What the variables do

Lesson 4 gave you this course's question: trained whom, for how long, measured on what? This lesson puts it to the arguments that fill gyms and forums: how heavy, how many sets, to failure or not, how many days a week. Each has a real answer, and for most of them the answer is smaller than the argument. By the end you'll be able to read a programme line by line and say which of its choices matter, for which outcome, and on what evidence.

Two outcomes, four arguments

Lesson 4's table showed that the typical study behind "the research shows" lasts two to three months, in untrained people in their twenties, more often men, tested on the lift they practised. Keep it beside you, because every finding below carries it.

The other thing to keep beside you is that there are two outcomes, not one. Strength here almost always means the one-repetition maximum, 1RM, on the trained lift. Muscle size is a measure of the muscle itself, from a scan or a biopsy; the papers call its growth hypertrophy. The four arguments often have one answer for strength and a different one for size, and most confusion about training comes from not saying which.

Load: heavy or light?

This is the one where the question does the most work, so it is set out step by step.

Step 1: name the two outcomes. "Strength" is 1RM. "Muscle size" is the muscle, measured. They're different measurements, and they needn't agree.

Step 2: what the load studies found for each. A 2017 meta-analysis by Schoenfeld and colleagues pooled 21 studies, read here at abstract level, in which every set went to "momentary muscular failure", the point where no further rep is possible, comparing loads of 60 per cent of 1RM or less against heavier ones.¹ Its conclusion: "maximal strength benefits are obtained from the use of heavy loads while muscle hypertrophy can be equally achieved across a spectrum of loading ranges."¹ A 2021 network meta-analysis by Lopez and colleagues, read in full, pooled 28 studies of 747 healthy adults with a mean age of 23.4, again all to failure, and agreed: "Although muscle hypertrophy improvements seem to be load independent, increases in muscle strength are superior in high-load RT programs."¹ RT is resistance training.

The one single trial on load this course read is a 2016 study by Morton and colleagues, and unlike most of the pooled studies it was in men who already trained: forty-nine of them, for twelve weeks, randomised to 20 to 25 reps with a light load or 8 to 12 reps with a heavy one, "with all sets being performed to volitional failure".¹ This course took its figures from the abstract. Muscle grew similarly in both groups. And 1RM rose in both too, "with only the change in bench press being significantly different between groups".¹

Step 4: what you're entitled to conclude. Heavy loads build a bigger 1RM, measured as 1RM. Load barely matters for muscle size: the 2026 position stand from the American College of Sports Medicine (ACSM), the overview of 137 reviews that lesson 4 introduced, lists loads from 30 to 100 per cent of 1RM among the things that didn't change growth.³ Both findings come mostly from young adults over a few weeks. Whether heavy builds more general strength once the test is unfamiliar is unresolved: a 2026 meta-analysis of ten studies, read in full, was "inconclusive as to whether high- and low-load isotonic training induced differential changes in non-specific strength", with its point estimate leaning towards heavy.² Isotonic means lifting a weight that moves, as opposed to isometric.

And one condition sits under the whole light-load finding. In all three sources, every set was taken to failure. Light loads build muscle when the sets are very hard, and a set of 25 is hard to judge, which comes up again under effort. So "you don't need to lift heavy to build muscle" is a fair summary, with the condition attached. "If you want a bigger 1RM, practise lifting heavy" is also fair.

Morton's trial also tested a myth about hormones, and its authors' conclusion is blunt: "acute postexercise systemic hormonal rises are not related to or in any way indicative of RT-mediated gains in muscle mass or strength."¹

Sets: how much is enough?

Volume in this literature usually means hard sets per muscle per week. Here the finding is a curve rather than a winner.

A 2017 meta-analysis of fifteen studies, read at abstract level, found "a graded dose-response relationship whereby increases in RT volume produce greater gains in muscle hypertrophy".⁴ It compared under 5, 5 to 9, and 10 or more weekly sets per muscle, and the difference between those bands was only a trend, "(P = 0.074)".⁴ Keep that in mind about a figure that gets repeated a lot. In this 2017 analysis, ten sets was a band that only trended ahead. Whether this paper is where the figure started, this course hasn't verified. The 2026 stand, pooling later reviews, does list "≥10 sets/wk" among the things that helped growth,³ and the next analysis shows why a threshold is still the wrong picture: its curve has no step at ten.

The biggest analysis is Pelland and colleagues' meta-regression, which fits a curve across studies rather than comparing two groups: 67 studies and 2,058 participants, published in 2026. This course read the published abstract, and the full text of an earlier preprint that had not been peer reviewed. The abstract says gains in size and strength both rise with volume, but "both best-fit models suggest diminishing returns, with the diminishing returns for strength being considerably more pronounced."⁵

The preprint gives the shape, and its figures may differ from the published version. To count volume it used "fractional" sets: a set that works a muscle only indirectly, such as a bench press for the triceps, counts as half. For strength it found "one set was identified as the minimum effective dose", with detectable extra gains up to about four fractional sets a week "but not beyond this point."⁵ For size there was "no clear plateau in the primary meta-regression", though "caution is warranted as few studies have explored ~25+ ‘fractional’ weekly sets."⁵ The authors' own hedge on all of it: "multiple dose-response forms are compatible with the present analysis".⁵

So strength flattens early and muscle size keeps creeping up, each extra set buying less. A few hard sets a week bring most of the strength gain a beginner will see in a short study. The ACSM stand reads it the same way: "Clearly, one set is superior to zero sets (CTRL), and two sets are superior to one set", but "the exact number of sets required to optimize adaptations cannot be ascertained."³ CTRL is a group that didn't train. Its practical line is that "healthy adults are advised to complete at least two sets per exercise."³

The stand cites Pelland's published paper, its reference 187, as showing a curve that "plateaued and showed diminishing returns beyond ~2–3 sets/exercise for strength and ~18–20 weekly sets for hypertrophy".³ Notice the two units: per exercise for strength, per week for size. The preprint this course read in full found "no clear plateau" for size,⁵ and the published abstract says only that both curves show diminishing returns. So either the analysis changed between preprint and publication, or the stand summarised a curve that bends as one that stops. This course cannot tell which. When a summary and a source seem to differ, first check you're looking at the same version of the source.

Effort: to failure, or not?

Training to failure means going until you can't complete another rep: "momentary muscular failure", in the papers' phrase. Some studies stop earlier, when form breaks, and that difference matters below. Lesson 2 taught you repetitions in reserve (RIR): how many more reps you could have done when you stopped.

A 2022 meta-analysis by Grgic and colleagues, read in full, pooled fifteen studies in which "All participants in the studies were young adults", training for a median of eight weeks.⁶ It found no overall difference for strength or for size, and concluded: "Training to muscle failure does not seem to be required for gains in strength and muscle size. However, training in this manner does not seem to have detrimental effects on these adaptations, either."⁶ In people who already trained, it found "a significant effect of training to failure for muscle hypertrophy (ES = 0.15, 95%CI: 0.03-0.26)", which is below what this field usually calls a small effect.

Whether going closer to failure adds muscle is contested. Here are the three positions in their own words.

• A 2024 meta-regression by Robinson and colleagues, read at abstract level, estimated how close to failure each study's sets had been and found "changes in muscle size increased as sets were terminated closer to failure", with a negligible relationship for strength. The authors add that "caution is warranted when interpreting the present analysis due to its exploratory nature."⁶
• A 2023 meta-analysis by Refalo and colleagues, read here in part, found "a trivial advantage" for failure with any definition of failure, and with failure strictly defined "no advantage for either" approach. Its reading: "a potential non-linear relationship between proximity-to-failure and muscle hypertrophy."⁶
• The ACSM stand: "Completing sets to fatigue (momentary muscular failure) does not enhance gains in strength, hypertrophy, and power, and so is not necessary for benefits to occur."³

All three agree that a set doesn't have to reach failure to count. Where they part is whether the last few reps before failure add muscle: Robinson's analysis says they may, Refalo's says any advantage is trivial or absent, and the stand says failure doesn't enhance gains. The stand's own target, which lesson 2 gave you, is two to three reps in reserve, with the admission that the exact target cannot yet be pinned down.³

Lesson 2 also gave you the catch. On average people had about one more rep in them than they thought, and in Halperin's review they judged slightly better in sets of 12 reps or fewer.⁶ That is the link back to load. Light loads build muscle when sets are taken hard, and long light sets are where people's guesses are a little worse, which is this course's inference from that pattern. So the half of the load finding that frees you from heavy weights is also the half that asks most of your judgement.

Frequency: how many days?

Frequency is the argument where the headline numbers mislead most easily.

For muscle size the story changed as studies accumulated. A 2016 analysis of ten studies found training twice a week beat once. The 2019 update, by the same lead author with 25 studies, concluded: "there is strong evidence that resistance training frequency does not significantly or meaningfully impact muscle hypertrophy when volume is equated."⁷ Both were read here at abstract level. That is not a failure of science. It is what a meta-analysis is supposed to do when the evidence grows.

The ACSM stand agrees for size: growth didn't differ between one day a week and more than five "when total volume was equated".³ For strength it lists "≥2 sessions/wk" among the things that helped.³ Pelland's preprint found strength rising with frequency, with diminishing returns, and offered a reason as a hypothesis rather than a finding: "Higher frequencies allow for more frequent practice with the assessed exercise or a similar motor pattern."⁵

How the advice changed, 2009 to 2026

The 2009 ACSM stand, read here at abstract level, was detailed. For novices it recommended "loads correspond to a repetition range of an 8-12 repetition maximum (RM)", and it set frequency by experience: "2-3 d x wk(-1) for novice training, 3-4 d x wk(-1) for intermediate training, and 4-5 d x wk(-1) for advanced training."⁸ That is the familiar "8 to 12 reps", in an official recommendation. It also said its recommendations "should be applied in context and should be contingent upon an individual's target goals, physical capacity, and training status."⁸

The 2026 authors say both the 2002 and 2009 stands were criticised for lacking evidence-based rigour. They give an example: the 2009 recommendation that novices train two or three full-body sessions a week for muscle growth was graded the highest quality of evidence, yet, in their account, rested on three studies with 59 participants in all, two of which did not investigate frequency.³ That is the 2026 authors' description; this course didn't open the 2009 text to check it. They also cite an estimate, from a 2009 paper by Carpinelli written to challenge the 2009 stand, that following the old guidelines for all-round muscular fitness "may, in some cases, require training for 20 h or more per week".³

The 2026 replacement, read here in full, is as long as the 2009 one, but its advice is much shorter. Its primary recommendation:

"Our primary recommendation is that healthy adults perform RT with high effort (effort can be measured through various scales, but can be achieved with various loads and sets per the FITT-VP principle) at least twice weekly, with all major muscle groups being engaged."³

FITT-VP is the stand's shorthand for frequency, intensity, time, type, volume and progression; you will not need the acronym. And the list of things that did not consistently matter: "Training to momentary muscle fatigue, equipment type, exercise complexity, set structure, time under tension, blood flow restriction, and periodization did not consistently impact training outcomes."³ Three of those you'll meet in gyms: time under tension is how long each set keeps the muscle working, blood flow restriction is light training with a cuff round the limb, and periodisation is changing the programme in planned blocks. What did help strength was heavier loads, "≥80% one-repetition maximum", a full range of motion, two or three sets, doing the exercise early in the session and at least two sessions a week; for size, "higher volumes (≥10 sets/wk) and eccentric overload",³ which means extra load on the lowering half of a lift.

The authors also say something that is a view rather than a finding, and they mark it as one: "we propose that individualizing programs to increase RT participation is, from our perspective, more important than conforming to specific RTx criteria outlined in previous Position Stands."³ RTx is their shorthand for a training prescription. They also allow that the older stands' programme details "may be an appropriate starting point for some individuals".³ Phillips, the stand's senior author, put the view more bluntly in the press release: "The best resistance training program is the one you’ll actually stick with".³ Whether guidance should aim to get more people training or to squeeze the most out of those already training is partly a question of values about public health. This course read no written case for the more prescriptive side beyond the 2009 stand itself, so it leaves that question open.

The same field and the same kind of evidence, and the advice moved from a table of rep ranges and days to something closer to train hard, at least twice a week, all of you. On the 2026 authors' account, that happened because the evidence was pooled more carefully and didn't support the detail. Guidance is the best current reading of the evidence, dated, and you can check its date.

One programme, read line by line

This programme is constructed for teaching, and no source read for this course prescribes it.⁹ It's here to be read, not followed; lesson 7 builds a first plan.

A friend hands a beginner this plan: three days a week, five exercises a session covering the whole body, four sets of 8 to 12 reps at about 70 per cent of 1RM, every set to failure, and the whole thing arranged in four-week blocks that change the rep range each block. Take it line by line against what you've now read.

Three days a week, whole body. Inside the stand's "at least twice weekly" with all major muscle groups. The third day mainly buys more sets and more practice; with volume equal it wouldn't change growth.⁷

Four sets per exercise, three days a week. Two different counts are in play here. Per session, four sets is above the stand's "at least two" per exercise. Per week, the volume curve counts sets per muscle: three days of four sets is 12 weekly sets for each muscle a lift trains directly, and more once indirect work is counted at half. On Pelland's preprint curve that is well past the four or so fractional sets where extra strength stopped being detectable, and in the range where size still creeps up, each set buying less.⁵

8 to 12 reps at about 70 per cent. The 2009 novice range. Fine for size, where load barely mattered. For 1RM the stand's list says heavier, 80 per cent or more, helps, so this line suits a size goal better than a 1RM goal.³

Every set to failure. Not required for strength or size in the trials, and not shown to harm those gains either.⁶ It makes each session harder with no benefit a beginner can count on, which is this course's judgement from the evidence, not a finding. The stand also warns that going to failure "may also be" inadvisable for some people, older adults for example, because of the strain on blood vessels and the risk of injury when form breaks down.³

Four-week blocks. This is periodisation, and for strength it's contested. The stand says its effect on strength "could not be determined, although one review found that periodized programs were slightly favored over nonperiodized programs" when volume was equal.³ That review, by Moesgaard and colleagues in 2022 and read here at abstract level, found a modest 1RM advantage, an effect size of 0.31, and none for muscle size.¹⁰ An earlier one by Williams and colleagues, which didn't hold volume equal, concluded that "Variation in training stimuli appears to be vital for increasing maximal strength".¹⁰ On the other side, Buckner and colleagues call periodisation's reputation a narrative that "persists despite a lack of experimental evidence to demonstrate its superiority."¹⁰ For size it didn't matter. For a beginner's 1RM, it's optional, with a small possible edge, and lesson 7 takes the argument further.

So what's the verdict? Most of it is sound. The line worth changing for any beginner is the effort: stopping with two or three reps in reserve is the stand's target, costs nothing the trials could detect, and leaves room for form, which lesson 6 teaches. The lines people argue about most, failure and blocks, make small or uncertain differences. And the line that would change the result for a strength goal, the load, is the one the plan got least right for that goal.

What people get wrong

"You have to lift heavy to build muscle." For size, loads from 30 per cent of 1RM up performed similarly in the trials, provided sets were taken very hard. Heavy loads matter for 1RM, which partly means practice at the test.

"Every set should go to failure." Not needed for strength or size in the trials, and not shown to hurt those gains either. Whether it adds a little muscle is contested. And the stand's caution applies, as in the programme above: for some people, older adults among them, going to failure may be a poor idea, for blood vessels and for form.³ Stopping with two or three reps in reserve is its target.

"More is always better." Every extra set buys less. For strength the curve flattens after a few sets a week; for size it keeps rising slowly, and very high volumes have hardly been studied. The mirror, that a set or two is all anyone needs, fits the strength curve and drops the size one.

"Train each muscle twice a week or it won't grow." With weekly volume held equal, one session or several made no meaningful difference to growth. Frequency is mostly a way to fit sets in.

"The workout hormone surge builds the muscle." In the trial that tested it, the rises after exercise were unrelated to gains in muscle or strength.

Practice

Connections

Back. Lesson 4 gave you the question and the table of who these studies trained; every finding here carries both. Lesson 2 gave you repetitions in reserve, which is how the stand's effort advice is set. From earlier courses, Mental Fitness asked what the comparison group got, and the frequency result turned on the same question: what else differed between the groups? Protein for people who train is Nutrition lesson 5, which this course doesn't re-teach.

Forward. Lesson 6 teaches how to do the lifts, heavier ones included. Lesson 7 turns the stand's primary recommendation into a first plan, takes up periodisation properly, and deals with what to do when progress stalls. Lesson 10 joins the course's question to the institute's claim sort.

Go deeper

• ACSM 2026 position stand, "Resistance training prescription for muscle function, hypertrophy, and physical performance in healthy adults", Currier and colleagues. Free. Read here in full, apart from the supplemental appendices. The results tables are the fastest way to see which variables mattered for which outcome.
• Grgic and colleagues 2022, failure against non-failure, Journal of Sport and Health Science. Read here in full. Short, open access, and a clean example of a meta-analysis stating its population and duration.
• Pelland and colleagues, the volume and frequency preprint, SportRxiv, 2024. Read here in full as a preprint; the published version was read at abstract level only. Free, and the fullest account of the dose-response curves this course read. Remember it hadn't been peer reviewed.

Sources

1. Load. B. J. Schoenfeld, J. Grgic, D. Ogborn and J. W. Krieger, "Strength and hypertrophy adaptations between low- vs. high-load resistance training: a systematic review and meta-analysis", Journal of Strength and Conditioning Research 31(12), 2017, pp. 3508 to 3523, doi 10.1519/JSC.0000000000002200, abstract only; R. W. Morton, S. Y. Oikawa, C. G. Wavell and others, S. M. Phillips, "Neither load nor systemic hormones determine resistance training-mediated hypertrophy or strength gains in resistance-trained young men", Journal of Applied Physiology 121(1), 2016, pp. 129 to 138, doi 10.1152/japplphysiol.00154.2016, full text saved; abstract used for figures; P. Lopez, R. Radaelli, D. R. Taaffe and others, R. S. Pinto, "Resistance training load effects on muscle hypertrophy and strength gain: systematic review and network meta-analysis", Medicine & Science in Sports & Exercise 53(6), 2021, pp. 1206 to 1216, doi 10.1249/MSS.0000000000002585, full text (a corrigendum exists, MSSE 2022;54(2):370, not opened). Supports: the load definitions, the isometric result, both conclusions, Morton's design, bench press result and hormone sentence, and Lopez's sample.
2. Specificity and load. R. W. Spitz, Z. W. Bell, V. Wong and others, "Strength testing or strength training: considerations for future research", Physiological Measurement 41(9), 2020, 09TR01, abstract only; W. B. Hammert, R. Kataoka, Y. Yamada and others, "Non-specific strength changes between high- and low-load isotonic resistance training: a systematic review and meta-analysis", Sports Medicine 56(3), 2026, pp. 763 to 773, doi 10.1007/s40279-025-02370-8, full text. Supports: the practice-effect sentence and the "inconclusive" non-specific result.
3. B. S. Currier, A. C. D'Souza, M. A. F. Singh and others, S. M. Phillips (last author), "Resistance training prescription for muscle function, hypertrophy, and physical performance in healthy adults: an overview of reviews", American College of Sports Medicine position stand, Medicine & Science in Sports & Exercise 58(4), 2026, pp. 851 to 872, doi 10.1249/MSS.0000000000003897, PMC12965823; and the ACSM press release "ACSM Unveils Landmark 2026 Resistance Training Guidelines". **Read level: full text of the article (introduction, methods, all results sections, Tables 1 to 6, discussion, limitations, disclosures, reference list). Supplemental appendices (per-review data, AMSTAR scores, evidence grades) not opened. Press release read in full.** Supports: the hypertrophy list, the volume and failure passages and the caution about failure for some people, the frequency findings, the primary recommendation, the list of what did not consistently matter, the strength and size factors, the periodisation sentence and its reference to Moesgaard, the "20 h" estimate, the "from our perspective" view and the "starting point" concession, and the Phillips quotation (press release). The press release gives the load as 80 per cent rather than the paper's 80 or more; the lesson follows the paper. The "20 h" estimate is the stand's quotation of R. N. Carpinelli, "Challenging the American College of Sports Medicine 2009 position stand on resistance training", Medicine and Sport 13(2), 2009, which this course has not read; the stand's reference list names it. Its reference 187 names Pelland's published paper. The 2026 authors' account of the 2009 grading is theirs, as the body says.
4. B. J. Schoenfeld, D. Ogborn and J. W. Krieger, "Dose-response relationship between weekly resistance training volume and increases in muscle mass: a systematic review and meta-analysis", Journal of Sports Sciences 35(11), 2017, pp. 1073 to 1082, doi 10.1080/02640414.2016.1210197. **Read level: abstract only.** Supports: the fifteen studies, the graded dose-response and the P = 0.074 trend. Whether it is the origin of "ten sets a week" is unverified, as the body says.
5. J. C. Pelland, J. F. Remmert, Z. P. Robinson, S. R. Hinson and M. C. Zourdos, "The resistance training dose response: meta-regressions exploring the effects of weekly volume and frequency on muscle hypertrophy and strength gains", Sports Medicine 56(2), 2026, pp. 481 to 505, doi 10.1007/s40279-025-02344-w; preprint on SportRxiv, 2024. Read level: published version, abstract only. Preprint: full text, marked "Preprint not peer reviewed". Supports: the published headline on diminishing returns and the sample (abstract); the fractional-set method, the minimum doses, the plateau passages, the authors' hedge and the frequency hypothesis (preprint, labelled as such in the body).
6. Failure and RIR. J. Grgic, B. J. Schoenfeld, J. Orazem and F. Sabol, "Effects of resistance training performed to repetition failure or non-failure on muscular strength and hypertrophy", Journal of Sport and Health Science 11(2), 2022, pp. 202 to 211, doi 10.1016/j.jshs.2021.01.007, full text; M. C. Refalo, E. R. Helms, E. T. Trexler, D. L. Hamilton and J. J. Fyfe, "Influence of resistance training proximity-to-failure on skeletal muscle hypertrophy", Sports Medicine 53(3), 2023, pp. 649 to 665, doi 10.1007/s40279-022-01784-y, full text (read: abstract, methods summary, results headings, parts of discussion); Z. P. Robinson, J. C. Pelland, J. F. Remmert and others, "Exploring the dose-response relationship between estimated resistance training proximity to failure, strength gain, and muscle hypertrophy", Sports Medicine 54(9), 2024, pp. 2209 to 2231, doi 10.1007/s40279-024-02069-2, abstract only; I. Halperin, T. Malleron, I. Har-Nir and others, "Accuracy in predicting repetitions to task failure in resistance exercise: a scoping review and exploratory meta-analysis", Sports Medicine 52(2), 2022, pp. 377 to 390, doi 10.1007/s40279-021-01559-x, abstract only. Supports: Grgic's sample, duration, result, conclusion and trained-subgroup effect; the three positions on closeness to failure; the average underprediction of about one rep and the slightly better accuracy in sets of 12 or fewer, which lesson 2 quotes. That long light sets are where guesses are worse is the course's inference, as the body says.
7. Frequency. J. Grgic, B. J. Schoenfeld, T. B. Davies and others, "Effect of resistance training frequency on gains in muscular strength: a systematic review and meta-analysis", Sports Medicine 48(5), 2018, pp. 1207 to 1220, doi 10.1007/s40279-018-0872-x; B. J. Schoenfeld, D. Ogborn and J. W. Krieger, "Effects of resistance training frequency on measures of muscle hypertrophy", Sports Medicine 46(11), 2016, pp. 1689 to 1697; B. J. Schoenfeld, J. Grgic and J. Krieger, "How many times per week should a muscle be trained to maximize muscle hypertrophy?", Journal of Sports Sciences 37(11), 2019, pp. 1286 to 1295, doi 10.1080/02640414.2018.1555906. Read level: abstract only, all three. Supports: the four effect sizes, the volume-equated result, the untrained-participants note, and the 2016 to 2019 change.
8. American College of Sports Medicine, "Progression models in resistance training for healthy adults", Medicine & Science in Sports & Exercise 41(3), 2009, pp. 687 to 708, doi 10.1249/MSS.0b013e3181915670. **Read level: abstract only (PubMed). The evidence grades attached to each recommendation were not read.** Supports: the novice load, the frequency recommendations, and the stand's own sentence on applying them in context.
9. The course's own constructions, each labelled where it appears in the body. The programme read line by line is invented, and the body says so where it begins; its judgement that failure on every set makes sessions harder with no benefit a beginner can count on is marked there as the course's judgement. The practice-effect exercise is this course's design, the body says so where it begins, and it says the result is a demonstration rather than evidence. Its safety set-up follows the course's standing lines on a stable chair and on breathing under effort.
10. Periodisation. L. Moesgaard, M. M. Beck, L. Christiansen, P. Aagaard and J. Lundbye-Jensen, "Effects of periodization on strength and muscle hypertrophy in volume-equated resistance training programs: a systematic review and meta-analysis", Sports Medicine 52(7), 2022, pp. 1647 to 1666, doi 10.1007/s40279-021-01636-1; T. D. Williams, D. V. Tolusso, M. V. Fedewa and M. R. Esco, "Comparison of periodized and non-periodized resistance training on maximal strength: a meta-analysis", Sports Medicine 47(10), 2017, pp. 2083 to 2100, doi 10.1007/s40279-017-0734-y; S. L. Buckner, M. B. Jessee, J. G. Mouser and others, J. P. Loenneke, "The basics of training for muscle size and strength: a brief review on the theory", Medicine & Science in Sports & Exercise 52(3), 2020, pp. 645 to 653. Read level: abstract only, all three. Supports: Moesgaard's 1RM and size results, Williams's conclusion (volume was not required to be equal in that analysis), and Buckner's sentence.