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Core

Reverse crunch: how to do it

Main muscles: Lower abs. Helpers: Upper abs, Obliques. Below: step-by-step form, common mistakes, a muscle map, reps and rest, and what to swap it for.

Equipment
Bodyweight
Reps
12–20
Rest
60 s
Muscle group
Core

How to do it

  1. Lie on your back, arms alongside the body, knees bent.
  2. Curl the pelvis and bring the knees to the chest, the lower back stays on the floor.
  3. Lower slowly, do not drop the legs.

Common mistakes

Swinging the legs, lifting the lower back, pushing with the hands.

▶ Form video on YouTube

Muscles worked

Front
Back
primary·secondary
Primary
Lower abs
Secondary
Upper abs, Obliques

A secondary muscle gets roughly half the stimulus of a set — that is also how the log’s stats count it.

Programs that use it

Alternatives: similar exercises

Plank Bodyweight · Upper abs, Lower abs Ab wheel rollout Bodyweight · Upper abs, Lower abs Bicycle crunch Bodyweight · Obliques, Lower abs Crunches Bodyweight · Upper abs Hanging leg raise Bodyweight · Lower abs Dead bug Bodyweight · Lower abs

Log your sets — the app suggests the next weight

GymAssist tracks the load on each of 40 muscles, paints it on a body map and uses double progression to tell you when to add weight.

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