Lesson 8 · How do the systems of the body influence and respond to movement?
Seven systems, one movement, and what to do when it goes wrong
Seven lessons have taken the body apart. This one puts it back together, because the syllabus does not ask you to know seven systems — it asks you to analyse how they work together, which is a different and harder skill. The analytical move that makes it possible is to stop asking what each system does and start asking which system runs out first, because that question has a different answer for a one-repetition maximum, a 400 metre race and a three-hour hike. The lesson then closes on the syllabus's other requirement here: what first aid is for when the answer turns out to be an injury, a collapse or a person in real trouble.
A powerlifter can lift more than almost anybody alive, and is exhausted after six seconds. A marathon runner can keep going for two hours, and cannot lift anything like as much. Both are superbly trained athletes.
Write down, in your own words, what each of them ran out of. Not "energy" — be more specific than that, using anything from Lessons 1 to 7. Then the harder question: if you asked each athlete to do the other's event, which body system would fail them first, and would it be the same system in both cases?
- Trace a single movement through all seven systems studied in this focus area, in the order they act.
- Analyse a movement by phase — preparation, execution, follow-through, recovery — rather than as one undifferentiated event.
- Identify the limiting system in a given movement, and justify the choice with evidence from the movement itself.
- Compare how the systems combine across a variety of movements of different duration and intensity.
- Explain the role of first aid in response to movement, and where its role ends.
- Apply DRSABCD, TOTAPS and soft tissue management to realistic incidents.
- Respond appropriately to the syllabus's three named contexts: inefficient movement, dehydration and undue stress on the body.
- Movement analysis — breaking a movement into phases and identifying what each body system contributes to each phase.
- Limiting system — the system whose capacity is exhausted first, and which therefore determines when the movement must stop or slow.
- Integration — the coordinated operation of several systems so that the output is a single movement rather than several separate responses.
- First aid — the immediate care given to an injured or ill person before professional medical help is available.
- Duty of care — the responsibility to take reasonable steps to avoid foreseeable harm to those in your charge.
- DRSABCD — the action plan for an unresponsive casualty: Danger, Response, Send for help, Airway, Breathing, CPR, Defibrillation.
- TOTAPS — the assessment sequence for a conscious, injured athlete: Talk, Observe, Touch, Active movement, Passive movement, Skills test.
- Soft tissue injury — damage to muscle, tendon or ligament, classified as a sprain (ligament), a strain (muscle or tendon) or a contusion (bruise).
- Dehydration — a fluid deficit large enough to impair physiological function and performance.
- Heat illness — the spectrum from heat cramps and heat exhaustion to heat stroke, which is a medical emergency.
- Overuse injury — tissue damage caused by repeated loading without adequate recovery, rather than by a single event.
- Concussion — a disturbance of brain function caused by an impact, requiring immediate removal from activity and medical clearance.
Take a single movement — a netball player receiving a pass and shooting — and follow it through. The point is not that seven systems are involved. The point is that they are involved in a sequence, on different timescales, and some of them started work long before the ball arrived.
| System | Contribution to this movement | When it acted |
|---|---|---|
| Nervous | Detects the ball, decides the shot, issues the motor commands, and corrects the movement continuously through proprioception | Milliseconds, and continuously throughout |
| Muscular | Agonists at the shoulder, elbow and wrist produce the force; antagonists control it; stabilisers hold the trunk still so the arms have something to work against | During the movement itself |
| Skeletal | Supplies the levers and the joint types that permit the required actions, and bears the load through the legs and trunk | During the movement itself |
| Respiratory | Has already loaded the blood with oxygen; ventilation rises to meet the rising demand across a quarter of play | Seconds before, and continuously |
| Circulatory | Delivers that oxygen and glucose to the working muscle and removes carbon dioxide and heat; cardiac output rises and blood flow is redistributed | Seconds before, and continuously |
| Endocrine | Adrenaline has already raised heart rate and released glucose before the ball arrived; glucagon maintains blood glucose as the match continues | Minutes before, and throughout |
| Digestive | Supplied the glucose, amino acids and micronutrients hours earlier, and its function is currently suppressed so that blood can go elsewhere | Hours before, and deliberately reduced now |
Two things in that table are worth more than the rest.
First, the digestive system contributes by having finished. Its work was done hours ago, and during the movement it is actively shut down. A system can contribute to a movement by being suppressed, and an analysis that only looks for systems that are busy will miss it.
Second, nothing here is a chain of command. It is easy to write "the nervous system tells the muscles to move, which needs oxygen, which the lungs supply". That reads well and is wrong in an important way: the circulatory and respiratory responses were triggered by the same sympathetic activation that prepared the movement, before the muscles had used any oxygen at all. The body anticipates rather than reacts, which is exactly what Lesson 7's autonomic table and Lesson 6's adrenaline sequence described.
Quick check: During a netball match, the digestive system's contribution to movement is best described as:
Every movement uses all seven systems. That is true, and on its own it is useless — it says nothing different about a shot put and a marathon. The analytical question that does distinguish them is: which system's capacity is reached first? That system is the limiting system, and identifying it is what turns a description into an analysis.
| Movement | Dominant demand | Limiting system, and why |
|---|---|---|
| A one-repetition maximum lift | Maximal force for two to three seconds | Nervous and muscular. The limit is how many large motor units can be recruited and driven at once, plus the force the fibres and connective tissue can produce and withstand. Oxygen delivery is irrelevant on this timescale. |
| A 100 metre sprint | Maximal power for about ten seconds | Muscular, by fuel. The stored phosphocreatine that powers maximal effort is depleted within roughly ten seconds, which is why the last twenty metres of a 100 metre race are run slower than the middle, by everyone. |
| A 400 metre run | Near-maximal effort for 45 to 60 seconds | Muscular and circulatory together. Energy is supplied faster than oxygen can be delivered, so by-products accumulate faster than the circulation can clear them, and contraction itself is impaired. This event is famous for feeling worse than any other, and this is why. |
| A three-hour hike | Low intensity, very long duration | Digestive, endocrine and circulatory. Oxygen delivery is never the constraint. Glycogen depletion, fluid and electrolyte loss, and the endocrine defence of blood glucose and plasma volume decide whether the hike is finished comfortably or badly. |
This is also the answer to Card 01. The powerlifter and the marathon runner have not trained "different amounts" — they have trained different limiting systems, and each would be limited by a system they have barely developed if placed in the other's event.
How to justify a limiting system, rather than guess one
Do not choose the system that sounds most impressive. Choose it with evidence from the movement itself, in three steps. One: how long does the movement last, and at what intensity? Two: what does the performer's failure actually look like — do they slow down, lose technique, become breathless, cramp, or simply stop? Three: which system's known capacity matches that timescale and that failure? A sprinter who slows in the final metres while still moving well is fuel-limited; a footballer whose passes go astray in the final ten minutes while still running is neurally limited; a hiker who becomes light-headed and stops sweating is in trouble with fluid regulation. The failure mode identifies the system.
True or false: Because every movement uses all of the body's systems, identifying which system limits a particular movement is not a meaningful distinction.
The dot point says demonstrate and analyse, and the demonstration is not decoration — you cannot analyse a movement you have not watched carefully. The standard method is to split it into four phases and ask the same questions of each.
| Phase | What happens | What to analyse |
|---|---|---|
| Preparation | The countermovement: hips, knees and ankles flex; the extensor muscles lengthen under tension | Eccentric contraction of the quadriceps and gluteals, stretching of the muscles about to shorten, and the nervous system pre-activating the units it is about to need |
| Execution | Explosive extension of the hip, knee and ankle, driving the body upwards | Concentric contraction of the same muscles, maximal recruitment of large fast-twitch motor units, and force transmitted through the skeletal levers to the ground |
| Follow-through | Full extension and flight, then the approach to landing | Stabilisers controlling body position, and proprioceptive information preparing the landing before contact |
| Recovery | Landing and absorption, then the return towards resting state | Eccentric contraction absorbing landing forces, joints and bone bearing load, and the parasympathetic return of heart rate and ventilation |
Two habits make this analysis good rather than merely complete.
- Name the contraction type in every phase. Lesson 2 established that the same muscle acts eccentrically in one phase and concentrically in the next. An analysis that says "the quadriceps contract" has said nothing that distinguishes the jump from the landing, and the landing is where the injury risk lives.
- Do not stop at execution. Most student analyses are excellent on the phase that produces the result and silent on the two either side, yet the preparation phase determines how much force is available, and the recovery phase determines whether the athlete is injured. The phases that get least attention are the ones that get people hurt.
Match each movement to the system most likely to limit it.
- A one-repetition maximum lift
- A 100 metre sprint
- A 400 metre run
- A three-hour hike
- Nervous and muscular: how many large motor units can be recruited and driven at once
- Muscular by fuel: stored phosphocreatine is depleted within about ten seconds
- Muscular and circulatory: by-products accumulate faster than the circulation can clear them
- Digestive, endocrine and circulatory: glycogen depletion and fluid and electrolyte loss
The syllabus asks you to discuss the role first aid plays in response to movement, and discuss means considering more than one side. So state the role precisely, and then state its limits, because a discussion that only lists benefits is incomplete by definition.
The role of first aid has four parts, and they are in priority order:
- Preserve life. A collapsed and unresponsive person needs an airway, breathing and circulation, before anything else is even considered.
- Prevent the injury getting worse. Removing the person from the danger, stopping the activity, immobilising what needs immobilising, and cooling or warming as required.
- Promote recovery. Early appropriate management of a soft tissue injury measurably shortens the time to return to sport.
- Make the decision about what happens next. Continue, stop, seek medical assessment, or call an ambulance. In practice this is the part performed worst, and it is the part with the most serious consequences.
For an unresponsive casualty the action plan is DRSABCD: check for Danger to yourself and others, check for a Response, Send for help, open the Airway, check for Breathing, begin CPR if they are not breathing normally, and attach a Defibrillator as soon as one is available. Danger is first for a reason that sounds callous and is not: a second casualty helps nobody.
For a conscious, injured athlete the assessment sequence is TOTAPS:
| Step | What you do |
|---|---|
| Talk | Ask what happened, where it hurts, what they felt and heard |
| Observe | Look for swelling, deformity, discolouration, and how they are holding the limb |
| Touch | Palpate gently for tenderness, heat and deformity |
| Active movement | Ask them to move the joint themselves, without help |
| Passive movement | Only if active movement was possible and painless, move the joint through its range for them |
| Skills test | Only if everything above was normal, have them stand, walk, jog and perform the skill |
Every step is a gate, not a box to tick. If the athlete cannot move the joint actively, the assessment stops there and they do not play. Running a skills test on someone who failed the active movement step is not a thorough assessment; it is the error the sequence exists to prevent.
Where first aid's role ends, which is the other half of "discuss"
First aid is immediate care by a non-professional. It does not diagnose, it does not treat, and it does not clear anybody to return. Three limits are worth naming in an answer. It cannot exclude a fracture — only imaging can, so an inability to weight-bear goes to a doctor regardless of how the joint looks. It cannot clear a concussion — suspected concussion means immediate and permanent removal from that day's activity and medical clearance before return, and no coach, parent or athlete may override that. And it cannot fix the cause: first aid responds to the overuse injury, the dehydration and the collapse, but the reason each happened lies in training load, fluid planning and preparation, which is prevention rather than first aid. A strong discussion says that first aid is indispensable and insufficient, and names what has to sit alongside it.
Two truths and a lie. Which statement is false?
The syllabus offers three contexts for first aid in response to movement: inefficient movement, dehydration, and undue stress on the body. Each produces a characteristic injury or illness, and each has a response.
1. Inefficient movement — poor technique, fatigue-driven breakdown, inadequate warm-up, unsuitable surfaces or footwear. The typical result is an acute soft tissue injury: a sprain (ligament), a strain (muscle or tendon) or a contusion (bruise).
- Assess with TOTAPS and remove the athlete from play.
- Manage with rest, ice, compression, elevation and referral — RICER. Ice for around 20 minutes every two hours in the first 48 to 72 hours, wrapped rather than applied directly to skin.
- Avoid heat, alcohol, running and massage in that early period — the HARM list — because each increases blood flow and therefore swelling.
- Refer where there is deformity, an inability to weight-bear, a sound at the moment of injury, rapid swelling, or no improvement — any one of these is a doctor's decision, not a coach's.
2. Dehydration — fluid loss through sweat that is not replaced. Lesson 5 established the mechanism: falling plasma volume reduces stroke volume, so heart rate must rise to maintain cardiac output, and the same fluid loss impairs the body's ability to shed heat. The signs run in a sequence and the sequence is the important part: thirst and dark urine, then headache and rising heart rate, then cramping and dizziness, then confusion.
- Mild to moderate: stop, move to shade, drink cool fluid in small frequent amounts, loosen clothing, and do not return to play.
- Heat exhaustion: pale, sweating heavily, weak and dizzy with a rapid pulse. Lie them down, elevate the legs, cool actively with water and airflow, give fluids if fully conscious, and seek medical help.
- Heat stroke is an emergency. The distinguishing features are a very high body temperature and altered mental state — confusion, aggression, slurred speech or collapse — sometimes with sweating that has stopped. Call an ambulance immediately, cool aggressively with whatever is available, and follow DRSABCD. Confusion in a hot athlete is never a discipline problem and never something to run off.
3. Undue stress on the body — a training load, an intensity or a duration beyond what the person is currently prepared for. This one is different because the harm accumulates instead of happening in an instant.
- Overuse injuries such as stress fractures, tendinopathy and shin pain: the tissue is loaded repeatedly without adequate recovery, so damage accumulates faster than repair. The first aid response is to stop the activity and refer; the real response is a load and recovery review, which is where Lesson 13's FITT principle comes in.
- Exertional collapse: an athlete who collapses at or after the end of maximal effort. Treat as DRSABCD, do not assume it is simple exhaustion, and get medical help.
- Cardiac events, which are rare in young people and catastrophic when missed. Chest pain, unusual breathlessness, or collapse during exertion require an ambulance and, if the person is unresponsive and not breathing normally, immediate CPR and defibrillation.
- Psychological stress, which Lesson 6 covered: chronic stress impairs recovery, and that is one of the mechanisms by which an unchanged training load becomes an undue one.
Fill the gaps. Type one word in each box.
The action plan used for an unresponsive casualty begins with checking for . A ligament injury is called a , while a muscle or tendon injury is called a strain. The distinguishing feature of heat stroke, which makes it a medical emergency, is an altered mental state such as .
Text description
- Above, the seven body systems arranged down a time arrow by when they contribute to a single movement: the digestive and endocrine systems hours before, the respiratory and circulatory systems minutes to seconds before, and the nervous system at the instant of movement, followed by the muscular and skeletal systems.
- Below, the three situations named by the syllabus — inefficient movement, dehydration and undue stress on the body — each mapped to its typical presentation and its first aid response, with the point at which professional help is required given as the last line of each.
Activities · put the method to work
This activity delivers the demonstrate half of the dot point, so it has to be performed rather than imagined. Work in pairs. Choose a movement with a clear start and finish — a vertical jump, a netball chest pass, a soccer instep kick, a bodyweight squat. Perform it while your partner films from the side, then swap.
Split the footage into the four phases from Card 06. Note the approximate time of each transition. Most people are surprised how short the execution phase is compared with everything around it.
For each phase, name the joint actions, the agonist, and the contraction type using Lessons 1 and 2. Be specific: "knee extension, quadriceps, concentric" rather than "the legs push".
Add the other five systems across the whole movement, with the timescale on which each acted, as in the Card 04 table.
Repeat the movement after thirty seconds of hard work — burpees, shuttle runs — and film it again. Compare the two clips frame by frame and describe what changed.
The analysis: name the system responsible for each difference you observed, and say which phase deteriorated most. Then the injury question: given what changed, at which instant is this movement now most likely to injure the performer, and which tissue would be damaged?
Odd one out. Three of these are things first aid can appropriately do. Which one is not?
You are the responsible adult at a Saturday junior competition on a hot day. For each incident, write down: what you do first, the sequence you follow, whether the player returns, and whether professional help is required. Then say which situation from Card 08 it belongs to.
A player lands awkwardly and sits down holding her ankle. She is alert, distressed, and says she heard a pop. There is already visible swelling.
Late in the second half, a player who has been playing well starts making uncharacteristic errors, complains of a headache, and is walking rather than running. It is 34 degrees. He tells you he is fine and wants to keep playing.
A player collides head to head with an opponent, gets up after a few seconds, and asks what the score is. She then asks the same question again a minute later. She has no visible injury and insists she is fine.
A player crosses the line at the end of a race and collapses. He is unresponsive to your voice and to a firm squeeze of the shoulders.
Finally, the question that makes this a discussion rather than a checklist: in which of these four incidents is the greatest risk that the correct action is not taken, and what makes it hard to take? Be honest about the pressure involved — from the player, the parents, the coach and the scoreboard.
Analyse how the systems of the body work together to produce and sustain a 400 metre run.
Analyse means identify components and show the relationships between them, then draw out the implication. A list of seven systems with one sentence each is a description and will sit around half marks however accurate it is. The organising idea that turns it into an analysis here is the limiting system, because a 400 metre run is the event in which the limit is most obviously reached.
Plan: the sequence at the start, the systems interacting during, the limit and what it feels like, then what changes in the last hundred metres and why.
Before the gun, adrenaline released from the adrenal glands has already raised heart rate, stroke volume and ventilation and dilated the bronchioles, and sympathetic activity has redistributed blood flow towards skeletal muscle and away from the digestive organs. The nervous system then initiates the movement from the motor cortex, recruiting large fast-twitch motor units immediately because the effort is near-maximal, and the muscular system produces force through the skeletal levers of the legs.
Once running, the respiratory system increases the rate and depth of breathing to load the blood with oxygen, and the circulatory system delivers it, with cardiac output rising through increases in both heart rate and stroke volume. The demand of near-maximal effort, however, exceeds what oxygen delivery can supply within the time available, so a large part of the energy must be released without oxygen, and the by-products of doing so accumulate faster than the circulation can clear them. This is the limit: it impairs the contractile process itself, so force output falls even though the nervous system is still issuing commands.
A 400 metre run requires every body system, but they do not contribute equally or simultaneously, and the event is best analysed by asking which system reaches its capacity first. The digestive system's contribution was made hours earlier, supplying the glucose stored as muscle and liver glycogen, and during the race its own activity is suppressed so that blood can be directed elsewhere. In the minutes before the start, the endocrine system releases adrenaline, raising heart rate and stroke volume, dilating the bronchioles and releasing glucose from glycogen, while sympathetic activity of the nervous system produces the same effects immediately and redistributes blood flow from the gut and skin to the working muscles — so the circulatory and respiratory systems are already responding before any oxygen has been consumed. At the gun the nervous system initiates the movement from the motor cortex, recruiting large fast-twitch motor units at once because the effort is near-maximal, and driving them at a high firing rate; the muscular system generates force and the skeletal system transmits it through the levers of the legs, with the joints of the hip, knee and ankle permitting the required actions and bearing the resulting load. Throughout the run the respiratory system raises the rate and depth of ventilation and the circulatory system raises cardiac output, but because the intensity is near-maximal the rate at which energy is required exceeds the rate at which oxygen can be delivered and used, so a substantial proportion of the energy must be released anaerobically and its by-products accumulate faster than the circulation can remove them. That accumulation, together with the depletion of the muscle's most rapidly available fuel, is what limits the event: in the final hundred metres force output and stride length fall, the nervous system's ability to drive the motor units declines with central fatigue, and technique deteriorates even though the athlete is trying no less hard. The systems therefore work together in a strict order of timescales — digestive hours before, endocrine minutes before, respiratory and circulatory seconds before and continuously, nervous and muscular in the instant — and the performance is determined not by the strongest of them but by the first to reach its limit, which in a 400 metre run is the muscular system's capacity to keep contracting in the chemical conditions the circulatory system cannot clear quickly enough.
Discuss the role first aid plays in response to movement.
Discuss requires points for and against, or at least more than one perspective. Here that means the role first aid plays and the limits of that role. An answer that lists DRSABCD, TOTAPS and RICER accurately and stops has described procedures without discussing anything, and will not reach the top band.
Plan: state the four purposes; give the procedures as evidence against the syllabus's three situations; then the limits; then a judgement about what has to sit alongside first aid.
First aid is the immediate care given before professional help arrives, and in the context of movement it serves four purposes in priority order: preserving life, preventing the injury or illness from worsening, promoting recovery, and determining what happens next — whether the person continues, stops, is referred, or requires an ambulance.
Each of the situations arising from movement calls on a different part of that role. Where inefficient movement produces a soft tissue injury, TOTAPS establishes whether the athlete can safely continue and RICER limits swelling and speeds recovery. Where dehydration develops, first aid removes the person from the heat, replaces fluid gradually and recognises the altered mental state that distinguishes heat stroke as an emergency. Where undue stress on the body produces an overuse injury or a collapse, first aid stops the activity and, in a collapse, applies DRSABCD and summons an ambulance.
First aid is the immediate care given to an injured or ill person before professional medical help is available, and in response to movement it plays four roles in priority order: preserving life, preventing the condition from worsening, promoting recovery, and deciding what happens next. Each of the situations that arises from movement calls on a different part of that role. Where inefficient movement — poor technique, fatigue, an inadequate warm-up — produces a sprain, strain or contusion, the TOTAPS sequence of talk, observe, touch, active movement, passive movement and skills test establishes whether the athlete can safely continue, and stops at the first abnormal step rather than running to completion; management by rest, ice, compression, elevation and referral then limits swelling and measurably shortens the time to return, while heat, alcohol, running and massage are avoided in the first 48 to 72 hours because each increases blood flow. Where dehydration develops, first aid removes the person from the heat and replaces fluid in small frequent amounts, and its most important function is recognition: the progression from thirst and headache to cramping and dizziness is manageable on the sideline, but confusion or collapse indicates heat stroke, which is a medical emergency requiring an ambulance and aggressive cooling. Where undue stress on the body produces an overuse injury or an exertional collapse, first aid stops the activity, and for an unresponsive casualty the DRSABCD plan — danger, response, send for help, airway, breathing, CPR, defibrillation — is applied in that order, with danger first because a second casualty helps nobody. The role of first aid is therefore substantial and, in the case of an unresponsive athlete, decisive. It is nonetheless limited in ways that must be acknowledged. First aid cannot diagnose: a fracture cannot be excluded without imaging, so an athlete unable to bear weight is referred regardless of how the limb appears. It cannot clear anyone to return, and in suspected concussion the correct action is immediate and permanent removal from that day's activity with medical clearance required before return, a decision that no coach, parent or player may override. Most importantly, first aid addresses the event and not its cause: the overuse injury, the dehydration and the collapse each originated in training load, fluid planning or preparation, and none of those is altered by an excellent sideline response. First aid is therefore best judged as indispensable but insufficient — a necessary last line of defence that works properly only alongside prevention, in the form of appropriate loading and recovery, hydration planning, adequate warm-up, safe technique and competent supervision.
Multiple choice · 5 questions
MC 1. In DRSABCD, the first action taken is to:
- A. check for a response
- B. open the airway
- C. check for danger to yourself and others
- D. send for help
MC 2. An athlete injures an ankle and cannot move the joint actively when asked. Following TOTAPS, the correct next action is to:
- A. move the joint passively to test its range
- B. stop the assessment, remove the athlete from play and manage the injury
- C. ask the athlete to jog to see whether the pain settles
- D. complete a skills test to confirm the diagnosis
MC 3. During a netball match, the activity of the digestive system is:
- A. increased, to release glucose for the working muscles
- B. unchanged, because digestion is independent of exercise
- C. reduced, as blood is redirected to working muscle
- D. reduced, because the small intestine loses its villi during exertion
MC 4. A player on a hot day becomes confused and stops making sense. The most appropriate response is to:
- A. call an ambulance, begin cooling aggressively, and follow DRSABCD
- B. give a sports drink and allow a short rest before returning to play
- C. apply ice to the muscles and elevate the limbs
- D. encourage the player to walk it off while sipping water
MC 5. Which system is most likely to limit performance in a one-repetition maximum lift?
- A. the respiratory system, because oxygen delivery cannot meet demand
- B. the digestive system, because glycogen stores are depleted
- C. the circulatory system, because by-products cannot be cleared quickly enough
- D. the nervous and muscular systems, because of the limit on motor unit recruitment and force
Short answer · exam style
SA 1. Remember Band 3 Outline the steps of TOTAPS and state the rule that governs when the sequence should be stopped. (4 marks)
SA 2. Analyse Band 5 Analyse how the systems of the body work together to produce and sustain a 400 metre run. (5 marks)
SA 3. Evaluate Band 6 Discuss the role first aid plays in response to movement, referring to inefficient movement, dehydration and undue stress on the body. (6 marks)
📖 Comprehensive answers (click to reveal)
Multiple choice: 1 → C. 2 → B. 3 → C. 4 → A. 5 → D.
Activity 1 guidance: Step 1 usually produces the first genuine surprise: in a vertical jump the execution phase is typically well under a third of a second, while preparation and recovery together take several times longer. That ratio is the reason the phases either side of execution deserve equal attention. In step 4 the consistent findings after fatigue are a shallower countermovement, a slower transition from the eccentric to the concentric phase, less height, and — the one that matters — a stiffer, less controlled landing. The systems responsible differ by observation: reduced height is muscular and energetic, while the degraded landing is neural, because eccentric control during landing depends on proprioceptive feedback and precise recruitment timing, both of which deteriorate with central fatigue. That is also the answer to the injury question. The greatest risk is at landing, in the recovery phase, where eccentric contraction absorbs forces several times body weight; the tissues at risk are the anterior cruciate ligament and the patellar and Achilles tendons. Note the pattern this shares with Lesson 7's Activity 1: the system that fails first under fatigue is the control system, not the engine, which is why fatigued athletes look careless rather than weak.
Activity 2 guidance: Incident 1 is inefficient movement producing an acute soft tissue injury. TOTAPS, stopping early given the swelling and the reported sound; RICER; no return; medical referral, because an audible pop with rapid swelling suggests significant ligament damage that first aid cannot exclude. Incident 2 is dehydration and developing heat illness. The uncharacteristic errors are the tell, and they matter more than the headache: Lesson 7 established that neural function degrades before physical capacity is exhausted, so a good player suddenly playing badly in 34 degree heat is a physiological sign, not a motivational one. Remove from play, shade, cool, fluids in small amounts, monitor closely, and do not return him regardless of what he says. Incident 3 is a suspected concussion and it is the clearest decision of the four: repeated questioning is a recognised sign, and the response is immediate and permanent removal from that day's activity plus medical clearance before any return, with no discretion available to anyone present. Incident 4 is DRSABCD, immediately: danger, response, send for help, airway, breathing, CPR if not breathing normally, defibrillation when available. Do not assume exhaustion, because collapse during or immediately after maximal effort can be cardiac, and the cost of being wrong is asymmetric. On the final question, the honest answer is incident 3, and sometimes incident 2. Both involve a player who appears functional and insists they are fine, in a situation where removing them visibly costs the team, and where nothing observable will punish the wrong decision in the next ten minutes. That is precisely why concussion protocols are mandatory rather than discretionary: the rule exists to remove the decision from the moment when the pressure is greatest.
SA 1 (4 marks): Talk — ask what happened, where it hurts, and what they felt or heard [½]. Observe — look for swelling, deformity, discolouration and how the limb is being held [½]. Touch — palpate gently for tenderness, heat and deformity [½]. Active movement — ask the athlete to move the joint themselves [½]. Passive movement — move the joint through its range for them, only if active movement was possible and painless [½]. Skills test — have them stand, walk, jog and perform the skill, only if everything prior was normal [½]. The governing rule, worth the final mark in full: the sequence is ordered from least to most demanding and stops at the first step the athlete cannot complete normally, at which point they are removed from play and the injury managed [1]. Without that rule the answer is a list, and listing is not what the question asks.
SA 2 (5 marks): Endocrine and sympathetic preparation before the start, raising heart rate, stroke volume and ventilation and redistributing blood flow before any oxygen has been consumed [1]. Nervous initiation with immediate recruitment of large fast-twitch motor units, muscular force production and skeletal transmission through the levers of the legs [1]. Respiratory and circulatory responses during the run, with cardiac output raised through both heart rate and stroke volume [1]. The limit identified: near-maximal intensity means energy is required faster than oxygen can be delivered, so by-products accumulate faster than they can be cleared and impair contraction itself [1]. The consequence described — falling force output, shortening stride, deteriorating technique in the final hundred metres, with central fatigue reducing neural drive — and the systems related by timescale rather than listed [1]. An answer that describes all seven systems separately and never identifies the limit is a description and caps at three.
SA 3 (6 marks): First aid defined and its purposes given in priority order: preserve life, prevent worsening, promote recovery, decide what happens next [1]. Inefficient movement: soft tissue injury assessed with TOTAPS and managed with RICER, with what to avoid [1]. Dehydration: recognition of the progression, sideline management, and heat stroke identified as an emergency by altered mental state [1]. Undue stress: overuse injury and exertional collapse, with DRSABCD applied to an unresponsive casualty [1]. The limits stated: first aid cannot diagnose, cannot clear a return, and in particular cannot clear a concussion [1]. An explicit judgement that first aid is necessary but not sufficient, naming prevention through load management, hydration planning, warm-up, technique and supervision as what must sit alongside it [1]. The verb is discuss: an answer containing only correct procedures forfeits the last two marks, which is the most common way this question is lost.
Together, not separately. Every movement uses all seven systems, on wildly different timescales — the digestive system hours before and now suppressed, the endocrine system minutes before, the respiratory and circulatory systems seconds before and continuously, the nervous, muscular and skeletal systems in the instant. The point that separates a good answer from a list is that the circulatory and respiratory changes are anticipatory: they are triggered by the same sympathetic activation that prepared the movement, not by the muscles running short.
Which system runs out first? That question is the whole analysis. Recruitment in a maximal lift, stored fuel in a sprint, by-product accumulation in a 400 metre, glycogen and fluid in an endurance event. And the failure mode identifies the system, which means you can justify your choice from what the performer actually does rather than from a guess.
Analyse by phase. Preparation, execution, follow-through, recovery — naming the contraction type in each. The phases that get least attention are the ones that get people hurt, and the landing is almost always where the risk lives.
And first aid. Preserve life, prevent worsening, promote recovery, decide what happens next. DRSABCD for the unresponsive, TOTAPS for the conscious injured — stopping at the first abnormal step — and RICER for soft tissue. Then the half that the verb discuss actually requires: first aid cannot diagnose, cannot clear a concussion, and cannot touch the cause. Indispensable and insufficient.
That closes the first inquiry question of this module. Lesson 9 opens the second, starting with the energy systems — which is where the phrase "ran out of fuel" finally acquires a precise meaning.
Mark lesson as complete
Tick when you've finished the practice and review.