smc-5528-30-Causes of fatigue

HMS, BM 2015 HSC 10 MC

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

Lack of essential amino acids
Lack of muscle glycogen stores
Inability to re-synthesise phosphate creatine
Inability to convert carbohydrates to glycogen

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\(C\)

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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?

Dehydration
Accumulation of lactic acid
Depletion of muscle glycogen
Depletion of phosphate creatine

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\(D\)

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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.

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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.

♦♦ Mean mark 55%.

HMS, BM 2020 HSC 23

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)

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Predominant energy system used by this athlete

Source of fuel

Energy system duration

Cause of fatigue

Rate of recovery
Compare how anxiety and arousal may have affected the athlete’s performance
when competing in this 100-metre final. Provide examples to support your
answer. (4 marks)

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a.	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

b. Similarities:

Both anxiety and arousal can negatively impact the sprinter’s performance if levels become too high.
Both factors influence the athlete’s ability to execute optimal technique and can cause muscle tension that restricts smooth movement patterns during the race.

Differences:

Anxiety is a psychological state involving fear and worry about competitive outcome. High anxiety may cause the sprinter to overthink race strategy, leading to delayed reaction time from starting blocks and mental distraction affecting stride mechanics.
Arousal refers to physiological activation levels. Optimal arousal enhances alertness and muscle readiness for explosive starts. However, excessive arousal creates physical tension that reduces stride length and power output through restricted movement patterns.

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a.	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

b. Similarities:

Both anxiety and arousal can negatively impact the sprinter’s performance if levels become too high.
Both factors influence the athlete’s ability to execute optimal technique and can cause muscle tension that restricts smooth movement patterns during the race.

Differences:

Anxiety is a psychological state involving fear and worry about competitive outcome. High anxiety may cause the sprinter to overthink race strategy, leading to delayed reaction time from starting blocks and mental distraction affecting stride mechanics.
Arousal refers to physiological activation levels. Optimal arousal enhances alertness and muscle readiness for explosive starts. However, excessive arousal creates physical tension that reduces stride length and power output through restricted movement patterns.

♦♦ Mean mark 49%.

HMS, BM 2021 HSC 4 MC

What is the predominant energy system used by an athlete in a 400-metre running event?

Aerobic
ATP-PC
Phosphate
Lactic acid

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\(D\)

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D is correct: 400m primarily uses lactic acid system for duration.

Other Options:

A is incorrect: Too short for predominantly aerobic contribution.
B is incorrect: ATP-PC depleted after first 10-15 seconds.
C is incorrect: Phosphate system same as ATP-PC system.

HMS, BM 2024 HSC 22

Compare the by-products of TWO different energy systems. (4 marks)

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Sample Answer

Similarities:

Both ATP-PCr and glycolytic systems produce by-products during ATP generation.
Both by-products must be managed by the body for continued performance.

Differences:

ATP-PCr produces creatine and phosphate which cause no muscle fatigue or performance impairment.
Glycolytic system generates lactic acid which creates burning sensation and impairs muscle contraction.
ATP-PCr by-products remain in muscle cells for immediate reconversion within minutes.
Lactic acid must be transported via bloodstream to the liver for removal, taking much longer.
Chemical nature determines impact: harmless phosphates versus performance-limiting acid.

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Sample Answer

Similarities:

Both ATP-PCr and glycolytic systems produce by-products during ATP generation.
Both by-products must be managed by the body for continued performance.

Differences:

ATP-PCr produces creatine and phosphate which cause no muscle fatigue or performance impairment.
Glycolytic system generates lactic acid which creates burning sensation and impairs muscle contraction.
ATP-PCr by-products remain in muscle cells for immediate reconversion within minutes.
Lactic acid must be transported via bloodstream to the liver for removal, taking much longer.
Chemical nature determines impact: harmless phosphates versus performance-limiting acid.

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.

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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.

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.

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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.

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.

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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.

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.

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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.

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?

Depletion of phosphocreatine stores
Accumulation of lactic acid in the muscles
Depletion of muscle and liver glycogen
Increased use of fat as a fuel source

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\(B\)

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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 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.

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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.

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.

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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.

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.

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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.

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.

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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.

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.

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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.

HMS, BM EQ-Bank 186 MC

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

\begin{align*}
\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*}

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\(A\)

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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?

Accumulation of lactic acid
Depletion of ATP stores
Depletion of muscle glycogen
Insufficient oxygen availability

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\(A\)

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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.

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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.

HMS, BM EQ-Bank 161 MC

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

Depletion of glycogen stores
Accumulation of lactic acid
Lack of oxygen
Depletion of creatine phosphate

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\(B\)

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?

Depletion of creatine phosphate stores
Accumulation of lactic acid
Insufficient oxygen supply
Depleted glycogen stores

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\(B\)

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