The Numbers in the Back Extension Program, Explained

Updated September 25, 2026 · 7 min read · 6 sources

Written for adults with long-running low back pain who are cleared to exercise. I have no medical training; this is the method I used and what the research says about it. Some symptoms need emergency care or a clinician before any exercise: check the red flags.

The program card prints the numbers, and the progression guide walks through the stages. This page says where each number came from. A few rest on lumbar-extension studies or standard strength-training guidance. Most are my own choices, set on the cautious side so a sore back can move forward without guessing. No trial has tested them as a complete program.

Exercise in general has trial support for chronic low back pain. Searle and colleagues reviewed 45 randomised trials in 2015 and pooled 39 of them, and found benefits for strength and coordination programs. That supports the direction of this program, not its exact numbers.

How to read the tables

The middle column says what each number rests on. "Study" means a published study tested something close to it. "Training practice" means it follows ordinary strength-training programming. "My rule" means I picked it. "Mix" means the direction is published and the exact number is mine.

Starting doses and stage targets

Number	Rests on	Why
3 holds of 15 s, 60 s rest Stage 1 start	My rule	A hold puts tension on the back without moving it. 15 seconds is short enough that all 3 holds finish and the next morning can still land at baseline. A minute of rest means the next hold is limited by your back rather than your breathing. No lumbar study sets either number.
A hold of about a minute, or about 3 minutes of holding across the session Stage 1 target	My rule	A hold of about a minute, or about 3 minutes of holding across a session, means holding the position is no longer the limit, so a small range is the next thing to add. The lumbar studies cited here (Graves on strength, Steele's review on pain and disability) used no 60-second cutoff.
3 sets of 3 reps at 50% of range, 60 s rest Stage 2 start	My rule	Half range is the first real movement after holds, and 3 reps keeps the first sets short.
At least 5 reps at 80% of range or more Stage 2 target	My rule	Enough controlled reps through most of the range that full range is a small next step. No study set 5 reps or 80%.
3 sets of 5, 90 s rest Stage 3 start	Training practice	Multiple sets are the default in strength training, as in the ACSM position stand. Full-range reps are harder than partials, so the rest gets longer.
About 20 full reps in a session Stage 3 target	My rule	About 20 clean bodyweight reps is enough work that a light plate is the next thing to change.
3 sets of 8 with 10 lb, 120 s rest Stage 4 start	Mix	The ACSM position stand puts beginner strength work at 8 to 12 reps a set. 10 lb is a common small plate. Heavier sets get the longest rest.
Every set at 12 reps on each of the last two training days, both with a qualifying next-morning check-in, then add 5 lb and drop to 8 Stage 4 load step	Mix	ACSM recommends a small load increase (2 to 10%) once you can do 1 or 2 reps more than the target. The program uses the 8 to 12 range and the smallest common plate step. Weight and reps never go up together, so each next morning reflects one change. That pairing is mine.
3 rounds of a 10 s prone hold, 6 bird-dogs, 8 glute bridges, 60 s rest Floor start	My rule	The easiest version of the extension pattern, with two support moves, for use only until you have a bench.
About 30 s prone holds Floor to bench	My rule	Tapping “I have a 45° bench now” starts Stage 1 at an easy dose, unless a flare or a leg-pain stop is on. On its own, the app moves you only while you are still on the floor after the setup questions said you have a bench, and only when each of the last three floor training days includes a 30 s hold or 90 s of holding in total (partial sessions do not count), with pain logged on at least 3 of the past 7 days (none above baseline or in the legs) and next-morning check-ins that allow a step up. Past that point, longer floor holds turn into an endurance test. The bench adds the range and the plate the floor cannot.
45 degrees Bench angle	Program design	The program is written for a 45-degree back-extension bench and not for the vertical 90-degree Roman chair. No trial compares the two for chronic low back pain. The 45 vs 90 guide covers the difference.

The next-morning rule

Number	Rests on	Why
Baseline on a 1 to 10 scale	My rule	Your usual pain on an ordinary day. Every decision compares against it, so it should be a normal day, not your best one.
The newest log after your last workout, normally the next morning	My rule	Training soreness often shows up the day after rather than in the hour after, and a log from before the workout cannot describe the response to it. Sleep also changes pain, as Finan and colleagues review, so any single morning is noisy. No trial has shown the next morning to be the best checkpoint.
Above baseline: the next session is cut (about 30% off holds and full reps, a rep and 10% of range off partials, 5 lb off the plate down to a 5 lb floor, then up to 2 reps at 5 lb)	My rule	Cuts are large and steps up are small because undershooting on a good day costs one easy session, while overshooting on a bad day can cost several bad days.
Same as baseline: repeat	My rule	A morning at baseline shows the dose was tolerable. The step up waits for a better morning, or for a second training day in a row at or below baseline. Neither check-in may be higher than the pain you logged before that session.
Below baseline, and not higher than the pain logged before the session: 5 more seconds on the shortest hold (the first, if several match), one more rep on the set with the fewest, or, once every partial-rep set has 5 reps, 10% more range on every set (Stage 4: one more rep on the lowest set, or +5 lb once every set has reached 12 reps on each of the last two training days, both with a qualifying next-morning check-in)	Mix	One small change at a time, in line with ACSM's small increments. The sizes are mine.
Stage move: target met on the last 3 training days (partial sessions do not count), pain logged on at least 3 of the past 7 days with none above baseline or in the legs, and next-morning check-ins that allow a step up	My rule	One good session or one good morning can be luck, a light day, or a good night's sleep. Three of each keeps a stage change from resting on a fluke.
7 or more days off: next session eased	Mix	In Tucci's study, the group that stopped training lost much of its lumbar strength over 12 weeks. A week is far shorter than that, and 7 days is my cutoff for playing the first session back safe.
Flare-up mode ends after two days at or below baseline	My rule	Two days shows the flare is settling. The restart is eased anyway, below the pre-flare dose.
Pain in the legs: stop the extension work	Safety rule	Pain running into the legs is outside what a pacing rule should handle. The app shows no session and says not to add load. The red-flag list says when to go to emergency care now and when to see a clinician today.

Schedule and maintenance

Number	Rests on	Why
2 or 3 sessions a week	Study and training practice	Graves and colleagues trained adults on an isolated lumbar-extension machine for 12 weeks. Groups training every other week, once, twice, or 3 times a week all gained strength compared with no training. ACSM recommends 2 to 3 days a week for beginners. The program uses 2 or 3 because each session is small and each one gives a morning reading to adjust from. The frequency guide has more.
A rest day between sessions	My rule	It leaves a morning to read before the next session, so two changes never stack up unseen. The studies above did not test back-to-back days.
About 10 minutes a session	Arithmetic	3 sets plus the rests between them.
Maintenance: about two sessions a week, offered on Stage 4 after 6 weighted sessions and pain logs on at least 5 different days of the past 14, all at or below baseline (after a not now, it waits 14 days to ask again)	Mix	Tucci and colleagues found lumbar strength held for 12 weeks with one session every 2 or 4 weeks. Two a week is more than that. It keeps the movement familiar and keeps pain logs coming, so drift shows up early.

Print the card for the gym. The sample training log shows these rules applied to a month of sessions.

Sources

Graves JE, Pollock ML, Foster D, et al. Effect of training frequency and specificity on isometric lumbar extension strength. Spine. 1990;15(6):504–509. link
Tucci JT, Carpenter DM, Pollock ML, Graves JE, Leggett SH. Effect of reduced frequency of training and detraining on lumbar extension strength. Spine. 1992;17(12):1497–1501. link
Steele J, Bruce-Low S, Smith D. A review of the clinical value of isolated lumbar extension resistance training for chronic low back pain. PM R. 2015;7(2):169–187. link
Searle A, Spink M, Ho A, Chuter V. Exercise interventions for the treatment of chronic low back pain: a systematic review and meta-analysis of randomised controlled trials. Clin Rehabil. 2015;29(12):1155–1167. link
American College of Sports Medicine. Progression models in resistance training for healthy adults. Med Sci Sports Exerc. 2009;41(3):687–708. link
Finan PH, Goodin BR, Smith MT. The association of sleep and pain: an update and a path forward. J Pain. 2013;14(12):1539–1552. link

The app

I built Low Back Pain Coach to run this program: it reads your pain logs, writes the next session, and a voice counts the holds, reps and rest. A notebook can run the same rules if you would rather keep the decisions on paper.