Lower back exercise
Back Extension (45 Degrees)How to do it, with form in numbers
- Main muscles
- Lower back, Glutes
- Also works
- Hamstrings
- Equipment
- Machine
- Level
- Beginner
How to do it
How do you do the Back Extension?
- Set the pad just below your hip bones and hook your heels under the rollers.
- Cross your arms on your chest and line your body up straight.
- Hinge at your hips and lower your chest towards the floor, back flat.
- Squeeze your glutes to lift until your body is straight again.
- Stop in a straight line, without arching back.
Cues
- Hinge at the hips, not the spine.
- Finish straight, not arched.
- Neck long, eyes on the floor.
Common mistakes
- Arching back at the top: stop as soon as your body forms a straight line.
- Rounding your back at the bottom: lower only as far as you can keep it flat.
- Swinging up fast: lift and lower slowly with a short pause.
Form in detail
What does good form look like?
Starting position
45° back extension bench (legs held at 45° to the floor). Hip pad set so its top edge sits just below the front hip bones, leaving the hips free to fold over it. Heels under the ankle rollers, feet on the platform hip-width apart, knees straight or very slightly bent (0–10°). Arms crossed on the chest, hands on the opposite shoulders. Stomach braced, neck in line with the spine.
The movement
The trunk swings as one rigid piece about the hip joint over the pad. The spine keeps its shape; the head moves with the trunk. On the way up, squeeze the glutes and stop when the body is straight again. Legs stay still on the platform.
End position
Fold forward at the hips over the pad with the back still flat until the trunk is about horizontal to 20° below it: hip flexion about 50°. Stop just before the back starts to round. Brief 0.5 s pause, then lift.
Tempo
Lower 2 s / pause 0.5 s / lift 1.5 s / hold straight 0.5 s.
Form in numbers
What are the angles and distances?
| Measure | Target | Good range | Sources |
|---|---|---|---|
| Bench angle (legs to the floor) | 45° | fixed | |
| Knee flexion | 5° | 0–10°, no change in the rep | |
| Trunk angle from vertical at the top | 45° | 40–50° (in line with the legs) | |
| Hip extension at the top | 0° | −5 to 0° (no arch past the straight line) | |
| Pad top edge | just below the hip bones | 0–5 cm below |
The targets our 3D demo was built to, from the references below. Bodies differ, so treat the ranges as a guide for your own build.
For coaches
Use this demo in your clients’ programs
The Back Extension is in Trainaq’s exercise library. Add it to a workout, and your client sees this demo in the free Trainaq app above the sets they log.
