muscular movement - lesson 5

Question 1

what is the all or none principle?

Answer 1

states that when a motor unit receives a neural impulse at the required threshold, all muscle fibers associated with that motor unit will contract at the same time with 100% force

Question 2

what happens when there is an impulse below the required threshold?

Answer 2

the motor unit isn’t activated = no muscle fibers contract

Question 3

what happens when there is a smaller motor unit?

Answer 3

more precise action

Question 4

what happens when there is a larger motor unit?

Answer 4

gross motor skills

Question 5

what happens when the force produced by a muscle is increased?

Answer 5

neural process > brain recognizes the need for greater force

1) increasing the number of motor units recruited by increasing the size of the stimulus
2) increasing the rate at which impulses are sent to the motor unit = motor unit firing repeatedly to increase the force generated

Question 6

describe motor unit recruitment

Answer 6

= process of the increasing the number of motor units firing to increase the force being generated

Question 7

what does the order of motor unit recruitment depend on?

Answer 7

• intensity

Question 8

describe the order of motor unit recruitment

Answer 8

• slow-twitch (type 1) have low activation levels + required first for light to moderate activity
• intensity increase = higher threshold units = fast twitch (type a) are recruited - slow twitch still activated
• peak force = fast twitch (type 2b) = fastest threshold = slow twitch and 2a still activated due to size of stimulus

Question 9

what is the neuromuscular response to strength training?

Answer 9

= improvements are 2-8 weeks without muscle size change = improvements in the neuromuscular level

• improved technique
• increased firing rate of motor units
• more motor units recruited
• firing pattern of motor units is better coordinated