Dead Bug

• Core
• Beginner-friendly
• Timed — 30 seconds per set

The dead bug extends one arm and the opposite leg while the lower back stays glued to the floor — anti-extension core work at its purest.

It looks easy and is quietly demanding: the moment the lower back arches, the rep stopped counting. That makes it the exercise physiotherapists reach for first — and a smarter starting point than crunches for anyone with a cranky back.

How to do it

1. Lie on your back, arms up, knees bent at 90 degrees.
2. Lower one arm and the opposite leg toward the floor.
3. Return and repeat on the other side.

Breathing: Exhale as you extend.

Common mistakes

• Letting the resting knee drift in toward your chest as the other leg extends.
• Scissoring the legs quickly so the drill turns into flutter kicks.
• Resting the heel on the floor at the bottom so the abs unload each rep.

Form tips

• Slide a hand under your lower back; if the gap opens as the leg drops, you went too far.
• Keep the traveling knee bent until you can hold the back flat with the leg straight.
• Move slowly enough that the opposite arm stays pointed at the ceiling and quiet.

Muscles worked

Alternatives with the same focus

• Bird Dog
• Plank
• Straight-Arm Plank

Where it appears in the 30-day plan

Programs in the app that schedule this movement:

• Core & Abs
• Lower Belly
• Love Handles
• Upper Abs