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Exercises

Sit-ups

Classic torso curl from supine to upright sitting — the simplest direct ab exercise.

Execution

  1. Lie on your back, knees bent, feet flat on the floor (anchored or tucked under something).
  2. Hands behind the head or crossed over the chest — do not yank on the neck.
  3. Curl the torso up under abdominal control until you sit upright.
  4. Lower back down with the same control — do not drop into the floor.

Tips

  • If your neck complains, use crunches or dead bugs instead.
  • The decline variant (feet elevated) makes it noticeably harder.

What spine research says about the sit-up

The sit-up is the most famous ab exercise there is — and the one that has aged worst. Biomechanist Stuart McGill spent decades measuring the forces core exercises place on the lumbar spine. The classic sit-up produces compressive forces on the discs well above 3,000 newtons — a figure that occupational medicine treats as the threshold for repeated loading. Repeated flexion under load is exactly the mechanism that damages discs in lab studies.

For most people, the sit-up is therefore a bad trade: high risk to the discs for little benefit toward what the trunk actually needs to do — stabilize, not flex.

When it still makes sense

Flexion isn't forbidden. A healthy back is allowed to flex, and if you're training for a fitness test that includes sit-ups, you need to practice them. As a small part of an overall program, low rep counts are also unproblematic. What doesn't make sense: a hundred sit-ups a day as your main core training.

Execution, if you do them

Knees bent, feet flat on the floor, hands in front of the chest rather than behind the head — pulling on the head shifts the load into the cervical spine. Curl up under control, vertebra by vertebra, and lower back down with the same control. No momentum from the arms, no jerky movement from the hips.

The better alternatives

For stability: the plank, dead bug and side plank. For targeted flexion work with less load: the hollow hold, leg raises and small-range crunches. If you have ten minutes a day, you'll get further with these than with sit-ups.