Bird dog
On hands and knees, extending opposite arm and leg without letting the hips turn.
- Pattern
- Anti-rotation
- Equipment
- Nothing needed
- Space
- Floor space
- Difficulty
- Foundational
- Load
- Leverage
- Side
- One side at a time
What it is
On hands and knees, hands under shoulders and knees under hips, back flat.
Extend one arm straight forward and the opposite leg straight back, until both are roughly level with your torso. Hold for a moment, return, and repeat on the other side.
The whole difficulty is in what does not happen: the hips stay level and square to the floor, and the back does not arch.
What it demands
Resisting rotation. Lifting a leg on one side creates a turning force on the pelvis, and stopping the hips from twisting is the job — mostly the obliques and the deep spinal muscles including multifidus.
Hip extension on the working side, from gluteus maximus.
Shoulder stability on the supporting arm, and enough balance to hold three points of contact.
Wrist extension tolerance, since the weight is on flat hands.
What usually goes wrong
The hips rotate. The leg side lifts as the leg goes back. Almost universal and almost never noticed without a check — balancing something light across the lower back makes it immediate.
Arching the lower back. Reaching the leg higher than horizontal usually means the back has extended rather than the hip. Level is high enough.
Rushing. As with the dead bug, moving slowly is what makes it work.
Looking up. Keeping the neck in line with the spine means looking at the floor.
Where it sits
The bird dog and the dead bug are a pair: both move opposite limbs while the trunk stays still, but the dead bug resists the back arching and this one primarily resists the hips turning. Between them they cover two of the three ways a trunk has to hold still, with the side plank covering the third.
It also carries a genuine hip extension component, which makes it a reasonable warm-up for hinging as well as a trunk movement.