lecture 27 Flashcards
strength
max force that can be generated by a muscle or muscle group, through a full ROM.
so, by default what is strength also (3)
1 max voluntary contraction (MVC)
also called 1 repitition max (1RM)
is at a particular velocity (=slow)
what is the primary determinant of strength
muscle mass
is muscle mass absolute or relative to body mass?
both
how does the endocrine system influence muscle mass?
insulin - increase protein synthesis and decreases protein breakdown.
cortisol - promoting protein breakdown
GH - increase protein synthesis
what are the severak modulators on muscle to control its protein balance?
nutritional status
genetics
nervoud system activation
environmental factors
endocrine
PA
how do we generate more force?
use more or bigger muscles.
recruit more motor units (fastests and strongest fibres later)
increase firing frequency
decrease co-contraction of antagonists
6 reasons strength is important
health and wellnes
sport
occupational (how physically demanding it is and overuse)
prehibiltation and rehabilitation
hobby/preference
cofidence and self esteem
what is overuse of strength
Applying excessive force or strain on muscles and joints repeatedly, which can lead to injury or chronic pain
what happens to protein breakdown and synthesis in resistance ex
decrease protein breakdown and increase its synthesis.
what is the largest component of lean body mass?
muscle mass
glycolysis
what does resistance training do to muscle glycogen
decrease muscle glycogen via glycolysis.
how does resistance exercise help lessen major modifiable drivers of CHD and diabetes?
blood glucose regulation
blood insulin levels
blood pressure regulation
why do we measure strength? (5)
muscular function and functional capacity
identify weak muscle groups
inform training and rehab programs
pre and post measures from intervention
physiological profile
how could we identify weak muscle grops?
biodex
why might physiological profile be a problem?
when we need something specific, does not actually mean what we want it to mean.
what is a tensiometer
cheap and versatile to measure strength (only isometric). high reliability but low validity
isokinetic dynamometer
gives very precise info, safe, reliable, specific velocities and ranges; can have poor validity. (most tasks use multi joints so doesnt show just one)
1 RM
common, often isotonic. not so good for clinical population (can cause injury) high effort, not necessarily specific.
rule of thumb for calculating 1RmM
10RM ~66% 1RM for untrained
10RM ~75-80% 1RM for trained.
what is the neural adaptations time course in strength
first week - 1 month strength is because of neural adaptations.
after is because of hypertrophy
is muscle adaptation more or less with people with lower initial strength?
generally more
what genetics are relevant to muscle adaptation
fibre type proportions, alpha-actinin-3, myostatin, testosterone.
break down of stress - strain - adaptation. (protein synthesis)
mechanical strech - ^ IGF-1 - ^ Akt - ^ mTORC1 - protein synthesis
what actually is hypertrophy (what is happening)
more myofibrils (they split to form new ones) and bigger myofibrils. more nuclei and more satellite cells.
what is the 1/2 life of myofibrils
1-2 weeks
what happens is you restrict the blood when resistance training
you will not need as much mechanical tension.
other local effects with resistance training.
increase connectuve tissue
hypertrophy causes a dilution effect
increase enzyme concentrations
increase bone mineral content
can you have maxed out endurance levels and strength levels in muscles?
no
