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.
The bicycle crunch, an ab exercise with no equipment
The bicycle crunch is done lying on the floor, legs in the air, pedalling in mid-air. You bring the right elbow towards the left knee, then switch. The torso flexes and rotates at the same time.
This bodyweight exercise needs no bench and no load. A mat is enough. It is one of the most heavily studied ab movements in electromyography research.
Which muscles the bicycle crunch works
The main muscle is the rectus abdominis, the vertical band running from the sternum down to the pubic bone. Flexing the torso upwards shortens it along its whole length.
The rotation brings in the obliques, internal and external. That is what sets the movement apart from a standard crunch, which only flexes in a straight line.
- Rectus abdominis: main driver of trunk flexion
- Obliques: rotation and side-to-side stability
- Psoas and hip flexors: moving the legs
- Transverse abdominis: holding the brace through the alternation
The back muscles do no work here. On the contrary, they should stay relaxed, with the lower back pressed into the floor. To see how these groups fit into a full session, have a look at the programmes structured by goal.
How to perform the movement properly
Starting position
Lie on your back, hands behind your head without interlacing your fingers. Lift your shoulder blades a couple of centimetres off the floor. Raise your legs, knees bent to 90 degrees.
The active phase
Extend your right leg forward without touching the floor. At the same time, rotate your torso towards the left knee as it comes up. The right elbow moves towards that knee, without necessarily touching it.
Alternating sides
Come back to the centre, then switch sides. Keep the pace slow: count roughly 2 seconds per rep. Coordinating the legs and the trunk is the real difficulty of this movement.
Most people pedal fast and barely flex the torso at all. The crunch turns into a leg exercise.
Mistakes to avoid
Three faults show up again and again. They cut down the work on the abs and load the neck for nothing.
- Pulling on your head with your hands: your fingers just rest against your skull, nothing more
- Arching the lower back: raise your legs higher if your back lifts off the floor
- Going too fast: speed replaces the contraction with momentum
A fourth point often slips through unnoticed: letting the torso drop all the way back down between reps. Keep your shoulders off the floor for the whole set. The tension should never drop.
Bicycle crunch or standard crunch
Both are equally good for the rectus abdominis. The difference comes down to rotation and technical difficulty.
| Criterion | Bicycle crunch | Standard crunch |
|---|---|---|
| Rectus abdominis | High | High |
| Obliques | High | Low |
| Coordination | Demanding | Simple |
| Equipment | None | None |
| Useful reps | 15 to 25 | 15 to 30 |
So the bicycle crunch replaces two exercises: a flexion movement and a rotation movement. That is its best argument when you are short on time.
Machines and variations on the market
Several machines borrow the name. The total crunch bike and crunch air bike style machines offer a seated or guided version, with a sliding seat and handles. The range of motion is set by the frame.
These machines are comfortable, but they limit trunk rotation. On the floor, you control the angle, the side and the speed yourself. For oblique work, the free version is still the more complete option.
Useful variations
- Bent legs: the easy version, less leverage on the back
- Straight legs: the hard version, only if your pelvis stays stable
- Slow tempo: 3 seconds per side, no rest between reps
Where to place the bicycle crunch in a session
The trunk recovers fast. You can train it 2 to 3 times a week, at the end of a session, for 3 sets of 15 to 25 reps per side.
Avoid putting it before a squat or a deadlift. Tired abs hold the brace less well on heavy lifts. The body loses its rigidity exactly when it needs it most.
If you are not sure how many sets to programme for your level, automatic session generation from your profile handles it, with a form video for every exercise in the catalogue of 1,800 movements. The tracking and guided session features are detailed on the site.