Oblique Crunch

What is the Oblique Crunch?

The oblique crunch is a bodyweight trunk crunch performed with a twist, curling one shoulder toward the opposite knee or hip so the abdominal wall works through rotation instead of straight flexion. It is a simple, equipment-free way to target the internal and external obliques on the sides of the trunk.

Muscles worked

Primary — Obliques

The obliques are the prime mover: they rotate the ribcage toward the opposite hip and side-flex the trunk, which is exactly the twisting shortening this crunch loads.

Secondary — Abs

The abs — the rectus abdominis — assist by flexing the trunk to lift the shoulder blades off the floor, so the obliques have a stable base to rotate against.

How to perform the Oblique Crunch

1. Lie on your back with the knees bent and rolled to one side so both knees rest toward the floor.
2. Place the hands lightly behind the head without pulling on the neck during the movement.
3. This rotated position pre-shortens the obliques on the up side so the crunch loads them directly.
4. Curl the upper torso toward the hip, lifting the shoulder blade off the floor by contracting the obliques.
5. Lower back down slowly under control, then finish all reps before switching the knees to the other side.

Suggested working range: 12–20 reps. Default progression: double progression.

Mechanics

A single-joint trunk isolation combining flexion with rotation: the spine curls and twists over a short range as one shoulder drives toward the opposite knee, then returns. Because the movement is a controlled twist rather than a hip or leg action, the work stays on the obliques rather than the hip flexors.

Form cues

• •Drive the shoulder — not the elbow — toward the opposite knee so the rotation comes from the trunk, not from yanking on the neck.
• •Curl up on a short range and squeeze the working side hard at the top before lowering under control.
• •Keep the low back down and exhale as you twist so the obliques do the work rather than momentum.

Common mistakes

• •Pulling on the head and neck with the hands instead of lifting the torso with the obliques.
• •Only twisting the shoulders without curling the ribs toward the hip, so the obliques barely fire.
• •Dropping the torso back to the floor quickly rather than lowering it under control.

Variations & alternatives

• •Russian twist — a seated rotational hold that trains the same twist against a weight and a longer lever.
• •Hanging oblique raise — the harder, hanging progression that loads the lower obliques with bodyweight.
• •Cable woodchopper — a standing loaded rotation to overload the same pattern once bodyweight is easy.

Side Plank Hip Dip

Obliques · Bodyweight

Cable Side Bend

Obliques · Cable

Hanging Oblique Raise

Obliques · Machine

Seated Spinal Twist

Obliques · Bodyweight

Standing Side-Bend Stretch

Obliques · Bodyweight

Programming: sets, reps & when to use it

Train it for higher reps, roughly 12–20 per side, since it is a light bodyweight isolation where quality of the twist beats load. Work both sides evenly and add reps or a slower tempo before reaching for a weighted rotational variation.

Frequently asked questions