How do I do a proper sit-up or crunch?

Sit-ups are the exercise everyone learned at school and one of the most commonly done badly. The version that works well is smaller and slower than the one people picture.

Safety

Step by step

1. Know the difference between a sit-up and a crunch.A crunch lifts the shoulder blades a few inches with the lower back staying in contact with the floor. A full sit-up brings the whole torso up, which brings in the hip flexors and pulls on the lower back.
2. Choose the crunch for most purposes.It targets the abdominals more directly and loads the spine less. Full sit-ups have largely fallen out of favour for general fitness and are commonly advised against with back problems.
3. Set up properly.On your back, knees bent, feet flat and about hip-width apart, lower back in its natural slight curve rather than pressed flat or arched.
4. Support your head, do not pull it.Fingertips lightly behind the ears or hands crossed on the chest. Hands laced behind the head means people pull, which strains the neck and is the single most common fault.
5. Keep a gap under your chin.About a fist's width. Chin dropping to the chest is what causes the neck ache people blame on the exercise itself.
6. Lead with the ribs, not the head.Think about bringing the bottom of the ribcage towards the hips. It produces the right movement automatically, where thinking about lifting the head produces the wrong one.
7. Move slowly and control the way down.Two seconds up, two down. The lowering half is where much of the benefit is, and it is the half people let gravity do.
8. Keep the range small.Shoulder blades just clearing the floor. Coming higher adds hip flexor work rather than abdominal work, and that is what pulls on the lower back.
9. Breathe out on the way up.Exhale as you curl, inhale as you lower. Holding your breath raises blood pressure and does nothing helpful at this intensity.
10. Do not anchor your feet.Hooking them under something lets the hip flexors take over almost entirely, which defeats the exercise and increases the pull on the lower back.
11. Include the other directions.The abdominals also resist rotation and extension. Planks, dead bugs, bird dogs and side planks train those, and a programme of only crunches is a narrow one.
12. Prefer anti-movement work if you have back trouble.Planks, dead bugs and bird dogs load the spine far less than repeated flexion, and they are what most physiotherapists suggest first.
13. Do not expect it to change your midsection.Abdominal exercises strengthen the muscles; they do not reduce fat over them, which is determined by overall energy balance. This is the most persistent myth in fitness.
14. Stop for pain.Neck strain usually means technique. Lower back pain means stop and reconsider the exercise choice, and get it looked at if it persists.

Tips

• Fingertips behind the ears, never hands laced behind the head. That one change removes most neck complaints.
• A fist's width under the chin throughout. It is the simplest check that the neck is in a reasonable position.
• Think about the ribs moving towards the hips rather than lifting the head. The cue produces the movement.

Common mistakes

• Pulling on the head or neck — It strains the neck and takes the work away from the abdominals. Support the head lightly with fingertips instead.
• Hooking the feet under something — It lets the hip flexors do most of the work and increases the pull on the lower back, which is the opposite of what the exercise is for.

If it doesn't work

Questions people ask