Lying Knee Raise
The lying knee raise is a floor exercise in which you lie on your back and draw your bent knees in towards your chest, then take them back out under control. Bending the knees shortens the lever, making it the easier version of the lying leg raise; it trains the hip flexors and the abs.
Also called: Floor Knee Raise, Supine Knee Raise, Bent-Knee Lying Leg Raise, Lying Knee-Up · Equipment: bodyweight · Pattern: isolation
Step by step
- Lie on your back on a mat with your hands flat beside your hips, your knees bent to about 90° and your feet just off the floor.
- Brace your abs and press the small of your back flat into the floor.
- Draw your knees in towards your chest, keeping the 90° bend.
- At the top, curl your hips a few centimetres off the floor to finish the rep with your abs.
- Take your feet back out and down under control until your heels are just above the floor, keeping the small of your back flat.
- Keep your head relaxed on the mat and breathe out as your knees come in.
- Repeat at a steady pace, with no swing.
- Small of your back flat on the floor
- Knees in towards your chest
- Curl your hips up at the top
- Knee bend fixed at 90°
- Slow on the way back out
- Head relaxed on the mat
In VALDA, these cues are one tap away on the exercise while you train.
What it trains
| Muscle | Role | Evidence |
|---|---|---|
| Hip flexors | Prime mover | B |
| Rectus abdominis: lower (infraumbilical) | Secondary | C |
| Rectus abdominis: upper (supraumbilical) | Secondary | C |
| Obliques (internal/external) | Stabiliser | C |
| Quadriceps: rectus femoris | Stabiliser | C |
Evidence grades: A = strong research base · B = good · C = limited · D = coaching consensus.
What goes wrong, and the fix
Back arching as the feet go out
Fix: Keep the small of your back flat and take your feet out only as far as it stays flat.
Knees straightening on the way out
Fix: Hold the knee bend at about 90° for the whole rep.
Skipping the hip curl
Fix: Finish each rep by curling your hips a few centimetres off the floor.
Swinging the legs
Fix: Move slowly in both directions and pause briefly with your knees in.
Lifting the head and neck
Fix: Rest your head on the mat and let your abs and hips do the work.
What the research says
Rehab & prehabGeneral fitnessEndurance
- Lever length — EMG research shows leg raises are led by the hip flexors. Bending the knees shortens the lever, which makes this version easier than the straight-leg raise.
- Effort — Studies show muscle growth is similar across a wide range of loads when sets are taken close to failure, and sets that finish a rep or two short of failure capture most of that benefit.
- Endurance — Reviews of loading find lighter loads and higher reps tend to favour local muscular endurance, which is the quality this exercise mainly trains.
- Sets and reps — A common approach is 2–3 sets of 10–20 reps. Many lifters progress by gradually straightening the legs towards the full lying leg raise. There is no direct research on knee-raise programming.
Log the lying knee raise in VALDA, with these cues one tap away while you train and your history for it in one place.
General information about exercise technique, not medical advice. If you have an injury or a health condition, your healthcare provider is the right person to ask.