Chapter 2

Question 1

Biomechanics

Answer 1

focuses on the mechanisms through which the musculoskeletal components interact to create movement

Question 2

Origin

Answer 2

proximal attachment (toward center of body)
-attached to stationary structure

Question 3

Insertion

Answer 3

distal attachment (away from center of the body)
-attached to mobile structure

Question 4

Fleshy attachements

Answer 4

muscle fibers directly attached to bone over a wide area so force is distributed rather than localized.
-most often found at proximal end of a muscle

Question 5

Fibrous attachments

Answer 5

i.e. tendons

blend into and are continuous with both the muscle sheaths and the connective tissue surrounding the bone.

Question 6

Agonist

Answer 6

muscle that brings about movement

Question 7

Antagonist

Answer 7

muscle that can slow down or stop movement

-assist in joint stabilization

Question 8

Cartilaginous joint

Answer 8

joints connected by cartilage

Question 9

Synergist

Answer 9

a muscle that assists indirectly in a movement

-ex. muscles that stabilize scapula act as synergists during upper body arm movement

Question 10

First-class lever

Answer 10

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

Question 11

Fulcrum

Answer 11

pivot point of a lever

Question 12

Lever

Answer 12

rigid or semirigid body that, when subjected to a force whose line of action does not pass through its pivot point, exerts force on any object impeding its tendency to roate

Question 13

Mechanical Advantage

Answer 13

ratio of moment arm through which an applied force acts to that through which a resistive force acts.

Question 14

Moment arm

Answer 14

perpendicular distance from the line of action of the force to the fulcrum.
-aka force arm, lever arm, or torque arm

Question 15

Line of Action

Answer 15

infinitely long line passing through the point of application of the force, oriented in the direction in which the force is exerted.

Question 16

Muscle Force

Answer 16

force generated by biomechanical activity, or the stretching on non-contractile tissue, that tends to draw the opposite ends of a muscle toward each other

Question 17

Resistive Force

Answer 17

force generated by a source external to the body (gravity, inertia, friction) that acts contrary to muscle force

Question 18

Second-class lever

Answer 18

lever for which the muscle force and resistive force act on the same side of the fulcrum, which the muscle force acting through a moment arm longer than that through which the resistive force acts
-i.e. calves raising the body onto the balls of the feet

Question 19

Third-class lever

Answer 19

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

Question 20

Torque

Answer 20

degree to which a force tends to rotate an object about a specified fulcrum.
-defined quantitatively bas the magnitude of force x length of its moment arm.
aka moment

Question 21

Anatomical position

Answer 21

body erect
arms down at sides
palm forward

Question 22

Sagital plane

Answer 22

left right

Question 23

Frontal plane

Answer 23

front back

Question 24

Transverse plane

Answer 24

top bottom

Question 25

Strength

Answer 25

ability to exert force

Question 26

Acceleration

Answer 26

change in velocity per unit time

Question 27

Power

Answer 27

time rate of doing work

-Power = Work / Time

Question 28

Work

Answer 28

product of force exerted on an object and the distance the object moves in the direction in which the force is exerted
-Work = Force x Displacement

Question 29

Weight to equal Newtons

Answer 29

N = pounds x 4.448
N = kg mass x 9.8 m/s2 (gravity)
N = kg force x 9.807

Question 30

Angular Displacement

Answer 30

angle through which an object rotates

-measured by radians (rad)

Question 31

Angular Velocity

Answer 31

object’s rotational speed

-measured in rad/s

Question 32

Rotational work equation

Answer 32

Work = torque x angular displacement

Question 33

Rotational power equation

Answer 33

Power = Work / Time (same are power eq.)

Question 34

Recruitment

Answer 34

recruiting motor units during muscle contraction

Question 35

Rating Coding

Answer 35

rate at which motor units are fired

Question 36

Muscle force is greater when:

Answer 36

More motor units are involved in a contraction.
Motor units are greater in size.
Rate of firing is faster.

Question 37

Pennate Muscle

Answer 37

fibers that align obliquely with the tendon

-featherlike arrangement

Question 38

Angle of Pennation

Answer 38

angle between muscle’s origin and insertion

-0 degrees corresponds to no pennation

Question 39

Concentric Muscle Action

Answer 39

muscle shortens bc contractile force is greater than the resistive force.
-forces generated within the muscle and acting to shorten it are greater than the external forces acting at its tendons to stretch it

Question 40

Eccentric Muscle Action

Answer 40

muscle lengthens bc contractile force is less than the resistive force.
-forces generated within muscle and acting to shorten it are less than the external forces acting at its tendons to stretch it (increases risk of soreness/injury)

Question 41

Isometric Muscle Action

Answer 41

muscle length does not change, bc contractile force is equal to resistive force.
-force generated within in the muscle and acting to shorten it are equal to the external forces acting at its tendons to stretch it

Question 42

Classic Formula

Answer 42

load lifted / body weight^2/3