Copy of 10.06.20 - Types of Muscle Fibers (5/28/2026)

Last updated about 2 hours ago

29 questions

1

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Copy of 10.06.20 - Types of Muscle Fibers (5/28/2026)

Last updated about 2 hours ago

29 questions

Types of Muscle Fibers
Objectives:
distinguish between slow twitch and fast twitch muscle fibers in skeletal muscle.
distinguish between aerobic resipration and anaerobic respiration in skeletal muscle.
determine how aerobic and anaerobic respiration relate to the different types of muscle fibers.

Why?

Which are you better at: Sprinting for a short distance or running for a long distance? Are you decent at both?

Within skeletal muscles are different types of muscle fibers (muscle cells), each with their own set of characteristics and specialties.  In this activity, you'll learn the difference between aerobic and anaerobic respiration and why different types of muscle cells have different methods of using energy.  You'll also investigate the effects of athletic training on muscle cells.

1

What do you think of when you hear the word 'aerobics?'

1

Make an educated guess: Can you gain muscle fibers by exercising more?

1

Make an educated guess: How do you think muscles grow in size?

1

Make an educated guess: Why might it be common to be REALLY sore after working out for the first time in a while?

1

Make an educated guess: What might happen to someone's heart rate and breathing rate after a period of exercise? Why?

Part 1: Aerobic and Anaerobic Respiration
Before we can talk about different types of muscle fibers, we need to talk about the different ways in which your body makes and uses ATP.

Watch the video below, then answer questions 6-7.

(Do not worry about the end of the video - I won't ask about plants!)

1

Examine the diagram and passage below from our textbook.

Sources of ATP

1

Part 2: Type I and Type II Muscle Fibers
Visit the following website.  Read through it, then use it to answer questions 11-16.

Fast and Slow Twitch Muscle Fiber with Performance

1

Part 3: Aerobic and Anaerobic Exercise
Visit the following website.  Read through it, then use it to answer questions 17-20.

Aerobic and Anaerobic Exercise

1

Draw two examples of aerobic exercises and two examples of anaerobic exercises NOT provided on the website or in the question above.

1

Compare and contrast the benefits of both aerobic and anaerobic exercise.

1

As one's heart rate and breathing rate increase during exercise, are they more likely to be doing aerobic or anaerobic exercise? Explain.

1

Watch the following video of the finish line at the 1997 Ironman World Championship:

Both of these athletes "hit the wall" or "bonk" at the end of the race. You may have heard this term before, or even experienced it for yourself:

Hit the Wall - In endurance sports such as cycling and running, hitting the wall or the bonk is a condition of sudden fatigue and loss of energy which is caused by the depletion of glycogen stores in the liver and muscles. Milder instances can be remedied by brief rest and the ingestion of food or drinks containing carbohydrates. (retrieved from Wikipedia)

In your own words, describe what is happening to the muscle fibers in athletes when they "hit the wall." Think about and include information from today's lesson!

Part 4: Extension Questions
Visit the page below about athletic training and different types of muscle fibers.  After reading through the page, answer questions 22-25.

Developing Fast-Twitch Muscle Fibers

1

Can muscle fibers be "changed" into different types of muscle fibers? Explain your answer.

1

Extension: Examine the picture from the website:

Which type of chicken meat do you like more: dark meat or light meat? (If you are a vegetarian - good for you! Seriously, its way better for the environment, and I applaud your efforts. Just bear with me and pick one :))
The light meat tends to come from the breast and wings of a chicken, while the dark mean tends to come from the legs of a chicken. Considering the picture above, explain WHY that part of the bird might have the types of muscle fibers that it does.

Revisiting your educated guesses from the beginning of the lesson.

Skim through / use the reading from your textbook to answer the following questions: Exercise and Muscle Performance

1

Why might it be common to be REALLY sore after working out for the first time in a while? Be specific!

1

What might happen to someone's heart rate and breathing rate after a period of exercise? Why? Be specific!!!

Types of Muscle Fibers
Objectives:
distinguish between slow twitch and fast twitch muscle fibers in skeletal muscle.
distinguish between aerobic resipration and anaerobic respiration in skeletal muscle.
determine how aerobic and anaerobic respiration relate to the different types of muscle fibers.

Why?

Which are you better at: Sprinting for a short distance or running for a long distance? Are you decent at both?

Within skeletal muscles are different types of muscle fibers (muscle cells), each with their own set of characteristics and specialties.  In this activity, you'll learn the difference between aerobic and anaerobic respiration and why different types of muscle cells have different methods of using energy.  You'll also investigate the effects of athletic training on muscle cells.

What do you think of when you hear the word 'aerobics?'

Make an educated guess: Can you gain muscle fibers by exercising more?

Make an educated guess: How do you think muscles grow in size?

Make an educated guess: Why might it be common to be REALLY sore after working out for the first time in a while?

Make an educated guess: What might happen to someone's heart rate and breathing rate after a period of exercise? Why?

Part 1: Aerobic and Anaerobic Respiration
Before we can talk about different types of muscle fibers, we need to talk about the different ways in which your body makes and uses ATP.

Watch the video below, then answer questions 6-7.

(Do not worry about the end of the video - I won't ask about plants!)

Which of the following most accurately describes why muscle cells contain more mitochondria than other cells in the body?

Muscle cells need more energy than other cells.

Mitochondria are the powerhouse of the cell

Muscle cells need more power than other cells

Mitochondria produce ATP, and ATP is needed in order for muscles to contract.

Categorize the following characteristics of anaerobic and aerobic respiration

Produces carbon dioxide and water
Requires oxygen
Produces a large amount of energy (ATP)
Does not require oxygen
Produces a small amount of energy (ATP)
Uses glucose
Produces lactic acid

Aerobic Respiration
Anaerobic Respiration

Examine the diagram and passage below from our textbook.

Sources of ATP

What is diagram (a) displaying?

Muscles at rest store small amounts of creatine phosphate.  When a signal for contraction reaches the resting muscle, the creating phosphate is used up quickly.  Some creating phosphate is used to make ATP, which can make a small amount of ADP.

In order for the mitochondria to produce a large amount of ATP, multiple substances must be available: especially oxygen and glucose.  When the mitochondria have enough oxygen and glucose, a large amount of ATP is produced (along with CO2 and H2O)

Muscles at rest store small amounts of ATP.  When a signal for contraction reaches the resting muscle, the ATP is used up quickly.  Some ATP is used to make creatine phosphate, which can then be used to make a small amount of ATP.

Some sugars (glucose and glycogen) are present in the bloodstream and muscles. This glucose can be transported to muscle tissue to make a small amount of ATP and pyruvate.  If oxygen is available, a large amount of ATP can be made using aerobic respiration.  If no oxygen is present, a small amount of ATP and lactic acid are produced.

What is diagram (b) displaying?

Some sugars (glucose and glycogen) are present in the bloodstream and muscles.  If oxygen is available, a small amount of ATP can be made using anaerobic respiration.  If no oxygen is present, a large amount of ATP and lactic acid are produced.

Some sugars (glucose and glycogen) are present in the bloodstream and muscles. This glucose can be transported to muscle tissue to make a small amount of ATP and pyruvate.  If oxygen is available, a large amount of ATP can be made using aerobic respiration.  If no oxygen is present, a small amount of ATP and lactic acid are produced.

Muscles at rest store small amounts of ATP.  When a signal for contraction reaches the resting muscle, the ATP is used up quickly.  Some ATP is used to make creatine phosphate, which can make a small amount of ATP.

In order for the mitochondria to produce a large amount of ATP, multiple substances must be available: especially oxygen and glucose.  When the mitochondria have enough oxygen and glucose, a large amount of ATP is produced (along with CO2 and H2O)

What is diagram (c) displaying?

Some sugars (glucose and glycogen) are present in the bloodstream and muscles.  If oxygen is available, a small amount of ATP can be made using anaerobic respiration.  If no oxygen is present, a large amount of ATP and lactic acid are produced.

In order for the mitochondria to produce a large amount of ATP, multiple substances must be available: especially oxygen and glucose.  When the mitochondria have enough oxygen and glucose, a large amount of ATP is produced (along with CO2 and H2O)

Muscles at rest store small amounts of ATP.  When a signal for contraction reaches the resting muscle, the ATP is used up quickly.  Some ATP is used to make creatine phosphate, which can make a small amount of ATP.

In order for the mitochondria to produce a large amount of ATP, multiple substances must be available: especially carbon dioxide (CO2) and glucose.  When the mitochondria have no or glucose, they can produce ADP using aerobic respiration.  Oxygen is also produced.

Part 2: Type I and Type II Muscle Fibers
Visit the following website.  Read through it, then use it to answer questions 11-16.

Fast and Slow Twitch Muscle Fiber with Performance

What is another name for type I muscle fibers?

Intermediate fast twitch

Slow twitch

Fast twitch

What is the function of type I muscle fibers?

Generate ATP using both aerobic and anaerobic respiration for long periods of muscle contraction

Generate ATP using both aerobic and anaerobic respiration for short periods of muscle contraction

Generate ATP using aerobic respiration for long periods of muscle contraction

Generate ATP using anaerobic respiration for short bursts of muscle contraction

What is another name for type II muscle fibers?

Intermediate fast twitch

Fast twitch

Slow twitch

What is the function of type II muscle fibers?

Generate ATP using both aerobic and anaerobic respiration for long periods of muscle contraction

Generate ATP using aerobic respiration for long periods of muscle contraction

Generate ATP using anaerobic respiration for short bursts of muscle contraction

Generate ATP using both aerobic and anaerobic respiration for short periods of muscle contraction

There are two types of fast twitch muscle fibers: IIa and IIb

Use anaerobic respiration only
Contracts with the most force
"Classic" fast twitch
Intermediate fast twitch
Fatigues quickly
Use both anaerobic and aerobic respiration

Type IIa
Type IIb

Consider your understanding of aerobic and anaerobic respiration and the different muscle fiber types. Place the following muscle fiber types in order of most mitochondria --> least mitochondria.

Type I
Type IIa
Type IIb

Part 3: Aerobic and Anaerobic Exercise
Visit the following website.  Read through it, then use it to answer questions 17-20.

Aerobic and Anaerobic Exercise

Translates to "exercise with oxygen"
Translates to "exercise without oxygen"
Example: cross country running
Example: lifting heavy weights
Can be sustained for long periods of time
Example: 100 m sprint
Example: open water swimming
Can be sustained for short periods of time

Aerobic exercise
Anaerobic exercise

Draw two examples of aerobic exercises and two examples of anaerobic exercises NOT provided on the website or in the question above.

Compare and contrast the benefits of both aerobic and anaerobic exercise.

As one's heart rate and breathing rate increase during exercise, are they more likely to be doing aerobic or anaerobic exercise? Explain.

Watch the following video of the finish line at the 1997 Ironman World Championship:

Both of these athletes "hit the wall" or "bonk" at the end of the race. You may have heard this term before, or even experienced it for yourself:

Hit the Wall - In endurance sports such as cycling and running, hitting the wall or the bonk is a condition of sudden fatigue and loss of energy which is caused by the depletion of glycogen stores in the liver and muscles. Milder instances can be remedied by brief rest and the ingestion of food or drinks containing carbohydrates. (retrieved from Wikipedia)

In your own words, describe what is happening to the muscle fibers in athletes when they "hit the wall." Think about and include information from today's lesson!

Part 4: Extension Questions
Visit the page below about athletic training and different types of muscle fibers.  After reading through the page, answer questions 22-25.

Developing Fast-Twitch Muscle Fibers

What is the primary factor in determining how many fast-twitch and slow-twitch fibers a person has?

A person's DNA

How often they participate in distance exercise

How often they lift weights

Diet

What is the average distribution of muscle fibers in the average human?

About 50% fast twitch and 50% slow twitch

About 30% fast twitch and 70% slow twitch

About 70% fast twitch and 30% slow twitch

Approximately 100% slow twitch.  Fast twitch fibers must be made.

Can muscle fibers be "changed" into different types of muscle fibers? Explain your answer.

Extension: Examine the picture from the website:

Which type of chicken meat do you like more: dark meat or light meat? (If you are a vegetarian - good for you! Seriously, its way better for the environment, and I applaud your efforts. Just bear with me and pick one :))
The light meat tends to come from the breast and wings of a chicken, while the dark mean tends to come from the legs of a chicken. Considering the picture above, explain WHY that part of the bird might have the types of muscle fibers that it does.

Revisiting your educated guesses from the beginning of the lesson.

Skim through / use the reading from your textbook to answer the following questions: Exercise and Muscle Performance

Can you gain muscle fibers by exercising more?

No, you can only increase the number of myofibrils in a muscle fiber

Yes - you can gain more Type I and Type II

Yes - You can gain Type II only

No, the number of muscle fibers can decrease but not increase.

How do muscles grow in size?

Muscles can not grow in size

Fascicles are added to the muscles

Proteins are added to the muscle fibers

Muscle fibers are added to the fascicles

Why might it be common to be REALLY sore after working out for the first time in a while? Be specific!

What might happen to someone's heart rate and breathing rate after a period of exercise? Why? Be specific!!!

Which of the following most accurately describes why muscle cells contain more mitochondria than other cells in the body?

Muscle cells need more energy than other cells.

Mitochondria are the powerhouse of the cell

Muscle cells need more power than other cells

Mitochondria produce ATP, and ATP is needed in order for muscles to contract.

Categorize the following characteristics of anaerobic and aerobic respiration

Produces carbon dioxide and water

Requires oxygen

Produces a large amount of energy (ATP)

Does not require oxygen

Produces a small amount of energy (ATP)

Uses glucose

Produces lactic acid

Aerobic Respiration

Anaerobic Respiration

What is diagram (a) displaying?

Muscles at rest store small amounts of creatine phosphate.  When a signal for contraction reaches the resting muscle, the creating phosphate is used up quickly.  Some creating phosphate is used to make ATP, which can make a small amount of ADP.

In order for the mitochondria to produce a large amount of ATP, multiple substances must be available: especially oxygen and glucose.  When the mitochondria have enough oxygen and glucose, a large amount of ATP is produced (along with CO2 and H2O)

Muscles at rest store small amounts of ATP.  When a signal for contraction reaches the resting muscle, the ATP is used up quickly.  Some ATP is used to make creatine phosphate, which can then be used to make a small amount of ATP.

Some sugars (glucose and glycogen) are present in the bloodstream and muscles. This glucose can be transported to muscle tissue to make a small amount of ATP and pyruvate.  If oxygen is available, a large amount of ATP can be made using aerobic respiration.  If no oxygen is present, a small amount of ATP and lactic acid are produced.

What is diagram (b) displaying?

Some sugars (glucose and glycogen) are present in the bloodstream and muscles.  If oxygen is available, a small amount of ATP can be made using anaerobic respiration.  If no oxygen is present, a large amount of ATP and lactic acid are produced.

Some sugars (glucose and glycogen) are present in the bloodstream and muscles. This glucose can be transported to muscle tissue to make a small amount of ATP and pyruvate.  If oxygen is available, a large amount of ATP can be made using aerobic respiration.  If no oxygen is present, a small amount of ATP and lactic acid are produced.

Muscles at rest store small amounts of ATP.  When a signal for contraction reaches the resting muscle, the ATP is used up quickly.  Some ATP is used to make creatine phosphate, which can make a small amount of ATP.

In order for the mitochondria to produce a large amount of ATP, multiple substances must be available: especially oxygen and glucose.  When the mitochondria have enough oxygen and glucose, a large amount of ATP is produced (along with CO2 and H2O)

What is diagram (c) displaying?

Some sugars (glucose and glycogen) are present in the bloodstream and muscles.  If oxygen is available, a small amount of ATP can be made using anaerobic respiration.  If no oxygen is present, a large amount of ATP and lactic acid are produced.

In order for the mitochondria to produce a large amount of ATP, multiple substances must be available: especially oxygen and glucose.  When the mitochondria have enough oxygen and glucose, a large amount of ATP is produced (along with CO2 and H2O)

Muscles at rest store small amounts of ATP.  When a signal for contraction reaches the resting muscle, the ATP is used up quickly.  Some ATP is used to make creatine phosphate, which can make a small amount of ATP.

In order for the mitochondria to produce a large amount of ATP, multiple substances must be available: especially carbon dioxide (CO2) and glucose.  When the mitochondria have no or glucose, they can produce ADP using aerobic respiration.  Oxygen is also produced.

What is another name for type I muscle fibers?

Intermediate fast twitch

Slow twitch

Fast twitch

What is the function of type I muscle fibers?

Generate ATP using both aerobic and anaerobic respiration for long periods of muscle contraction

Generate ATP using both aerobic and anaerobic respiration for short periods of muscle contraction

Generate ATP using aerobic respiration for long periods of muscle contraction

Generate ATP using anaerobic respiration for short bursts of muscle contraction

What is another name for type II muscle fibers?

Intermediate fast twitch

Fast twitch

Slow twitch

What is the function of type II muscle fibers?

Generate ATP using both aerobic and anaerobic respiration for long periods of muscle contraction

Generate ATP using aerobic respiration for long periods of muscle contraction

Generate ATP using anaerobic respiration for short bursts of muscle contraction

Generate ATP using both aerobic and anaerobic respiration for short periods of muscle contraction

There are two types of fast twitch muscle fibers: IIa and IIb

Use anaerobic respiration only

Contracts with the most force

"Classic" fast twitch

Intermediate fast twitch

Fatigues quickly

Use both anaerobic and aerobic respiration

Type IIa

Type IIb

Consider your understanding of aerobic and anaerobic respiration and the different muscle fiber types.  Place the following muscle fiber types in order of most mitochondria --> least mitochondria.

Type I

Type IIa

Type IIb

Translates to "exercise with oxygen"

Translates to "exercise without oxygen"

Example: cross country running

Example: lifting heavy weights

Can be sustained for long periods of time

Example: 100 m sprint

Example: open water swimming

Can be sustained for short periods of time

Aerobic exercise

Anaerobic exercise

What is the primary factor in determining how many fast-twitch and slow-twitch fibers a person has?

A person's DNA

How often they participate in distance exercise

How often they lift weights

Diet

What is the average distribution of muscle fibers in the average human?

About 50% fast twitch and 50% slow twitch

About 30% fast twitch and 70% slow twitch

About 70% fast twitch and 30% slow twitch

Approximately 100% slow twitch.  Fast twitch fibers must be made.

Can you gain muscle fibers by exercising more?

No, you can only increase the number of myofibrils in a muscle fiber

Yes - you can gain more Type I and Type II

Yes - You can gain Type II only

No, the number of muscle fibers can decrease but not increase.

How do muscles grow in size?

Muscles can not grow in size

Fascicles are added to the muscles

Proteins are added to the muscle fibers

Muscle fibers are added to the fascicles