S2L3 Physiology of strength and power Flashcards
1
Q
What 2 inputs lead to the production of force? where are the receptors located in the muscle?
A
- Reflexes - fast
- voluntary actions - slow
- muscle spindles – changes in length and rate of change
- GTO – sensation of muscle.
2
Q
What does a motor unit consist of?
A
- alpha motor neurone
- axon
- fibres it innovates – innervation ratio = ratio between no. of fibres innovated by a single neurone
3
Q
How can an increase in force be achieved?
A
- recruitment of motor units – recruit more motor units to increase twitch size of summation of twitches
- rate coding– discharge a given set of units at a higher frequency
4
Q
What are the 3 components of muscle in Hill’s muscle model?
A
- Contraction element – active portion - muscle fibres contract
- serial element
- active component = elasticity in myofibroblasts + crossbridges
- passive component = tendons and aponeuroses - parallel elastic element (PE) – modulator that transmits the force from fibres onto skeleton
5
Q
What is the force-length relationship?
A
- single fibre – muscle shortened = sarcomeres cant operate at highest capacity, muscle too stretched = wont be sufficient overlap so need optimal resting length to produce max force
- whole muscle –longer length = increase contribution of tendon recall so higher forces
6
Q
What is the force-velocity relationship?
A
- single fibre/ muscle – high load = slower contraction to produce force
- velocity depends on length of muscle. no impact on eccentric actions.
7
Q
How does fibre arrangement affect contraction?
A
- in series = ROM + velocity is maximised
- in parallel = force is maximised
8
Q
How would you therefore maximise muscle mechanical properties?
A
- to maximise force - operate at half the length of muscle
- to maximise power - need a balance between force and velocity
- high velocity - sacrifices force
- high force - sacrifices velocity
