muscles and exercise Flashcards
what mechanisms cam motor units use to produce more force?
increase discharge rate
increase motor unit recruitment
what is hypertrophy
an increase in muscle fibre size sue to addition of contractile proteins in the muscle cell
when protein synthesis is greater than protein breakdown
what doe hypertrophy depend on?
initial strength
duration of training programme
training technique
what is hyperplasia
an increase in the number of muscle fibres (evidence in animals but not humans)
which muscle fibre type as the greatest potential for hypertrophy
type II
what are the mechanisms of hypertrophy
-satellite cells activate when a muscle is injured. They fuse to damaged myofibre to repair the damage- increasing size of the fibre
-hormones and growth factors can promote increase in muscle mass
-mTOR (mammalian target of rapamycin) integrates hypertrophic input from mechanical signals and growth factors
what is anabolism
muscle gain
what is catabolism
muscle loss
how do we get muscle protein synthesis (MPS)
from food and exercise
how do we get muscle protein breakdown (MPB)
from starvation, stress, injury, illness and overexercise
what changes occur to a muscle following training
change in size of muscle fibres
changes in pennation angle (helps increase force)
how do you work out physical cross-sectional area (PCSA)?
(muscle mass x cosine of pennation angle) / (fibre length x muscle density)
