Ch 7: Muscle Structure

Question 1

2 ways Origin and Insertion is defined

Answer 1

Anatomically

Mechanically

Question 2

Anatomical definition to insertion and origin

Answer 2

Origin: proximal
Insertion: distal

Question 3

Mechanical definition for origins and insertion

Answer 3

Origin: stable part
Insertion: moveable part

Question 4

The movement a muscle produces is a result of …

Answer 4

Type of joint

Line of pull

Question 5

What does the angle of attachment have to do with strength?

Answer 5

There is a best mechanical advantage. [ex: biceps at 90°]

Question 6

How is the line of pull dynamic?

Answer 6

Depends on 1. Starting position 2. Anatomical pulleys

Question 7

7 fiber arrangement classifications

Answer 7

1. longitudinal
2. Quadrilateral
3. Triangular
4. Fusiform
5. Pennate
6. Bipennate
7. Multipennate

Question 8

What sarcomere arrangement results in greater force?

Answer 8

Bipennate/multipennate: more sarcomeres pulling

Question 9

What sarcomere arrangement results in greater shortening velocity?

Answer 9

Longitudinal: more displacement = more velocity

Question 10

What is the percentage rest length that muscles:
Have the least strength?
Have the most strength?
Reason?

Answer 10

Least: 60% and 160%+
-too much or too little cross bridge overlap

Most: 120%
-goldilocks zone for cross bridge overlap

Question 11

What happens as a muscle is stretched?

Answer 11

Titin provides recoil to bring sarcomere back to neutral. As the muscle is stretched, tension is created.

Question 12

What is the relationship between force and velocity in a trained and untrained person?

Answer 12

Force produced by a trained person is greater, no change in overall velocity.
-The velocity of a trained person is greater than untrained when moving at the same force.

Question 13

Describe the force-velocity relationship during eccentric movement. Example?

Answer 13

Arm extending when weight is too heavy to even maintain position.
Muscles are lengthening because weight it too heavy
Force produced highest, velocity % is low, increases with weight.

Question 14

Describe the force-velocity relationship during metric contraction. Example?

Answer 14

Arm maintaining position with weight too heavy to lift.
Muscles not shortening or lengthening.
Moderate amount of force with no velocity in either direction.

Question 15

Describe the force-velocity relationship during concentric movement. Example?

Answer 15

Arms can move the weight - low weight.

Muscles shorten, lighter the load, less force required, more velocity created.