Back Extension — CrossFit Accessory Technique Guide
By Borja Bes — CrossFit Athlete & Hyrox Finisher
The back extension is a foundational posterior-chain accessory exercise for CrossFit athletes. It trains the spinal erectors and glutes to maintain posture and resist fatigue, which matters in deadlifts, Olympic lifts, rowing, and gymnastics arch positions. In a glossary, it deserves its own page because it is more specific and scalable than a generic “lower back exercise” label. Whether done on a GHD, Roman chair, or floor variation, the goal is controlled extension with glutes and trunk working together.
Muscles Worked
Equipment
How to Do the Back Extension
Set up on the machine or floor with the hips supported and spine neutral.
Lower the torso under control without collapsing.
Extend back to neutral by driving through the glutes and spinal erectors.
Finish tall without hyperextending the lower back.
Common Mistakes
Finishing in excessive lumbar extension instead of neutral.
Moving too quickly and turning the exercise into a hinge swing.
Losing glute tension and putting all the load into the low back.
Coaching Tips
Think “finish tall” rather than “lean back.”
Back extensions pair well with hollow-body work to build balanced trunk capacity.
Scaling Options
Easier / Beginner
Floor supermans, reduced range, or assisted machine reps.
Harder / Advanced
Weighted back extensions, tempo reps, or single-leg variations.
Frequently Asked Questions
Are back extensions mainly for the lower back?
They train the spinal erectors, but strong reps also rely on the glutes and hamstrings. Done well, they build posterior-chain endurance more than isolated “low back strength.”
Build It Into a Workout
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Related Exercises
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