LifeSpan Muscle Changes - Lecture 33

Question 1

How does muscle mass develop through early life, adolescent and older age

Answer 1

Increase significantly in early life and then starts to decrease slightly through adolescent and older age.

Question 2

Is the change in muscle the same for everyone?

Answer 2

It’s different for those who are active their whole life and those are hardly active.

Question 3

What are the differences for those who exercise and don’t? (Muscle mass)

Answer 3

Those who exercise peak high and end high but those who don’t exercise won’t peak as high and will end low.

Question 4

What is the disability threshold?

Answer 4

Point in which we loser functional capacity.

Question 5

Independence?

Answer 5

Lose independence to do activities we once used to do

Question 6

How can disability threshold be held off for later in life?

Answer 6

Increase physical activity, occupational therapy, etc.

Question 7

What is the peak skeletal muscle mass for females?

Answer 7

20kg

Question 8

Peak skeletal muscle mass for males?

Answer 8

30kg

Question 9

Peak Height Velocity?

Answer 9

The point in which the muscle growth is the fastest. Earlier in women than men.

Question 10

Differences in gap of Composite Strength between males and females

Answer 10

Throughout puberty and after puberty men will have a larger gap in strength

Question 11

What is the trend between females and males in fat free mass?

Answer 11

Females tend to feel a plateau in FFM at around 14 while males experience it at around 17-18

Question 12

Percentage fat comparison

Answer 12

%BF decreases for males at 17 while for females it starts to increase at 14.

Question 13

How do males not have an increase in %BF?

Answer 13

Due to the increase in fat free mass (skeletal muscle) it offsets the increase in %BF

Question 14

What is the muscle mass trend in adult stages?

Answer 14

Men and women both decrease but men are still above in muscle mass.

Question 15

What age does peak muscle mass occur?

Answer 15

35

Question 16

What age does peak muscle mass start to deter?

Answer 16

45

Question 17

What are benefits of muscle strength in children?

Answer 17

Increase motor skills, increase PA participation, enhancing body composition changes and learning new skills

Question 18

What is the overall affect of muscle strength in children?

Answer 18

Life-long PA Participation and Health

Question 19

Sarcopenia

Answer 19

The relationship of increasing age and loss of muscle mass.

Question 20

How does Sarcopenia (the decline) happen more often? Risk factors

Answer 20

Through the presence of chronic disease and sedentary lifestyle.

Question 21

How do we mitigate the loss of muscle mass?

Answer 21

Slowed by regular PA participation; high intensity resistance training.

Question 22

In what ways does Sarcopenia affect muscle mass?

Answer 22

Size (atrophy) and fibre number

Question 23

Sarcopenia of Type 1 and Type 2 through Atrophy

Answer 23

Type 1: 1-25% decrease in cross sectional
Type 2: 25-50% decrease in cross sectional area

Question 24

Sarcopenia through number of fibres
(percentage loss throughout years)

Answer 24

50-70 yrs (1-2% per year)
70-80yrs (10-25%)
>80 yrs (40%)

Question 25

Is there a change in muscle fibre type through sarcopenia and aging?

Answer 25

No; aging does not alter overall fibre composition.

Question 26

Why is Type II likely to be more affected?

Answer 26

This is the functional one that we can easily grow through strength training, but the one we can easily lose through aging.

Question 27

What are potential mechanisms in which Sarcopenia happens?

Answer 27

Programmed Cell Losses, functional denervation, Metabolism, Nutrition, Hormones

Question 28

Programmed Cell Losses

Answer 28

Apoptosis (cell death) causes muscle fibres to be lost

Question 29

Functional Denervation

Answer 29

Motor Unit Recruitment decreases, so signalling to muscle fibres weakens

Question 30

Metabolic Implications

Answer 30

Rate of protein synthesis decreases as well as ATP production. Protein metabolism increases

Question 31

Sarcopenic-Obesity

Answer 31

Increase in %BF, decreases skeletal muscle which causes more fat than muscle

Question 32

Nutrition Implications

Answer 32

Inadequate nutrition causes protein synthesis to shift and not favour muscle production.

Question 33

Hormonal Implication

Answer 33

Reduction in testosterone reduces anabolic processes, which results in loss of muscle mass. Aging affects the effectiveness of anabolic hormones to target tissues

Question 34

What age does muscle strength start to peak?

Answer 34

Ages 25-35

Question 35

What age does muscle strength start to decline?

Answer 35

Around 40-49

Question 36

What is low muscle strength highly associated with?

Answer 36

Low functional activities

Question 37

Dose-response pattern of muscle strength

Answer 37

Older adults participate in more frequent and more intense PA increase muscle strength

Question 38

Dynapenia

Answer 38

Loss of muscle strength not muscle mass

Question 39

How much loss of Skeletal Muscle Mass explains loss of skeletal muscle strength?

Answer 39

6-10% overall through aging

Question 40

Where does the remaining 90% go?

Answer 40

Neuromuscular changes to muscle strength. Muscle strength declines much quicker than Muscle Mass

Question 41

Prevalence of dynapenia in Men

Answer 41

46-87%

Question 42

Prevalence of Dynapenia in Women

Answer 42

50-82%