Lying Leg Raise (Bent Knees)
The lying leg raise with bent knees is a bodyweight core exercise targeting the lower abs and hip flexors. Bending the knees reduces the lever arm compared to a straight-leg raise, making it more accessible while still effectively loading the abdominal muscles.
How to do it
- Lie flat on your back with your legs extended and your hands placed beneath your lower back or flat at your sides.
- Bend your knees to approximately 90 degrees and lift your feet slightly off the ground.
- Raise your bent legs upward, bringing your knees toward your chest.
- Pause at the top, engaging your abs.
- Slowly lower your feet back toward the ground without fully resting them and repeat for the desired number of repetitions.
Form cues
- Press your lower back firmly into the floor.
- Keep your knees bent at a steady ninety-degree angle.
- Exhale as you lift your knees toward your chest.
- Lower your feet slowly under control.
Breathing: Exhale as you lift your knees upward, and inhale gently as you return your legs toward the starting position.
Common mistakes
- Arching the lower back off the floor, which strains the lumbar spine instead of working the abs.
- Using momentum to swing the legs up rather than relying on muscle control.
- Resting the feet completely on the floor between reps, which relieves tension on the core.
Muscles worked
Primary: abs. Secondary: hip flexors, obliques.
Suggested sets & reps
Get fitter
3 sets × 10–12 reps, rest 60 s
Lose weight
3 sets × 12–15 reps, rest 45 s
Build muscle
3 sets × 10–12 reps, rest 60 s
Easier, harder & alternatives
Take care if…
- If you feel lower back discomfort, reduce your range of motion or take a break.
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
Where should I feel this exercise?
You should feel your abdominal muscles working. It is also normal to feel mild effort in the front of your hips.
What if my lower back lifts off the floor?
Try placing your hands beneath your lower back for extra support, or do not lower your feet as close to the floor.
How many times a week can I do this?
Two to three times per week is a great starting point for recovery and consistency.