Chapter 2 - Biomechanics

Question 1

Proximal (toward the center of the body) attachment

(Origin/Insertion)

Answer 1

Origin

Question 2

Distal (away from the center of the body) attachment

(Origin/Insertion)

Answer 2

Insertion

Question 3

A lever applies a force on the object ______ in magnitude to but _______ in the direction from F_R.

Answer 3

Equal; Opposite

Question 4

Equation for Mechanical Advantage of Moment Arm

Answer 4

M_AF/M_R

Question 5

M_AF/M_R > 1

Answer 5

Mechanical Advantage; Allows the applied force to be less than the resistive force to produce an equal amount of torque.

Question 6

M_AF/M_R < 1

Answer 6

Mechanical Disadvantage; Apply a greater force than the amount of resistive force present, creating an obvious disadvantage for the muscle.

Question 7

A lever for which the muscle force and resistive force act on opposite sides of the fulcrum.

Hint: See-saw

Answer 7

First-class lever

Example: Tricep Extension.

Question 8

A lever for which the muscle force and resistive force act on the same side of the fulcrum, with the muscle force acting through a moment arm longer than that through which the resistive force acts. Due to its mechanical advantage, the required muscle force is smaller than the resistive force.

Hint: Wheelbarrow

Answer 8

Second-class Lever

Example: Standing Heel Raise

Question 9

A lever for which the muscle force and resistive force act on the same side of the fulcrum, with the muscle force acting through a moment arm shorter than that through which the resistive force acts. The mechanical advantage is < 1.0, the muscle force has to be greater than the resistive force to produce torque equal to that produced by the resistive force.

Hint: Shovel

Answer 9

Third-class lever

Example: Bicep Curl

Question 10

Tendons insertion farther from the joint center results in the ______ to lifting heavier weights.

Answer 10

Ability

Question 11

“Negative” power and work occur during _____ muscle actions.

Answer 11

Eccentric

Question 12

Work performed on, rather than by, a muscle.

Answer 12

Negative Work

Question 13

Required to start an object rotating about an axis or to change the velocity at which it rotates, even if the object as a whole does not move through space at all.

Answer 13

Angular Work and Power

Question 14

The angle through which an object rotates.

Answer 14

Angular Displacement (rad/s)

Question 15

The degree to which a force tends to rotate an object about a specified fulcrum.

Answer 15

Torque or Moment

N*m

Question 16

Torque * Angular Displacement

Answer 16

Rotational Work

Question 17

Muscle force is greater when (3):

Answer 17

A. More motor units are involved in a contraction.

B. The motor units are greater in size

C. The rate of firing is faster.

Question 18

A muscle with fibers that align obliquely with the tendon, creating a featherlike arrangement.

Answer 18

Pennate

Question 19

The angle between the muscle fibers and an imaginary line between the muscle’s origin and insertion

Answer 19

Angle of Pennation

Question 20

Nonlinear, but in general, the force capability of a muscle declines as the velocity of contraction increases.

Answer 20

Muscle Contraction Velocity

Question 21

Use relatively light weights when introducing new exercises or resuming training after a layoff of ____ or more weeks.

Answer 21

Two