Chapter 2

Question 1

What is the origin of the muscle?

Answer 1

The proximal attachment, or the less mobile segment

Question 2

What is the insertion of the muscle?

Answer 2

The distal attachment, the more mobile segment.

Question 3

What do antagonist muscles do?

Answer 3

Aid in joint stabilization by providing a braking force at the end of motions.

Question 4

What do synergist muscles do?

Answer 4

Aid indirectly with a movement, stabilize body movement when a muscle crosses two joints.

Question 5

Describe a first class lever?

Answer 5

Muscle and resistance force act on opposite sides of the lever. Seesaw.

Question 6

Describe a second class lever?

Answer 6

Muscle force and resistance force act on the same side of the lever, and the muscle has a longer moment arm and thus a greater mechanical advantage.

Question 7

Describe a third class lever?

Answer 7

Muscle force and resistance force act on the same side of the lever, and the resistance force has a longer moment arm and thus a greater mechanical advantage.

Question 8

What is a mechanical advantage?

Answer 8

When the applied force moment arm to resistive force moment arm is greater than 1.0. Allows muscle force to be less than resistive force.

Question 9

What is a moment arm?

Answer 9

Perpendicular force from the line of action of the force to the fulcrum.

Question 10

What is torque?

Answer 10

Degree of rotation about a fulcrum due to a force. T=force x moment arm.

Question 11

What is the benefit of long moment arms? Short moment arms?

Answer 11

Long are good for generating high forces with low effort (mechanical advantage) but short are good for generating high velocities and are good for power but have a mechanical disadvantage.

Question 12

Define strength

Answer 12

The ability to exert force

Question 13

Define power

Answer 13

Explosive strength, change in velocity per unit time. Power = work/unit time

Question 14

How can you fully assess strength?

Answer 14

Ability to exert force at various velocities. Use isometrics and different loads to assess sport specific abilities.

Question 15

What is work?

Answer 15

work = force x displacement

Question 16

What is negative power?

Answer 16

Eccentrics. When force is exerted in the opposite direction of the movement of a weight. The weight is working on the muscle.

Question 17

What is angular displacement?

Answer 17

The angle about which an object rotates?

Question 18

What is angular velocity?

Answer 18

The rotational speed of an object in radians per second.

Question 19

What is the difference between work and torque?

Answer 19

Torque’s distance component refers to the length of the moment arm which is perpendicular to force, whereas the distance component of work is the distance moved along the line of action of the force.

Question 20

What is rotational work?

Answer 20

torque x angular displacement.

Question 21

What is recruitment?

Answer 21

Which and how many motor units are firing

Question 22

What is rate coding?

Answer 22

The rate at which motor units are fired

Question 23

When is force “greater”?

Answer 23

a) More motor units are involved with contraction
b) Motor units have a greater cross sectional area
c) The rate of firing is faster

Question 24

What is the primary cause of early strength gains?

Answer 24

Neural adaptation

Question 25

What occurs in muscles with great angles of pennation?

Answer 25

Greater force production due to increased # of fibers in parallel

Question 26

What occurs in muscles with lesser angles of pennation?

Answer 26

Greater velocities, due to increased # of fibers in series

Question 27

At what length can muscles generate the greatest force and why?

Answer 27

Resting length, due to overlap of actin and myosin.

Question 28

Does torque very throughout ROM?

Answer 28

Yes, due to the alterations in moment arm length.

Question 29

What is the relationship between the force capability of a muscle and the velocity of contraction?

Answer 29

Decreased force as contraction increases.

Question 30

What type of muscle contraction can generate the most force?

Answer 30

Eccentric

Question 31

What is the strength to mass ratio?

Answer 31

Ability to accelerate one’s body. You want a high ratio.

Question 32

What is the classic formula?

Answer 32

Weight lifted divided by the body weight to the two-thirds power.

Question 33

What are benefits of free weights?

Answer 33

• Whole body training
• Simulate real life actions
• More muscle groups involved

Question 34

What are the benefits of machines?

Answer 34

Safety, ease of use, flexibility of design (can weight motions you can’t weight with free weights).

Question 35

What is bracket training?

Answer 35

Trains acceleration. Use of low weight and then high weights to resist a motion.

Question 36

What type of contractions do fluid resisted motions generate?

Answer 36

Alternating concentric, no eccentric. Higher velocity=higher resistance.

Question 37

What is the relationship between stretch and resistance with elastic materials?

Answer 37

Greater stretch = greater resistance. More resistance at the end range of motions where there is the greatest stretch.

Question 38

Would you recommend elastic bands for jumping resistance?

Answer 38

No the resistance is lower where muscle force can be greatest and vice versa.

Question 39

Pros and cons of valsalva maneuver?

Answer 39

Pros: increased rigidity of torso. Cons increased compression of heart, impedes blood return possibly.

Question 40

Should weight belts be used all of the time?

Answer 40

No, only during heavy sets that strain the low back. May decondition abdominal musculature.