What do the obliques do?

They rotate the trunk, bend it sideways, and resist both of those movements when an outside force tries to produce them. The external oblique on one side rotates you to the opposite side; the internal oblique rotates you to the same side. Together they also help compress the abdomen when you brace.

Do oblique exercises make your waist wider?

Heavy, low-rep loaded side bends can add enough muscle thickness at the waist to be visible over time. Anti-rotation and anti-lateral-flexion work at moderate loads builds function without much added girth, which is why most people should default to it.

What is the difference between abs and obliques?

The rectus abdominis runs vertically down the front and flexes the trunk forward. The obliques run diagonally along the sides and handle rotation and side bending. They are separate muscles with separate jobs, and a complete core routine trains both.

Are side planks enough for obliques?

They are a good start and train anti-lateral-flexion well, but they are isometric and only cover one of the obliques' jobs. Adding a Pallof press for anti-rotation and a woodchop or landmine rotation for loaded rotation gives you full coverage.

Core

Obliques

Obliquus externus and internus abdominis

Also called: side abs, external oblique, internal oblique

The obliques are two layers of muscle running diagonally along the sides of the abdomen. The external oblique's fibres run down and inward; the internal oblique's run the opposite way underneath. Together they rotate the trunk, bend it sideways, and — most importantly — resist rotation.

front

The obliques highlighted on the front of the body.

Obliques anatomy

The external oblique is the outer layer, with fibres running downward and inward, in the direction your hands would slide into your front pockets. Working on one side, it rotates the trunk to the opposite side.

The internal oblique lies directly beneath, with fibres running roughly perpendicular to the external. Working on one side, it rotates the trunk toward the same side. The two therefore work as a pair: the right external oblique and left internal oblique fire together to rotate you left.

Both layers attach into the linea alba via a broad sheet of connective tissue, which means they also contribute to the tension across the front of the abdomen — the obliques are part of how you brace, not just how you twist.

Deep to both is the transverse abdominis, whose fibres run horizontally and which acts almost entirely as a stabiliser.

Part	What it does
External oblique	Outer layer, fibres down-and-in. Rotates the trunk to the opposite side.
Internal oblique	Deeper layer, fibres perpendicular to the external. Rotates the trunk to the same side.

Origin: External oblique: the outer surfaces of ribs 5–12. Internal oblique: the thoracolumbar fascia, the iliac crest and the inguinal ligament.
Insertion: External oblique: the iliac crest and the linea alba via the abdominal aponeurosis. Internal oblique: the lower ribs, the linea alba and the pubic crest.

What the obliques does

Trunk rotation — twisting the torso left and right.
Lateral flexion — bending sideways at the waist.
Anti-rotation — resisting a twisting force, which is the obliques' most common real-world job.
Anti-lateral-flexion — staying upright while carrying a load on one side.
Compressing the abdomen and contributing to intra-abdominal pressure when bracing.

Best obliques exercises

Exercise	Equipment	Role	Level	Why
Pallof press	Cable machine or band	primary	Beginner	The definitive anti-rotation exercise. You resist a twist rather than producing one.
Suitcase carry	Dumbbell or kettlebell	primary	Beginner	Anti-lateral-flexion under heavy load. Deceptively hard and highly transferable.
Cable woodchop	Cable machine	primary	Intermediate	Loaded rotation through a diagonal path, which is how the obliques actually work together.
Side plank	Bodyweight	primary	Beginner	Isometric anti-lateral-flexion. Progress by adding a reach or a load rather than by holding longer.
Hanging knee raise with twist	Bar	primary	Advanced	Combines trunk flexion with rotation. Control the return — swinging defeats it.
Landmine rotation	Barbell + landmine	primary	Intermediate	Loaded rotation with a fixed arc, which makes it easier to control than a free-weight twist.
Bicycle crunch	Bodyweight	secondary	Beginner	Simple, equipment-free rotation work. Slow it down — speed makes it much easier and much less useful.

How to train the obliques

Sets per week

6–12 hard sets

Rep range

10–20 per side, or 20–45 second holds

Frequency

2 sessions per week

Prioritise anti-rotation and anti-lateral-flexion over loaded twisting. Resisting force is what the obliques do most of the time, and it is easier on the spine.
Heavy loaded side bends are largely unnecessary and can thicken the waist, which is usually the opposite of what people training obliques want.
Every unilateral carry, single-arm press and offset load trains the obliques hard without a dedicated exercise.

Stretches and mobility

Standing side bend

Reach one arm overhead and lean gently to the opposite side. 20–30 seconds each side.

Supine spinal twist

Lie on your back, drop both knees to one side while keeping the shoulders down. 30 seconds each side.

Common mistakes

Heavy weighted side bends

They load the obliques, but they also load the lumbar spine in lateral flexion under a heavy weight, and they tend to add thickness at the waist. Anti-lateral-flexion work like a suitcase carry gives you most of the benefit with less downside.

Rushing rotation exercises

Fast twisting is mostly momentum. The obliques are trained by controlling the movement, especially the return, not by how many reps you can generate.

Only training one side

Most people rotate better in one direction. Doing equal work per side, and starting with the weaker one, keeps the imbalance from widening.

Obliques FAQ

What do the obliques do?: They rotate the trunk, bend it sideways, and resist both of those movements when an outside force tries to produce them. The external oblique on one side rotates you to the opposite side; the internal oblique rotates you to the same side. Together they also help compress the abdomen when you brace.
Do oblique exercises make your waist wider?: Heavy, low-rep loaded side bends can add enough muscle thickness at the waist to be visible over time. Anti-rotation and anti-lateral-flexion work at moderate loads builds function without much added girth, which is why most people should default to it.
What is the difference between abs and obliques?: The rectus abdominis runs vertically down the front and flexes the trunk forward. The obliques run diagonally along the sides and handle rotation and side bending. They are separate muscles with separate jobs, and a complete core routine trains both.
Are side planks enough for obliques?: They are a good start and train anti-lateral-flexion well, but they are isometric and only cover one of the obliques' jobs. Adding a Pallof press for anti-rotation and a woodchop or landmine rotation for loaded rotation gives you full coverage.

References

This page is general educational information about exercise and anatomy. It is not medical advice and not a substitute for assessment by a qualified clinician. If you have pain, an injury or a health condition, speak to a professional before changing how you train.