Dépense estimée selon votre poids
Poids du corps, rythme soutenu · 2 s par répétition
| Répétitions | Dépense estimée |
|---|---|
| 1 | 0,35 kcal |
| 10 | 3,5 kcal |
| 20 | 7,0 kcal |
| 50 | 17,5 kcal |
| 100 | 35,0 kcal |
Estimation à partir des équivalents métaboliques (MET) du Compendium of Physical Activities. La charge, le tempo et la durée des repos font varier le résultat du simple au double : à lire comme un ordre de grandeur, pas comme une mesure.
What exactly is a bicycle crunch?
The bicycle crunch is a floor ab exercise. You flex the trunk and bring one knee toward the opposite elbow, alternating sides. The legs move back and forth like a pedal stroke, which is where the name comes from.
No equipment needed. A mat and two square metres are enough. That's why it shows up in almost every ab program published online, in the gym as much as at home.
One thing sets it apart from the standard crunch: here the trunk doesn't just lift, it rotates. That rotation changes how the work is shared out completely.
Which muscles work during bicycle crunches?
The movement loads the core as a whole, not one isolated spot. Four groups split the effort.
- Rectus abdominis: handles the flexion, the visible part of the abs.
- Obliques, internal and external: rotation is their main job.
- Transverse abdominis: stabilises the pelvis while the legs float.
- Psoas and quads: they kick in as soon as a leg extends.
A 2001 study run at San Diego State University for ACE ranked this exercise first out of thirteen ab movements tested, on rectus and oblique activation. Take it as a ballpark, not a guarantee of results.
The lower back, meanwhile, should do nothing. If it arches, the load leaves the abs and goes into the spine. That's the most reliable signal to stop.
How to do it properly
Starting position
Lie on your back, lower back pressed into the floor. Hands behind the head, fingers not laced, elbows wide. Lift the shoulder blades a couple of centimetres and raise the legs, knees bent to 90 degrees.
The movement
Bring the right knee toward the left elbow by turning the shoulders, not just the arm. The left leg extends without touching the floor. Then reverse, slowly. One full rep takes about 3 seconds, not one.
The mistakes that keep coming back
- Pulling on the neck with the hands: your neck pays for it.
- Moving the elbows instead of the trunk: the obliques stop working.
- Going fast: speed replaces muscle with momentum.
- Dropping the leg too low before the core can hold it.
In practice, nine lifters out of ten do bicycle crunches too fast. Halving the tempo is enough to make the exercise hard, without adding a single rep.
Bicycle crunch, standard crunch or plank: which one
These three don't replace each other. They cover different needs.
| Criterion | Bicycle crunch | Basic crunch | Plank |
|---|---|---|---|
| Obliques | High | Low | Medium |
| Rotation | Yes | No | No |
| Lower-back load | Medium | Medium | Low |
| Equipment | None | None | None |
| Typical duration | 40 s | 30 s | 60 s |
If your lower back is touchy, start with planks and keep the knees high on the bicycle crunch. You adjust the difficulty with the leg angle, not the rep count.
How many sets to program
A beginner rarely holds more than 20 clean reps. Aim for 3 sets of 10 per side, 45 seconds rest, twice a week. The quality of the rotation ends the set, not the counter.
An experienced lifter can go to 4 sets of 20 per side, legs lower, or add a one-second pause at the top. Placed at the end of a session, it fits well into a six to eight minute ab circuit, closer to light cardio than to strength work.
The real problem is elsewhere: knowing where to slot those sets into the week without wrecking your legs or your back. Our week-by-week structured programs spread core work between the heavy sessions, and the guided session on your phone sets the slow tempo instead of leaving you to count on your own.
Making sense of the usual cues
Most videos and gifs on this movement repeat the same handful of instructions. They're worth reading properly rather than nodding along.
- Keep your core tight: stay braced, don't let go between reps.
- Lift your shoulder blades off the floor: the blades leave the mat, the head stays neutral.
- Do not pull your head forward with your hands: your hands support, they don't pull.
- If you feel your back arching, you need to raise the legs: bring the knees back up.
They all say the same thing: keep the lower back in contact with the floor. That's the only criterion that matters when you judge a set of bicycle crunches filmed from the side.
Variations worth using
Three versions cover nearly everything. The weighted bicycle crunch, with a 2 kg plate held against the chest, adds load without speeding the movement up. The arms-extended-forward version removes the temptation to pull on the neck. And the isometric version, where you hold the knee-to-elbow position for three seconds, hits the obliques hard.
The muscu.pro video library holds over 1,800 filmed exercises, these variations included; the breakdown of the tracking features shows how they string together in a real session.
That leaves the volume question. Three ab sessions a week aren't worth more than two if the rotation falls apart. Film yourself once, compare it to the cues, adjust. That pays off more than any increase in the number of crunches.