Dead Bug — CrossFit Core Technique Guide
The dead bug is one of the best entry-level core drills for learning how to brace the trunk while moving the limbs. That makes it especially valuable for beginners in CrossFit, because it teaches the same ribcage and pelvis control needed for hollow body positions, overhead pressing, and efficient lifting. It may look simple, but a strict dead bug quickly reveals whether an athlete can keep the lower back organised under movement.
Muscles Worked
Equipment
Watch the movement demo
Video tutorial on YouTube — opens in new tab
How to Do the Dead Bug
Lie on your back with arms straight up and knees bent to 90 degrees.
Press the lower back gently into the floor.
Extend one arm and the opposite leg slowly away from the body.
Return to the start and alternate sides without losing trunk position.
Common Mistakes
Letting the lower back arch as the leg extends.
Moving too fast and turning the drill into momentum.
Shrugging the shoulders instead of keeping the ribs organised.
Coaching Tips
Only move as far as you can while keeping the lower back controlled.
Exhale as the leg reaches long to reinforce trunk bracing.
Scaling Options
Easier / Beginner
Shorter limb range, arms only, or legs only.
Harder / Advanced
Longer range, tempo reps, or light external load in the hands.
Frequently Asked Questions
Why include dead bugs in a CrossFit glossary?
Because they teach the trunk control beginners need before harder gymnastics core drills. They are one of the cleanest ways to learn anti-extension mechanics.
Related Exercises
Ready to put the Dead Bug to work?
Generate a WOD that includes this movement, calibrated to your level and equipment.