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HMS, BM 2014 HSC 27

Compare the two anaerobic energy systems.   (5 marks)

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ATP-PCr system and Glycolytic (Lactic Acid) system

Similarities:

  • Both systems operate without oxygen during anaerobic metabolism processes.
  • Both provide energy for high-intensity, short-duration explosive activities.
  • Both systems work together during power-based movements like sprinting.
  • Both use stored energy sources available within muscle tissue.
  • Both produce ATP for immediate muscular contraction requirements.

Differences:

  • ATP-PCr uses stored phosphocreatine whilst glycolytic system uses muscle glycogen and glucose.
  • ATP-PCr operates for 10-15 seconds maximum, glycolytic system functions 15 seconds to 2 minutes.
  • ATP-PCr produces ATP most rapidly but glycolytic system has greater total capacity.
  • ATP-PCr fatigues when phosphocreatine stores deplete, glycolytic fatigues from lactate accumulation.
  • ATP-PCr recovers completely in 2-3 minutes, glycolytic requires longer recovery periods.
  • ATP-PCr produces no fatiguing by-products, glycolytic creates lactate causing muscle burn.

Summary:

  • ATP-PCr provides immediate explosive power whilst glycolytic sustains high-intensity efforts for longer periods.
Show Worked Solution

ATP-PCr system and Glycolytic (Lactic Acid) system

Similarities:

  • Both systems operate without oxygen during anaerobic metabolism processes.
  • Both provide energy for high-intensity, short-duration explosive activities.
  • Both systems work together during power-based movements like sprinting.
  • Both use stored energy sources available within muscle tissue.
  • Both produce ATP for immediate muscular contraction requirements.

Differences:

  • ATP-PCr uses stored phosphocreatine whilst glycolytic system uses muscle glycogen and glucose.
  • ATP-PCr operates for 10-15 seconds maximum, glycolytic system functions 15 seconds to 2 minutes.
  • ATP-PCr produces ATP most rapidly but glycolytic system has greater total capacity.
  • ATP-PCr fatigues when phosphocreatine stores deplete, glycolytic fatigues from lactate accumulation.
  • ATP-PCr recovers completely in 2-3 minutes, glycolytic requires longer recovery periods.
  • ATP-PCr produces no fatiguing by-products, glycolytic creates lactate causing muscle burn.

Summary:

  • ATP-PCr provides immediate explosive power whilst glycolytic sustains high-intensity efforts for longer periods.

♦♦ Mean mark 54%.

HMS, BM 2015 HSC 10 MC

What is the cause of fatigue for the alactacid (ATP-PCr) system?

  1. Lack of essential amino acids
  2. Lack of muscle glycogen stores
  3. Inability to re-synthesise phosphate creatine
  4. Inability to convert carbohydrates to glycogen
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\(C\)

Show Worked Solution
  • C is correct: ATP-PCr system fatigues when PCr stores are depleted.

Note: The 2015 exam used “alactacid system” terminology from the 2012 PDHPE syllabus. In HMS, this is called the “ATP-PCr system.”

Other Options:

  • A is incorrect: Amino acids not used in ATP-PCr system.
  • B is incorrect: Glycogen relates to glycolytic system not ATP-PCr.
  • D is incorrect: Carbohydrate conversion unrelated to ATP-PCr fatigue.

HMS, BM 2016 HSC 2 MC

What is the most likely cause of fatigue in a runner completing a 100 m sprint?

  1. Dehydration
  2. Accumulation of lactic acid
  3. Depletion of muscle glycogen
  4. Depletion of phosphate creatine
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\(D\)

Show Worked Solution
  • D is correct: 100m sprints primarily use ATP-PCr system which fatigues from phosphocreatine depletion.

Other Options:

  • A is incorrect: Dehydration unlikely in such short duration activity.
  • B is incorrect: Lactic acid builds up but PCr depletion occurs first.
  • C is incorrect: Glycogen depletion occurs in longer duration activities.

HMS, BM 2017 HSC 25

Compare TWO different energy systems by exploring their duration, sources of fuel and causes of fatigue. Use examples to support your answer.   (7 marks)

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Energy Systems Being Compared:

  • ATP-PCr System (Phosphocreatine System)
  • Aerobic System (Oxidative System)

Similarities

  • Both energy systems produce ATP to fuel muscle contractions during exercise activities. They work together seamlessly during most physical activities to meet energy demands.
  • Both systems can operate without requiring external oxygen supply from the respiratory system. This allows immediate energy production when exercise begins before breathing rate increases.

Differences – Duration

  • The ATP-PCr system operates for very short durations of 10-15 seconds maximum. This occurs because stored ATP and creatine phosphate supplies are limited in muscle cells.
  • The aerobic system functions for hours or even days. This happens because oxygen allows continuous fuel breakdown without harmful byproduct accumulation.

Differences – Fuel Sources

  • The ATP-PCr system sources fuel from stored ATP and creatine phosphate already present in muscles. This enables immediate energy release without requiring glucose breakdown.
  • The aerobic system utilises carbohydrates, fats and proteins as fuel sources.  This process requires oxygen to completely break down these substrates.

Differences – Causes of Fatigue

  • Fatigue in the ATP-PCr system results from depletion of stored phosphocreatine reserves. For instance, a weightlifter cannot continue once stores are exhausted.
  • Aerobic system fatigue occurs due to fuel depletion or oxygen limitations. Marathon runners experience this when glycogen stores become depleted.
Show Worked Solution

Energy Systems Being Compared:

  • ATP-PCr System (Phosphocreatine System)
  • Aerobic System (Oxidative System)

Similarities

  • Both energy systems produce ATP to fuel muscle contractions during exercise activities. They work together seamlessly during most physical activities to meet energy demands.
  • Both systems can operate without requiring external oxygen supply from the respiratory system. This allows immediate energy production when exercise begins before breathing rate increases.

Differences – Duration

  • The ATP-PCr system operates for very short durations of 10-15 seconds maximum. This occurs because stored ATP and creatine phosphate supplies are limited in muscle cells.
  • The aerobic system functions for hours or even days. This happens because oxygen allows continuous fuel breakdown without harmful byproduct accumulation.

Differences – Fuel Sources

  • The ATP-PCr system sources fuel from stored ATP and creatine phosphate already present in muscles. This enables immediate energy release without requiring glucose breakdown.
  • The aerobic system utilises carbohydrates, fats and proteins as fuel sources.  This process requires oxygen to completely break down these substrates.

Differences – Causes of Fatigue

  • Fatigue in the ATP-PCr system results from depletion of stored phosphocreatine reserves. For instance, a weightlifter cannot continue once stores are exhausted.
  • Aerobic system fatigue occurs due to fuel depletion or oxygen limitations. Marathon runners experience this when glycogen stores become depleted.

♦♦ Mean mark 55%.

HMS, BM 2020 HSC 23a

An athlete ran in the 100-metre final at an Olympic Games.

In the table below, identify the predominant energy system used by the athlete, and the features of that energy system.   (3 marks)

Predominant energy system used by this athlete  
Source of fuel  
Energy system duration  
Cause of fatigue  
Rate of recovery  
Show Answers Only
    
 Predominant energy system used by this athlete ATP-PCr system (Alactacid system)
  Source of fuel Creatine phosphate (CP)
  Energy system duration 6-12 seconds
  Cause of fatigue Depletion of creatine phosphate stores
  Rate of recovery 2-3 minutes for complete recovery
Show Worked Solution
    
 Predominant energy system used by this athlete ATP-PCr system (Alactacid system)
  Source of fuel Creatine phosphate (CP)
  Energy system duration 6-12 seconds
  Cause of fatigue Depletion of creatine phosphate stores
  Rate of recovery 2-3 minutes for complete recovery

HMS, BM EQ-Bank 768

To what extent do the causes of fatigue affect a tennis player's ability to maintain serve speed and accuracy throughout a long match?    (8 marks)

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Sample Answer

Position Statement:

  • Fatigue moderately affects serve performance, with impact increasing as matches extend beyond two hours.
  • Primary factors: phosphocreatine depletion for serves and glycogen reduction affecting overall match play.

ATP-PCr System and Serve Power:

  • Each serve requires maximum explosive power from the ATP-PCr system lasting 1-2 seconds.
  • Brief recovery between points allows substantial PCr replenishment before the next serve.
  • However, accumulated serves throughout a match create incomplete recovery cycles.
  • First serves typically maintain speed early but show slight decreases in later sets.
  • Second serves, requiring precise control, suffer more from fatigue than pure power serves.
  • The system’s quick recovery between points limits severe serve speed reduction.

Glycolytic and Aerobic Demands:

  • Extended rallies between serves engage glycolytic and aerobic systems substantially.
  • Lactic acid from intense rallies can affect serving motion and timing.
  • Long matches gradually deplete glycogen stores, reducing overall movement quality.
  • This indirect fatigue impacts serve preparation, footwork and balance.
  • Players compensate by reducing first-serve percentage to maintain control.

Reaffirmation:

  • Fatigue moderately impacts serving, with noticeable but not dramatic effects.
  • players maintain most serve speed through efficient PCr recovery between points.
  • Accuracy suffers more than raw power as fatigue affects coordination.
  • Match duration and rally intensity determine fatigue’s extent more than serve count alone.
  • Therefore, while fatigue influences serve performance, the impact remains manageable through tactical adjustments.
Show Worked Solution

Sample Answer

Position Statement:

  • Fatigue moderately affects serve performance, with impact increasing as matches extend beyond two hours.
  • Primary factors: phosphocreatine depletion for serves and glycogen reduction affecting overall match play.

ATP-PCr System and Serve Power:

  • Each serve requires maximum explosive power from the ATP-PCr system lasting 1-2 seconds.
  • Brief recovery between points allows substantial PCr replenishment before the next serve.
  • However, accumulated serves throughout a match create incomplete recovery cycles.
  • First serves typically maintain speed early but show slight decreases in later sets.
  • Second serves, requiring precise control, suffer more from fatigue than pure power serves.
  • The system’s quick recovery between points limits severe serve speed reduction.

Glycolytic and Aerobic Demands:

  • Extended rallies between serves engage glycolytic and aerobic systems substantially.
  • Lactic acid from intense rallies can affect serving motion and timing.
  • Long matches gradually deplete glycogen stores, reducing overall movement quality.
  • This indirect fatigue impacts serve preparation, footwork and balance.
  • Players compensate by reducing first-serve percentage to maintain control.

Reaffirmation:

  • Fatigue moderately impacts serving, with noticeable but not dramatic effects.
  • players maintain most serve speed through efficient PCr recovery between points.
  • Accuracy suffers more than raw power as fatigue affects coordination.
  • Match duration and rally intensity determine fatigue’s extent more than serve count alone.
  • Therefore, while fatigue influences serve performance, the impact remains manageable through tactical adjustments.

HMS, BM EQ-Bank 767

During a half-marathon (21.1km), many runners experience varying types of fatigue at different stages of the race. Explain the causes of fatigue in the aerobic energy system and how these impact performance.   (6 marks)

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Sample Answer

  • Glycogen depletion gradually affects the aerobic system during a half-marathon race.
  • After 60-90 minutes of running, muscle glycogen stores become partly used up, which forces the body to rely more on fat for fuel.
  • This causes problems as fat needs more oxygen to produce ATP than carbohydrate does.
  • Therefore, runners must slow their pace as energy becomes harder to produce efficiently.
  • Dehydration also impacts the aerobic system by reducing the body’s ability to deliver oxygen to muscles.
  • Sweating during the race decreases blood volume, which means less oxygen reaches working muscles.
  • As a result, the aerobic system cannot work as well despite the runner’s fitness level.
  • Rising body temperature further affects performance because heat makes it harder for muscles to produce energy.
  • This leads to decreased efficiency even when oxygen is available.
  • Mental tiredness develops separately from physical fatigue, causing runners to feel the effort is harder than it actually is.
  • Consequently, motivation drops and perceived effort increases during the race.
  • All these factors combine, making runners progressively slower as the race continues despite trying to maintain pace.
Show Worked Solution

Sample Answer 

  • Glycogen depletion gradually affects the aerobic system during a half-marathon race.
  • After 60-90 minutes of running, muscle glycogen stores become partly used up, which forces the body to rely more on fat for fuel.
  • This causes problems as fat needs more oxygen to produce ATP than carbohydrate does.
  • Therefore, runners must slow their pace as energy becomes harder to produce efficiently.
  • Dehydration also impacts the aerobic system by reducing the body’s ability to deliver oxygen to muscles.
  • Sweating during the race decreases blood volume, which means less oxygen reaches working muscles.
  • As a result, the aerobic system cannot work as well despite the runner’s fitness level.
  • Rising body temperature further affects performance because heat makes it harder for muscles to produce energy.
  • This leads to decreased efficiency even when oxygen is available.
  • Mental tiredness develops separately from physical fatigue, causing runners to feel the effort is harder than it actually is.
  • Consequently, motivation drops and perceived effort increases during the race.
  • All these factors combine, making runners progressively slower as the race continues despite trying to maintain pace.

HMS, BM EQ-Bank 766

A swimmer completes a 200-metre freestyle race and feels significant muscle fatigue in the final 50 metres. Analyse the physiological causes of this fatigue and how it affects performance.   (5 marks)

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Sample Answer

  • The 200-metre freestyle predominantly uses the glycolytic energy system, with increasing aerobic system contribution toward the end of the race.
  • The primary cause of fatigue is the accumulation of lactic acid in the working muscles, which occurs when production exceeds the rate of removal.
  • Lactic acid accumulation reduces the muscle’s ability to contract forcefully by disrupting calcium binding and cross-bridge formation in the muscle fibres.
  • The increasing acidosis in the muscle environment affects enzyme function, reducing the rate of ATP production through glycolysis.
  • The swimmer experiences a noticeable decline in stroke efficiency and power output as muscle fibre recruitment patterns change in response to fatigue.
  • Coordination and technique deteriorate in the final 50 metres as the central nervous system adapts to the changing muscle fibre capabilities.
  • The perception of effort significantly increases as the body requires increased nervous system activation to maintain the same power output with fatiguing muscles.
Show Worked Solution

Sample Answer 

  • The 200-metre freestyle predominantly uses the glycolytic energy system, with increasing aerobic system contribution toward the end of the race.
  • The primary cause of fatigue is the accumulation of lactic acid in the working muscles, which occurs when production exceeds the rate of removal.
  • Lactic acid accumulation reduces the muscle’s ability to contract forcefully by disrupting calcium binding and cross-bridge formation in the muscle fibres.
  • The increasing acidosis in the muscle environment affects enzyme function, reducing the rate of ATP production through glycolysis.
  • The swimmer experiences a noticeable decline in stroke efficiency and power output as muscle fibre recruitment patterns change in response to fatigue.
  • Coordination and technique deteriorate in the final 50 metres as the central nervous system adapts to the changing muscle fibre capabilities.
  • The perception of effort significantly increases as the body requires increased nervous system activation to maintain the same power output with fatiguing muscles.

HMS, BM EQ-Bank 765

Explain how causes of fatigue differ between the ATP-PCr system and the glycolytic system during high-intensity exercise.   (4 marks)

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Sample Answer

  • The ATP-PCr system experiences fatigue solely from phosphocreatine depletion after 10-15 seconds of maximal effort.
  • This occurs because stored PCr becomes exhausted without producing any fatiguing by-products.
  • Heat is the only by-product, which enables rapid recovery within 2 minutes.
  • Therefore, ATP-PCr fatigue is temporary and quickly reversible.
  • The glycolytic system fatigues due to lactic acid accumulation in muscle cells.
  • Lactic acid forms when glucose breaks down anaerobically, accumulating faster than removal rates.
  • As a result, the acid interferes with enzyme function and muscle contraction.
  • Consequently, glycolytic fatigue persists longer, requiring 30-60 minutes for complete recovery.
Show Worked Solution

Sample Answer 

  • The ATP-PCr system experiences fatigue solely from phosphocreatine depletion after 10-15 seconds of maximal effort.
  • This occurs because stored PCr becomes exhausted without producing any fatiguing by-products.
  • Heat is the only by-product, which enables rapid recovery within 2 minutes.
  • Therefore, ATP-PCr fatigue is temporary and quickly reversible.
  • The glycolytic system fatigues due to lactic acid accumulation in muscle cells.
  • Lactic acid forms when glucose breaks down anaerobically, accumulating faster than removal rates.
  • As a result, the acid interferes with enzyme function and muscle contraction.
  • Consequently, glycolytic fatigue persists longer, requiring 30-60 minutes for complete recovery.

HMS, BM EQ-Bank 764 MC

During a 200-metre sprint, an athlete experiences significant fatigue in the final 50 metres. Which of the following best explains the primary cause of this fatigue?

  1. Depletion of phosphocreatine stores
  2. Accumulation of lactic acid in the muscles
  3. Depletion of muscle and liver glycogen
  4. Increased use of fat as a fuel source
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\(B\)

Show Worked Solution

Consider Option B: 

  • In a 200-metre sprint (lasting approximately 20-30 seconds), the glycolytic system is the predominant energy system.
  • The primary cause of fatigue is the accumulation of lactic acid in the muscles, which occurs when lactic acid is produced faster than it can be removed, interfering with muscle contraction.

Other Options:

  • A is incorrect: While PCr stores are depleted during the sprint, this occurs within the first 10-15 seconds and is not the primary cause of fatigue in the final stages of a 200m race.
  • C is incorrect: Glycogen depletion is a cause of fatigue in longer duration activities (typically > 60 minutes), not in short-duration, high-intensity events like a 200m sprint.
  • D is incorrect: Increased fat metabolism is associated with longer endurance events and is not a cause of fatigue in sprint events; fat metabolism actually increases during recovery, not during the sprint itself.

\(\Rightarrow B\)

HMS, BM EQ-Bank 763

Analyse how the availability of different fuel sources influences energy system dominance and fatigue during a 1500-metre running race.   (8 marks)

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Sample Answer

Overview Statement

  • Fuel availability determines energy system dominance throughout the 1500m race.
  • Phosphocreatine, glucose and oxygen availability interact to shape pacing and fatigue patterns.

PCr Availability and Sprint Performance

  • Limited phosphocreatine stores enable explosive acceleration for only 10-15 seconds at the start.
  • This leads to rapid PCr depletion, forcing reliance on glycolytic system by the first curve.
  • PCr partially replenishes during the middle laps, allowing a final sprint if managed correctly.
  • Therefore, PCr availability dictates tactical positioning opportunities throughout the race.

Glucose Supply and Sustained Speed

  • Abundant muscle glucose supports high-intensity running through anaerobic glycolysis after PCr depletion.
  • This process generates lactic acid accumulation, which progressively impairs muscle contraction efficiency.
  • The glycolytic system depends on glucose availability but is limited by rising acidity, not fuel depletion.
  • Consequently, glucose availability permits sustained speed while lactic acid constrains maximum effort duration.

Oxygen and Aerobic Contribution

  • Increasing oxygen uptake enables aerobic metabolism to contribute more ATP as the race progresses.
  • The aerobic system utilises glucose more efficiently than glycolysis, producing more ATP per glucose molecule.
  • This efficiency allows sustained pace during middle laps while preserving some glucose for the finish.
  • Thus, oxygen availability determines the balance between efficient and inefficient fuel use.

Implications and Synthesis

  • Fuel availability creates a hierarchy: PCr exhausts first, glucose remains adequate, oxygen increases gradually.
  • This pattern means energy systems shift from ATP-PCr to glycolytic to increasingly aerobic dominance.
  • Fatigue results from PCr depletion initially, then lactic acid accumulation, rather than fuel exhaustion.
  • Therefore, understanding fuel availability reveals why pacing strategies must match energy system capabilities.
Show Worked Solution

Sample Answer

Overview Statement

  • Fuel availability determines energy system dominance throughout the 1500m race.
  • Phosphocreatine, glucose and oxygen availability interact to shape pacing and fatigue patterns.

PCr Availability and Sprint Performance

  • Limited phosphocreatine stores enable explosive acceleration for only 10-15 seconds at the start.
  • This leads to rapid PCr depletion, forcing reliance on glycolytic system by the first curve.
  • PCr partially replenishes during the middle laps, allowing a final sprint if managed correctly.
  • Therefore, PCr availability dictates tactical positioning opportunities throughout the race.

Glucose Supply and Sustained Speed

  • Abundant muscle glucose supports high-intensity running through anaerobic glycolysis after PCr depletion.
  • This process generates lactic acid accumulation, which progressively impairs muscle contraction efficiency.
  • The glycolytic system depends on glucose availability but is limited by rising acidity, not fuel depletion.
  • Consequently, glucose availability permits sustained speed while lactic acid constrains maximum effort duration.

Oxygen and Aerobic Contribution

  • Increasing oxygen uptake enables aerobic metabolism to contribute more ATP as the race progresses.
  • The aerobic system utilises glucose more efficiently than glycolysis, producing more ATP per glucose molecule.
  • This efficiency allows sustained pace during middle laps while preserving some glucose for the finish.
  • Thus, oxygen availability determines the balance between efficient and inefficient fuel use.

Implications and Synthesis

  • Fuel availability creates a hierarchy: PCr exhausts first, glucose remains adequate, oxygen increases gradually.
  • This pattern means energy systems shift from ATP-PCr to glycolytic to increasingly aerobic dominance.
  • Fatigue results from PCr depletion initially, then lactic acid accumulation, rather than fuel exhaustion.
  • Therefore, understanding fuel availability reveals why pacing strategies must match energy system capabilities.

HMS, BM EQ-Bank 762

How does the depletion of fuel sources in the aerobic energy system contribute to an athlete "hitting the wall" during a marathon at around the 32-kilometre mark?   (5 marks)

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Sample Answer

  • Marathon runners begin by using both carbohydrate and fat for fuel, with glycogen providing easy energy at steady pace.
  • After about 2 hours, muscle glycogen stores run very low, which forces the body to use mainly fat for energy.
  • Fat needs more oxygen to make ATP than carbohydrate does, resulting in higher oxygen demands that the body cannot meet at the same running speed.
  • This change causes runners to slow down immediately as their bodies cannot get enough oxygen for the pace.
  • Body temperature goes up because fat burning is less efficient, creating extra heat that makes runners feel hotter.
  • Breathing rate increases to get more oxygen for fat burning, which makes runners feel breathless even though they’ve slowed down.
  • The brain also lacks glucose, causing poor concentration and less motivation to continue.
  • These problems together create the sudden tiredness known as “hitting the wall”.
  • Therefore, glycogen depletion forces the body to use harder-to-burn fat for fuel.
Show Worked Solution

Sample Answer

  • Marathon runners begin by using both carbohydrate and fat for fuel, with glycogen providing easy energy at steady pace.
  • After about 2 hours, muscle glycogen stores run very low, which forces the body to use mainly fat for energy.
  • Fat needs more oxygen to make ATP than carbohydrate does, resulting in higher oxygen demands that the body cannot meet at the same running speed.
  • This change causes runners to slow down immediately as their bodies cannot get enough oxygen for the pace.
  • Body temperature goes up because fat burning is less efficient, creating extra heat that makes runners feel hotter.
  • Breathing rate increases to get more oxygen for fat burning, which makes runners feel breathless even though they’ve slowed down.
  • The brain also lacks glucose, causing poor concentration and less motivation to continue.
  • These problems together create the sudden tiredness known as “hitting the wall”.
  • Therefore, glycogen depletion forces the body to use harder-to-burn fat for fuel.

HMS, BM EQ-Bank 761

Describe how fuel sources contribute to fatigue during the final stretch of a 400-metre race.  (3 marks)

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Sample Answer

  • The 400m relies heavily on the glycolytic system which uses glucose as fuel for the final stretch.
  • This system produces ATP quickly but creates lactic acid as a by-product.
  • Lactic acid builds up rapidly in muscles, making them increasingly acidic and reducing their ability to contract.
  • Additionally, the intense effort uses up muscle glucose stores quickly.
  • These combined effects cause severe fatigue, forcing runners to slow dramatically in the final metres.
Show Worked Solution

Sample Answer

  • The 400m relies heavily on the glycolytic system which uses glucose as fuel for the final stretch.
  • This system produces ATP quickly but creates lactic acid as a by-product.
  • Lactic acid builds up rapidly in muscles, making them increasingly acidic and reducing their ability to contract.
  • Additionally, the intense effort uses up muscle glucose stores quickly.
  • These combined effects cause severe fatigue, forcing runners to slow dramatically in the final metres.

HMS, BM EQ-Bank 191

A swimmer performs a 200 metre freestyle race.

Explain how TWO different energy systems contribute to fatigue during this event.   (4 marks)

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Sample Answer

ATP-PCr System

  • In the first 10-15 seconds, the ATP-PCr system rapidly depletes its phosphagen stores, reducing the power output available for the explosive start and initial sprint phase, forcing reliance on less efficient energy systems for immediate power generation.

Glycolytic System

  • The glycolytic system dominates throughout most of the race, causing progressive lactic acid accumulation that decreases muscle contraction efficiency and interferes with enzyme function, leading to the characteristic “burning” sensation and pace decline.
Show Worked Solution

Sample Answer

ATP-PCr System

  • In the first 10-15 seconds, the ATP-PCr system rapidly depletes its phosphagen stores, reducing the power output available for the explosive start and initial sprint phase, forcing reliance on less efficient energy systems for immediate power generation.

Glycolytic System

  • The glycolytic system dominates throughout most of the race, causing progressive lactic acid accumulation that decreases muscle contraction efficiency and interferes with enzyme function, leading to the characteristic “burning” sensation and pace decline.

HMS, BM EQ-Bank 190

During a summer time beach volleyball tournament, an athlete begins to experience fatigue during their third game of the day.

Identify TWO causes of fatigue and explain their impact on performance.   (3 marks)

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Sample Answer – Any TWO of the following

Glycogen depletion

  • The depletion of muscle glycogen throughout multiple games reduces energy availability for explosive movements like jumping and diving, leading to decreased power output in attacking plays.

Dehydration

  • Progressive dehydration occurs during play in hot conditions, causing a decrease in blood plasma volume which reduces oxygen delivery to working muscles and impairs coordination for precise ball skills.

Electrolyte imbalance

  • Electrolyte imbalance from excessive sweating in hot conditions leads to altered nerve impulse transmission and muscle contraction efficiency, resulting in cramping and reduced reaction times for defensive plays.

Lactic acid accumulation

  • Accumulation of lactic acid from repeated high-intensity rallies causes muscle pH to decrease, interfering with enzyme function and muscle contraction processes, leading to reduced jumping height and slower court movement.
Show Worked Solution

Sample Answer – Any TWO of the following

Glycogen depletion

  • The depletion of muscle glycogen throughout multiple games reduces energy availability for explosive movements like jumping and diving, leading to decreased power output in attacking plays.

Dehydration

  • Progressive dehydration occurs during play in hot conditions, causing a decrease in blood plasma volume which reduces oxygen delivery to working muscles and impairs coordination for precise ball skills.

Electrolyte imbalance

  • Electrolyte imbalance from excessive sweating in hot conditions leads to altered nerve impulse transmission and muscle contraction efficiency, resulting in cramping and reduced reaction times for defensive plays.

Lactic acid accumulation

  • Accumulation of lactic acid from repeated high-intensity rallies causes muscle pH to decrease, interfering with enzyme function and muscle contraction processes, leading to reduced jumping height and slower court movement.

HMS, BM EQ-Bank 189

Explain how different causes of fatigue affect performance in a 2-minute rowing sprint.   (5 marks)

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Sample Answer

  • During the initial explosive start, ATP-PCr stores become rapidly depleted within 10 seconds, resulting in an immediate decrease in power output for the rowing stroke.
  • The accumulation of lactic acid from the dominant glycolytic system causes the blood pH to drop significantly, interfering with the efficiency of muscle contractions and power generation through the middle section.
  • Local muscle glycogen stores begin depleting as the intensity continues, reducing the availability of immediate energy for the working muscles in the latter stages.
  • Neural fatigue progressively reduces the efficiency of muscle fibre recruitment, particularly affecting the large muscle groups required for maintaining proper rowing technique.
  • The psychological impact of fatigue affects technique execution and power application, leading to a decline in stroke efficiency and overall performance output.
Show Worked Solution

Sample Answer

  • During the initial explosive start, ATP-PCr stores become rapidly depleted within 10 seconds, resulting in an immediate decrease in power output for the rowing stroke.
  • The accumulation of lactic acid from the dominant glycolytic system causes the blood pH to drop significantly, interfering with the efficiency of muscle contractions and power generation through the middle section.
  • Local muscle glycogen stores begin depleting as the intensity continues, reducing the availability of immediate energy for the working muscles in the latter stages.
  • Neural fatigue progressively reduces the efficiency of muscle fibre recruitment, particularly affecting the large muscle groups required for maintaining proper rowing technique.
  • The psychological impact of fatigue affects technique execution and power application, leading to a decline in stroke efficiency and overall performance output.

HMS, BM EQ-Bank 188

Compare the causes of fatigue between a 400 metre sprint and a marathon runner.   (4 marks)

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Sample Answer

Similarities:

  • Both events cause fatigue that limits performance and forces athletes to slow down.
  • Both require recovery time before the athlete can perform at the same level again.

Differences:

  • The 400m sprint causes rapid lactic acid build-up from anaerobic glycolysis, making muscles acidic within 45 seconds.
  • Marathon running depletes glycogen stores after about 2 hours, forcing inefficient fat use.
  • Sprint fatigue includes immediate burning sensations and muscle tightness.
  • Marathon fatigue involves gradual energy loss, dehydration and overheating.
  • Sprint fatigue clears within an hour while marathon recovery takes days.
Show Worked Solution

Sample Answer

Similarities:

  • Both events cause fatigue that limits performance and forces athletes to slow down.
  • Both require recovery time before the athlete can perform at the same level again.

Differences:

  • The 400m sprint causes rapid lactic acid build-up from anaerobic glycolysis, making muscles acidic within 45 seconds.
  • Marathon running depletes glycogen stores after about 2 hours, forcing inefficient fat use.
  • Sprint fatigue includes immediate burning sensations and muscle tightness.
  • Marathon fatigue involves gradual energy loss, dehydration and overheating.
  • Sprint fatigue clears within an hour while marathon recovery takes days.

HMS, BM EQ-Bank 187

Outline TWO causes of fatigue when an athlete performs a 100 metre sprint.   (3 marks)

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Sample Answer

Any 2 of the following

  • Phosphocreatine stores run out within 10 seconds of maximal sprinting. This means the ATP-PCr system cannot make enough ATP for explosive movements, forcing the body to use slower energy systems and causing speed to drop.
  • Neural fatigue happens when fast-twitch muscle fibres work continuously. The brain and nerves cannot keep sending strong signals throughout the sprint, so muscles produce less force even when in the final metres.
  • Lactic acid builds up as the glycolytic system works near the sprint’s end. This makes muscles more acidic and prevents them contracting properly in the final metres, causing runners to slow down at the finish.
Show Worked Solution

Sample Answer

Any 2 of the following

  • Phosphocreatine stores run out within 10 seconds of maximal sprinting. This means the ATP-PCr system cannot make enough ATP for explosive movements, forcing the body to use slower energy systems and causing speed to drop.
  • Neural fatigue happens when fast-twitch muscle fibres work continuously. The brain and nerves cannot keep sending strong signals throughout the sprint, so muscles produce less force even when in the final metres.
  • Lactic acid builds up as the glycolytic system works near the sprint’s end. This makes muscles more acidic and prevents them contracting properly in the final metres, causing runners to slow down at the finish.

HMS, BM EQ-Bank 186 MC

Which row correctly identifies the main cause of fatigue for different duration activities?

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\begin{array}{l}
\rule{0pt}{2.5ex} \ \rule[-1ex]{0pt}{0pt}& \\
\rule{0pt}{2.5ex}\textbf{A.}\rule[-1ex]{0pt}{0pt}\\
\rule{0pt}{2.5ex}\textbf{B.}\rule[-1ex]{0pt}{0pt}\\
\rule{0pt}{2.5ex}\textbf{C.}\rule[-1ex]{0pt}{0pt}\\
\rule{0pt}{2.5ex}\textbf{D.}\rule[-1ex]{0pt}{0pt}\\
\end{array}
\begin{array}{|l|l|l|}
\hline
\rule{0pt}{2.5ex}\textbf{10 second sprint}\rule[-1ex]{0pt}{0pt}& \textbf{2 minute swim}& \textbf{2 hour run} \\
\hline
\rule{0pt}{2.5ex}\text{ATP depletion}\rule[-1ex]{0pt}{0pt}&\text{Lactic acid}&\text{Glycogen depletion}\\
\hline
\rule{0pt}{2.5ex}\text{Lactic acid}\rule[-1ex]{0pt}{0pt}& \text{Glycogen depletion}&\text{ATP depletion}\\
\hline
\rule{0pt}{2.5ex}\text{Glycogen depletion}\rule[-1ex]{0pt}{0pt}& \text{ATP depletion}&\text{Lactic acid} \\
\hline
\rule{0pt}{2.5ex}\text{Lactic acid}\rule[-1ex]{0pt}{0pt}& \text{ATP depletion}&\text{Glycogen depletion} \\
\hline
\end{array}
\end{align*}

Show Answers Only

\(A\)

Show Worked Solution
  • A is correct: A is correct: ATP depletion occurs <10s, lactic acid peaks at 1-2 min, glycogen depletes after 90+ min

Other Options:

  • B is incorrect: Lactic acid doesn’t cause fatigue at 10s; glycogen doesn’t deplete at 2 min
  • C is incorrect: Completely reverses the correct fatigue mechanisms
  • D is incorrect: Lactic acid doesn’t occur at 10s; ATP doesn’t deplete at 2 min

HMS, BM EQ-Bank 185 MC

A gymnast performing a 90-second floor routine begins to experience muscular fatigue during their final tumbling pass. What is the MOST likely cause?

  1. Accumulation of lactic acid
  2. Depletion of ATP stores
  3. Depletion of muscle glycogen
  4. Insufficient oxygen availability
Show Answers Only

\(A\)

Show Worked Solution
  • A is correct: The glycolytic energy system produces lactic acid during high-intensity activity, which accumulates and interferes with muscle contraction efficiency

Other Options:

  • B is incorrect: ATP depletion occurs in very short efforts (<10 sec)
  • C is incorrect: Glycogen depletion occurs in longer endurance events 
  • D is incorrect: While oxygen debt occurs, lactic acid is the main cause of fatigue at this duration

HMS, BM EQ-Bank 183

Describe the interplay of energy systems during a 90-minute soccer match.   (6 marks)

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Sample Answer

  • The aerobic system provides most of the total energy throughout the match, sustaining jogging, positioning, and recovery between high-intensity efforts.
  • ATP-PCr system activates for explosive movements that occur regularly throughout the game.
  • These include sprints to beat defenders, jumping for headers, and rapid direction changes lasting 5-10 seconds.
  • The glycolytic system engages during extended high-intensity sequences such as overlapping runs, chasing opponents and consecutive sprints lasting 30-60 seconds.
  • This accumulates lactic acid, causing temporary fatigue until recovery occurs.
  • All three systems operate simultaneously with constantly shifting contributions based on immediate demands.
  • A midfielder transitions from aerobic jogging to ATP-PCr sprinting to intense defensive work within seconds.
  • Natural breaks allow partial energy system recovery during throw-ins, free kicks and tactical pauses.
  • These brief rests permit some phosphocreatine replenishment for the next explosive effort.
  • Energy system contributions vary by position, with central midfielders using more aerobic energy while wingers need more ATP-PCr for repeated sprints.
  • Fatigue increasingly affects system interplay as matches continue, with accumulated lactic acid and glycogen use reducing high-intensity actions in final stages.
  • Substitutions strategically introduce fresh energy systems when starters show declining performance.
Show Worked Solution

Sample Answer

  • The aerobic system provides most of the total energy throughout the match, sustaining jogging, positioning, and recovery between high-intensity efforts.
  • ATP-PCr system activates for explosive movements that occur regularly throughout the game.
  • These include sprints to beat defenders, jumping for headers, and rapid direction changes lasting 5-10 seconds.
  • The glycolytic system engages during extended high-intensity sequences such as overlapping runs, chasing opponents and consecutive sprints lasting 30-60 seconds.
  • This accumulates lactic acid, causing temporary fatigue until recovery occurs.
  • All three systems operate simultaneously with constantly shifting contributions based on immediate demands.
  • A midfielder transitions from aerobic jogging to ATP-PCr sprinting to intense defensive work within seconds.
  • Natural breaks allow partial energy system recovery during throw-ins, free kicks and tactical pauses.
  • These brief rests permit some phosphocreatine replenishment for the next explosive effort.
  • Energy system contributions vary by position, with central midfielders using more aerobic energy while wingers need more ATP-PCr for repeated sprints.
  • Fatigue increasingly affects system interplay as matches continue, with accumulated lactic acid and glycogen use reducing high-intensity actions in final stages.
  • Substitutions strategically introduce fresh energy systems when starters show declining performance.

HMS, BM EQ-Bank 161 MC

During a 400 m race at high intensity, an athlete experiences muscular fatigue. What is the main cause?

  1. Depletion of glycogen stores
  2. Accumulation of lactic acid
  3. Lack of oxygen
  4. Depletion of creatine phosphate
Show Answers Only

\(B\)

Show Worked Solution
  • B is correct: Lactic acid accumulation during high intensity glycolytic system use causes fatigue

Other Options:

  • A is incorrect: Glycogen depletion occurs over longer duration events
  • C is incorrect: Oxygen debt occurs after exercise completion
  • D is incorrect: CP depletion occurs in shorter activities under 10 seconds

HMS, BM EQ-Bank 143 MC

During a 400 metre race, an athlete experiences heavy legs and reduced performance in the final 100 metres. Which statement best explains this occurrence?

  1. Depletion of creatine phosphate stores
  2. Accumulation of lactic acid
  3. Insufficient oxygen supply
  4. Depleted glycogen stores
Show Answers Only

\(B\)

Show Worked Solution
  • B is correct: The glycolytic system produces lactic acid as a by-product causing fatigue

Other Options:

  • A is incorrect: CP stores are depleted in first 10 seconds
  • C is incorrect: Oxygen supply is limited but lactic acid accumulation is the main fatigue factor in 400m events
  • D is incorrect: Glycogen depletion occurs in much longer events