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Single Leg Plank Hold (Modified)

The modified single-leg plank starts from a knee-supported plank and extends one leg long, holding the line while three points of contact carry the body. It teaches the trunk to stay quiet as a limb leaves the ground — a core skill that later powers full planks with leg lifts. Coached by Maddy (NASM-CPT) — these are the exact form cues he gives on every client's first week.

Muscles worked

Abs · rectus abdominis Deep core · transverse abdominis Obliques Lower back · erector spinae Front shoulders · anterior deltoid

Sets & reps by goal

GoalSets × RepsRest
Strength4 × 10–15 s per leg90 s
Muscle3 × 20–30 s per leg60 s
Endurance3 × 30–45 s per leg45 s

Rep ranges per Helms 2014 · Schoenfeld 2016.

Level — Beginner

Beginner-plus — the knee base keeps it accessible while the hovering leg adds the first taste of instability.

Proper form — 5 cues

  1. Set a forearm plank with both knees down and a straight head-to-hip line
  2. Extend one leg back until it hovers in line with the body
  3. Squeeze the extended leg's glute to hold it level
  4. Keep the hips square to the floor — no tilt toward the support knee
  5. Hold, then switch legs without the hips ever sagging

Breathing: Even, unhurried breaths for the whole hold — the leg switch happens on an exhale.

The 3 mistakes Maddy corrects most

Lifting the extended leg high above hip height. Hiking the leg arches the lower back and swaps abdominal work for lumbar compression. Fix: Keep the hovering heel level with the hip — a straight body line matters more than leg height.
Hips rotating toward the side of the lifted leg. The tilt reveals the obliques giving up the anti-rotation job the drill is designed to train. Fix: Imagine headlights on the front of your hips that must keep shining at the floor throughout.
Weight sinking backward into the support knee. Shifting into the knee unloads the abs and turns the hold into rest disguised as a plank. Fix: Nudge your chest slightly forward over the elbows so the trunk stays honestly loaded.

Common questions

What does lifting one leg add to a plank?

Removing a contact point shrinks your base of support, so the deep trunk muscles and obliques must work harder to stop sagging and twisting. The extended leg's glute also joins in to hold the hover. It converts a static endurance hold into a stability challenge without adding any equipment.

Is the modified version enough, or do I need the full single-leg plank?

The modified version is a complete exercise in its own right and the correct dose for anyone still building plank capacity. Move to the full version — both legs long, one hovering — once you can hold 30 controlled seconds per side here with square hips and normal breathing.

Why does my lower back ache in this position?

Almost always the hovering leg has risen too high or the hips have sagged, both of which fold the load into the lumbar arch. Re-set the line, tuck the pelvis slightly, and lower the leg to hip height. If ache persists even with clean form, shorten the holds and rebuild gradually.

Related exercises

Easier: Plank Hold  ·  Harder: Plank Single Leg Hold

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