velocity + muscular contraction - lesson 3

Question 1

describe the force-velocity relationship during a concentric contraction (muscle shorten)

Answer 1

concentric muscle contraction with a low velocity means a greater force can be produced

Question 2

reasons why the relationship between velocity and force occurs in a concentric contraction

Answer 2

• extra time available allows for more cross bridges to attach to and pull the actin myofilaments in order to shorten each sarcomere
• more motor units are able to be activated simultaneously = greater force generation

Question 3

what is the force-velocity relationship in an eccentric contraction?

Answer 3

as force increases velocity increases

muscles can resist an increased force with an increased velocity of eccentric contraction

Question 4

what is the force-velocity relationship in an isometric contraction?

Answer 4

• the greatest amount of force can be developed during an isometric contraction
• there is no movement so myosin and actin are held firmly together
• greatest amounts of cross-bridges and motor units are engaged

Question 5

at what muscle length can the greatest force be generated?

Answer 5

• towards the middle of the joints range (resting length) as this allows for max attachment of cross-bridges
• actin is neither too far away from myosin nor overlapping each other

Question 6

how much force can be produced when the muscle is fully lengthened?

Answer 6

will not be able to generate large force as only a few of the cross-bridges will be able to reach actin filaments

Question 7

how much force can be produced when the muscle is fully shortened?

Answer 7

will produce the least force as actin and myosin have reached their limit on sliding over each other and actin filaments partially overlap, covering cross-bridge binding sites