control rather than strength.
Movement guide
Bent-knee fall-out
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Make it easier or harder
Start where you can move well, then step up.
Easier option
3D demoSupine heel slideBeginner · No equipmentSuggested next step, beginner grade.
Harder option
3D demoDead bug heel tapsBeginner · No equipmentSuggested next step, beginner grade.
Source-researched guide. Clinical review is pending.
How to move
- Lie on your back with your knees bent, feet flat and hip-width apart, and your head on a pillow.
- Breathe in. As you breathe out, gently draw up your pelvic floor and lower tummy.
- Let one knee fall slowly out to the side, only as far as your pelvis stays still.
- Bring the knee back to the middle.
- Relax fully, then repeat on the other side.
Form cues
- Keep both hip bones level, as if a cup of tea were balanced on your tummy.
- Move only as far as the pelvis stays still.
- Avoid: holding your breath or letting the other knee drift.
Practice and cautions
2 sets of 5 to 10 each side, every other day: the dose a UK pelvic health physiotherapy booklet (POGP) gives for its progressing tummy exercises. It is taught after birth and listed for the first 2 weeks in the UK return-to-running guideline, but no trial has tested it on its own.
After a caesarean, move within comfort, and roll onto your side to get up. In pregnancy after the first trimester, or if lying flat makes you dizzy, do it propped up on pillows. This is movement education, not an assessment or treatment prescription. Stop for sharp or increasing pain, dizziness, numbness or tingling; seek individual guidance for symptoms, injury or restrictions.
Sources and review status
Sources support the educational description; they do not establish that this exercise is suitable for you.
- POGP 2024 · Fit for the Future: essential advice and exercises following childbirth (physiotherapy booklet) ↗
- Goom 2019 · Returning to running postnatal: guidelines for medical, health and fitness professionals (lists a bent knee drop out for the first 2 weeks) ↗
- Benjamin 2023 · Conservative interventions may have little effect on postnatal diastasis recti (meta-analysis, Physiotherapy) ↗
- Beamish 2025 · Postpartum exercise, pelvic floor disorders and diastasis recti (meta-analysis, BJSM) ↗
No variation is labeled clinically validated.
What it works
Muscles
Main: Abs. Also: Adductors, Hip abductors.
Anatomy: Rectus abdominis, Obliques, Transversus abdominis.
Equipment
None: body weight and floor space.
Level
Beginner. See the easier and harder options above.
Workouts that use it
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Questions people ask
What muscles does the Bent-knee fall-out work?
Mainly the abs, with help from the adductors and hip abductors.
What equipment do I need for the Bent-knee fall-out?
No equipment: your body weight and a little floor space.
Is the Bent-knee fall-out good for beginners?
It is graded beginner, so it suits most people starting out. When it feels easy, try the Dead bug heel taps.
What is an easier alternative to the Bent-knee fall-out?
Try the Supine heel slide. It is the suggested step down from this move.
How do I make the Bent-knee fall-out harder?
Progress to the Dead bug heel taps, or add load, range or slower lowering once your form is solid.