Week 6 - Determinants of Muscle Force Flashcards
what 4 things determine the number of cross-bridges formed in a muscle ?
- length of the muscle (force-length)
- contraction velocity (force-velocity)
- level of activation
- time since onset of activation
define force-length relationship of a sarcomere
describes how the force of a sarcomere can produce changes with the length of the sarcomere
what happens with larger cross-sectional areas
more force
what happens with smaller cross-sectional areas
less force
define force-length relationship of a muscle
describes how the force of a muscle can produce changes according to the length of the contractile and elastic components of the muscle
define force-velocity relationship of a muscle
describes how the force a muscle can produce changes according to the velocity with which it is changing length
define level of activation
as activation increases, the level of force generated for a given length and given velocity increases
define force-time relationship
describes how force is developed over time in a muscle
what are the 3 phases of a twitch contraction ?
- latent period
- contraction phase
- relaxation phase
what are the 3 muscle types ?
- type I
- type IIa
- IIx
which type of muscle fibres are recruited fast for a contraction
small slow fibres (type I)
define axial muscles
- stabilisers
- short fibres, fatigue resistant
define distal limb muscles
- force producers and fine control
- moderate fibres, mixed fibre type
define proximal limb muscles
- movement producers
- long fibres, mixed fibre type
what are the 2 types of muscle fibre arrangements
- fusiform
- pennate
