Extension work on the GHD can be both similar and dissimilar in action to CrossFit’s nine foundational movements. The GHD hip extension is similar because the spine is held in neutral throughout each rep. Both the GHD back extension and the GHD hip and back extension require deliberate flexion and extension of the spine. While the spine is always held rigid when lifting, training flexion and extension on the GHD builds strength, positional awareness, and coordination that can be applied to other movements.

Brian Chontosh of CrossFit's Level 1 Seminar staff explains the GHD hip and back extension.