Spine Stability Big Three 12 min

The curl-up, side plank and bird dog — the 'big three' developed by spine biomechanics researcher Stuart McGill — done as a descending 5-3-1 pyramid engage the muscles needed to improve spine stability.

The bird dog is easy to do wrong, which can raise the risk of straining the back or neck: beginners can start by extending just the arms or just the legs.

The session at a glance

• Focus: isometric
• Intensity: low
• Duration: 12 minutes
• Equipment: mat

The protocol

1. Warm-up — 2 min. Easy walking in place and gentle cat-camel on hands and knees.
2. Curl-up — pyramid 5-3-1. Lie on your back, hands under the low back to keep its natural arch; on an exhale lift head, shoulders and chest just enough to feel the muscles work, as one unit; do not bend the low back or tuck the chin; hold up to 10 s, lower slowly.
3. Side plank (knees bent) — pyramid 5-3-1 each side. Elbow under shoulder, knees at 90 degrees, lift hips into a straight line head to knees, hold up to 10 s.
4. Bird dog — pyramid 5-3-1 each side. On hands and knees extend one arm and the opposite leg toward parallel with the floor, hips and shoulders square, back not arching; hold up to 10 s; beginners extend only the arm or only the leg.
5. Cool-down — 1 min. Lie on your back, slow breathing.

Why this works

• Whole-trunk coverage. Together the three moves engage the muscles from the abdominals to the whole back.
• Short holds, low load. Holds of up to 10 s in a 5-3-1 pyramid keep total time at 12 minutes.
• Form over reach. The cues keep the low back neutral rather than flexed or arched.

How to scale it

• Beginners: extend only the arm or only the leg in the bird dog.
• Keep side plank knees bent until the straight line from head to knees is easy to hold.
• Stop a rep short of losing form — shorter holds with clean position beat longer ones.

Related protocols

• Zone 2 Row Erg, 40 Min
• Yoga Sun Salutation — 15-Minute Daily Mobility Flow
• Weighted-Vest Hill Walk 30 min

Sources

• Harvard Health — Three moves for better spine health
• Harvard Health — Bird dog exercise for your core

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