Back Extension
Also known as: back extensor exercise, hyperextension, 45 degree back extension, lower back extension
Simple, scalable, and easy on the joints, the back extension strengthens the spinal erectors, glutes, and hamstrings through a controlled hinge on a 45-degree or horizontal bench. It builds the endurance your lower back needs to support squats and deadlifts, and it is one of the few lower-back movements you can train close to failure without loading the spine heavily. Hold a plate when bodyweight gets easy.
How to do the back extension, step by step
- Set the pad of the extension bench so it sits at the crease of your hips, not on your stomach.
- Hook your heels under the ankle pads and cross your arms over your chest.
- Lower your torso by hinging at the hips, keeping a long, neutral spine, until you feel a stretch in the hamstrings.
- Pause briefly at the bottom without letting the back round into a slump.
- Squeeze the glutes and raise your torso back up until your body forms one straight line.
- Stop level — do not hyperextend past straight — and repeat with a two-second descent each rep.
Form cues that fix most reps
Lead the lift with your glutes, as if pinching a coin between them at the top.
Keep your chin gently tucked so your neck follows the line of your spine.
Reach long through the crown of your head at the bottom instead of collapsing over the pad.
Common mistakes (and the fix)
Back Extension sets and reps
Match the rep range to your goal, not the other way around. These are the standard evidence-based ranges:
| Goal | Sets × Reps | Rest |
|---|---|---|
| Strength | 3–5 × 3–6 | 2–3 min |
| Muscle growth | 3–4 × 8–12 | 60–90 sec |
| Endurance | 2–3 × 15–20 | 30–60 sec |
Back Extension FAQ
What muscles do back extensions work?
The spinal erectors work isometrically to hold the spine long while the glutes and hamstrings power the hinge. Shifting your toes outward biases the glutes; a rounded-upper-back setup shifts more work to the erectors. Either way it trains the whole posterior chain.
How many sets and reps of back extensions?
Do 3 sets of 10–15 controlled reps. Once 15 bodyweight reps feel comfortable, hold a plate against your chest and drop back to 8–12 rather than adding endless reps.
Are back extensions safe if my lower back is weak?
They are one of the better starting points, because the load is only your torso and the range is easy to shorten. Start with partial ranges and low reps, keep the movement smooth, and progress gradually. Sharp pain is a stop sign; a working-muscle burn in the erectors and glutes is the goal.
More lower back exercises
Track your back extension progress.
Log sets in two taps, see last session's weights pre-filled, and watch your e1RM climb — free in your browser, works offline in the gym.