Proprioception & kinesthesis

Question 1

What are proprioceptors?

Answer 1

internal receptors located in skin, joints, muscles, & tendons which provide feedback relative to tension, length, & contraction state of muscle, position of body & limbs, and movements of joints

Question 2

What is kinesthesis?

Answer 2

awareness of position & movement of the body in space

Question 3

Proprioceptors specific to muscles

Answer 3

• Muscle spindles

- Golgi Tendon organs (GTO)

Question 4

Muscle spindles

Answer 4

• concentrated primarily in muscle belly between the fibers

- sensitive to stretch & rate of stretch

Question 5

Golgi Tendon Organ (GTO)

Answer 5

• Found in tendon close to muscle tendon junction
• sensitive to both muscle tension & active contraction
• much less sensitive to stretch than muscle spindles
• require a greater stretch to be activated

Question 6

All or None Principle

Answer 6

regardless of number, individual muscle fibers within a given motor unit will either fire & contract maximally or not at all

Question 7

The number of muscle fibers recruited may be increase by ____

Answer 7

• activating those motor units with the greater number of muscle fibers
• activating more motor units
• increasing the frequency of motor unit activation

Question 8

What happens when muscle is contracting (concentrically or eccentrically)?

Answer 8

the rate of length change is significantly related to the amount of force potential

Question 9

What happens when muscle contracts concentrically against a light resistance?

Answer 9

Muscle is able to contract at a high velocity

Question 10

Muscle Force-Velocity Relationship

When resistance increases, _____

Answer 10

the maximal velocity at which muscle is able to contract decreases

Question 11

Muscle Force-Velocity Relationship

As load increases, _______

Answer 11

the velocity decreases to zero resulting in an isometric contraction

Question 12

Muscle Force-Velocity Relationship

As load increases beyond muscle’s ability to maintain isometric contraction, ______

Answer 12

the muscle begins to lengthen resulting in an eccentric contraction

Question 13

Biarticular muscles

Answer 13

cross & act on two different joints

Question 14

Advantages of biarticular muscles over uniarticular muscles

Answer 14

• can cause and/or control motion at more than one joint

- are able to maintain a relatively constant length due to “shortening” at one joint and “lengthening” at another joint

Question 15

Multiarticular muscles

Answer 15

act on three or more joints due to the line of pull between their origin and insertion crossing multiple joints

Question 16

Reciprocal inhibition

Answer 16

Antagonist muscles groups must relax & lengthen when the agonist muscle group contracts

Question 17

Active insufficiency

Answer 17

is reached when the muscle becomes shortened to the point that it cannot generate or maintain active tension

Question 18

Passive insuficiency

Answer 18

Is reached when the opposing muscles becomes stretched to the point where it ca no longer lengthen & allow movement