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Bird Dog (Modified)

The modified bird dog splits the classic into halves: extend just one leg, or just one arm, while the other three points stay planted. It is the honest starting square for anyone whose full version wobbles or whose lower back complains on all fours. Coached by Maddy (NASM-CPT) — these are the exact form cues he gives on every client's first week.

Muscles worked

Deep core · transverse abdominis Lower back · erector spinae Glutes · gluteus maximus Rear shoulders · posterior deltoid

Sets & reps by goal

GoalSets × RepsRest
Strength3 × 3–6 per limb (5 s holds)60 s
Muscle3 × 9–12 per limb45–60 s
Endurance2–3 × 18–27 per limb45 s

Level — Beginner

The ground floor of the bird-dog family — and a diagnostic tool disguised as an easy drill.

Proper form — 5 cues

  1. Start on all fours with a neutral spine — a shallow dip in the lower back, ribs not flared.
  2. Slide one leg back along the floor first, then lift it only to torso height.
  3. Keep both hands pressing the floor away so the shoulder blades stay spread.
  4. Do all reps on one limb before switching — no alternating rush.
  5. Stop each rep for a one-second check: are the hips still level?

Breathing: Breathe normally throughout; exhale gently on each extension rather than holding air.

The 3 mistakes Maddy corrects most

Starting with the arm lift when balance is poor. The arm version narrows your base more than the leg version — it is the harder of the two halves. Fix: Master leg-only extensions first; add the arm lift as its own separate stage.
Sagging into the supporting shoulder. The planted side collapses, the spine twists, and the drill trains the exact leaning it should prevent. Fix: Push the floor away continuously with both hands — tall between the shoulder blades.
Treating it as a throwaway warm-up filler. Rushed, unfocused reps build none of the control this progression exists to develop. Fix: Give it the same attention as a heavy set: slow reps, level hips, deliberate breathing.

Common questions

Is the modified bird dog too easy to bother with?

Ask your hips: if a slow single-leg extension with a five-second hold keeps them perfectly level, you have outgrown it — move up. Most beginners discover they cannot, which is exactly the information the drill provides. Easy done badly is not easy; it is unfinished business.

Leg first or arm first — which half should I train?

Leg first. Extending a leg keeps both hands planted, so your base stays wide and the trunk learns the anti-rotation job with maximum support. The single-arm reach removes a hand and is noticeably harder on balance. Own the leg version, add the arm version, then combine them into the full bird dog.

How long before I can do the full bird dog?

For most beginners, two to four weeks of consistent practice — a few sets, most days — is enough to earn the combined version. The test is boring reliability: ten slow reps per side of each half with level hips and no wobble. The calendar matters less than passing that test.

Related exercises

Harder: Bird Dog

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