Progressive overload

Progressive overload is usually introduced as a first principle, the thing all training rests on. It is a good idea and it has a much more specific history than that, along with two findings that should make anyone less certain about how to apply it.

The short version

It was invented to empty a hospital

At the end of the Second World War, American military hospitals were overwhelmed with servicemen who had orthopedic injuries. Part of the backlog was sheer numbers. Part of it was that the rehabilitation protocols of the day took a very long time.

In 1945 an army physician named Thomas DeLorme tried something else. He had used strength training himself to recover from a childhood illness, and reasoned that heavy work would help injured men more than the gentle progressions then in use. He had patients lift their ten-repetition maximum for multiple sets.

By 1948 he had refined it into three progressively heavier sets of ten reps, and he gave it a name: Progressive Resistance Exercise. It worked far better than what it replaced, it became the standard in military and then civilian physiotherapy, and his 1951 textbook carried it into medicine at large.

That is the origin of the principle now printed as though it were physics. Knowing it was designed to clear a hospital backlog does not make it wrong. It should make it sound less absolute.

One thing this page will not do is take training advice from that context. DeLorme's subjects were injured patients, and findings from a rehabilitation population do not transfer to a healthy reader. The history is history.

The weight does not have to go up

This is the most practically useful finding here, and it was tested head to head.

In 2022 Daniel Plotkin's group took 43 people with at least a year of consistent lower body training and split them for eight weeks. One group added weight and kept the reps the same. The other kept the weight the same and added reps. Same exercises, same four sets, twice a week.

Growth in the rectus femoris modestly favored the reps group. Strength slightly favored the weight group. Both differences were small enough that the researchers described them as of questionable practical significance, and every other measure came in at under a millimeter or under one percent.

So if the weight will not go up this week, adding a rep is not a consolation prize. Over eight weeks it produced about the same result.

Which route suits you depends partly on the load you are working at, and how many reps to build muscle covers where the useful range starts and stops.

Some of your progress is skill, not adaptation

The uncomfortable study is Kevin Mattocks's, from 2017.

Thirty-eight untrained people trained for eight weeks. One group did four sets to failure on knee extension and chest press. The other group did nothing except attempt their one-rep max, up to five attempts per visit. No sets, no volume, just repeated attempts at a single heavy lift.

The training group grew more muscle at most sites, as you would expect. But the strength gains were not different between the groups. Not on the one-rep max, not on isometric measures, not on isokinetic ones.

The gap in work done was enormous: around eleven thousand kilograms more total load in the leg exercise for the training group, and about thirteen thousand more on chest press.

The reading is not that training is pointless. It grew more muscle, which is the thing most people are after. It is that a rising one-rep max is a noisy way to measure whether your training is working, because part of what improves is your skill at the lift itself.

Eight weeks, untrained people, two exercises. Do not stretch it further than that.

Whether the plan matters

Structured progression does beat just turning up, and the size of the effect is worth knowing.

Tyler Williams's group pooled 81 effects from 18 studies published between 1988 and 2015. Periodized training, meaning training organized into planned phases, produced greater one-rep max gains than unstructured training, with an effect size of 0.43.

Two details matter more than the headline. Programs that varied the work frequently did better than ones that changed gradually over a long block. And the benefit was larger in people who were new to training, which is the opposite of how periodization is usually pitched.

If you are starting out, that finding is on the beginners page too, alongside the other numbers that differ for you specifically.

What nobody has tested

You will be told to add 2.5 kg a week, or 5%, or to increase whenever you hit the top of a rep range. None of the research here compared rates of progression against each other.

Those numbers are convention. Reasonable convention, in most cases, but not findings, and it is worth knowing the difference before treating a specific increment as a rule you are failing.

The same applies to the longer list every article prints. More weight, more reps, more sets, shorter rest, more sessions, better form. Only weight against reps has been run head to head. Treat the rest as plausible.

What this leaves you with

Make the work harder over time. Use whichever route is available this week, because they appear to be closer to interchangeable than the lists suggest. Expect your early strength numbers to flatter you slightly.

And write it down. That sounds like the least interesting sentence on this page and it is the operative one. Every route to overload is a comparison against last week: one more rep than what, five kilos more than what. Without a record you are comparing against a memory, and a memory is exactly the thing that tells you a session went well.

The workout builder logs each set against a weight, which is what makes any of this checkable rather than felt.

How to read this evidence

Three studies and one history. The trials run eight weeks each, which is short for a question about long-term progress, and two of the three used untrained people.

Plotkin's is the best balanced study in this library on one measure worth naming: 16 of its 43 participants were women, which is rare in this literature and worth more than it should have to be.

Common questions

What is progressive overload?

Making the work harder over time so your body has a reason to keep adapting. It started as a rehabilitation protocol: an army physician named Thomas DeLorme built it in 1945 to get injured servicemen out of hospital faster, and by 1948 had settled on three progressively heavier sets of ten.

Do I have to add weight to progress?

No, and this has been tested directly. Forty-three trained lifters spent eight weeks either adding weight with reps held constant, or adding reps with weight held constant. Muscle growth slightly favored adding reps, strength slightly favored adding weight, and the researchers called both differences of questionable practical significance.

How fast should I add weight?

Nobody has tested that, which is worth knowing before you accept a number. None of the research here compared rates of progression, so the specific percentages that circulate are convention rather than findings.

Is progressive overload really necessary?

As an organizing idea it holds up, but with less force than it is usually sold with. Pooling 18 studies, structured progression beat unstructured training for maximum strength by a moderate margin. Real, and smaller than the certainty attached to it.

Why did I get stronger without getting bigger?

Partly because getting stronger at a lift is partly a skill. In one study, a group that did nothing but practice the one-rep max test matched a group doing four hard sets to failure. That held on every strength measure, despite roughly eleven thousand kilograms less work. The training group did grow more muscle.

What are the ways to progressively overload?

More weight, more reps, more sets, shorter rest, more sessions. The one comparison that has been run head to head is weight against reps, and they came out about even. Treat the rest of the list as plausible rather than proven.

Should I use a structured program or just train hard?

Structure has a modest edge for maximum strength, and the effect was larger in people who were new to training. Programs that varied the work more often did better than ones that changed it gradually.

How do I know if I am actually progressing?

By writing it down, which sounds trivial and is the whole thing. Every route to overload is a comparison against what you did last week, so without a record of the weight and the reps you cannot tell progress from a good day.

Where these numbers come from

Three trials and one historical account, read in full before anything here was written.

• Todd JS, Shurley JP, Todd TC (2012). Thomas L. DeLorme and the science of progressive resistance exercise. Journal of Strength and Conditioning Research 26(11):2913-23. PMID 22592167. The origin, and used for nothing else.
• Plotkin D, Coleman M, Van Every D, Maldonado J, Oberlin D, Israetel M, Feather J, Alto A, Vigotsky AD, Schoenfeld BJ (2022). Progressive overload without progressing load? The effects of load or repetition progression on muscular adaptations. PeerJ 10:e14142. PMID 36199287. Load against reps.
• Mattocks KT, Buckner SL, Jessee MB, Dankel SJ, Mouser JG, Loenneke JP (2017). Practicing the test produces strength equivalent to higher volume training. Medicine and Science in Sports and Exercise 49(9):1945-1954. PMID 28463902. The skill finding.
• Williams TD, Tolusso DV, Fedewa MV, Esco MR (2017). Comparison of periodized and non-periodized resistance training on maximal strength: a meta-analysis. Sports Medicine. PMID 28497285. The effect size of 0.43.

What this page does not claim: that progressive overload does not work, that adding weight is a bad idea, or that training volume is pointless. It is a useful way to organise training with a shorter history than its status suggests. Plotkin found load progression slightly better for strength, and Mattocks' high-volume group grew more muscle.

If a lift hurts rather than being hard, stop and see a physiotherapist.