Muscle Ageing Flashcards
Does strength loss appear greater for upper or lower body?
lower body - 40% decline
upper body - 33% decline
Muscle power decreases, what does this mean in older people?
Fall likelihood increases.
What underlies the functional declines with age?
1) A loss of Muscle mass -sarcopenia /muscle atrophy
2) Muscle quality is reduced
3) Neuromuscular alterations
The average rate of muscle mass loss after 40 years old is approximately?
8% per decade or 0.5 to 1% per annum until 70 years old
What is the average rate of muscle mass loss past 70 years?
~15 % per decade
When does the regression line slope start (age)?
∼45 years old for both men and women
declines more rapidly after 70 years old
Is the muscle relative to body mass slope of regression steeper in women or men?
Men
What atrophies faster, type I or type II fibres?
Type II
What is greater, losses in muscle strength or muscle loss?
Losses in muscle strength are FAR greater
What happens to % of muscle in muscle with ageing?
Ageing increases fat accumulation in muscle, more fat less muscle WITHIN muscle!
What happens to motor units with age?
Increased age = less motor units
What does less motor units = ?
Less motor units = less force
What is denervation?
Where what was previously a type II fibre, is now innervated by a type I fibre. Therefore this type II fibre starts to behave more like a type I fibre
Complete denervation = type II fibre loss
Does a larger MU = more efficient?
No, less efficient
Can atrophying fibres be reinnervated by remaining MU’s?
Yes but it creates larger MUs.
