Lying Bike Bent Knee
The lying bike bent knee is a bodyweight core exercise targeting the abdominal muscles. Performed on the back, it mimics a slow cycling motion with bent knees to engage the abs and hip flexors while minimizing strain on the lower back.
How to do it
- Lie flat on your back with your hands placed lightly behind your head.
- Lift both feet off the ground and bend your knees to a 90-degree angle.
- Begin a slow pedaling motion, drawing one knee toward your chest while extending the opposite leg.
- Keep your lower back pressed into the floor and your core engaged throughout the movement.
- Continue alternating legs in a controlled cycling motion for the desired number of repetitions.
Form cues
- Press your lower back flat into the floor.
- Keep your core engaged throughout the entire motion.
- Move slowly and control every inch of the pedal.
- Breathe steadily as you alternate leg extensions.
Breathing: Exhale as you extend each leg outward, and inhale as you bring the knee back toward your center.
Common mistakes
- Arching the lower back away from the floor, which places unnecessary strain on your spine.
- Moving too fast and using momentum instead of core control.
- Holding your breath, which prevents proper abdominal bracing.
Muscles worked
Primary: abs. Secondary: hip flexors, obliques.
Suggested sets & reps
Get fitter
3 sets × 12 reps per leg, rest 60 s
Lose weight
3–4 sets × 12–16 total reps, rest 45–60 s
Build muscle
3 sets × 10–14 controlled reps, rest 60 s
Easier, harder & alternatives
Make it easier
Make it harder
Take care if…
- If you feel sharp lower back discomfort, ease off and stop the movement.
General educational guidance, not medical advice. Stop on sharp pain and check with a qualified professional if unsure.
Get this in your plan
Create a free account for an AI-built plan that puts moves like this into your week.
Start free →Frequently asked questions
Where should I feel this exercise?
You should feel your abdominal muscles working to keep your pelvis and lower back stable against the floor.
What if my lower back starts to lift off the floor?
This means your core muscles are fatiguing or you are extending your legs too low. Try extending your legs higher toward the ceiling to keep your back pressed flat.
How often can I do this movement?
You can include this exercise 2 to 4 times per week as part of your regular home workout routine.