Side Lying Oblique Crunch

Also known as: side crunch, side crunches, lying side crunch, side lying crunch, floor oblique crunch, oblique crunch

Secondary muscles
Obliques
Body part
Core
Position
Lying
Laterality
Bilateral (both sides together)
Category
Strength

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Lying on your side stacks the obliques directly against gravity, so the sideways crunch works lateral flexion through a range no twisting floor crunch reaches. Each side works alone, which exposes the strength gap most lifters carry between left and right - start with the weaker side and match its reps.

How to do the Side Lying Oblique Crunch

  1. Lie on your back with your knees bent and feet flat on the floor.
  2. Place your hands behind your head or cross them over your chest.
  3. Engage your abs and lift your shoulder blades off the floor, rotating your torso to one side.
  4. Pause for a moment, then lower your shoulder blades back down to the floor.
  5. Repeat on the other side, alternating sides with each repetition.

Tip: Breathe out as you crunch and let the last bit of air leave the lungs at the top of each rep.

Muscles worked

Primary

Abs · Core

The rectus abdominis shortens to bend the spine forward, and each rep should end with the upper abs fully contracted and the ribs pulled down.

Secondary

  • Obliques — Twisting or side crunch variations bring the obliques in, and you should feel them along the side of the waist on the working side.

Common mistakes

  • Pulling on the neck — hands behind the head should support, not yank; keep the elbows wide and the chin about a fist away from the chest.
  • Sitting all the way up — a crunch is a curl of the ribs toward the pelvis, not a sit-up; the lower back should stay on the floor the whole time.
  • Cranking out fast reps — momentum does the work if you bounce; lift to a squeeze, hold for a count and lower slowly.
  • Never adding load — once bodyweight reps get easy, hold a plate on the chest or use a cable rather than doing sets of 50.

Where it fits in a workout

Crunches close out a session after the heavy work, or they can fill the rest periods between sets of a lift that does not need much bracing. Pair a cable crunch with a cable side bend on the same stack.

How many sets, how heavy and how hard: see what the ACSM position stands support.

Variations and alternatives

When to talk to someone

  • Chest discomfort, feeling faint or lightheaded, or trouble breathing during or after exercise can be signs of a heart attack. In the US, call 911 right away; elsewhere, call your local emergency number.
  • Heart, metabolic or kidney disease, or symptoms like these when you are active: talk to your doctor before you start or step up training.
  • Pregnant: ask your obstetric care provider which exercise suits you.

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More exercises

Sources

  1. ACSM position stand on exercise quantity and quality (Garber et al., 2011)
  2. ACSM preparticipation health screening (Riebe et al., 2015)
  3. ACOG Committee Opinion No. 804 on exercise in pregnancy (2020)
  4. CDC: About Heart Attack Symptoms, Risk, and Recovery (2024)

Sources checked on October 17, 2026. Full citations are in the exercise library.

Animation and exercise data: ExerciseDB, licensed to SetGrip. General information, not medical or coaching advice.