Bird dog
Muscles worked : Core, lower back · Glutes, shoulders
How to do it
- Get on all fours, hands under the shoulders, knees under the hips.
- Brace the core to keep the back flat, in line with the head.
- Extend one arm in front of you and the opposite leg behind you at the same time.
- Pause, keeping the hips still and level.
- Return to the start and repeat on the other side.
Common mistakes
- The pelvis rotating or tipping to one side during the extension.
- The lower back arching to gain more range.
- Moving too fast: stability matters more than speed.
Where you should feel it
A deep stabilising effort in the trunk and in the glute of the extended leg, more than a sense of strength in the limbs themselves. If you feel nothing in the trunk, the pelvis is probably moving and absorbing the work.
Range of motion
Extend arm and leg to horizontal, no higher. Lifting the leg further arches the lower back without adding anything — horizontal is the useful limit.
Tempo and breathing
Two seconds to extend, one to two seconds held, two seconds to return. The hold is the part that counts: that is when stabilisation is genuinely working.
What works, precisely
The erector spinae and the multifidus, a deep segmental muscle of the spine, keep the back neutral. The obliques resist pelvic rotation, the gluteus maximus extends the hip, and the deltoid with the lower trapezius hold the arm horizontal.
Movement mechanics
An anti-rotation and anti-extension exercise: the weight of the opposing limbs creates a torque that tends to twist and arch the trunk, and the entire task is to prevent it. It is cross-body motor control — the same pattern as walking.
Benefits
- Strengthens lumbar stability with no compressive load on the spine, which often makes it well tolerated even with a sensitive back.
- Trains cross-body coordination of opposite arm and leg, directly transferable to walking.
- Reveals asymmetries immediately: one side will often be noticeably less stable than the other.
Adapt and progress
- Easier : Extend one limb at a time, arm alone then leg alone.
- Harder : Extend the hold, or add a knee-to-elbow draw under the body between each extension.
- Move on when : When ten repetitions per side go by with a perfectly still pelvis, extend the hold to five seconds.
Precautions
A mat or cushion under the knees stops joint discomfort ending the set before the muscles tire.