Lying Bicycle Crunch
The lying bicycle crunch is a floor exercise on your back with the lower back pressed down, pedaling the legs by alternating one extended leg with one bent leg to work the lower abs and the hip flexors.
ABS · CORE
How it is executed
- Lie on your back with your arms resting by your sides or under your hips.
- Raise both legs off the floor and bring your knees toward a 90° position.
- Pedal your legs in a smooth bicycle motion, alternating the extension of one leg while pulling the opposite knee toward your chest.
- Keep your lower back pressed into the floor and core engaged throughout.
- Muscles worked
- Abs
- Primary muscle
- Lower abs
- Equipment
- Bodyweight
- Movement pattern
- Core
- Difficulty
- Intermediate
- What it is for
- StrengthHypertrophyCore strengthStability
Common mistakes
- Extending the leg so low that the lower back lifts. As soon as the back arches, the work moves from the abs to the lumbar spine. Raise the extended leg to the angle where the lower back touches the floor again.
- Pedaling fast, with momentum. At speed, the legs move on inertia and the abs barely have to resist anything. Set a pace of about two seconds per leg and feel the lower abs holding each extension.
- Lifting the head and straining the neck. With the arms at your sides nothing supports the head, so looking at the legs loads the neck without adding work to the abs. Rest the head on the floor and look at the ceiling.
- Cutting the knee's range short. If the knee does not come close to the chest, the pelvis does not fully tilt back and the abs work halfway. Bring each knee past the hip and extend the other leg completely.
Frequently asked questions
- Which muscles does the lying bicycle crunch work?
- The rectus abdominis, helped by the obliques, is what holds the pelvis tucked and the lower back pressed into the floor while the weight of the legs tries to arch it; that isometric tension is felt in the lower abs and grows the lower and straighter the leg travels. The legs themselves are moved by the hip flexors, mainly the iliopsoas and the rectus femoris, and the quads straighten the knee on every pedal stroke.
- Lying bicycle crunch or twisting bicycle crunch: which one should you choose?
- Here the torso stays still and only the legs pedal: the abs work by resisting the arch of the lower back, mostly in the lower portion. In the twisting bicycle crunch the torso rotates and the elbow reaches for the opposite knee, so the obliques and the upper rectus abdominis come in. The lying version teaches you to fix the pelvis and loads the lower abs; the twisting crunch targets the obliques.
- How many reps or how long should you do the bicycle crunch for?
- A common starting point is 3 sets of 10 to 15 pedal strokes per leg, or 30 to 45 seconds, at a slow pace of about two seconds per leg. The set ends the moment the lower back lifts off the floor, even if reps are left: from there the work shifts to the lower back. It goes at the end of the session, in the core block, or as part of the warm-up before legs, with fewer reps.
- How high should the legs go so the lower back stays down?
- As high as it takes to keep the lower back pressed into the floor for the whole set. Start with the extended leg high, at about 45 degrees, and lower the angle week by week as the abs can hold it. Placing the hands under the hips helps tilt the pelvis back and gives a little margin. If the back arches, raise the legs or shorten the set: the lower the extended leg travels, the harder it gets.
Sources and editorial approach
The explanation, variations and FAQs are Kaizer’s editorial synthesis. ACSM’s 2026 guidance provides general context on progression and resistance training in healthy adults; it does not independently validate the technique of each variation.
No individual professional review is recorded for this page.
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