ProgreviaBack extensions: proper form, muscles worked and common mistakes
Home › Exercises › Lower back › Back extensions
How to do it
With the hips on the pad, lower the torso with a neutral spine and rise until the trunk lines up with the legs without going past; the glutes and hamstrings finish the movement. Don't hyperextend the lower back.
Muscles worked
Main muscle: lower back. Also worked: glutes and hamstrings. When it plans weekly volume, the generator counts each set of this exercise as one full set for lower back and half a set for each secondary muscle (what is known as fractional counting).
Back extensions with body weight or on the 45° machine: the most accessible version of the family
Body weight back extensions are the starting point of this family: you only have the lever of your own torso. Compared with the 45° back extension machine, there's no mechanism giving a fixed angle here, and depending on the bench or apparatus, the incline varies; the more horizontal, the harder it gets. Compared with good mornings, where the weight rests on your back, there's no bar here and no axial load. They train the lower back, glutes and hamstrings with far less risk of overdoing the weight.
Choose them if you're starting out, if you want a lower back exercise for long sets of 12 to 20 reps, or as a posterior chain warm-up before squats and deadlifts. When body weight falls short, you can hold a plate to your chest or move to the 45° machine with more room to progress. A reverse hyper or good mornings are alternatives for variety.
Set the pad just below the hip bones so you can fold there, with your arms crossed over your chest. Rise until torso and legs are aligned, no higher. To progress, lengthen the lowering to three seconds, add a pause at the top with your glutes squeezed, and later reach your arms forward to lengthen the lever.
Technical sheet
- Movement pattern
- Hip hinge
- Minimum level
- Beginner
- Technical demand
- Basic
- Fatigue it generates
- Moderate (0.8 out of 2.2)
- Risk if technique breaks down
- Medium
- Peak tension in the stretched position
These are the values the generator uses to decide where the exercise goes within the session.
Recommended sets and reps
As a compound lift, it fits in 3–5 sets of 5–12 reps leaving 1–3 reps in reserve (RIR). Prioritize it at the start of the session, when you're fresh.
Common mistakes to avoid
- Hyperextending the lower back at the top of the movement instead of finishing in a neutral position.
- Sticking with the same version once you can do more than 20 reps: move to a harder variation or add load.
- Cutting short the part of the range where the muscle is stretched: that is exactly where this exercise gives the most stimulus.
What the research says
This is a multi-joint lift, and with these the rep range matters less than it seems: Schoenfeld and colleagues (2021) concluded that muscle growth is similar with heavy or moderate loads as long as sets end close to failure, while maximal strength improves more with heavy loads.
It loads the muscle in the stretched position, which is where several trials find more growth: more hypertrophy from seated than lying leg curls (Maeo and colleagues, 2021) and better quad results from training the long part of the range (Pedrosa and colleagues, 2022). So do not cut the bottom of the rep short.
On how hard to push: the meta-analysis by Refalo and colleagues (2023) found no clear advantage in going to failure over stopping just short of it. That is why the generator programs it with reps in reserve (RIR) instead of asking for failure on every set.
- Schoenfeld BJ, Grgic J, Van Every DW, Plotkin DL. Loading recommendations for muscle strength, hypertrophy, and local endurance: a re-examination of the repetition continuum. Sports. 2021;9(2):32.
- Maeo S, Huang M, Wu Y, et al. Greater hamstrings muscle hypertrophy but similar damage protection after training at long versus short muscle lengths. Medicine & Science in Sports & Exercise. 2021;53(4):825-837.
- Pedrosa GF, Lima FV, Schoenfeld BJ, et al. Partial range of motion training elicits favorable improvements in muscular adaptations when carried out at long muscle lengths. European Journal of Sport Science. 2022;22(8):1250-1260.
- Refalo MC, Helms ER, Trexler ET, Hamilton DL, Fyfe JJ. Influence of resistance training proximity-to-failure on skeletal muscle hypertrophy: a systematic review with meta-analysis. Sports Medicine. 2023;53(3):649-665.
How Back extensions compares with other lower back exercises
Of the 6 lower back exercises in the catalogue, ranked from least to most fatiguing by the values the generator uses, Back extensions is number 3.
It sits in the middle of its group: it works as the day's main exercise or as a second or third one.
With different equipment, the same movement pattern offers 3 alternatives, such as 45° back extension machine, Reverse hyper on bench and Good mornings.
| Exercise | Equipment | Fatigue | Technique |
|---|---|---|---|
| Back extensions | bodyweight | Moderate (0.8 out of 2.2) | Basic |
| 45° back extension machine | machine | Moderate (0.9 out of 2.2) | Basic |
| Reverse hyper on bench | machine | Moderate (1 out of 2.2) | Needs coaching |
| Good mornings | barbell | High (1.6 out of 2.2) | Advanced |
Tension with the muscle stretched. Back extensions loads the muscle when it is longest. In the review by Kassiano et al. (2023), across eleven studies, full range of motion and partials performed in the initial part of the movement — with the muscle long — produced more growth than partials performed at the end.
Bodyweight. In the trial by Kotarsky et al. (2018), four weeks of progressively harder push-ups significantly improved bench press 1RM, just like training the bench press itself. It is a strength result, not a hypertrophy one, and the condition is the word progressive: the exercise has to keep getting harder.
- Kassiano W, Costa B, Nunes JP, Ribeiro AS, Schoenfeld BJ, Cyrino ES. Which ROMs lead to Rome? A systematic review of the effects of range of motion on muscle hypertrophy. Journal of Strength and Conditioning Research. 2023;37(5):1135-1144.
- Kotarsky CJ, Christensen BK, Miller JS, Hackney KJ. Effect of progressive calisthenic push-up training on muscle strength and thickness. Journal of Strength and Conditioning Research. 2018;32(3):651-659.
Related guide
The best back exercises: a zone-by-zone guide
Alternative exercises
More hip hinge exercises
Add it to your routine
Progrevia can generate a personalized routine that includes Back extensions based on your level, goal and available days.
Build your lower back workout
Generate a full routine with the emphasis on lower back and Back extensions among your preferred exercises. Free, no sign-up.
Not sure what to pick? The setup assistant walks you through it, one question at a time. Open the assistant
Frequently asked questions
What muscles does Back extensions work?
Back extensions mainly works the lower back muscle group, plus synergist and stabilizer muscles depending on the variation.
How many sets of Back extensions should I do?
Between 3 and 5 sets per session, adjusting the total weekly volume for lower back to your level (about 10–20 sets per muscle per week).
Are back extensions good for strengthening the lower back?
Yes, they work the spinal extensors along with the glutes and hamstrings, and they're a simple way to do it without heavy equipment. What matters is rising only until your body is aligned, without arching past that, and controlling the descent. If lower back pain appears, shorten the range or switch to another option and get it checked.
Progrevia builds gym routines from your own data: periodization, RIR and week-by-week progression. Free, no card.