Sex Differences in Skeletal Muscle Flashcards
1
Q
What is biological sex?
A
- Sex assigned at birth
2
Q
Compare female and male body compositon
A
- Males tend to have a higher % of muscle tissue
- Women have a higher % of essential and non-essential fats
- Males have a higher bone density
- ## Males may have a higher resting metabolic rate
3
Q
Describe the muscle fibre differences between sexes
A
- Strength and size of myscle differs between the sexes
- Similar pattern in old and young fibres
- Fibre distribution varies between males and females
- Dependent on the muscle
4
Q
Describe the strength and size of muscles between sexes
A
- Males tend to have larger and stronfer muscles compared to females
- When presented as a relative % difference are reduced
- Females are more fatigue resistant, possibly due to differences in fibre type distribution
- Fatigue differences are task specific
5
Q
Describe sex hormone profiles in relation to skeletal muscle
A
- Sex hormones can cross the blood brain barrier
- They can affect some of the nerve signal release from the brain to the muscle and impact how we use them
6
Q
Explain the difference in motor units and firing rates between sexes
A
- Men have a stronger muscle/force than women
- Firing rate was identified to be different between the sexes
- Motor unit potential = smaller at both contraction levels in females than males
- Recruitment strategies between contraction level are similar between sexes
7
Q
What are some significant findings of testosterone’s role in SKM?
A
- Has an anabolic impact on SKM
- Dehydroepiandrosterone (DHEA), DHEAS, the precursors of T (DHT), progressively decrease with ageing
- Some of the associated sex hormones demonstrate associations with MU firing rate
8
Q
What role does the menstrual cycle play in SKM?
A
- Can be used to identify the key parameters of muscle function that sex hormones may influence
- Number of key stages of MC are already eluded to
- No difference in muscular performance
- Differences at low level contractions firing rate but not firing rate variability
- Possibel influence of hormones at low level contractions
- Suggest a stronger influence of progesterone over oestrogen
9
Q
What are some muscle changes with age?
A
- Muscle reduces in size and strength with age
- Neuromuscular capacity of muscle also changes with age
10
Q
What is the correlation of exercise and muscle?
A
- Exercise can alleviate some of the muscle loss with age
- Both males and females can gain advantages in muscle no matter when they take up exercise
11
Q
Explain the role of neuromuscular function in exercise and muscle
A
- Long-term athletic training does not prevent age-related loss of muscle size, regardless of athletic discipline
- Physical activity into older age may facilitare more successful axxonal sprouting and reinervation of denervated dibres, preventing rapid loss of muscle strength
- These benefits may be localised to muscle most involved in the exercise regime
12
Q
Describe middle age and its influence on SKM
A
- Majority of declines begin to occur here
- Similar betwen men and women but firing rate differs
- Sex hormones could also influence neuromuscular adaptationns to exercise across the life span
- Menopause - key stage of life