MUSCLE MECHANICS TERMS

Question 1

a muscle that is known to be the principle mover or one of the principle movers of a lever

Answer 1

Agonist:

Question 2

a muscle that in contracting tends to produce movement opposite to that of an agonist

Answer 2

Antagonist:

Question 3

the bodies sense of position of its own parts

Answer 3

Proprioception:

Question 4

receptor located in muscle, tendons and joints that respond to mechanical changes within the body

Answer 4

Proprioceptor:

Question 5

muscle develops tension without changing length

Answer 5

Isometric contraction

Question 6

muscle changes length during contraction keeping tension near constant

Answer 6

Isotonic contraction

Question 7

occurs when a muscle develops sufficient tension to overcome resistance and shortens

Answer 7

Concentric contraction

Question 8

occurs when resistance is not overcome, but the muscle lengthens during the action

Answer 8

Eccentric contraction

Question 9

appear redder due to an increased amount of myoglobin present

Answer 9

Red muscles

Question 10

adapted to performing fast contractions

Answer 10

White muscles

Question 11

muscles having a larger moving component

Answer 11

Spurt muscles

Question 12

muscles having a larger stabilizing component than moving component

Answer 12

Shunt muscles

Question 13

Muscles relative to joints?

The lever arm in this situation stays the same throughout the motion

▪ See a change in length of the muscle altering the proximity of the origin to the insertion (insertion brought closer to origin)

Answer 13

Single joint muscles

Question 14

Muscles relative to joints?

Muscle will be maintained at or near its resting length, no change in the distance of origin to insertion

▪ However, the effective lever arm will change in this situation

Answer 14

Multi joint Muscle

Question 15

Mechanical efficiency?

Mechanical efficiency will be greater if the arrangement is a 3rd class lever

Long resistance arm and short effort arm magnify speed

More movement obtained with less muscle shortening increasing efficiency of contraction

Answer 15

Lever arm

Question 16

Mechanical efficiency?

The higher the angle of application of the muscle pull, the more efficient the contraction will be

Will see greater distance of movement of body part with a minimal amount of contraction

Answer 16

Angle of application

Question 17

Mechanical efficiency?

Multiple joint muscles are more efficient than single joint muscles

They act at each joint they pass over, with each joint acting as a pulley

Answer 17

Pulley

Question 18

name this example of elastic response

• At the end of midstance, the gastroc is stretched, eliciting the elastic response
• Contraction of the muscle lifts the heel and plantarflexes the foot

Answer 18

Gastrocnemius

Question 19

name this example of elastic response

• As the leg rotates the fibula moves in relation to the tibia
• This motion applies a stretch to the syndesmotic ligament between the two bones

Answer 19

Tibio-fibular syndesmosis

Question 20

name this example of elastic response

• When stretched during pronation, or decrease of the medial arch height, will elicit the elastic response and muscles
that supinate the foot will counteract the pronation

Answer 20

Spring ligament (AKA inferior calcaneonavicular ligament)

Question 21

name this example of elastic response

• When elastic response is elicited it promotes muscles to rotate these portions in opposite directions

Answer 21

Upper trunk in gait rotates opposite of the lower trunk

Question 22

When a muscle is stretched or contracted, at a certain point the tension capacity of the muscle slowly decreases

Answer 22

resting length

Question 23

name this curve?

▪ When muscle is at its normal physiological length or resting length, it is capable of
developing maximum tension
▪ Normal physiological length is roughly 50% of the length of the muscle

Answer 23

Blix curve