Bird Dog

The bird-dog is a bodyweight anti-rotation core exercise and one of Stuart McGill's Big 3. From a quadruped position, the opposite arm and leg extend to a flat line while the hips and ribs stay square. Return under control, then alternate. It trains trunk stiffness and rotary stability against the diagonal pull of the long levers, with no equipment and little spinal load. The loaded bird-dog row is a separate movement: a one-arm row held in the same quadruped or bench-supported base.

Mechanics and load path

Start on hands and knees, hands under the shoulders, knees under the hips, spine neutral. Extend one arm forward and the opposite leg back until both reach a flat line level with the torso. Hold briefly, then return under control and switch sides. There is no external load. The long levers of the reaching arm and leg supply the resistance, and the work is holding the trunk still against them.

The failure mode is the hips or ribs rotating, or the lower back sagging into extension as the limbs reach. When the trunk twists, the anti-rotation demand is lost and the movement drifts into a hip-flexor reach. The trunk holds square while the deep braces resist the diagonal pull, keeping the load off the spine and in the anterior chain and the hips. It sits in McGill's anti-movement core work next to the side plank.

The loaded bird-dog row

A common loaded variant, the bird-dog row, is a different exercise rather than a weighted bird-dog. The lifter holds a one-arm row from a three-point quadruped base, often with one knee and one hand supported on a bench. The free arm pulls a kettlebell or dumbbell to the ribs while the opposite leg extends behind. It adds a horizontal pull and a heavier anti-rotation demand, where the classic bird-dog stays a slow bodyweight hold. The two share a name and a base, not a training effect.

Used in: Program 03 — Kettlebell Hypertrophy