biomechanics of muscles

Question 1

muscle function

Answer 1

Maintenance of upright body posture
Movement of the trunk and limbs
Shock absorption

Question 2

extracellular matrix of muscle function

Answer 2

Support and protection, enabling the muscle to stretch safely and return to its resting length.
A pathway for neurovascular tissues to provide stimulation and nutrition for the muscle cells.
Smooth transmission of muscular force to bone via the tendon. (When muscle cell contracts and shortens, it pulls on the sarcolemma, which pulls on the endomysium, which pulls on the perimysium, which pulls on the epimysium, which pulls on the tendon.)

Question 3

biomecahnical properties

Answer 3

contractile component: convert electrical stimulation into force of a contraction

parallel elastic comp: supply resistance when a muscle is passively stretched (protection)

series elastic comp: act as a spring to store elastic energy when a tensed muscle is stretched

Question 4

type 1 sensory neurons in muscles

Answer 4

monitors the rate/velocity of stretch + the amount of stretch (stimulated by gamma motor neurons activating the contractile ends of the spindle)

Question 5

type 2 sensory neurons in muscles

Answer 5

monitors the amount of stretch (stimulated by the entire muscle being stretched)

Question 6

golgi tendon organ

Answer 6

monitors force or tension in the muscle to ensure the right amount of force is applied for a given load. The GTO protects the muscle from fatigue-induced contraction injuries by inhibiting the output of the alphamotor neuron to the muscles at the spinal cord. This is sometimes called the inverse stretch reflex.

Question 7

factors that influence muscle perfromance

Answer 7

size
moment arm
fibre arrangment
muscle lentgh
contraction velocisty
recruitment
fibre type

Question 8

muscle size

Answer 8

primary impact
physiological cross sectional area
area of a slice that passes through all muscle fibres

Question 9

moment arm

Answer 9

easy to produce torque and to produce force

Question 10

fibre arrangement

Answer 10

parallel - biceps .muscle length proportinal to fibre size

pennate- muscle length is not equal to muscle length, force genereate in a diff direction to muscle, smaller ROM

Question 11

muscle length

Answer 11

active insurficent
passive insurficent

strecthed shortnening cycle:
if procced a concentric muscle action with a stretch then increase the enrgy and force

Question 12

contraction velocity

Answer 12

max length velocity/ eccentric > max shortening/ concentric

Question 13

muscle fibre type

Answer 13

slow twitch- type 1-aerobic

fast twitch- type 2 ( type 2a// type 2b)- anerobic high forces and power

Question 14

type 1/ slow twitch muscle fibre

Answer 14

Small diameter
* Dark (mitochondria and more
myoglobin)
* Slow twitch (slow oxidative)
* Fatigue resistant
* More capillaries and higher O2
supply
* Aerobic metabolism due to the
presence of oxidative enzymes

Question 15

type 2/ fast twitch muscle fibre

Answer 15

Larger diameter
* Pale (less mitochondria and
myoglobin)
* Fast twitch (fast glycolitic)
* Faster to contract, stronger force
production but fatigue quickly
* Anaerobic metabolism

Question 16

viscoelasciticty