Reading a claim about your training

You'll meet the next claim about training within a day of finishing this course, probably on your phone. Ten minutes of this circuit a day for a flat stomach. Stay in the fat-burning zone. Change your routine every week so your muscles never adapt. Get your protein in within half an hour. Several of those have been tested, and the tests are small and clear enough to hold in your head. This lesson gives you a way to read the next claim, an account of what this course can't tell you about your own body and who can, and a decision about your own training that only you can make. The four claims above, and the others this lesson sorts, are worded here in the forms people meet them; none is a quotation from anywhere.

A grade has an address

You met the institute's sort in Digital Literacy lesson 8, sharpened in Using AI Effectively lesson 11, and several closing lessons since have used it. Three bins. Measurable: some result could count against the claim. Unmeasurable as stated: nothing in it could come out the other way, usually because a word in it has no agreed measure. False: somebody checked, and it didn't hold.

A measured claim then gets one of the institute's three grades. Established: settled among the people who work on it. Contested: an empirical question that serious people read differently. A value question: one that evidence can inform and cannot decide.

Two conventions keep the bins and grades from tangling, and this lesson uses both. When a measured claim fails, it moves to the false bin, and the grade then belongs to the finding that sank it: "false" with an established finding behind it is a stronger verdict than "false" on one small trial. And a measurable claim that nobody has tested gets no grade at all. "Not tested in anything read" is its own verdict, and it isn't the same as false.

Six courses before this one each added a question. Memory asked who was in the sample, Focus and Deep Work which instrument, Note-Taking where it was measured, Sleep how much or when, Mental Fitness what the comparison group got, and Nutrition "instead of what?". This course's is the one lesson 4 set out: trained whom, for how long, measured on what?

The course's question joins the sort at the grade. In training research a grade is rarely established or contested in general. It's established for some people, over some number of weeks, on some test. Call those three answers the grade's address. The course's question is how you read the address, and the address tells you where the grade stops. That is this course's way of joining its question to the sort, and the word "address" is its own.²⁰

Addresses go wrong in two ways, and the rest of the lesson keeps finding both. A claim can drop its address, so that "in nine sedentary men over twelve weeks in a laboratory" becomes "science says". Lesson 3 watched that happen to the one-minute interval study. Or a claim can move its address, so that a finding about trained cyclists on a laboratory bike is retold as advice for you over months. The second is harder to see, because the numbers survive the move.

A flat stomach, run through the sort

Take the claim in its commonest form: ab exercises burn belly fat. The trade name is spot reduction, the belief that working a muscle takes fat off the part of the body it sits in. It's treated here as a claim about where fat comes off, not as advice about losing it: lesson 1's boundary stands, and weight belongs to Nutrition. Sort: measurable. You could train one part of the body and measure fat there against a part that was not trained.

The first test. Vispute and colleagues randomised 24 healthy sedentary adults, 14 men and 10 women aged 18 to 40, to seven abdominal exercises, two sets of ten, five days a week for six weeks, or to nothing, on a diet meant to hold weight steady. Fat was measured several ways, from skinfolds and waist size to the fat around the abdomen. This course read the abstract. No fat measure changed significantly. Their conclusion: "Six weeks of abdominal exercise training alone was not sufficient to reduce abdominal subcutaneous fat and other measures of body composition".¹ Subcutaneous fat is the fat under the skin.

Keep the word "alone", which is the authors' hedge: it leaves open what ab work does alongside a diet that cuts energy, which this trial didn't test. And notice what did change: at the end the exercise group managed 47 curl-ups on average against the control group's 32.¹ The training worked on the thing it trained, which is lesson 4's specificity again.

The better design uses each person as their own control. Ramírez-Campillo and colleagues had 11 young adults, seven men and four women aged about 23, train only their non-dominant leg for twelve weeks: three sessions a week, one set of 960 to 1,200 leg presses at 10 to 30 per cent of their one-rep maximum. The other leg did nothing. Fat was measured by DXA before and after, and this course read the abstract.²

Whole-body fat mass fell 5.1 per cent, from 13.5 to 12.8 kilograms (29.8 to 28.2 lb). Fat didn't change significantly in either leg, trained or untrained. It fell in the arms, by 10.2 per cent, and in the trunk, by 6.9 per cent, while energy intake, from a food-recall questionnaire, stayed about the same.² The authors: "In conclusion, the training program was effective in reducing fat mass, but this reduction was not achieved in the trained body segment".²

So a thousand repetitions a session took fat off the arms and trunk, and the leg doing the work lost no more than the leg that did nothing, in one small study. Nothing read for this course explains why fat comes off where it does. The tests measured only whether it came off where people were told it would.²⁰

The pooled test. A 2022 meta-analysis, whose authors include two names from the 2013 paper, Ramirez-Campillo and Andrade, pooled controlled studies of this one-limb design, the 2013 trial among them. Every study in it trained an arm or a leg; none trained the trunk. The meta-analysis, read here in full, took in 13 studies and 1,158 participants of both sexes, aged 14 to 71, in programmes of 2 to 20 weeks, making 37 comparisons between a trained limb and an untrained one.³ Seventeen favoured the trained limb and twenty the untrained, which sounds like disagreement, but the authors report low heterogeneity: the studies' results varied little more than chance would explain.³ Pooled, in their words: "The effects were consistent, with a pooled ES = –0.03, 95% CI: –0.10 to 0.05, p = 0.508, meaning that spot reduction was not observed".³ ES is an effect size, and an interval this narrow, from just below zero to just above it, means no detectable effect.

One more sentence from that paper sorts differently from the paper's finding. The abstract adds: "The popular belief concerning spot reduction is probably derived from wishful thinking and convenient marketing strategies".³ That is a claim about why people believe something, and nothing in the meta-analysis measured belief, wishes or marketing. It may be right. It's the authors' opinion, printed beside their finding, and a sentence in a good paper doesn't inherit the paper's grade.

One measurement, and the claim on the machine

The fat-burning zone is printed on gym machines' displays. It rests on a real measurement, and it's worth watching what happens to that measurement's address when a claim like it is printed on a machine. Where the machines' bands come from isn't something this course read about, so setting the two side by side is this course's comparison, not a history.²⁰

The measurement. Achten, Gleeson and Jeukendrup wanted a laboratory test for the intensity at which the body burns fat fastest, which they called Fatmax. They tested 18 moderately trained cyclists on a bike, stepping the resistance up to exhaustion and analysing their breath, and each rode four to six steady tests on other days as well. This course read the abstract.⁴ Fat burning peaked at 64 per cent of VO2max (give or take 4), lesson 3's measure of aerobic fitness, which was about 74 per cent of maximum heart rate. Within 10 per cent of that peak lay a band from about 55 to 72 per cent of VO2max, and above 89 per cent fat's contribution became negligible. Their summary: "Fat oxidation rates are high over a large range of intensities; however, at exercise intensities above Fat(max), fat oxidation rates drop markedly".⁴

Run the question. Whom: eighteen trained cyclists. How long: a few laboratory visits each, a graded test and four to six steady rides; nobody trained. Measured on what: fat burned during the exercise, from their breath.⁴ That is established physiology, and nothing here disputes it.

The claim on the machine. There, it reads: exercise in this band and you'll lose more body fat. Read the new address. Whom: you, not a trained cyclist. How long: weeks and months, not one test. Measured on what: the fat on your body, not the fuel in your breath during an hour. All three answers have moved, and nothing on the screen tells you so.

Wewege and colleagues pooled 13 trials comparing interval training with moderate continuous training in overweight or obese adults aged 18 to 45, for about ten weeks at three sessions a week, measuring body fat directly and indirectly. This course read the abstract. Both kinds of training reduced fat mass and waist size, and: "There were no significant differences between HIIT and MICT for any body composition measure, but HIIT required ~40% less training time commitment".⁵ HIIT is high-intensity interval training; MICT is moderate-intensity continuous training. The abstract also reports that running reduced fat mass while "cycling training did not induce fat loss", a surprising detail it doesn't explain and this course can't either.⁵

A cousin claim is that training fasted, which raises the share of fat burned during the session, takes more fat off. Schoenfeld and colleagues put 20 young women on a calorie-reduced diet for four weeks, with an hour of steady cardio three days a week, half of them fasted and half fed. This course read the abstract. Both groups lost weight and fat, and "no significant between-group differences were noted in any outcome measure".⁶ Twenty women for four weeks is a small, short test, and it is the one this course has.

So the machine's claim gets this grade: not supported by the trials read, at their address: overweight or obese adults aged 18 to 45, and 20 young women dieting, over four to about ten weeks, with body fat measured. Why doesn't the fuel mix in one hour settle it? This course's reading, not a finding of either trial, is that body fat over weeks follows the energy balance across whole days, which Nutrition lesson 3 teaches, and the fuel mix in one hour of exercise is a small part of that.²⁰

Lesson 3's zone 2 raises the same question. The critics' review it quoted, by Storoschuk and colleagues, read here at abstract level, says the recommendations "largely stem from observational data of elite endurance athletes", and what it rejects is zone 2 as "the optimal intensity" for the general population, not the athletes' physiology.⁷ One of its authors declares an advisory role and equity in a company whose services partly relate to exercise.⁷ On the critics' account, athletes' measurements were retold as the best way for anyone to train. The physiology paper the advice draws on, which lesson 3 read, also tested moderately active men and men with metabolic syndrome, though in one test each and with nobody trained.²³ No proponent's case was read, so the grade stays lesson 3's: contested, with one side read.

Four more claims, and the tests behind them

Every study in this section was read at abstract level only; ACSM's stand, which it also cites, was read in full.

"Light weights tone, heavy weights bulk." Sort it first, and it doesn't reach the evidence. "Tone" has no agreed measure, and no source this course read uses it as a physiological term.²⁰ It becomes measurable once translated: do light loads build less muscle than heavy ones? Lesson 5 took that version apart. A 2017 meta-analysis of 21 studies found that "Changes in measures of muscle hypertrophy were similar between conditions", with heavy loads building a bigger one-rep maximum, in trials where every set went to failure.⁹ Translated, the claim is false for muscle size, at that address: sets taken to failure, six weeks or more, healthy adults. One fair translation of "toned", this course's, is some muscle and less fat over it: two outcomes, and this lesson has read evidence on where the fat comes off, not on how much.²⁰

"Change your routine constantly so your muscles never adapt." The trade name is muscle confusion, and "confused" is unmeasurable as stated. Translated, it asks whether frequent, varied exercise selection builds more than a fixed set of exercises. Kassiano and colleagues reviewed eight studies, 241 participants, "comprising all young men". Their summary: "Some degree of systematic variation seems to enhance regional hypertrophic adaptations and maximize dynamic strength, whereas excessive, random variation may compromise muscular gains".¹⁰ A separate trial, by Fonseca and colleagues, trained 49 physically active people twice a week for twelve weeks. The whole quadriceps, the big muscle at the front of the thigh, grew in every training group, by roughly 9 to 12 per cent. The groups that varied their exercises grew all four of its heads, while the fixed-exercise groups missed one or two, and strength rose most in the group that varied the exercises and kept the load constant. The authors still read growth as similar "as long as the training intensity reaches an alleged threshold", whatever the variation.¹⁰ And ACSM's 2026 stand, read in full, found "insufficient data to determine if strength was affected by ... varied exercise selection".¹¹

So the translated claim splits. Planned variation has some support in young men. Constant, random change, which is what "confusion" promises, is what the review warns against. No proponent of muscle confusion was read, so this course can't say how they'd answer.

"Get protein in within 30 minutes or the session is wasted." This is the anabolic window, and protein belongs to Nutrition lesson 5, so it gets one paragraph. Schoenfeld, Aragon and Krieger pooled 20 studies with 478 participants for strength and 23 with 525 for muscle size.¹² Unadjusted, timing showed "a small to moderate effect on muscle hypertrophy with no significant effect found on muscle strength". Once other differences between the studies were allowed for, there was no significant effect on either, and "total protein intake was the strongest predictor" of the effect on growth. The authors say this refutes the belief that timing is "critical".¹² So the claim is false in its strong form, at a 2013 address; a published comment on the paper wasn't read.

"The more you sweat, the more fat you burn." Split it first, because it hides two claims. "The weight you lose in a sweaty session is fat" runs into ACSM's 2007 position stand on fluids, which treats that weight as water to replace: "Individual sweat rates can be estimated by measuring body weight before and after exercise".¹³ "Sweating more means burning more fat" is measurable, and this course found no study that tested it directly. The same stand gives a reason to doubt it: sweat rates vary a lot between people, so two people doing the same work can sweat very differently.¹³ That undercuts the second claim without testing it. Its honest verdict is not tested in anything read, with a reason to doubt it, which is different from "false".

Seven claims, with their addresses

The table lines up this lesson's claims. The claims, the bins and the last column are this course's reading; the populations, durations and measures come from the sources above, at the read levels given where each was used.²⁰

Read the fourth column first. Where a duration has an upper end, it is twenty weeks at most. Then the third: only one row names anyone past middle age, and one leans on a review of young men alone. That is lesson 4's table turning up again, claim by claim. When a claim about training says "science shows", those are usually the people and the weeks it means.

True in the study, false in the headline

The course's question does a lot, and it isn't the whole sort.

Suppose you read: "High-intensity intervals cut the risk of early death by a third in older adults." Lesson 1 read the trial it would come from, Generation 100, in full.¹⁴

It doesn't pass, and the reasons sit outside the question.

The comparison wasn't the one the trial was built for. Its primary test, both training groups together against control, found no difference in deaths. The 0.63 comes from splitting the training groups apart afterwards, a secondary comparison: one the trial reports but was not designed and sized to settle. And the paper's only stated hypothesis about intervals was an exploratory one, against the moderate group: "An exploratory hypothesis was that HIIT lowers mortality more than MICT."¹⁴

The interval includes no effect. Intervals against control gave a "hazard ratio 0.63, 95% confidence interval 0.33 to 1.20".¹⁴ "A third" is the 0.63. The interval runs from about two thirds fewer deaths to about a fifth more, and a result that includes "no difference" can't carry "cut".

The comparison group trained too. That is Mental Fitness's question. The authors write that "participants in the control group had a high level of activity throughout the study, and many exercised using HIIT", and that "only 50% of participants in the HIIT group were able to follow the strict criteria for fulfilling the HIIT protocol."¹⁴

The authors' own reading is that their data "suggest that HIIT lowers the risk of premature death compared with recommended guidelines and MICT", and lesson 1 set the intervals beside that sentence.¹⁴ The headline takes a suggestion from a secondary comparison, drops its interval, and drops the fact that the other group exercised. The question found nothing wrong with the address. The grade was wrong, which is why the course's question joins the sort rather than replacing it: it tells you where a finding lives, and the earlier courses' questions and the interval tell you whether there was one.

Practitioners, and one position stand

Lesson 7 read three practitioners in their own words, Rippetoe, Renaissance Periodization and Greg Nuckols, and said where each sells something.¹⁵ Sort their claims and they split the same way each time. Part of the shape they share fits the trials: beginners progress fast, and more work helps, with diminishing returns. The ceiling some of them put on it, set by recovery, is their claim; the volume trials this course read found no clear ceiling for muscle size, as lessons 5 and 7 said. The specific rules each adds (weight on the bar every session, a named number of sets, a checklist that includes soreness) are measurable and, in what this course read, untested against anything else. A framework is a tool, not a finding and not a fraud, and its authors wrote the best labels for it: RP calls its numbers "starting points, not gospel", and Nuckols calls for "directed self-experimentation".¹⁵

The course project is directed self-experimentation, and if you did it, its report is where you worked out what that can and can't show: one person, no comparison group, a test practised for eight weeks.

Who is speaking matters for institutional sources too. This is the one place the course names creatine, a supplement you'll meet in gyms. The International Society of Sports Nutrition's 2017 position stand, read here in full, says: "Creatine monohydrate is the most effective ergogenic nutritional supplement currently available to athletes with the intent of increasing high-intensity exercise capacity and lean body mass during training."¹⁶ Ergogenic means performance-enhancing. Sort it: measurable, with an address of athletes, high-intensity capacity and lean mass. Then read its declarations. The stand was prepared "at the request of the Council for Responsible Nutrition and ISSN", the first being a trade association of the supplement industry, and its first author "has received externally-funded grants from industry to conduct research on creatine, serves as a scientific and legal consultant, and is a university approved scientific advisor for Nutrabolt." Other authors declare industry ties too.¹⁶

None of that makes the finding wrong, and the stand declares its interests openly. It means that before recommending anything on it you would want an independent review beside it. This course didn't read one, so it neither recommends creatine nor advises against it. Supplements in general are Nutrition lesson 10, which covers what a supplement's label has and has not been checked for; it does not take up creatine by name.

Questions evidence can inform and can't settle

People train to be healthier, to get stronger, to run a race, for company, for the pleasure of it, and to look a particular way: leaner, bigger, more defined. Body image and appearance goals are reasons people train. Whether any of them is a good reason, whether wanting a different-looking body is healthy or vain, how much appearance should matter to anyone: those are value questions. This course didn't research them, and it doesn't judge them in either direction. "Training for looks is shallow" and "you should want to look fit" are both value claims, and neither is this course's to make.

What evidence can do is inform the empirical parts inside such a goal. On the tests above, over up to twenty weeks, training a part didn't take fat off it. Muscle grows across a range of loads when sets are taken to failure, as lesson 5 showed; how far that holds two or three reps short of failure is lesson 5's question too. In the trials Roberts and colleagues pooled, women's muscles grew with effect sizes similar to men's, and, as lesson 9 said, how much that changes how anybody looks was not measured in anything read.¹⁷ And lesson 1 drew one line this course keeps: it sets no weight, body-fat or calorie goal.

There is a second value question inside most training advice: how much of your life training should take. ACSM's 2026 stand said, marking it as a view "from our perspective", that fitting programmes to people so that more of them train matters more than conforming to its older, more detailed criteria, and lesson 5 labelled that as partly a question of values.¹¹ Asked of one person, the question is yours: evidence can tell you roughly what extra hours would buy, and it can't tell you what they're worth to you.

If food, eating, exercise or your weight has started to feel out of your control, tell a doctor, or call Beat on 0808 801 0677 in the UK or ANAD's peer-support helpline on 1-888-375-7767 in the US. The NHS lists "exercising too much" among the signs of an eating disorder.²⁴ The box at the top of every Nutrition lesson gives the same route.

What this course can't tell you about your own body

Everything this course showed you sits inside general-population guidance for healthy adults, as lesson 1 promised. That promise has an edge, and four things lie past it.

Whether a symptom is safe to train through. The box at the top lists the signs that mean stopping and getting help. No course can tell you whether a particular chest discomfort, a dizzy spell or a knee that aches more each session is harmless. That needs someone who can examine you.

How you'll respond. Lesson 4 read a trial of 585 people who all trained one arm for twelve weeks, in which one-rep maximum gains "ranged from 0 to +250%".¹⁸ Some of a spread like that is measurement noise and day-to-day variation, as lesson 4 said, and how much is real difference between people is argued over. Not all of it is noise. Your log will tell you what you did; nothing can tell you in advance where on the spread you'll land.

Your own numbers. Lesson 2's formulas for maximum heart rate each missed individuals by about 20 beats either way: "The 95% LOA spanned approximately ±20 bpm for all formulas", LOA being limits of agreement.¹⁹ Medicines such as beta-blockers make heart-rate targets less reliable still, as lesson 2 noted.

A plan for a condition. Pregnancy, diabetes, high blood pressure, osteoporosis, a bad back, a child's training: lesson 9 said what the named guidance supports and what conditions attach, and prescribed for none of them. This course does not write that plan.

Who can.

• A doctor, for anything in the box, and emergency services for chest pain, as the box says. A doctor also comes before starting or stepping up if you have a heart, kidney or metabolic condition or are pregnant. The PAR-Q+ from lesson 1 is how you find out whether that's you: it says it will tell you whether you need "further advice from your doctor OR a qualified exercise professional".²¹
• A qualified exercise professional, whom the same form names. If you answer yes on one of its follow-up pages, the form says: "You should seek further information before becoming more physically active or engaging in a fitness appraisal." It sends you on to its online follow-up, the ePARmed-X+, or to a qualified exercise professional to work through it with you. Even with every answer no, it adds: "If you are over the age of 45 yr and NOT accustomed to regular vigorous to maximal effort exercise, consult a qualified exercise professional before engaging in this intensity of exercise."²¹ The form never says which qualifications count, and this course did not research them. So ask anyone offering the service what their qualification is, and whether it covers people with your condition.
• A physiotherapist or doctor, for a pain that changes how you move and does not settle, as lesson 3 said and the project repeats. For osteoarthritis, lesson 9's NICE guideline tells clinicians to offer exercise "tailored to their needs", which is a sentence about somebody doing the tailoring.²²
• Someone who can watch you move. Lesson 6 asked you to film yourself because a page can describe a squat and can't see yours.

Going to any of them isn't a failure of the course or of you. And the refusal runs both ways: this course will not tell you that you're fine to push on, and it will not tell you that you're at risk. Neither is something a course built from averages can know about one reader.

What people get wrong

"A study showed it, so it'll work for me." A study shows what happened to its people, over its weeks, on its test. Check the address first, and even when it fits you, lesson 4's spread means an average is a forecast for a group.

"If a claim failed, the exercise is useless." Spot reduction failed, and the ab group in Vispute's trial still did 15 more curl-ups than the control group at the end.¹ "Doesn't take fat off your stomach" isn't "does nothing". A failed claim tells you about what its test measured, and nothing about the outcomes it did not.

"Nobody has tested it, so it's false." The sweat claim has not been tested in anything read here, and that is a verdict of its own: measurable, untested, with reasons to doubt it. Calling it false would claim a test nobody ran.

"The fat-burning zone is a myth." A band of intensities where fat's share of the fuel is high is real physiology, measured in trained cyclists. What failed was the claim that training in such a band takes more fat off your body over weeks, and the two are worth keeping apart.

Practice

Connections

Back. Lesson 1's three sentences were the sort run on "exercise is good for you", and its Generation 100 came back here with a good address and a wrong grade. Lesson 2's watch is the table's last row. Lesson 3's one-minute study and zone 2 showed a dropped and a moved address. Lesson 4 gave the question and the spread, lessons 5 and 7 the rules and the practitioners, lesson 6 the reason someone should watch you move, lesson 8 the soreness that isn't a measure of a good session, and lesson 9 the people each permission is for.

From earlier courses, Memory's sample is inside the question's "whom", Focus and Deep Work's instrument meets its "measured on what", and Mental Fitness's comparison group is one of the three things that sank the Generation 100 headline. Nutrition owns weight, energy balance, protein and supplements, and this lesson pointed there each time one came up.

Forward. First Aid and CPR, later this term, starts from the warning signs in the box at the top of every lesson here. Longevity: Evidence vs Hype and Medical Literacy, both planned later on the Core path and not yet written, will need the three sentences and Generation 100, and Habits and Addiction, also planned, can assume you have built and logged a plan. The question itself travels to any claim about a body changing over time.

Go deeper

• Ramirez-Campillo and colleagues, 2022, the spot-reduction meta-analysis, open access and read in full here. It proposes a model for testing the idea as well as pooling the tests, which makes it a short lesson in what a fair test of a training claim has to hold constant.
• Storoschuk and colleagues, 2025, "Much ado about zone 2", read here at abstract level only. Read it as one camp's case, and look for a proponent's reply beside it, which this course didn't read.
• The PAR-Q+, read here in full. Fill it in again when your health changes; the form says its clearance lasts twelve months at most.
• ACSM's 2026 position stand, read here in full. Its limitations section is worth reading now that you've finished: small samples and poor reporting of harms are on the authors' own list of what holds their evidence back.

Sources

1. S. S. Vispute, J. D. Smith, J. D. LeCheminant and K. S. Hurley, "The effect of abdominal exercise on abdominal fat", Journal of Strength and Conditioning Research 25(9), 2011, pp. 2559 to 2564, doi 10.1519/JSC.0b013e3181fb4a46. Read level: abstract only. Supports: the design, the fat measures and results, the curl-ups and the conclusion. The abstract doesn't name the scanner used, so the body doesn't either.
2. R. Ramírez-Campillo, D. C. Andrade, C. Campos-Jara and others, "Regional fat changes induced by localized muscle endurance resistance training", Journal of Strength and Conditioning Research 27(8), 2013, pp. 2219 to 2224, doi 10.1519/JSC.0b013e31827e8681. Read level: abstract only. Supports: the one-leg design, the fat changes by region (none in either leg), the energy intake and the conclusion.
3. R. Ramirez-Campillo, D. C. Andrade, F. M. Clemente, J. Afonso, A. Pérez-Castilla and P. Gentil, "A proposed model to test the hypothesis of exercise-induced localized fat reduction (spot reduction), including a systematic review with meta-analysis", Human Movement 23(3), 2022, pp. 1 to 14, doi 10.5114/hm.2022.110373. Read level: full text. Supports: the studies, participants, ages, durations and comparisons, that every study trained a limb and that the 2013 one-leg trial is among them, the low heterogeneity, the pooled effect, the authors' caution that fat in different regions isn't directly comparable, the conclusion, the sentence on wishful thinking, and the limit on longer programmes (paraphrased, because the sentence is split across the PDF's columns). The authors declare no conflict.
4. J. Achten, M. Gleeson and A. E. Jeukendrup, "Determination of the exercise intensity that elicits maximal fat oxidation", Medicine & Science in Sports & Exercise 34(1), 2002, pp. 92 to 97, doi 10.1097/00005768-200201000-00015. Read level: abstract only. Supports: the cyclists, the graded test and the four to six steady rides, the Fatmax figures and the summary sentence. Nothing read says how gym machines set their bands.
5. M. Wewege, R. van den Berg, R. E. Ward and A. Keech, "The effects of high-intensity interval training vs. moderate-intensity continuous training on body composition in overweight and obese adults: a systematic review and meta-analysis", Obesity Reviews 18(6), 2017, pp. 635 to 646, doi 10.1111/obr.12532. Read level: abstract only. Supports: the trials, ages and durations, fat loss in both groups with no difference between them, and the running and cycling detail.
6. B. J. Schoenfeld, A. A. Aragon, C. D. Wilborn, J. W. Krieger and G. T. Sonmez, "Body composition changes associated with fasted versus non-fasted aerobic exercise", Journal of the International Society of Sports Nutrition 11(1), 2014, 54, doi 10.1186/s12970-014-0054-7. Read level: abstract only. Supports: the design and the absence of a difference between groups.
7. K. L. Storoschuk, A. Moran-MacDonald, M. J. Gibala and B. J. Gurd, "Much ado about zone 2: a narrative review assessing the efficacy of zone 2 training for improving mitochondrial capacity and cardiorespiratory fitness in the general population", Sports Medicine 55(7), 2025, pp. 1611 to 1624, doi 10.1007/s40279-025-02261-y. Read level: abstract only, plus the PubMed record's declarations. Supports: where the recommendations come from, the conclusion, and Gibala's declared advisory role and equity. As lesson 3 says, no proponent of zone 2 training was read.
8. A. Shcherbina, C. M. Mattsson, D. Waggott and others, "Accuracy in wrist-worn, sensor-based measurements of heart rate and energy expenditure in a diverse cohort", Journal of Personalized Medicine 7(2), 2017, 3, doi 10.3390/jpm7020003, full text; D. Fuller, E. Colwell, J. Low and others, "Reliability and validity of commercially available wearable devices for measuring steps, energy expenditure, and heart rate: systematic review", JMIR mHealth and uHealth 8(9), 2020, e18694, doi 10.2196/18694, full text. Supports: the devices, the energy errors in both, heart rate as the better figure, and the dates.
9. 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. Read level: abstract only. Supports: 21 studies, all sets to failure, at least six weeks, similar hypertrophy and a larger 1RM with heavy loads.
10. W. Kassiano, J. P. Nunes, B. Costa, A. S. Ribeiro, B. J. Schoenfeld and E. S. Cyrino, "Does varying resistance exercises promote superior muscle hypertrophy and strength gains? A systematic review", Journal of Strength and Conditioning Research 36(6), 2022, pp. 1753 to 1762, doi 10.1519/JSC.0000000000004258, abstract only; R. M. Fonseca, H. Roschel, V. Tricoli and others, "Changes in exercises are more effective than in loading schemes to improve muscle strength", Journal of Strength and Conditioning Research 28(11), 2014, pp. 3085 to 3092, doi 10.1519/JSC.0000000000000539, abstract only. Supports: eight studies, 241 young men, the summary sentence, and Fonseca's design, its quadriceps and strength findings, and its conclusion. The review's list of included studies wasn't read, so the body treats Fonseca's trial as separate.
11. 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. Read level: full text of the article; supplemental appendices not opened. Supports: the sentence on insufficient data for varied exercise selection, and "from our perspective" as the authors' marking of a view.
12. B. J. Schoenfeld, A. A. Aragon and J. W. Krieger, "The effect of protein timing on muscle strength and hypertrophy: a meta-analysis", Journal of the International Society of Sports Nutrition 10(1), 2013, 53, doi 10.1186/1550-2783-10-53. Read level: abstract only. A 2016 comment on the paper was not read. Supports: the study and participant counts, the unadjusted and adjusted results, total intake as the strongest predictor, and the conclusion.
13. American College of Sports Medicine, M. N. Sawka, L. M. Burke, E. R. Eichner and others, "Exercise and fluid replacement", position stand, Medicine & Science in Sports & Exercise 39(2), 2007, pp. 377 to 390, doi 10.1249/mss.0b013e31802ca597. Read level: abstract only. Supports: the sentences on sweat rates. No study that tests the sweat-and-fat belief directly was found, and the body presents this as reasoning, not a refutation.
14. D. Stensvold, H. Viken, S. L. Steinshamn and others, "Effect of exercise training for five years on all cause mortality in older adults, the Generation 100 study: randomised controlled trial", BMJ 371, 2020, m3485, doi 10.1136/bmj.m3485, PMC7539760. Read level: full text. Supports: the participants, arms, exclusions and duration, the exploratory hypothesis, the hazard ratio, the control group's activity, the adherence and the authors' concluding sentence.
15. M. Rippetoe, ["The Novice Effect"](https://startingstrength.com/article/the_novice_effect), StartingStrength.com, © 2010 The Aasgaard Company, and "The Starting Strength Program"; Renaissance Periodization, "Training Volume Landmarks for Muscle Growth", RP Strength, dated 4 January 2017; G. Nuckols, "When does training volume reach the point of diminishing returns?", Stronger By Science, 3 August 2022. Read level: full text of each, the Starting Strength pages through Internet Archive copies. Supports: the frameworks as lesson 7 describes them, RP's "starting points, not gospel" and Nuckols's "directed self-experimentation". Each sells programmes or coaching, as lesson 7 states.
16. R. B. Kreider, D. S. Kalman, J. Antonio and others, "International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine", Journal of the International Society of Sports Nutrition 14, 2017, 18, doi 10.1186/s12970-017-0173-z. Read level: full text. Supports: the position sentence, the request by the Council for Responsible Nutrition and the ISSN, and the first author's declared ties. This course read no independent review of creatine.
17. B. M. Roberts, G. Nuckols and J. W. Krieger, "Sex differences in resistance training: a systematic review and meta-analysis", Journal of Strength and Conditioning Research 34(5), 2020, pp. 1448 to 1460, doi 10.1519/JSC.0000000000003521. Read level: abstract only. Supports: similar effect sizes for muscle growth in men and women (the abstract reports effect sizes, not per cents), and the point that appearance wasn't measured.
18. M. J. Hubal, H. Gordish-Dressman, P. D. Thompson and others, "Variability in muscle size and strength gain after unilateral resistance training", Medicine & Science in Sports & Exercise 37(6), 2005, pp. 964 to 972, PMID 15947721. Read level: abstract only. Supports: 585 people, twelve weeks of training one arm, and the range of one-rep maximum gains.
19. J. Martin, B. Lindsey, C. Gerrity and J. Ambegaonkar, "Exploratory analysis of the accuracy of age-based maximal heart rate equations across cardiorespiratory fitness levels", PLoS One 20(10), 2025, e0335842, doi 10.1371/journal.pone.0335842. Read level: full text. Supports: limits of about ±20 beats for every formula, and the caution about beta-blockers.
20. The course's own constructions, labelled where they appear. The idea of a grade's "address" and the way it joins the course's question to the sort; the observation that nothing read explains why fat comes off where it does; the statement that no source read uses "tone" as a physiological term; the reading that the fuel mix in one session doesn't settle fat lost over weeks, which leans on Nutrition lesson 3's energy balance rather than on either trial; setting the machines' "fat burn" band beside Fatmax, since nothing read traces where the bands come from; the two conventions for joining bins and grades; the translation of "toned"; the table's selection, its bins and its grade column; and the specimens in the quiz, which were written for this lesson.
21. D. E. R. Warburton and colleagues, on behalf of the PAR-Q+ Collaboration, The Physical Activity Readiness Questionnaire for Everyone (PAR-Q+), form dated 01-11-2024. Read level: full text (all four pages). Supports: the opening sentence, the sentences on seeking further information and on the over-45 line, the route to the ePARmed-X+, and the point that the form never defines a qualified exercise professional. The form is linked, not reproduced, as its terms require.
22. National Institute for Health and Care Excellence, [*Osteoarthritis in over 16s: diagnosis and management*](https://www.nice.org.uk/guidance/ng226/chapter/Recommendations), NG226, 19 October 2022. Read level: the Recommendations chapter, full text. Supports: recommendation 1.3.1's "tailored to their needs".
23. I. San-Millán and G. A. Brooks, "Assessment of metabolic flexibility by means of measuring blood lactate, fat, and carbohydrate oxidation responses to exercise in professional endurance athletes and less-fit individuals", Sports Medicine 48(2), 2018, pp. 467 to 479, doi 10.1007/s40279-017-0751-x. Read level: full text. Supports: the three groups tested (professional cyclists, moderately active men, men with metabolic syndrome), one graded test each and no training. The paper doesn't use the phrase zone 2.
24. NHS, ["Eating disorders"](https://www.nhs.uk/mental-health/feelings-symptoms-behaviours/behaviours/eating-disorders/overview/), page last reviewed 23 January 2024; Beat, helplines page; ANAD, helpline page. Read level: each page in full, read for this institute's Nutrition course and checked on 24 September 2026. Supports: "exercising too much" among the NHS's signs, the Beat and ANAD numbers, and ANAD as peer support rather than clinical care. Helpline hours change; the pages give them.