Back Extension
The back extension is a lower back (spinal erectors) hip hinge done with bodyweight only. It also works the glutes and hamstrings. On weyt.ai it counts toward Balance as Back (minimum 10 sets per 30 days) and toward Gains at an effective load of 45% of your bodyweight per rep, plus any added weight.
At a glance
| Muscle group | Lower Back |
|---|---|
| Primary muscles | lower back (spinal erectors) |
| Secondary muscles | glutes, hamstrings |
| Equipment | Bodyweight |
| Logged as | Reps per set |
| Gains scoring | Load-scored, bodyweight factor 0.45 |
| Balance group | Back · minimum 10 sets per 30 days |
| Strength standards | none (standards exist for barbell and dumbbell lifts with published norms) |
How weyt.ai scores it
- Balance: every logged set counts toward the Back group, which needs at least 10 sets per 30 days for full credit.
- Gains: load-scored with a bodyweight factor of 0.45. Each rep counts as 45% of your bodyweight plus any added weight, so it earns volume, e1RM and PR credit like a loaded lift.
- Routine: any session that includes it counts toward your weekly target, the 4-week consistency window and your streak.
Scoring is deterministic code, not AI: the same sets always give the same Weyt Score. Read the method on the about page.
Also called
back extensions, 45 degree back extension, roman chair back extension
Log it under any of these names and weyt.ai resolves it to the same exercise, so your history and progression never split across spellings.
Related back exercises
Everything else that counts as back
Bent Over Barbell Row · Pendlay Row · Underhand Barbell Row · T-Bar Row · Single-Arm Dumbbell Row · Dumbbell Rear Delt Row · Incline Dumbbell Row · Renegade Row · Seated Cable Row · Standing Cable Row · Single-Arm Cable Row · Machine Row · Resistance Band Row · Kettlebell Row · Lat Pulldown · Wide Grip Lat Pulldown · Close Grip Lat Pulldown · Reverse Grip Lat Pulldown · Straight-Arm Pulldown · Weighted Pull-Up · Assisted Pull-Up · Dumbbell Pullover · Cable Face Pull · Band Face Pull · Band Pull-Apart · Barbell Shrug · Dumbbell Shrug · Barbell Upright Row · Dumbbell Upright Row · Farmer's Walk · Barbell Deadlift · Trap Bar Deadlift · Dumbbell Deadlift · Ski Erg · Rowing Erg · Sled Pull