Lesson 15 · What factors influence movement and performance?
Measuring it properly, and arguing about whether to measure it at all
This lesson closes the inquiry question with two tasks that look unrelated and are not. The first is to design an investigation into the physiological responses to aerobic training that would survive somebody trying to pull it apart. The second is to argue both sides of a question schools have got wrong for fifty years: what is fitness testing actually for, and for whom? They belong together because the first teaches you what a measurement can and cannot support, and the second is what happens when a measurement is used for something it was never able to support.
A class investigates whether aerobic training lowers resting heart rate. Eighteen students train for six weeks. Resting heart rate is measured at the start and at the end, and the average falls from 74 to 68 beats per minute. The class concludes that aerobic training lowers resting heart rate.
The conclusion happens to be true. The investigation does not support it. Write down as many reasons as you can find why this data cannot establish that claim — and be specific about what is wrong with each one, not just that it is "not accurate". Then the harder question: a true conclusion drawn from evidence that does not support it is still a failure. Say why, in your own words, in one sentence.
- Write a research question that is answerable, specific and measurable.
- Select a method to collect data, and justify the choice against what the question actually asks.
- Identify the ethical considerations of a method, including consent, risk, privacy and the pressures specific to measuring bodies.
- Distinguish validity, reliability and credibility, and explain why the three are independent.
- Present findings honestly, and draw a conclusion no larger than the evidence.
- Identify further research questions that follow from what was and was not shown.
- Debate the purpose and outcomes of fitness testing for different groups in the population, arguing both sides from evidence.
- Research question — a specific, answerable question that names what is being measured, in whom, and under what conditions.
- Validity — whether the method measures what it claims to measure.
- Reliability — whether repeating the measurement gives a consistent result.
- Credibility — whether the source and the process can be trusted, including expertise, independence and transparency.
- Control group — a comparable group that does not receive the intervention, so that change can be attributed to it.
- Confounding variable — something other than the intervention that could have produced the observed change.
- Informed consent — agreement given with full knowledge of what is involved and the freedom to refuse or withdraw.
- Fitness testing — the measurement of components of fitness, whether for screening, program design, selection or monitoring.
- Norm-referenced — a result interpreted by comparison with other people, as against comparison with the person's own previous result.
A vague question cannot be answered by any method, however good, because there is nothing for the data to be evidence of. A usable research question names four things: what is measured, in whom, under what conditions, and compared with what.
| Version | Question | Why it fails, or works |
|---|---|---|
| Too broad | Does training make you fitter? | Neither "training" nor "fitter" names anything measurable. No result could ever contradict it |
| Better, still unusable | Does aerobic training improve heart function? | Names the intervention but not the measure, the population or the comparison. Two people could do this study and measure different things |
| Usable | Does six weeks of continuous aerobic training, three times per week at 70 to 80 per cent of maximum heart rate, reduce resting heart rate in 16 year old students, compared with a matched group who do not train? | Measure, intervention, dose, population, duration and comparison are all named. The method now writes itself, and a result could contradict it |
The comparison clause is the one students leave out, and it is the one that makes a conclusion possible. Without a comparison, any change you observe has an unlimited number of candidate causes — which is the first and largest fault in the Card 01 investigation.
Quick check: The element most often missing from a student research question, and the one that most limits what can be concluded, is:
The method must be capable of answering the question, and it must be something you can actually do. For the physiological responses of Lesson 14, the realistic school-level methods are:
| Method | What it gives | Its main weakness |
|---|---|---|
| Palpated pulse count | Heart rate, at any point, with no equipment | Counting error, and an unavoidable delay after exercise during which the rate is already falling |
| Heart rate monitor | Continuous heart rate, including during the effort | Equipment availability, and a false impression of precision if the strap is fitted poorly |
| Sub-maximal step or cycle test | An estimate of aerobic capacity from the heart rate response to a standard workload | An estimate, resting on assumptions about maximum heart rate that Lesson 13 showed to be approximate |
| Multi-stage fitness test | A maximal field measure of aerobic capacity | Requires maximal effort, so it measures motivation as much as physiology, and carries the highest risk |
| Rating of perceived exertion | The participant's own experience of the intensity | Subjective, and systematically under-reported by inexperienced participants |
The ethical considerations are not a formality, and in this dot point they are specific. Four apply to any investigation, and the fourth is the one particular to measuring bodies.
- Informed consent, and consent from a parent or guardian for participants under 18. Participants must know what will be asked of them, and be able to withdraw at any point without giving a reason and without any consequence.
- Risk and screening. Any maximal test carries risk. Participants should be screened for relevant conditions beforehand, the test should be supervised, and a participant should never be encouraged past the point at which they wish to stop.
- Privacy and anonymity. Physiological data is personal. Results should be de-identified, stored securely, and never displayed in a way that lets one participant's result be attributed to them.
- Pressure, and the specific harm of measuring bodies in front of peers. A fitness test performed publicly is not a neutral measurement: it can be humiliating, and for some participants it carries a real risk in relation to body image and disordered eating. The ethical design question is not only whether participants agreed, but whether they could realistically have declined — a student in a class where everyone else is being tested has not made a free choice.
True or false: If every participant signed a consent form, the ethical requirements of the investigation have been met.
These three words are used interchangeably in ordinary speech and are not interchangeable here. The quickest way to hold them apart is to notice that a measurement can have any one of them without the others.
| Term | The question it asks | A case where it fails on its own |
|---|---|---|
| Validity | Does this measure what I claim it measures? | A scale that reads 3 kilograms heavy is perfectly consistent and perfectly wrong. Reliable, not valid. |
| Reliability | Would repeating it give the same result? | A pulse counted by eighteen different students with different techniques measures the right quantity inconsistently. Valid, not reliable. |
| Credibility | Can this source and this process be trusted? | A supplement company's own study may use a valid and reliable method and still lack credibility, because of who funded it and what was not published. Valid and reliable, not credible. |
Reliability is a precondition for validity in practice, but not the reverse. An unreliable measurement cannot be valid, because it is not measuring anything stable. A perfectly reliable one can be entirely invalid, as the mis-set scale shows. This asymmetry is worth stating explicitly because it is the part most often reversed in student answers.
The practical moves that raise each one in a school investigation:
- For validity: control what else could have changed. Use a control group. Measure at the same time of day, since resting heart rate varies through the day. Standardise what participants did beforehand — caffeine, exercise, sleep and anxiety all move heart rate, and any of them could produce your result without any training at all.
- For reliability: standardise the procedure and the people. The same measurer, the same technique, the same counting window, a written protocol, and repeat measurements averaged rather than taken once.
- For credibility: report your method fully enough for someone else to repeat it, report the results you did not like alongside the ones you did, and state your limitations yourself rather than waiting to be told.
Match each flaw to the quality it undermines.
- No control group, so growth could explain the change
- Eighteen different students each counting pulses their own way
- A study funded by the company selling the product, with unpublished results
- Students tested publicly in front of the whole class
- Validity
- Reliability
- Credibility
- Ethics
Presentation is not decoration. The choice of how to show data is itself a claim about what the data means, and three rules cover most of what goes wrong.
- Show the spread, not only the average. An average of eighteen people conceals whether everyone improved slightly or three people improved enormously and fifteen did not change at all. Those are different findings with different implications, and the mean is identical in both.
- Choose the display for the question. A line graph for change over time, a bar chart for comparison between groups, a table where the individual values matter. A pie chart almost never answers a question in this subject.
- Do not let the axis do the arguing. An axis that starts at 66 rather than 0 turns a six-beat change into a dramatic cliff. It is not technically false and it is not honest.
The conclusion must then be no larger than the evidence. This is the single most common failure in student investigations and it has a simple repair: write the conclusion as a sentence that includes the population and the conditions. "Aerobic training lowers resting heart rate" is a claim about everyone. "In this group of 16 year old students, resting heart rate fell by an average of six beats per minute over six weeks, though without a control group this cannot be attributed to the training" is a claim the data can carry.
Identifying further research questions is not an afterthought, and the syllabus asks for it directly. The good ones come from what the study could not show, and there are three reliable sources:
From the limitation. "Would the same result appear with a matched control group who did not train?" This is the question the missing comparison creates.
From the spread. "Why did four participants show no change at all?" The variation inside your own data is usually more interesting than its average, and it is free — you already collected it.
From the boundary. "Would three weeks have been enough, or is six the minimum?" Anything you held fixed by choice is a variable someone could vary next.
Two truths and a lie. Which statement is false?
The syllabus asks you to debate this, which means arguing it rather than summarising it, and arguing it for different groups in the population rather than in general. That second requirement is what makes the question interesting, because the answer genuinely changes by group.
| Group | The case for testing | The case against |
|---|---|---|
| Elite athletes | Testing sets training intensities, tracks adaptation, informs selection and identifies an athlete who is not recovering. The athlete has chosen this context and the data has a defined use | Tests can become the goal rather than the measure, and an athlete may train to improve a test score rather than performance in their event |
| School students | Provides a baseline, can teach measurement and self-monitoring, and can identify a student who needs support | Public, norm-referenced testing can be humiliating for students who score poorly, including those who may most need support and encouragement. A study of Finnish Grade 5 and Grade 8 classes found lower reported enjoyment during fitness-testing lessons than during general PE; this is a context-specific finding, not evidence that reduced enjoyment is the commonest outcome across all school testing |
| General adult population | Screening can detect cardiovascular risk before symptoms, and a concrete number can motivate behaviour change | A poor result can discourage a person from starting at all, and a maximal test in an unscreened adult carries genuine risk |
| Older adults | Functional testing — balance, sit-to-stand, gait speed — predicts falls and independent living, which is a use with a clear benefit | Tests designed for young athletes are neither valid nor safe here; using them measures the wrong thing and risks injury |
Two ideas resolve most of this debate, and they are the ones to bring into a written answer.
First: the harm usually lies in the purpose and the comparison, not in the measurement. The same beep test is a useful tool when a student compares their own result with their own result from eight weeks ago, privately, to see whether their program worked — and is harmful when it is run publicly and interpreted against a class ranking. Criterion-referenced and self-referenced use is defensible where norm-referenced public use is not. Notice that this is a design decision, not a property of the test.
Second: a test is only justified if a decision follows from it. The question to ask of any proposed test is "what will be done differently depending on the result?" If the answer is nothing, the test has cost time, dignity and goodwill and returned nothing. That single question is the most useful thing in this card, and it settles more of the debate than any argument about the tests themselves.
Fill the gaps. Type one word in each box.
Whether a method measures what it claims to measure is its . Whether repeating it gives a consistent result is its . A group who do not receive the intervention, included so that any change can be attributed to it, is called a group.
Text description
- Two parts, one above the other.
- Above, three target diagrams side by side illustrating validity and reliability: the first shows shots tightly grouped away from the centre, labelled reliable but not valid; the second shows shots scattered around the centre, labelled valid on average but not reliable; the third shows shots tightly grouped on the centre, labelled both valid and reliable, with a note that credibility is a separate question about the source rather than the shots.
- Below, four numbered questions in two rows for whether a fitness test is justified, asking in turn whether a decision follows from the result, whether the comparison is with the person's own previous result rather than with others, whether the test is valid for this population, and whether the participant could realistically have declined, with the outcome that only a test passing all four is justified.
Activities · put the method to work
This is the dot point, and its six sub-points are the six stages. Investigate a physiological response to aerobic training — heart rate, ventilation rate, recovery heart rate or a sub-maximal estimate of aerobic capacity. Work in pairs or small groups.
Create the research question. Name the measure, the population, the conditions and the comparison. Check all four are present before you go on.
Select a method and justify it. Say why this method can answer that question, and name one thing it cannot tell you. A method with no stated weakness has not been chosen, it has been assumed.
Discuss the ethical considerations of the method you chose. Consent including parental consent, screening and supervision, privacy and de-identification, and the freedom to decline. Make each one specific to your method.
Discuss validity, reliability and credibility. For each, name the specific threat in your design and the specific control you have put in place. "We will be careful" is not a control.
Collect, present and conclude. Show the spread as well as the average, choose the display for the question, and write a conclusion no larger than the evidence — including the population and the conditions.
Identify further research questions. Three of them: one from a limitation, one from the spread inside your own data, and one from a boundary you fixed by choice.
Then swap with another group and try to defeat their conclusion: find one alternative explanation for their result that their design does not rule out. Almost every design has one, and finding it is the skill HM-11-10 is assessing.
Odd one out. Three of these improve the reliability of a measurement. Which one improves its validity instead?
Motion: "Compulsory fitness testing in schools does more harm than good." You will be assigned a side rather than choosing one, which is the point — being able to argue a position you do not hold is what demonstrates that you have understood the evidence rather than your own opinion.
Build three arguments for your side. Each must name the population it applies to, give a mechanism or an outcome, and not rely on how anyone feels about it.
Write the strongest argument against you before you hear it. If you cannot state the other side's best point in a form they would accept, you do not yet understand the debate.
Find the reframe. Most of this debate dissolves once you separate testing from public norm-referenced testing. Whichever side you are on, use that distinction — it strengthens both cases and it is the physiologically literate move.
Apply it to a second group. Take your three arguments and check whether they still hold for older adults or for elite athletes. Any argument that transfers unchanged to every group is probably too vague to be true of any of them.
Afterwards, drop the assigned sides and write what you actually think, in three sentences, naming the one argument from the opposing side that you found hardest to answer. That last clause is the part worth marks.
A class investigates whether six weeks of aerobic training reduces resting heart rate. Discuss the validity, reliability and ethical considerations of an investigation of this kind.
Discuss means identify issues and provide points for and against. The question names three areas, so an answer that treats two of them thoroughly and the third in a clause has capped itself at about three marks. Allocate the space before writing.
Plan: validity with the confounders and the control group; reliability with the specific measurement threats and their controls; ethics with consent, risk, privacy and the freedom to decline; then a sentence on what each one, properly handled, lets you conclude.
The central validity threat is that any fall in resting heart rate could be caused by something other than the training. Over six weeks, adolescent participants grow and mature; the season and the temperature change; participants may alter their sleep, caffeine intake or other activity; and simply becoming familiar with having their pulse taken reduces the anxiety that elevates it. Without a matched control group who do not train, none of these can be separated from the intervention, so the design cannot support a causal claim however large the change.
Reliability is threatened by inconsistent measurement: different students counting with different techniques, different counting windows, and measurement at different times of day, since resting heart rate varies diurnally. These are controlled by a written protocol, the same measurer for each participant throughout, a standardised counting window, measurement at the same time of day after the same period seated, and by averaging three measurements rather than taking one. Ethically, participants under 18 require informed consent from a parent or guardian as well as their own, must be screened and supervised, must be able to withdraw at any point without giving a reason, and their data must be de-identified and stored securely.
Validity asks whether the investigation measures what it claims to measure, and the central threat here is that a fall in resting heart rate over six weeks could be produced by something other than the training. Adolescent participants grow and mature over that period; the season and ambient temperature change; participants may independently alter their sleep, caffeine intake or other physical activity; and familiarity with the measurement procedure itself reduces the anxiety that elevates a first reading. None of these can be separated from the training without a matched control group who do not train, so a single-group before-and-after design cannot support a causal conclusion however large the change appears. Validity is further threatened if the conditions of measurement differ between the two occasions, so the pre-test and post-test should be conducted at the same time of day, after the same period seated, and following the same instructions about caffeine and prior exercise. Reliability asks whether repeating the measurement would give a consistent result, and the threats are practical rather than conceptual: different students counting pulses with different techniques, different counting windows, and the fact that a 15 second count multiplied by four amplifies any miscount fourfold, while a 60 second count averages across a heart rate that may itself be changing. These are controlled by a written protocol that every measurer follows, by using the same measurer for a given participant on both occasions, by a standardised counting window, and by taking three measurements and averaging them rather than relying on one. It is worth noting that reliability is necessary for validity but not sufficient for it: a procedure that consistently produces the same wrong number is perfectly reliable and entirely invalid. Ethically, the participants are students under 18, so informed consent is required from a parent or guardian as well as assent from the participant, and both must be given with a full explanation of what is involved. Participants should be screened for relevant health conditions before any training, the sessions supervised, and every participant able to withdraw at any point without giving a reason and without academic or social consequence. Their physiological data is personal information and should be de-identified, stored securely and never displayed in a form that allows an individual result to be attributed. A further consideration specific to this context is whether participants could realistically have declined: in a class where everyone else is participating, agreement is not necessarily free, and a genuine opt-out requires an alternative activity that carries no visible cost. Handled properly, these three considerations do not merely improve the investigation; they determine what it is able to conclude. Without the control group the class may report that resting heart rate fell, but not that the training caused it, and a conclusion must be no larger than the evidence supporting it even when the larger claim happens to be true.
Discuss the purpose and outcomes of testing physical fitness for different groups in the population.
An answer that argues for and against fitness testing in general has answered a simpler question. The requirement is that the verdict changes by group, so the structure should be group by group, with the same two questions asked of each: what is the purpose, and what is the measured outcome?
Plan: distinguish purpose from outcome in the opening; then elite athletes, school students, general adults, older adults, each with both sides; then the two resolving ideas — the harm is in the comparison, and a test needs a decision to follow it.
For elite athletes the case is strong: testing establishes baselines, sets training intensities, tracks whether the prescribed adaptations are occurring, informs selection and can identify an athlete who is failing to recover before that becomes an injury. The athlete has chosen a context in which measurement is expected and the data has a defined use. The risk is that the test becomes the objective, so that an athlete improves a test score without improving performance in their event. For school students the balance is quite different. The stated purposes — providing a baseline, teaching self-monitoring, identifying students who need support — are legitimate, but the commonly measured outcome of public, norm-referenced testing is reduced enjoyment of physical activity, concentrated precisely among the students who score poorly and who are the ones the exercise was most meant to reach.
Two principles account for most of the variation. First, the harm generally lies in the purpose and the comparison rather than in the measurement: the same test is defensible when a participant compares their own result with their own earlier result, privately, to evaluate a program, and is damaging when it is administered publicly and interpreted as a ranking. Second, a test is justified only if a decision follows from it — if nothing will be done differently depending on the result, the test has cost time, dignity and goodwill and returned nothing.
The purpose of fitness testing and its actual outcomes are not the same thing, and the gap between them varies sharply by population, so the question cannot be answered in general. For elite athletes the case is strong. Testing establishes baselines against which training intensities can be prescribed relatively, tracks whether the adaptations a program was designed to produce are in fact occurring, informs selection decisions, and can identify an athlete whose output is declining before that becomes an injury. The athlete has chosen a context in which measurement is expected, and each result has a defined use. The principal risk is that the test displaces the event as the objective, so that an athlete trains to improve a test score rather than performance in competition, which is a real phenomenon where selection depends on test results. For school students the balance falls differently. The stated purposes are legitimate — establishing a baseline, teaching students to monitor themselves, and identifying those who would benefit from support — but the outcome most consistently measured from public, norm-referenced school testing is reduced enjoyment of physical activity, and it is concentrated among the students who score poorly, who are precisely the students the programme most needed to reach. A practice whose measured outcome is the opposite of its stated purpose requires a strong justification, and in its usual form it does not have one. For the general adult population, screening has genuine value: sub-maximal testing can detect cardiovascular risk before symptoms appear and can motivate behaviour change by making an abstract risk concrete. Against that, a poor result can discourage a person from beginning at all, and a maximal test administered to an unscreened adult carries real cardiovascular risk, so the method must be matched to the population rather than borrowed from athletic settings. For older adults the purpose changes again, and with it the appropriate tests: functional measures such as balance, sit-to-stand and gait speed predict falls risk and the capacity to live independently, which is a use with a clear and immediate benefit. Applying tests designed for young athletes to this group is both invalid, because they measure qualities that are not the relevant ones, and unsafe. Two principles account for most of this variation. First, the harm generally lies in the purpose and the comparison rather than in the measurement itself: the same beep test is defensible when a student compares their own result with their own result from eight weeks earlier, privately, in order to evaluate a training program they designed, and is damaging when the same test is run publicly and interpreted as a class ranking. That is a design decision, not a property of the test. Second, a test is justified only when a decision follows from it; the question to ask of any proposed testing is what will be done differently depending on the result, and if the answer is nothing then the test has cost time, dignity and goodwill and returned nothing in exchange. Applied together, these two principles explain why testing is straightforwardly justified for elite athletes and for older adults, conditionally justified for the general adult population, and justified for school students only in a form quite different from the one in which it is usually administered.
Multiple choice · 5 questions
MC 1. A set of bathroom scales reads exactly 3 kilograms heavy every time it is used. The scales are:
- A. reliable but not valid
- B. valid but not reliable
- C. neither valid nor reliable
- D. both valid and reliable
MC 2. The main reason a control group is included in an investigation is to:
- A. increase the number of participants so the average is more stable
- B. allow any observed change to be attributed to the intervention rather than to something else
- C. make the measurement procedure more consistent between measurers
- D. satisfy the ethical requirement for informed consent
MC 3. Which of the following most improves the reliability of a pulse measurement?
- A. Including participants who do not train
- B. Measuring more variables at the same time
- C. Using a written protocol, the same measurer and averaging repeat measurements
- D. Choosing a research question with a comparison in it
MC 4. A study of a supplement, funded by the company that sells it, uses a well-designed method but does not publish all of its results. The quality most directly in question is its:
- A. validity
- B. reliability
- C. credibility
- D. sample size
MC 5. The most defensible single test of whether a proposed fitness test is justified is whether:
- A. the participants enjoy taking part in it
- B. it produces a number that can be compared with a national average
- C. a decision will be made differently depending on the result
- D. it is the test most commonly used in schools
Short answer · exam style
SA 1. Remember Band 3 Distinguish between the validity and the reliability of a measurement, giving one example of each. (3 marks)
SA 2. Apply Band 5 A class measures resting heart rate before and after six weeks of training, with no control group, and concludes that training lowers resting heart rate. Explain why this conclusion is not supported, and describe two changes that would allow it to be. (5 marks)
SA 3. Evaluate Band 6 Discuss the purpose and outcomes of fitness testing for two different groups in the population, reaching a different verdict for each. (6 marks)
📖 Comprehensive answers (click to reveal)
Multiple choice: 1 → A. 2 → B. 3 → C. 4 → C. 5 → C.
Activity 1 guidance: Step 1 is where most investigations are won or lost, and the element that goes missing is almost always the comparison. A question without one commits the class to a design that cannot conclude anything, and no amount of careful measurement afterwards repairs it. On step 2, the requirement to name what the method cannot tell you is the one that produces the most honest work: a palpated pulse cannot capture the peak of a hard effort, because the rate is already falling by the time the first beat is counted, and students who notice this usually redesign their protocol rather than their conclusion. Step 4 asks for a threat and a control in each of the three; the frequent error is listing controls with no threat attached, which reads as a checklist, and the second most frequent is treating credibility as a property of the data rather than of the source and the process. On step 5, insist on the spread: in practice a class dataset almost always contains two or three participants who moved in the opposite direction to the average, and those participants are the most interesting thing collected. Step 6's best further questions come from exactly there. The final peer step usually succeeds, because almost every school design leaves at least one alternative explanation open; the productive response is to name it as a limitation rather than to defend the design.
Activity 2 guidance: The assignment of sides is deliberate and should not be negotiable, because a student arguing a position they hold tends to reach for how they feel rather than for evidence. Step 2 is the step that most improves the quality of the debate: a team that has written the opposing side's strongest argument in a form the opposition would accept argues far better than one that has prepared only its own case. Step 3 is the key intellectual move and both sides should reach it. Once testing is separated from public norm-referenced testing, the affirmative can concede that measurement has value while maintaining that the compulsory public form is harmful, and the negative can concede that the usual implementation is poor while maintaining that the practice is defensible when redesigned. A debate in which both sides make that distinction is a better debate than one in which either side wins. Step 4 is the check against vagueness: an argument such as "testing motivates people" applies equally to every group and is therefore doing no work, whereas "functional testing predicts falls risk in older adults, which changes what care is offered" is group-specific and survives scrutiny.
SA 1 (3 marks): Validity defined — whether the method measures what it claims to measure — with an example, such as a test of aerobic capacity that in fact measures motivation, or a scale that reads consistently 3 kilograms heavy [1]. Reliability defined — whether repeating the measurement produces a consistent result — with an example, such as pulses counted by different students with different techniques [1]. The distinction drawn explicitly: they are independent, and in particular a measurement can be perfectly reliable while being entirely invalid, though an unreliable measurement cannot be valid because it is not measuring anything stable [1]. An answer that treats the two words as synonyms, or that defines validity as "accuracy" without reference to what is being claimed, cannot earn the third mark.
SA 2 (5 marks): Identifies that with no control group the change cannot be attributed to the training [1]. Names at least two specific confounders that could produce the same result — growth and maturation over six weeks, seasonal or temperature change, changes in sleep, caffeine or other activity, or familiarity with the measurement reducing anxiety [1]. Notes that the size of the change matters: a difference of a few beats per minute in a group average may fall within ordinary measurement variation, so the study cannot distinguish its result from noise [1]. Change 1, with what it fixes — a matched control group who do not train, which addresses validity by allowing the change to be attributed [1]. Change 2, with what it fixes — a standardised protocol with the same measurer, the same time of day, the same seated period beforehand and averaged repeat measurements, which addresses reliability [1]. A strong answer also states what could legitimately have been concluded: that resting heart rate in this group fell over this period, without attributing the cause.
SA 3 (6 marks): Distinguishes stated purpose from measured outcome [1]. Group 1 handled with both sides and a group-specific reason — for example elite athletes, where testing sets intensities, tracks adaptation, informs selection and detects failing recovery, against the risk that the test displaces the event as the objective [1]. Group 1 verdict reached and justified [1]. Group 2 handled with both sides — for example school students, where the stated purposes are legitimate but the measured outcome of public norm-referenced testing is reduced enjoyment of physical activity, concentrated among the students it most needed to reach [1]. Group 2 verdict reached, and different from the first [1]. A principle offered that explains why the two verdicts differ — that the harm lies in the purpose and the comparison rather than in the measurement, or that a test is justified only when a decision follows from it [1]. An answer that argues for and against fitness testing in general, without the verdict changing by group, has answered a different question and caps at 3.
A research question decides everything downstream, and the clause students drop is the comparison. Name what is measured, in whom, under what conditions, and compared with what. Without the fourth, any change you see has unlimited candidate causes and no method can rescue it afterwards.
Validity, reliability and credibility are three separate questions and they come apart. A scale reading 3 kilograms heavy is reliable and invalid. Eighteen students counting pulses their own way is valid and unreliable. A company's study of its own product can be both and still lack credibility. Reliability is necessary for validity and nowhere near sufficient — that asymmetry is the part most often stated backwards.
Ethics here is specific, not a formality. Informed consent including a parent or guardian, screening and supervision, privacy and de-identification — and the one particular to this subject: whether a participant could realistically have declined. A student in a class where everyone else is being tested has not made a free choice, and a consent form does not change that.
Then present honestly and conclude small. Show the spread, not only the average; choose the display for the question; do not let the axis do the arguing. Write the conclusion with the population and the conditions in it. And remember the sentence Card 01 was built to teach: a true conclusion drawn from evidence that cannot support it is still a failure, because next time the same reasoning will produce a false one and you will have no way of telling.
On the debate, two ideas do most of the work. The harm in fitness testing lies overwhelmingly in the purpose and the comparison rather than in the measurement — the same test is useful privately against your own earlier result and damaging publicly against a class ranking, and that is a design decision. And a test is justified only when a decision follows from it: if nothing will be done differently depending on the result, it has cost time, dignity and goodwill and returned nothing.
That closes the second inquiry question of this module. Lesson 16 begins the third, and changes subject entirely: how movement skills are acquired, developed and improved — starting with the characteristics of learners and the stages of skill acquisition.
Mark lesson as complete
Tick when you've finished the practice and review.