Module 4

Question 1

Which broad factors contribute to exercise non response?

Answer 1

• training parameters
• measurement methods
• genetics
• epigenetics

Question 2

What factors contribute to Measurement Error?

Answer 2

• Technical error of the measurement
• Test-retest reliability

Technical error refers to the inherent variability of the testing method, while test-retest reliability indicates the consistency of results when a test is repeated.

Question 3

How does Measurement Error impact the assessment of training effects?

Answer 3

If observed changes fall within the measurement error, it’s difficult to conclude if a true physiological change has occurred.

This can lead to misclassification of individuals as non-responders.

Question 4

What happens if the change in measured value is smaller than the error associated with the measurement?

Answer 4

Individuals might be labeled as non-responders.

This mislabeling can occur despite potential physiological changes that are not detected due to measurement error.

Question 5

What is heritability (H²)?

Answer 5

The amount of variance in a population accounted for by inherited genetic information

Heritability can vary with environmental factors.

Question 6

How is heritability estimated?

Answer 6

Based on relatedness of individuals and trait similarity

For instance, siblings share about 50% of their genes.

Question 7

What was the heritability estimate for aerobic trainability found in studies?

Answer 7

Around 50%

The HERITAGE family study supported this estimate.

Question 8

What do genome-wide association studies (GWAS) aim to identify?

Answer 8

Specific genes important for trainability

GWAS look for single nucleotide polymorphisms (SNPs) associated with training responses.

Question 9

What is a polygenic score?

Answer 9

A score that combines effects of multiple SNPs to estimate variance explained by DNA

These scores often do not align with heritability estimates and can overfit to specific populations.

Question 10

Which candidate genes have been associated with performance phenotypes?

Answer 10

ACE and ACTN3

These genes suggest a slight increased or decreased propensity for certain activities, but are not deterministic.

Question 11

What role does the environment play in exercise adaptation?

Answer 11

A significant role, often overestimated compared to genetics

Factors include diet, lifestyle, sleep, and epigenetics.

Question 12

What do twin studies suggest about exercise adaptation?

Answer 12

Most differences in adaptation may be due to environmental factors rather than genetic differences

This is indicated by comparing identical and fraternal twins raised in similar environments.

Question 13

What is the estimated heritability of aerobic trainability?

Answer 13

Around 50%

This indicates that approximately half of the variability in aerobic trainability can be attributed to genetic factors.

Question 14

What are the cons of using GWAS?

Answer 14

• need big samples to find rare variants
• only correlational
• polygenetic scores don’t reach H2
• there is little consensus
• risk of model overfit

Question 15

What does epigenetics refer to?

Answer 15

Changes to our genome that do not involve alterations to the underlying DNA sequence.

Question 16

List the epigenetic changes we discussed in class

Answer 16

• histones
• methylation
• micro RNA
• acetylation

Question 17

What is DNA methylation?

Answer 17

The addition of a methyl group to specific parts of our DNA, making it harder for those genes to be expressed.

Question 18

How does exercise affect DNA methylation?

Answer 18

Exercise can lead to hypomethylation, a reduction in methylation, allowing for increased gene transcription.

Question 19

What are histones?

Answer 19

Proteins that DNA wraps around, affecting how tightly the DNA is packaged.

Question 20

What is the effect of histone modifications?

Answer 20

They can affect gene transcription by altering the accessibility of DNA.

Question 21

What are microRNAs (miRNA)?

Answer 21

Small, non-coding RNA molecules that bind to mRNA and can inhibit protein production.

Question 22

How does exercise influence microRNA levels?

Answer 22

Exercise can affect the transcription of microRNAs.

Question 23

What role does the environment play in epigenetics?

Answer 23

Factors like exercise, diet, and lifestyle can lead to changes in DNA methylation, histone modifications, and microRNA levels.

Question 24

What is the concept of Developmental Origins of Health and Disease (DoHaD)?

Answer 24

The idea that the environment a developing fetus or baby is exposed to can have long-term health consequences.

Question 25

What did the Dutch Hunger Winter study demonstrate?

Answer 25

Individuals born during severe food scarcity had a higher likelihood of obesity and metabolic issues later in life, potentially due to epigenetic changes.

Question 26

What role do epigenetic modifications play in exercise adaptation?

Answer 26

They can lead to fluctuations in the epigenetic state, affecting gene transcription and resulting in training adaptations.

Question 27

How can exercise affect gene transcription for muscle growth?

Answer 27

Exercise can decrease methylation on certain genes, allowing for increased transcription necessary for muscle growth.

Question 28

Fill in the blank: Epigenetics provides a layer of regulation above and beyond our _______.

Answer 28

DNA sequence.

Question 29

True or False: Epigenetic modifications can influence our ability to adapt to training.

Answer 29

True.

Question 30

What is prediction in exercise science?

Answer 30

Forecasting how an individual will respond to a specific training program before starting ## Footnote Involves identifying pre-training characteristics that could indicate response levels.

Question 31

What is the current ability to predict individual responses to exercise?

Answer 31

Limited, especially for resistance training-induced hypertrophy ## Footnote Many factors remain uncertain, indicated by the phrase 'a lot of things with three question marks.'

Question 32

What are potential predictors for exercise response according to current evidence?

Answer 32

Limited evidence for pre-training markers, including: * Fibrotic muscle * Satellite cell population and capillarization * Fiber type * Genetic markers

Question 33

How does fibrotic muscle affect exercise response?

Answer 33

Individuals with very fibrotic muscle might be lower responders ## Footnote Fibrotic muscle has more collagen and extracellular matrix.

Question 34

What impact do satellite cell populations have on muscle gain?

Answer 34

Depleted satellite cell populations might not gain as much muscle ## Footnote Evidence primarily comes from older, potentially impaired populations.

Question 35

Does pre-training fiber type composition predict hypertrophy?

Answer 35

No, it does not consistently predict hypertrophy in studies ## Footnote More type II fibers do not guarantee greater muscle growth.

Question 36

What is the status of genetic markers in predicting exercise response?

Answer 36

GWAS have not reliably identified specific genes or polygenic scores with strong predictive value ## Footnote Many identified genes lack consistent replication across studies.

Question 37

What does postdiction of exercise response involve?

Answer 37

Looking back after a training intervention to explain differences in individual responses ## Footnote Provides insights into why some individuals respond differently than others.

Question 38

List all the potential postdictions for exercise response

Answer 38

* Muscle Protein Synthesis (MPS) * RNA Concentration * Androgen Receptors (AR) * Satellite Cells and Myonuclei * MicroRNA (miRNA) Response * Collagen and Extracellular Matrix (ECM) * Inflammation * Angiogenesis and Mitochondria

Question 39

What is a key factor that differentiates high responders in muscle gain?

Answer 39

Superior increases in both basal and post-exercise muscle protein synthesis ## Footnote Particularly evident after the initial adaptation phase.

Question 40

What role does RNA concentration play in muscle gain?

Answer 40

Gainers often show a greater ability to increase their RNA concentration ## Footnote Reflects an expansion of the ribosome pool and translational capacity.

Question 41

What is suggested about androgen receptors in high responders?

Answer 41

They may have higher pre-training androgen receptor content ## Footnote This group experiences greater training-induced increases in AR protein.

Question 42

How do satellite cells and myonuclei relate to muscle gain?

Answer 42

High responders might experience superior training-induced increases in satellite cell number and myonuclear addition ## Footnote This is particularly relevant for extreme hypertrophy.

Question 43

What is the 'bag full hypothesis' regarding ECM?

Answer 43

A poorly organized extracellular matrix might constrain muscle fiber expansion ## Footnote Non-responders may have ECM characteristics that limit remodeling.

Question 44

How does inflammation affect hypertrophy?

Answer 44

Chronically high baseline inflammation might hinder hypertrophy ## Footnote This is especially relevant for older adults or those with certain conditions.

Question 45

What is the relationship between angiogenesis and hypertrophic response?

Answer 45

Differences in capillarization and mitochondrial content/function are less clearly linked to hypertrophic response ## Footnote Very low levels might be limiting but are not consistently predictive.

Question 46

What challenges exist in accurately predicting exercise response?

Answer 46

Complexity and interplay of factors, along with individual variability in genetics, epigenetics, and environment ## Footnote Makes it difficult to predict who will be high or low responders.

Question 47

What might the concept of 'non-responders' indicate?

Answer 47

An insufficient training stimulus or focusing on a single outcome measure ## Footnote Individuals may still experience other beneficial adaptations to exercise.

Question 48

What strategies can elicit a response in initially perceived non-responders?

Answer 48

Increasing training volume and adjusting other training variables ## Footnote Often effective in eliciting a response.