Primary Muscles
Internal/external obliques, quadratus lumborum
Core
Side Plank
The most targeted exercise for the obliques and lateral core stability — a staple in back-pain rehab protocols.
3D animation — watch the full movement
Secondary Muscles
Gluteus medius, transversus abdominis, anterior deltoid
Equipment
None (mat optional)
Location
Home / Gym
Difficulty
Beginner → Intermediate
How to Do It
- Lie on your side. Place your bottom elbow under your shoulder (90°). Feet stacked or staggered.
- Lift your hips off the floor. Outer foot edge, knee, hip, shoulder and ear should form one straight line.
- Engage core, squeeze glutes. Keep hips from rotating forward or backward.
- Breathe continuously. Fix your gaze on a point in front of you.
- Target: 20-40 s each side. Train both sides equally — symmetry is critical.
Common Mistakes
- Hips rotating forward or backward — hip flexors take over instead of obliques.
- Bottom shoulder caving in — rotator cuff stress. Keep the shoulder actively pushed away from the ear.
- Hips dropping — quadratus lumborum disengages. Lift fully.
- Doing longer holds on the stronger side — asymmetry worsens and opens the door to lateral back pain.
- Lateral neck bend — cervical strain. Maintain ear-shoulder-hip alignment.
Beginner Tips
- Start with knee side plank (bottom knee bent for support). 15 s × 2 sets × 2 sides.
- A cornerstone of Stuart McGill's 'Big 3' back-pain protocol.
- If there's left-right asymmetry, train the weak side twice as often.
- Progressions: star side plank (top leg raised), hip dips (lower and raise hips), rotation.
Frequently Asked Questions
Does the side plank strengthen the back?
Yes. The quadratus lumborum and obliques provide lateral lumbar stability. McGill's research lists side plank as one of the core exercises for back-pain rehabilitation.
Side plank or crunch — which works the obliques more?
Side plank. Crunches primarily target the rectus abdominis; obliques are secondary. Side plank makes the obliques the primary movers.
How long should I hold?
Beginner: 20 s × 2 sets. Intermediate: 30-45 s × 3 sets. Advanced: 60+ s or dynamic variations. Equal time each side is non-negotiable.
Related Exercises
Plank
The most evidence-backed isometric exercise for core, lower back and shoulder stability.
Russian Twist
The classic oblique isolation move — rotational core strength and the V-cut taper.
Crunch
The go-to isolation move for the rectus abdominis — effective with good form, neck-straining with bad.
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