Lesson 6 · Principles of training
Principles of training I: progressive overload, thresholds and specificity
A training program is a claim about cause and effect: do this, and the body will change in that direction. The principles of training are the conditions under which that claim is true. Break one and the program still looks like training, still costs the same hours, and produces nothing.
Someone joins a gym and does exactly the same session, with exactly the same weights, three times a week. In the first two months they get noticeably stronger. In the next four months they get no stronger at all, despite never missing a session.
Write down why the first two months worked and the next four did not. Then write the smallest change you would make.
- Explain progressive overload and name the variables through which load can be progressed.
- Explain training thresholds and use them to define the intensity band in which adaptation occurs.
- Explain specificity across movement pattern, energy system, muscle group, speed and context.
- Apply all three principles to aerobic training and to strength training, and say how the application differs.
- Evaluate a program against these principles, identifying which one has been breached and what the consequence is.
- Overload — a training stress greater than what the body is currently accustomed to.
- Progressive overload — increasing that stress gradually and systematically as the body adapts to it.
- Adaptation — the structural or functional change the body makes in response to a repeated stress.
- Plateau — the point at which a constant training stress stops producing further adaptation.
- Training threshold — the minimum intensity at which a training effect occurs for a given system.
- Aerobic training threshold — roughly 70 per cent of maximum heart rate.
- Anaerobic threshold — the intensity beyond which lactate accumulates faster than it can be cleared, often around 85 to 90 per cent of maximum heart rate in trained athletes.
- Specificity — the principle that adaptations are specific to the stress applied, so training must resemble the demands of the activity.
- Overtraining — accumulated training stress that exceeds the athlete's capacity to recover, producing declining performance.
The body adapts to a stress it is not accustomed to. Once it has adapted, the same stress is no longer unaccustomed, and it stops driving change. That single sentence is the answer to card 01: the first two months worked because the load was new, and the next four failed because it was not.
So the load must rise. But it must rise slowly enough that the athlete can recover, because adaptation happens during recovery, not during the session. Too little progression produces a plateau; too much produces accumulating fatigue, then declining performance, then injury or illness. The principle sits between two failure modes, and naming both of them is what turns a description into an evaluation.
| Variable | In aerobic training | In strength training |
|---|---|---|
| Frequency | Sessions per week, from 3 to 5 to 6 | Sessions per week, or sessions per muscle group |
| Intensity | Percentage of maximum heart rate, or pace | Percentage of one-repetition maximum, or load lifted |
| Time | Duration of the session or of the work intervals | Repetitions and sets, which is the volume of work |
| Type | Continuous progressing to interval work near the threshold | Machine progressing to free weight, bilateral progressing to unilateral |
| Density | Shorter recoveries between intervals | Shorter rest between sets |
The practical rule that follows is to progress one variable at a time. If load, volume and frequency all rise in the same week, and the athlete breaks down, nothing in the program says which change was responsible, so nothing can be learned from the failure.
Progressive overload has two failure modes, not one. Too little progression is a plateau; too much is accumulating fatigue and injury. A program that names only the first has understood half the principle.
Quick check: An athlete does the identical session with identical loads for four months and stops improving. The principle being breached is:
Overload answers how much more. Thresholds answer more than what. A threshold is the minimum intensity at which a training effect occurs for a given system, and below it the athlete is active without training.
In aerobic training the two thresholds you met in Lesson 4 bound the zone. Below the aerobic training threshold, around 70 per cent of maximum heart rate, the stimulus is too small. Above the anaerobic threshold, lactate accumulates faster than it is cleared and the session becomes anaerobic work.
Strength training has a threshold too, and it is expressed as a proportion of the one-repetition maximum rather than as a heart rate. Loads below roughly 65 per cent of maximum develop muscular endurance rather than maximal strength; loads at 85 per cent and above are the band in which maximal strength is developed. The principle is identical; only the units change.
Two things about thresholds that answers routinely get wrong
First, thresholds are individual and they move. Raising the anaerobic threshold is one of the main goals of endurance training, so a fixed percentage is a prescribing convention, not a physiological constant. Second, a threshold is a floor for a particular adaptation, not a floor for all benefit. Work below the aerobic threshold still aids recovery and still benefits a very deconditioned beginner, for whom that intensity may itself be an overload.
A threshold is defined relative to the athlete, not to the activity. The same 8 km jog is above the threshold for a beginner and below it for a trained runner, which is why the same session is training for one person and recovery for the other.
True or false: Because training thresholds are individual and shift as an athlete adapts, the same session can be above the threshold for one athlete and below it for another.
Students usually reduce specificity to “train the way you compete”. That is the idea, but the marks come from being precise about in which respect a session is or is not specific.
| Dimension | The question it asks | A failure |
|---|---|---|
| Energy system | Does the session stress the system the event uses? | A 100 m sprinter doing only continuous running |
| Muscle group | Are the muscles that do the work being trained? | A rower training legs heavily and neglecting the upper back |
| Movement pattern | Does the exercise resemble the sporting action? | Training a cyclist's legs only on a seated machine leg extension |
| Speed of movement | Is the training performed at the velocity the sport requires? | A jumper training only with very heavy, slow lifts and never explosively |
| Context and skill | Does the session include the decision and the pressure? | The fixed-spot shooting drill in Lesson 5 |
Specificity carries a genuine cost, and an evaluation must name it. Training that is entirely specific gives the athlete little variety, no chance to isolate and correct a weakness, and a monotony that reduces adherence. It can also load one tissue repeatedly, which is how overuse injuries develop. This is why general preparation dominates early in a season and specific work dominates as competition approaches, a structure Lesson 11 develops as periodisation.
Name the dimension. “The session is not specific” earns little; “the session is specific in muscle group but not in movement speed, so it will raise force production without raising the rate at which force is produced” is the answer that scores.
Fill the gaps. Increasing training stress gradually and systematically as the body adapts is called progressive . The minimum intensity at which a training effect occurs for a given system is called a training . The principle that adaptations match the stress applied is called .
The dot point asks you to evaluate the application of the principles to both aerobic and strength training. The principles do not change. What changes is the variable each one is expressed in, and the practical consequence of getting it wrong.
| Principle | Applied to aerobic training | Applied to strength training | Where the difference bites |
|---|---|---|---|
| Progressive overload | Progress duration first, then frequency, then intensity. A common guide is to raise weekly volume by roughly 10 per cent at a time. | Progress load once the target repetitions can be completed with sound technique, typically in small increments, then reset volume. | Aerobic overload is usually progressed through volume; strength overload is usually progressed through load. Progressing both by intensity alone is where athletes break down. |
| Thresholds | Work between the aerobic training threshold and the anaerobic threshold, expressed in heart rate. | Work above roughly 65 per cent of one-repetition maximum for strength, and above about 85 per cent for maximal strength. | The unit differs, heart rate against percentage of maximum load, but the logic is identical. |
| Specificity | Match the energy system and the movement, so a swimmer trains in the water rather than only running. | Match the muscle group, the movement pattern and the speed of contraction to the sporting action. | Speed of movement matters more in strength training than most programs allow, which is why a strong athlete can still be slow. |
One interaction is worth carrying into Lesson 9. High aerobic volume placed alongside heavy strength work can blunt the strength adaptation, so the two are usually separated within a week rather than stacked in the same session. That is a scheduling consequence of applying two principles at once.
Two truths and a lie. One of these statements about the principles of training is false. Find it.
The verb in this dot point is evaluate. An evaluation is not a list of principles with definitions; it is a judgement about a specific program, supported by reference to the principles.
A routine that works under exam conditions has four steps. Name the principle that has been applied or breached. Quote the feature of the program that shows it. Predict the consequence for the athlete. Recommend the change, in the specific variable.
| The program | Principle | Predicted consequence | Recommended change |
|---|---|---|---|
| A netballer runs 5 km at a steady pace three times a week, all season | Specificity, in energy system and movement pattern; and progressive overload, since nothing changes | Aerobic base is maintained but repeated-sprint ability and jumping power, which decide her position, do not improve | Replace two of the three runs with repeated-sprint work and lower-body power training, and progress volume from there |
| A lifter adds 10 kg to every lift every week | Progressive overload, breached at the upper failure mode | Technique degrades under a load that outruns adaptation, fatigue accumulates, performance declines and injury risk rises sharply | Progress in small increments and only once the target repetitions are completed with sound technique, and progress one variable at a time |
| A recreational walker walks 40 minutes at a conversational pace, unchanged for a year | Thresholds, and progressive overload | Real health benefit is retained, but no further aerobic adaptation occurs because the intensity has fallen below her now-higher threshold | Add gradient or intervals to lift part of the walk above the aerobic training threshold, progressing duration before intensity |
Notice the third row. The judgement is not that the program is worthless. It is that the program is achieving one thing, health maintenance, and not another, further adaptation. A calibrated judgement of that kind is what a top band looks like.
Activities · diagnose and repair
For each program, name the principle applied or breached, quote the feature that shows it, and predict the consequence for the athlete.
A 400 m runner trains exclusively with 90-minute continuous runs at a conversational pace.
A swimmer adds two sessions a week, raises the load in the gym and shortens all interval recoveries, all in the same week.
A long jumper trains only with heavy, slow lifts at 90 per cent of one-repetition maximum and never trains explosively.
A previously inactive adult walks 20 minutes daily at a pace that raises their heart rate to 75 per cent of maximum, and after four months finds the same walk no longer raises it above 60 per cent.
Match each term to its meaning.
- Progressive overload
- Training threshold
- Specificity
- Plateau
- Increasing training stress gradually and systematically as the body adapts
- The minimum intensity at which a training effect occurs for a given system
- Adaptations match the stress applied, so training must resemble the demands of the activity
- The point at which a constant training stress stops producing further adaptation
Return to card 01: the same session, the same weights, three times a week, strong gains for two months and none for four.
Write an eight-week repair. Choose one variable to progress and say why that one. State the size and the frequency of each increase. Name the evidence you would use each week to decide whether to progress, hold or reduce. Then answer the hardest part: describe what you would see if you were progressing too fast, and say how you would tell that apart from ordinary training fatigue.
Lock it in. In one sentence, explain why progressive overload has two failure modes rather than one.
Evaluate the application of progressive overload, specificity and reversibility to both aerobic and strength training.
Evaluate demands a judgement against criteria. Note what is judged: the application of the principles, not whether the principles are true.
Plan: criteria, where application succeeds, where it fails, a verdict that commits, then a qualification.
Application will be judged against whether each principle can be measured and prescribed precisely, whether it applies equally to aerobic and strength training, and whether following it reliably produces the intended adaptation.
Progressive overload applies well to both, and it applies most precisely to strength training, where load, repetitions and sets are directly countable so increments can be prescribed exactly. Specificity also applies strongly to both: aerobic training must match the energy system and duration of the event, and strength training must match the movement pattern, contraction type and velocity of the sport, so both can be designed against a clear specification of the demand.
Application is weaker for aerobic overload, because intensity must be inferred from heart rate or perceived exertion, both of which are affected by heat, hydration, sleep, illness and medication, so the same prescribed intensity produces a different actual stimulus on different days. Reversibility applies to both but at different rates, since aerobic adaptations decline within weeks while strength is retained longer, which means an athlete returning from a break has lost the two qualities unequally and a single return-to-training prescription will be wrong for one of them.
In practice the principles also conflict. Specificity pushes toward narrow, repeated training of the competition movement, while variety and injury prevention push away from it — so applying specificity strictly increases overuse injury risk, and the principles cannot all be maximised at once.
On balance the principles apply validly to both forms of training but with markedly different precision: their application to strength training is measurable and reliable, whereas their application to aerobic training depends on estimated intensity and is therefore approximate. Their limitation is not that they are wrong but that they are stated independently while acting simultaneously, so applying them requires trading them against one another rather than following each in turn.
The application of these principles will be judged against whether each can be measured and prescribed precisely, whether it applies equally to aerobic and strength training, and whether following it reliably produces the intended adaptation. Progressive overload applies well to both and most precisely to strength training, where load, repetitions and sets are directly countable so increments can be prescribed exactly. Specificity applies strongly to both, since aerobic training must match the energy system and duration of the event while strength training must match the movement pattern, contraction type and velocity of the sport, so both can be designed against a clear specification of demand. Application is weaker for aerobic overload, because intensity is inferred from heart rate or perceived exertion, both affected by heat, hydration, sleep, illness and medication, so the same prescription produces a different actual stimulus on different days. Reversibility applies to both but at different rates, as aerobic adaptations decline within weeks while strength is retained longer, so an athlete returning from a break has lost the two qualities unequally and one return-to-training prescription will be wrong for one of them. The principles also conflict in practice: specificity pushes toward narrow repeated training of the competition movement while variety and injury prevention push away from it, so strict specificity raises overuse injury risk. On balance the principles apply validly to both forms of training but with markedly different precision — measurable and reliable in strength training, approximate in aerobic training — and their real limitation is that they are stated independently while acting simultaneously, so application requires trading them against one another rather than following each in turn.
Explain how training thresholds determine whether a training session produces adaptation.
Explain asks for the mechanism linking intensity to adaptation. Defining a threshold is a starting point, not the answer.
Plan: name the principle, explain what happens below, within and above the range, then answer directly.
The body adapts only to a stimulus that disturbs its current homeostasis. A training threshold is the intensity at which that disturbance becomes large enough to trigger adaptation, so intensity determines not how much adaptation occurs but whether any occurs at all.
Below the aerobic threshold the demand is met comfortably within existing capacity, so homeostasis is barely disturbed and there is no signal to adapt, which means the session maintains fitness and aids recovery but produces no improvement however long it lasts.
Between the aerobic and anaerobic thresholds the cardiovascular and respiratory systems are stressed while the effort remains sustainable, so the disturbance is large enough to signal adaptation and can be maintained long enough to accumulate — which is why this range produces the central adaptations of stroke volume, cardiac output and capillary density.
Above the anaerobic threshold, by-products accumulate faster than they are cleared, so the effort can only be sustained briefly. The stimulus is intense and produces anaerobic adaptations, but its recovery cost is high, which means the volume that can be tolerated is limited and excessive work in this zone produces fatigue rather than further adaptation.
The body adapts only to a stimulus that disturbs its current homeostasis, and a training threshold is the intensity at which that disturbance becomes large enough to trigger adaptation — so intensity determines not how much adaptation occurs but whether any occurs at all. Below the aerobic threshold the demand is met comfortably within existing capacity, so homeostasis is barely disturbed and there is no signal to adapt; the session maintains fitness and aids recovery but produces no improvement however long it lasts, which is why duration cannot substitute for intensity. Between the aerobic and anaerobic thresholds the cardiovascular and respiratory systems are stressed while the effort remains sustainable, so the disturbance is large enough to signal adaptation and can be maintained long enough to accumulate, producing the central adaptations of stroke volume, cardiac output and capillary density. Above the anaerobic threshold, by-products accumulate faster than they are cleared, so effort is sustainable only briefly; the stimulus produces anaerobic adaptations but at a high recovery cost, so tolerable volume is limited and excessive work in this zone produces fatigue rather than further adaptation. Thresholds therefore determine adaptation by defining a window: too far below it and the session does nothing, too far above it and the athlete accumulates fatigue faster than the adaptation it was meant to produce.
Go back to card 01. Did your explanation say that the load stopped being unaccustomed, or did it say the person got bored, or reached their limit? All three are things people say, and only the first is the principle. Write down which you said, and then write the version you would now give in an exam, using the words overload and adaptation.
Multiple choice · 5 questions
MC 1. Progressive overload is best defined as:
- A. increasing training stress gradually and systematically as the body adapts to it
- B. training until failure in every session
- C. varying the exercises used from week to week
- D. training at the highest intensity the athlete can tolerate
MC 2. An athlete raises weekly volume, session load and training frequency all in the same week and breaks down. Beyond the overload itself, the clearest fault in the program design is that:
- A. the athlete should never increase volume and load in the same programme
- B. training frequency has no effect on adaptation
- C. progressing several variables at once means the cause of the breakdown cannot be identified
- D. the athlete has breached the principle of specificity
MC 3. A previously inactive adult finds that a walk which once raised their heart rate to 75 per cent of maximum now raises it only to 60 per cent. The best interpretation is that:
- A. their maximum heart rate has increased
- B. they have adapted, so the same walk now sits below their aerobic training threshold
- C. the walk was never above the aerobic training threshold
- D. they have become overtrained
MC 4. A long jumper trains exclusively with heavy, slow lifts. The dimension of specificity most clearly breached is:
- A. muscle group
- B. energy system
- C. context and skill
- D. speed of movement
MC 5. Which statement about training thresholds is most accurate?
- A. They are fixed physiological constants that are the same for all athletes
- B. They apply to aerobic training but have no equivalent in strength training
- C. They are individual and shift as an athlete adapts, so a percentage is a prescribing convention
- D. Work below a threshold has no value of any kind
Short answer · exam style
SA 1. Understand Band 4 Explain the principle of progressive overload, and describe two variables through which it can be applied in a strength program. (4 marks)
SA 2. Apply Band 5 Using training thresholds, explain why a session that is effective training for a beginner may be only recovery for a trained athlete. (5 marks)
SA 3. Evaluate Band 6 Evaluate the application of progressive overload, training thresholds and specificity to both aerobic and strength training. Use examples. (6 marks)
📖 Comprehensive answers (click to reveal)
Multiple choice: 1 → A. 2 → C. 3 → B. 4 → D. 5 → C.
Activity 1, indicative answers: 1 → Specificity, breached in energy system. The 400 m is a near-maximal effort of around 50 seconds, dominated by anaerobic glycolysis, while 90-minute conversational running trains the aerobic system almost exclusively. Consequence: a strong aerobic base and no improvement in the tolerance of disturbance that decides the final 100 m. 2 → Progressive overload, breached at the upper failure mode, and compounded by progressing several variables at once. Consequence: fatigue accumulates faster than adaptation, performance declines, injury and illness risk rises, and because three variables moved together the program cannot identify which change was responsible. 3 → Specificity, breached in speed of movement. The muscle groups and movement pattern may be well matched, but a jump is limited by the rate at which force is produced as well as by maximal force. Consequence: the athlete becomes stronger without becoming more powerful, and the jump may not improve. 4 → Thresholds, and progressive overload. The walk was above the aerobic training threshold when it began and adaptation has since raised the athlete's capacity, so the same absolute workload now sits below the threshold. Consequence: the health benefit of the activity remains, but further aerobic adaptation has stopped.
Activity 2, indicative answers: A defensible repair progresses load, because the goal is strength and load is the variable strength adaptation is most sensitive to; progressing frequency or volume first would raise fatigue without addressing the stimulus. A workable rule is a small increment, roughly 2 to 5 per cent, applied only once the target repetitions are completed with sound technique on the final set, which for most beginners is about once per exercise per week. The weekly evidence is repetition quality on the last set, the athlete's rating of exertion, technique observed by the coach, and whether the previous session's target was met. Signs of progressing too fast include technique degrading under load, targets being missed for two consecutive sessions, performance declining rather than plateauing, disturbed sleep, elevated resting heart rate and persistent soreness. The distinction from ordinary training fatigue is duration and direction: normal fatigue resolves within a session or two and performance still trends upward across weeks, whereas excessive progression produces a sustained decline that does not resolve with a normal rest day. The practical test is to reduce load for a week and observe whether performance recovers.
SA 1 (4 marks): The principle [2]: the body adapts to a stress greater than the one it is accustomed to, so training stress must be increased gradually and systematically as adaptation occurs [1]; if it is not, the stress is no longer unaccustomed and the athlete plateaus, while if it is raised faster than recovery allows, fatigue accumulates and performance declines [1]. Two variables, each with a mechanism [2]: load, raised in small increments once the target repetitions are completed with sound technique [1]; and volume, raised through repetitions or sets, or frequency, or reduced rest between sets [1]. Naming two variables without explaining how each is applied earns half.
SA 2 (5 marks): Define a threshold as the minimum intensity at which a training effect occurs for a given system, roughly 70 per cent of maximum heart rate for aerobic training [1]. State that a threshold is relative to the individual athlete and shifts as that athlete adapts [1]. The beginner has a low capacity, so a moderate absolute workload sits above their threshold and constitutes an overload, driving adaptation [1]. The trained athlete has a higher capacity, so the identical absolute workload falls below their threshold, providing too small a stimulus to force adaptation, though it still serves as recovery and assists blood flow and technique [1]. Consequence for prescription: intensity must be prescribed relative to the individual, as a percentage of a measured maximum rather than as an absolute pace or load, which is precisely why the baseline measurement of Lesson 2 is required [1].
SA 3 (6 marks): Two marks per principle, one for each type of training, with a judgement required for the top band. Progressive overload: in aerobic training it is usually progressed through volume, for example raising weekly duration by roughly 10 per cent, whereas in strength training it is usually progressed through load once target repetitions are completed with sound technique; the same principle, different primary variable [2]. Thresholds: in aerobic training the working band lies between the aerobic training threshold and the anaerobic threshold, expressed in heart rate, whereas in strength training it is expressed as a percentage of one-repetition maximum, with maximal strength requiring roughly 85 per cent and above; identical logic, different units [2]. Specificity: aerobic training must match the energy system and movement, so a swimmer trains in water rather than only running, whereas strength training must match muscle group, movement pattern and speed of contraction, which is why a jumper who trains only with heavy slow lifts becomes stronger without becoming faster [2]. A top-band judgement notes that the principles are not independent: overload must be applied to a specific quality above its own threshold, and applying two at once has scheduling consequences, such as separating high aerobic volume from heavy strength work within a week because the former can blunt the latter's adaptation.
Lessons 3 to 5 answered which method. This lesson and the next answer under what conditions any method works. Three principles down, three to go.
Test yourself with the four-step routine: name, quote, predict, recommend. Take any program you have seen, including one of your own, and run it. If you can produce a calibrated judgement rather than a verdict, you are working at the level this dot point is asking for.
Mark lesson as complete
Tick when you've finished the practice and review.