Side plank
Muscles worked : Obliques, lateral core
How to do it
- Lie on your side, resting on the forearm placed under the shoulder.
- Stack the feet one on the other, or stagger them for more stability.
- Lift the hips off the floor to line the body up straight.
- Hold the position breathing normally, without letting the hips drop.
- Finish the set, then switch sides.
Common mistakes
- Hips sagging towards the floor during the hold.
- The shoulder sinking towards the ear instead of staying stacked over the elbow.
- The body rotating forwards or backwards.
Where you should feel it
The side of the trunk, between the ribs and the hip, on the floor side. The supporting shoulder works too: if it sinks towards the ear, actively push the floor away to keep it stable.
Range of motion
No range, an alignment: ear, shoulder, hip and ankle on one line seen from the front. The hip is the point that gives way first — that is what to watch.
Tempo and breathing
A continuous hold, breathing normally. As with the standard plank, the stopping criterion is the position, not the clock: as soon as the hip drops, the set is over.
What works, precisely
The internal and external obliques on the floor side drive the hold, assisted by the quadratus lumborum. The gluteus medius stabilises the pelvis in the frontal plane, and the serratus anterior keeps the supporting shoulder blade flat against the ribs.
Movement mechanics
An anti-lateral-flexion isometric: gravity pulls the hip towards the floor and the lateral chain stops it. It is the direct complement to the standard plank, which barely works this plane.
Benefits
- Works the lateral chain, forgotten by the standard plank and by most abdominal exercises.
- Strengthens pelvic stability in single-leg stance, which carries over to walking and to carrying a load on one side.
- Makes left-right asymmetries very visible: the time held often differs markedly.
Adapt and progress
- Easier : Bend the knees and rest on them rather than the feet: the lever shortens sharply.
- Harder : Extend the duration, lift the free arm to the ceiling, or lift the top leg.
- Move on when : When thirty seconds per side go by with no hip drop, add complexity rather than extending indefinitely.
Precautions
The elbow must be exactly under the shoulder. Too far forward or back and the strain shifts onto the joint instead of staying on the muscle.