Bicycle Crunch: How to Do It, Muscles Worked and Benefits

The bicycle crunch is a floor exercise where you pedal your legs like you are on a bike while twisting your torso to bring each elbow towards the opposite knee. It is one of the few bodyweight ab moves that trains rotation, which is why it hits your obliques far harder than a plain crunch. You need no kit and no space beyond a bit of floor, and you can make it brutal or beginner-friendly just by changing the tempo and how low your legs go. Done well it builds the whole abdominal wall; done in a rush it becomes a flappy waste of time. Here is how to get it right.

How to do a bicycle crunch

All you need is a mat or a bit of soft floor. The whole move happens lying on your back, so there is nothing to set up.

1. Lie down and set your hands. Lie flat, then rest your fingertips lightly behind your head with your elbows out wide. Your hands are a cradle for the weight of your head, not a handle to pull on.
2. Lift into position. Curl your shoulder blades up off the floor and raise both legs so your knees are bent around 90 degrees, shins roughly parallel to the ceiling. This is your start.
3. Rotate and extend. Turn your torso to bring your left shoulder towards your right knee while you straighten your left leg out in front of you. The twist comes from your ribcage, not your arm.
4. Switch sides. Come back through the middle under control, then rotate the other way, right shoulder towards left knee, extending the right leg as the left knee draws in.
5. Keep pedalling. Alternate smoothly, breathing out as you crunch and twist. One rep on each side counts as a pair.

Muscles worked

Bicycle crunches are a full abdominal-wall exercise, and the rotation is what sets them apart from a standard crunch.

• Obliques. These are the stars here. Your internal and external obliques run down the sides of your waist and drive the twist, so the rotational demand of the bicycle crunch loads them far more than a straight-up crunch does.
• Rectus abdominis. The long sheet of muscle down the front of your abs, the bit that shows as a six-pack, flexes your spine to curl your shoulders off the floor on every rep.
• Hip flexors. As you cycle one leg out and draw the other in, your hip flexors do a lot of work. That is normal, though it is also why dropping the legs too low shifts strain onto your lower back.
• Transverse abdominis. This deep corset-like muscle braces your trunk to keep you stable while everything else moves. You cannot see it, but it is holding the whole thing together.

Abs respond to training like any other muscle: load them, let them recover, and they grow. What they will not do is decide where your body burns fat.

Benefits

• It actually trains rotation. Most home ab work is straight up and down. The bicycle crunch twists, so it builds the obliques and the movement pattern that a plank or a sit-up never touches.
• Zero kit, tiny footprint. A mat and a couple of square metres is the entire shopping list, which makes it a genuine home workout staple you can do next to the bed.
• It scales both ways. Beginners keep the legs high and go slow; stronger people extend the legs low and add tempo or weight. Same move, wildly different difficulty.
• It teaches control. Because rushing ruins it, learning to do bicycle crunches properly forces you to move your torso with intent, which carries over to other core work like the Russian twist.

Common mistakes

Yanking on your neck. Lacing your fingers and hauling your head forward strains your neck and takes the abs out of it. Keep your hands loose, elbows wide, and lift from your abs so your head just goes along for the ride.

Going way too fast. Speed is the number one killer of this exercise. When you pedal frantically, momentum does the work and your obliques barely fire. Slow down until each twist takes a full second or two.

Not rotating. Tapping your elbow across without turning your ribcage is the most common junk rep. The twist has to come from the trunk. Think shoulder to opposite knee, not elbow to knee.

Dropping the legs too low. If your extended leg sinks near the floor and your lower back peels up and arches, you have gone too far. Keep your lower back pressed down and only lower the leg as far as you can hold that position. Higher legs are safer while you build strength.

Variations

Pick the version that matches where you are, then progress by slowing down before you speed up.

• Feet-higher beginner version. Keep both legs bent and high throughout, barely extending them. This shortens the lever, takes load off your lower back, and lets you nail the rotation before you make it harder.
• Slow tempo bicycle crunch. Take two seconds into each twist and pause for a beat when your shoulder is closest to the knee. The reduced speed strips out momentum and makes a bodyweight set genuinely tough.
• Dead bug regression. If your lower back keeps arching or your neck complains, drop back to the dead bug: lie down, extend opposite arm and leg slowly while keeping your back flat, no crunch involved. It teaches the bracing you need first.
• Weighted bicycle crunch. Once the bodyweight version is easy, hold a light plate or dumbbell against your chest, or pinch a small exercise ball between your hands as you twist, to add resistance without wrecking your form.

Sets and reps

Reps here are about control, not a leaderboard. A simple approach:

• Standard: 3 sets of 10 to 20 reps per side, moving slowly, resting 45 to 60 seconds between sets.
• Learning it: 3 sets of 8 slow reps per side with the legs kept high, focusing only on rotating the torso.
• Building strength: 3 to 4 sets of 10 to 12 weighted reps per side once bodyweight feels easy.

The NHS recommends muscle-strengthening work for all the major muscle groups, including your abdomen, on at least two days a week, so slot bicycle crunches into a couple of sessions rather than grinding them daily.

One more time, because it matters: no amount of crunching burns belly fat. A controlled study of six weeks of abdominal training found it did not reduce abdominal fat at all. Bicycle crunches build the oblique and abdominal muscle; whether that muscle shows depends on your overall body fat, which comes down to diet and total activity. If seeing your abs is the goal, pair this with a sensible deficit and load-based core work like the hanging leg raise or an ab roller once you have the basics down.

Recommended reads

1. How to do a plank
2. Russian twist guide
3. How to do a hanging leg raise
4. The best ab roller in the UK
5. The best exercise ball in the UK