Resistance Training 2 Flashcards
Mastery
what motor units does one recruit with increased fatigue
which of the MU have higher growth potential from resistance training
how hard must you train to recruit the best growing MUS
more motor units are recruited and larger fatigue recruits FF
fast twitch motor units have higher growth potential than slow
we must get close to failure to recruit those motor units
two types of muscle growth
which is more beneficial to muscle growth
two types of hypertrophy
hypertrophy: increase in size of muscle fibres
Hyperplasia: increase in the NUMBER of muscle fibres
hypertrophy is the main way muscles grow
Myofibrillar and sarcoplasmic
Myofibrillar: increase in number of myofibrils in one fibres
sarcoplasmic: growth of sarcoplasm, non contractile portions
why does hypertrophy occur
what rate must be greater than the rate of protein breakdown
muscle hypertrophy must come from a net increase in the amount of protein in the muscle
the rate of protein synthesis must be larger than the rate of protein breakdown
how is mTOR used is Translation
what can individual exercise bouts do
what can repeated ones do
what do long term adaptations come from
used to regulate ribosomal biogenesis
increase mRNA expression and protein synthesis
result in an accumulation of protein
cumulative effects of many bouts
signalling pathways in muscle hypertrophy
why is mechanical tension important
TWO main signal pathways
downstream targets shift muscle protein balance to favor synthesis over degradation
important in muscle hypertrophy
mTOR= crucial element in increasing protein synthesis following resistance training. important signal molecule in hypertrophy induced in loading
Ca2+ = thru muscle activation acts as a signal molecule for increased protein synthesis thru its activation of MANY signal pathways.
increases muscle protein synthesis
Parallel and serial hypertrophy
if a sarcomere increase is length or in series, what happens to velocity and force output
Parallel hypertrophy = radial growth
* Increased fibre width
* Increased force production capacity
Serial hypertrophy = longitudinal growth
* Increased fibre/fascicle length
* Results from adding more sarcomeres in series (sarcomerogenesis)
* Increased shortening velocity/power
production capacity
more sarcomeres allows for a greater max shortening velocity
individual sarcomeres wont have the shorten as fast
this means that at the same velocity compared to other sarcomeres with less in succession, serial will produce more force
mechanical tension
metabolic stress
muscle damage
Mechanical tension
* Forces experienced by muscle fibres
* Most important factor in training-induced
muscle hypertrophy
Metabolic stress
* Exercise-induced accumulation of
metabolites
* E.g., inorganic phosphate, H+, lactate
* Associated with fatigue
Muscle damage
* Can set off series of subsequent reactions
* e.g., inflammation, satellite cell infiltration,
release of growth factors,
mechanical tension and muscular activation
Tension vs. Activation: Tension and activation may have different effects on muscle protein synthesis.
mTOR Pathway: Tension alone can activate mTOR, a key regulator of protein synthesis, even without muscle activation.
Optimal Muscle Growth: For maximum protein synthesis, both muscle tension and activation (via calcium) are necessary.
muscle damage in hypertrophy
metabolic stress in hypertrophy
Blood flow restriction
muscle damage triggers repair through protein synthesis, it doesn’t always result in overall muscle gain. Other factors, like tension, also play a role in hypertrophy.
high rates of anaerobic energy lead to buildup of metabolites. metabolic stress can play a role in hypertrophy
- increased fibre recruitment and more hormones can lead to increased muscle growth.
put a cuff on leg of arm to reduce blood flow, so more metabolites, can grow muscle with less load, rehab
