EXERCISE GUIDE

Oblique Crunch

Internal and External Obliques
Bodyweight
Beginner to Intermediate

How to Do the Oblique Crunch With Proper Form

01

Lie on your side with the hips stacked, knees bent comfortably, and the lower arm positioned to support the head without pulling on the neck.

02

Place the upper hand lightly behind the head or across the ribs and keep the top elbow relaxed.

03

Brace the trunk and keep the pelvis from rolling backward or forward.

04

Curl the upper rib cage toward the side of the pelvis using a controlled lateral bend.

05

Pause when the side of the trunk is shortened without forcing the shoulder toward the hip.

06

Lower slowly until the side body lengthens while keeping the hips stacked.

07

Complete the set, switch sides, and match the range and repetitions.

Form Check & Technique

DO THIS (Technique Tips)

  • Keep the hips stacked throughout the set
  • Think rib cage toward pelvis on the working side
  • Use light head support only
  • Pause at the shortened position
  • Match sides by repetitions and range

AVOID THIS (Common Mistakes)

  • Pulling the head toward the hip
  • Rolling the pelvis instead of bending the trunk
  • Using a fast bouncing rhythm
  • Lifting the hips off the floor to create range
  • Rotating forward instead of staying in a side bend
  • Training one side with more volume than the other

About Oblique Crunch

The oblique crunch is a side-bending trunk exercise that emphasizes the internal and external obliques. Set up on your side or with one shoulder supported, then bring the rib cage toward the pelvis without yanking the neck or rotating through momentum. Use a range you can control and train both sides evenly.

Target MuscleInternal and External Obliques
Secondary MusclesRectus Abdominis, Quadratus Lumborum, Transverse Abdominis, Hip Flexors
EquipmentBodyweight
DifficultyBeginner to Intermediate
MechanicIsolation
Force TypePull
Movement PatternInternal and External Obliques

Oblique Crunch Muscles Worked

The obliques create and control lateral trunk flexion while the deeper abdominal muscles help stabilize the torso.

  • The quadratus lumborum and hip muscles may assist depending on the setup, but the movement should be led by a controlled rib-cage-to-pelvis curl rather than a hip hike.
PRIMARY TARGET
Internal and External Obliques
SECONDARY ASSIST
Rectus AbdominisQuadratus LumborumTransverse AbdominisHip Flexors

Sets & Reps Guidance

BY TRAINING GOAL
LEARN MOVEMENT

Technique / Learning

2-3 sets of 8-12 bodyweight reps per side while learning to keep the hips stacked.

BUILD STRENGTH

Strength Focus

3-4 sets of 8-12 controlled reps per side with a stable setup.

BUILD MUSCLE

Muscle Growth (Hypertrophy)

2-4 sets of 10-20 reps per side with a slow return and brief top pause.

General training baseline. Need.fit automatically adjusts exact sets, reps, and working weight based on your individual fitness level, recovery, and progress over time.

Exercise Variations & Alternatives

Side-Lying Oblique Crunch Setup

Stack the hips and keep the knees bent enough to make the position stable. The more the pelvis rolls or the feet push into the floor, the more the exercise can become a hip movement instead of a side crunch.

Oblique Crunch vs Side Plank

An oblique crunch trains active lateral flexion.

  • A side plank trains the lateral trunk to resist that motion.
  • They are different patterns and can be programmed together.

How to Avoid a Hip Hike

Keep the hips stacked and avoid lifting the pelvis toward the ribs. If the hips move more than the rib cage, reduce the range and slow the lowering phase.

How to Progress the Exercise

Build control and symmetrical repetitions first. Then add a light load, extend the pause, or use a longer lever position while keeping the same side-bending path.

Sources & References

  1. [1]
    Side Crunch Exercise LibraryACE FitnessView Source
  2. [2]
    Strength Assessment of Trunk Rotator Muscles: A Multicenter Reliability StudyPubMedView Source
  3. [3]
    ACSM Position Stand: Resistance Training Prescription for Muscle Function, Hypertrophy, and Physical PerformancePubMedView Source
NEED.FIT ADAPTIVE SYSTEM

Train Your Obliques Without Turning the Rep Into a Hip Hike

Need.fit can combine lateral flexion, anti-lateral-flexion, and rotational work for a more complete trunk program.

Frequently Asked Questions

What muscles does an oblique crunch work?

It primarily trains the internal and external obliques, with the rectus abdominis, quadratus lumborum, and deeper abdominal muscles helping control the trunk.

Are oblique crunches good for side abs?

They can train the obliques through active lateral flexion when the rib cage moves toward the pelvis without the hips taking over.

Why do I feel oblique crunches in my hip?

The pelvis may be rolling or hiking toward the ribs. Keep the hips stacked, reduce the range, and slow the repetition.

Should I do oblique crunches on both sides?

Yes. Use comparable sets, repetitions, and range on both sides unless a qualified professional has prescribed otherwise.

Oblique crunch or side plank: which is better?

They train different actions. The oblique crunch practices active side bending, while the side plank practices resisting side bending.

Can I add weight to an oblique crunch?

Yes, after bodyweight form is consistent. Add a light load only if you can keep the neck, hips, and rib-cage path controlled.