phsyiology of strength and power

Question 1

muscle performance

Answer 1

neural activation + muscle tendon unit force

Question 2

reflexes

Answer 2

voluntary- slower
reflex- fast/sharp
golgi tendon organs- detect tension in muscles- protective mechanism against excessive tension
movement coordination- need the recpetord to be able to mpve in space and coordinate movement, help us to regulate force production
muscle spindles- stretch detectors that sense how much and how fast muscle is shortened or lengthened

Question 3

final common pathway

Question 4

size principle

Answer 4

size of motor unit
smaller motor units are recruited first then gets bigger as there is more force- orderly recruitment
twitch= response to an action potential
high force= higher frequency of twitches

as % peak forve increases, stimulus frequency will also increase

Question 5

post activation potentiation

Answer 5

if you perform maximal contraction for a few seconds, the twitch amplitide will increase
eg when athletes will jump before a 100m race

Question 6

control of muscle force

Answer 6

in order to increase force- recuit more motor units- in order to summate effects and increase force production
in some muscles- will recuit all muscle units at 50% of maximal force production

Question 7

rate coding

Answer 7

unit recruited last will not increase force by as much
first recruited units will produce higher discharge rates
in some cases, discharge rates will be much higher at the start and then drop greatly
how quickly units are recruited will dactate how much force the muscle can produce

Question 8

muscle fatigue

Answer 8

force production capacity is decreased with muscle fatigue
to maintain force level under fatigue- need to produce more muscle units + rate coding is adjusted
rate coding- have to increase the discharge frequency of motor units + cant rely on same motor units that were recruited from start

Question 9

motor unit vs muscle fibre

Answer 9

are seperate
motor unit- slow twitch, fast twitch fatigue resistant, fast twitch fatiguable

muscle fibre
slow twitch oxidative, fast twitch oxidative glycolytic, fast twitch glycolytic

Question 10

muscle mechanical properties

Answer 10

hill muscle model (picture in notes)
mechanical properties have a greater effect than fibre type on performance
arrangement of fibres- how fibres connect to skeleton

contractile element- interactions between myofilaments and generates the active force
serial elastic element (active)- elasticity in myofibrils, cross bridges and tendons
para elastic element (modulators)- connective tissue- transforms force from fibres onto the movement of the skeleton

Question 11

contractile element

Answer 11

serial elastic element- active- elasticity in myofibrils and cross bridges
passive- tendons
para elastic element- modulator- transforms force form fibres onto the moevment of the skeleton

Question 12

CE- force length relationship

Answer 12

single fibre- sarcomere movement- thick and thin filament overlap will determine how big a force a muscle fibre can produce
when a muscle is shortened, sarcomeres cannot work at their full capacity
when muscles are too lengthened, there wont be enough overlap to produce force

Question 13

whole muscle

Answer 13

medium muscle length- strongest
passive component- tenonds have a level of recoil which allows some force to be produced
at longer lengths there is greater contribution of tendon recoil so can produce greater forces

Question 14

muscle tendon unit- force length

Answer 14

produces torque
depends on muscle force length relationship- can train this but angles are genetically determined

Question 15

force velocity relationship

Answer 15

single fibre/ muscle - relationship will be skewed towards a lower velocity
low load- muscle contraction and fibre is much quicker than with a higher laod
high force- low velocity
some movements will require more velocity but wont be able to produce as much force
increasing the temp of a muscle will shift the FV relationship up- can produce more power
can also shift with training

Question 16

length dependency

Answer 16

concentric action- when lifting a load, muscle fibres are shortening, performing action fast but cant produce as much force
eccentric action - velocity doesnt effect on this action- lengthening muscle can depend on tendon recoil (can lower a load fast and doesnt need as much force)
muscle joint action- to increase force production (power) need to shift curve to the right to increase force and velocity

Question 17

muscle mechanical properties

Answer 17

in series- muscle production is maximised, will maximise velocity of force production
in parallel- maximising force, trying to increase hypertrophy, will make muscle thicker