October 27, 2023 Flashcards
where are Satellite cells located
underneath the basal lamina
what happens with regards to resistance exercise and cell nuclei donation
With resistance exercise, cells donate nuclei to the contracting muscle cell increasing its capacity for gene expression
Fusion of satellite cells to the muscle cell membrane causes what
“adds” nuclei to the cell, increasing the capacity for gene expression and protein synthesis (hypertrophy)
Explain Neural and Muscular Adaptations to Resistance Training
You can see strength gains independent of changes in the size of the muscle fibres - this is neural adaptations since you don’t see it at the muscular level
In the beginning You can increase strength with minimal hypertrophy
what is the Evidence for neural adaptations:
explain why this happens
Training 1 leg only leads to strength gains in other leg
Due to An increase in synchronization and recruitment of motor units (all working together at once)
Detected using EMG
what are the 5 Adaptations to Muscle Disuse/Inactivity
Fibre atrophy (all fibres, but especially Type IIa and Type I fibres)
Decreased capillary:fibre ratio (impacts endurance)
Decreased mitochondria (impacts endurance)
Greater reliance on anaerobic glycolysis and low-oxidative type IIx fibres
Decrease in strength and endurance
what are the three Phenotype adaptation characteristics:
Fibre type (myosin type)
Hypertrophy, atrophy, or no change
Oxidative capacity of muscle (mitochondria/endurance)
is there change in type I to type II ratio in endurance trained people?
No change in type I to type II ratio in endurance trained people (however there is a decrease in type IIx and an increase in type IIa)
is there change in type I to type II ratio in detrained people
No change in type I to type II ratio in detrained people (however there is atrophy in type IIa fibres)
Lack of activity turns on the activation of type IIx myosin ATPase
is there change in type I to type II ratio in strength trained people
No change in type I to type II ratio in strength trained people (same as endurance trained people)
So can fiber types be converted (transformed) by chronic exercise
Fast twitch fibres (II) can be converted to slow twitch fibres (I) only through extreme endurance training (8-10 hours a day; not in humans)
can all fibres be made more oxidative with training?
yes all fibers be made more oxidative with training, by increasing mitochondrial content
under the condition that you recruit them during exercise
so if you’re jogging at 50% of VO2 max all the time, you;re never recruiting type IIX fibres, they will not become more oxidative
can all fibres atrophy with disuse or lose of innervation?
yes all fibres atrophy with disuse or lose of innervation, some fiber types more than others
can all fibres hypertrophy if recruited with appropriate stimulus
yes all fibres hypertrophy if recruited with appropriate stimulus
is the process of changing contractile speed a more “resistant” transformation of fibres with regular training?
yes the process of changing contractile speed is a more “resistant” transformation of fibres with regular training?
