Bird Dog
On all fours, one arm reaches forward and the opposite leg reaches back until arm and leg are in line with your back — no higher. Hold briefly, lower them, swap sides. The work is keeping your trunk completely still while they move.
The bird dog is a baseline exercise for the spine — it belongs with the curl-up and the side bridge.
The point of it is the diagonal. An arm and the opposite leg create a pull that wants to twist your trunk and pull your pelvis out of line. The work is holding still while the arm and leg reach.
It needs no equipment and almost no space, which makes it as useful in a warm-up before hinge work as it is on its own.
Starting position
Start on all fours: hands under your shoulders, knees under your hips, eyes on the floor between your hands. From there one arm reaches forward and the opposite leg reaches back until arm and leg are in line with your back and no higher. Hold briefly, return to all fours, then swap to the other diagonal.
The three cues
- Both hip bones the same height off the floor — pelvis flat like a tabletop
- Push down through the supporting hand and knee
- Only as high as your back — as if the leg were sliding along a sheet of glass at that height
Common faults
| Fault | How to fix it |
|---|---|
| The arm and leg go higher than your back | Up to the height of your back and no further. If that's hard to feel, run a strip of tape along your back — when the tape goes tight, your spine has gone into extension. |
| The chin lifts and the neck extends | Look at the floor between your hands and keep the back of your head in line with your spine. Quick check: hold a tennis ball under your chin — if it drops, your neck has lifted. |
| The supporting knee slides out to the side | Press that knee down into the floor and feel the outside of that hip switch on. If the cue doesn't land, put a mini band around your thighs just above the knees so you can feel what you're pressing against. |
| You stop breathing | Say something out loud while the leg is out there — if you can talk, you're breathing. Bracing your middle and holding your breath are two different things. |
| The reps blur together and there's no pause at the top | Freeze at the top for a moment before you come back. Count the hold out loud if you keep rushing it. |
Variations
| Variation | When to use it |
|---|---|
| Leg only | The quietest version, and the one that puts least load on the spine. The place to start if the position is new or your back is sensitive. |
| Arm only | When the shoulder holds the position well and you want to work the trunk. Also a good halfway step for finding the position. |
| Arm and leg, diagonally | What we do in the studio. Adding the arm raises the demand considerably. |
| Braced first | The same movement, but you brace the trunk before the arm and leg move. |
| Drawing squares | Your hand and foot slowly draw squares in the air, moving only at the shoulder and hip. Your trunk stays still — and you find out straight away whether it really was still in the easier versions. |
Reps and load
Bodyweight only — this is a control exercise.
Short holds, repeated often, rather than long ones. The position sets the limit, not the rep count: the moment your pelvis turns or your lower back sags, the set is over.
Which muscles do the work
| Muscle | Role | What it does here |
|---|---|---|
| Spinal erectors M. erector spinae | Prime mover | Keeps the spine long while the arm and leg work as long levers |
| Deep back muscles M. multifidus | Prime mover | Secures the spine segment by segment — here with the least help from the superficial muscles around them |
| Glute max M. gluteus maximus | Prime mover | Extends the hip of the reaching leg and holds the leg at back height |
| Obliques Mm. obliqui abdominis | Synergist | Resists the twist the diagonal creates |
| Glute med M. gluteus medius | Synergist | Keeps the pelvis level on the supporting side |
| Lats M. latissimus dorsi | Synergist | Links the reaching arm to the pelvis |
| Abs M. rectus abdominis | Stabiliser | Holds the front so the back doesn't sink into extension |
| Delts M. deltoideus | Stabiliser | Holds the reaching arm up at back height |
The diagonal pull wants to twist your trunk and pull your pelvis out of line. Everything in the table is working to stop that — which is why most of the table sits under synergist and stabiliser.
Seeing it done right is not the same as doing it right
Video, cues and variations take you a long way. What they cannot give you is an outside eye at the moment the movement isn't quite there yet. That is what training with me is for — in the studio or in a workshop.
See the workshopsNew exercise pages are added all the time — the newsletter keeps you posted.
Sources
McGill SM, Karpowicz A. (2009). Arch Phys Med Rehabil 90(1):118–126. DOI: 10.1016/j.apmr.2008.06.026 — The paper the progression comes from: arm only, leg only, both, both with the trunk braced, shoulder elevation, and finally drawing squares. It also showed the spine staying still once an experienced coach had corrected the movement. Eight people, surface EMG. (Evidence type: EMG)
Souza GM, Baker LL, Powers CM. (2001). Arch Phys Med Rehabil 82(11):1551–1557. DOI: 10.1053/apmr.2001.26082 — The quadruped exercise across graded difficulty levels in 12 people: the back extensors and glute max worked hardest when the leg on their own side was lifted. (Evidence type: EMG)
Lawrence MA, Swanson BT, Silfies SP, Winchester JB. (2026). J Electromyogr Kinesiol 89:103179. DOI: 10.1016/j.jelekin.2026.103179 — Needle electrodes, 34 people, the bird dog compared against reverse hyperextension, glute bridge and back extension: the deep back muscles made up the largest share of total activity in the bird dog — the least help from superficial muscle of any exercise compared. (Evidence type: EMG)
Callaghan JP, Gunning JL, McGill SM. (1998). Phys Ther 78(1):8–18. DOI: 10.1093/ptj/78.1.8 — An EMG-driven model of loading at L4–L5 in 13 people: extending one leg alone on all fours keeps spinal load low; adding the opposite arm raises both the demand and the load. (Evidence type: Modelling)
A note on context: EMG studies show which muscles an exercise recruits — that is a good reason to pick it, but it does not replace adjusting things to the person in front of you. See a doctor for persistent or severe pain.