Chapter 2

Question 1

biomechanics

Answer 1

the study of how musculoskeletal systems interact to make movement

Question 2

muscle origin

Answer 2

a muscle’s proximal attachment

Question 3

muscle insertion

Answer 3

a muscle’s distal attachment

Question 4

fleshy attachment of muscle

characteristics, location

Answer 4

a type of muscle attachment typically found at the proximal muscle origin.
muscle fibers are directly attached to bone over a wide area

Question 5

Fibrous attachments of muscle

characteristics

Answer 5

type of muscle attachment.
contiguous with periosteum and epimysium.
has fibers that extend into bone

Question 6

agonist

Answer 6

the “prime mover”

the muscle most responsible for causing movement

Question 7

antagonist

Answer 7

the muscle that can slow down or stop a movement.

this protects the structure of joints

Question 8

synergist

Answer 8

the muscle that assists indirectly in a movement

especially important when an agonist crosses 2 joints

Question 9

first class lever

Answer 9

lever type in which muscle force and resistive force are on opposite sides of fulcrum

Question 10

fulcrum

Answer 10

the pivot point of a lever

Question 11

lever

Answer 11

a body that:

• doesn’t go through pivot point when subjected to force
• is rigid or semirigid
• exerts force on any impedance to its rotation

Question 12

mechanical advantage

Answer 12

the muscle force moment arm > the resistive force moment arm

Question 13

muscle force

Answer 13

the force generated by muscle tissue

Question 14

resistive force

Answer 14

the force generated by an external source in opposition to the agonist

Question 15

second class lever

Answer 15

a lever type in which:

• muscle force and resistive force are on same side of fulcrum
• mechanical advantage

Question 16

moment arm

aka force arm, torque arm, lever arm

Answer 16

the perpendicular distance from a force’s line of action to the fulcrum

Question 17

third class lever

Answer 17

a lever type in which:

• muscle force and resistive force are on same side of fulcrum
• mechanical disadvantage

Question 18

torque

definition, formula, unit

Answer 18

the measure of how much a force rotates an object around its fulcrum

Formula: force * length of moment arm

measured in Newtons * meters

Question 19

work

Answer 19

= (the force exerted on an object) x (the distance it moves) =

F * D =

measured in joules or Newtons * meters

Question 20

power

formula(s), unit, definition

Answer 20

the time rate of doing work

P = W/t
P = F * v

measured in Watts or Joules/seconds

Question 21

angular displacement

definition, unit

Answer 21

the angle through which an object rotates

measured in radians

Question 22

angular velocity

definition, unit/measurement

Answer 22

an objects rotational speed

measured in radians/sec

Question 23

rotational work

formula, unit, definition

Answer 23

the work done in rotating an object

measured in Joules

rotational work = Torque * angular displacement

Question 24

rotational power (formula)

Answer 24

rotational work / time

Question 25

recruitment

Answer 25

the involvement of motor units into a contraction

Question 26

rate coding

Answer 26

the rate motor units are fired

Question 27

pennate muscle

Answer 27

fibers align obliquely with tendon. featherlike arrangement

Question 28

angle of pennation

Answer 28

angle between muscle fibers and imaginary line connecting origin to insertion (rare to see pennation greater than 15 degrees)

Question 29

classic formula

Answer 29

used to equate loads lifted between athletes | = load/bodyweight^2/3

Question 30

bracketing technique

Answer 30

training method in which a lighter than competition load is used to develop acceleration, and a heaver than comp load is used to develop strength/force production

Question 31

friction

Answer 31

resistive force from one object pressed against another

Question 32

fluid resistance

Answer 32

resistance met from an object going through a fluid, or fluid around or through an opening in an object

Question 33

surface drag

Answer 33

1 of 2 forms of fluid resistance produced from friction of fluid on objects surface

Question 34

form drag

Answer 34

1 of 2 forms of fluid resistance produced from fluid meeting front or rear of object. (cross sectional area affects this)

Question 35

lordotic spine position

Answer 35

neutral spine position in which the lumbar region is arched ventral

Question 36

ventral

Answer 36

towards the front - anterior

Question 37

dorsal

Answer 37

towards the back - posterior

Question 38

Valsalva maneuver

Answer 38

closed glottis. rib + abdomen muscles are contracted to make torso rigid and support spine

Question 39

Factors in muscle force

Answer 39

- muscle length - arrangement of fibers - Neural control - Muscle cross sectional area - strength to mass ratio - joint angle - joint angular velocity - muscle contraction velocity ``` Loose Apples Never Can Slow JAV^2 ```

Question 40

factors of neural control component on muscle force production

Answer 40

more force when - more motor units involved (recruitment) - bigger motor units involved - higher firing rate (rate coding)

Question 41

effect of cross sectional area on muscle force

Answer 41

higher cross-sectional area indicates more strength

Question 42

effect of fiber arrangement (pennation) on muscle force

Answer 42

more pennation means more force potential, but less velocity potential

Question 43

effect of muscle length on muscle force

Answer 43

resting length = most potential crossbridge sites = most force potential

Question 44

factors contributing to effect of joint angle on muscle force

Answer 44

dependent on - moment arms - type of exercise - joint in question

Question 45

effect of contraction velocity on muscle force

Answer 45

force capability declines as velocity increases

Question 46

effect of joint angular velocity on muscle force

Answer 46

higher for eccentric actions vs. concentric | lower speeds = greater force capabilities

Question 47

importance of strength:mass ratio

Answer 47

important for sports with weight classes

Question 48

body size effect on strength

Answer 48

body mass increases faster than strength | the classic formula can equate lifts from different body sizes

Question 49

sources of resistance to muscle contraction

Answer 49

- gravity - inertia - friction - fluid resistance - elasticity

Question 50

gravity as resistance | things to know

Answer 50

F (weight) = mass * acceleration of gravity | gravity's effect differs due to moment arms

Question 51

inertia

Answer 51

inertia reduces resistance at the end of a movement heaver weights can be used in high acceleration movements than in slow movements

Question 52

back injury | location, how, avoidance

Answer 52

common location : L4 - S1 how: when the torso is supporting a heavy load avoidance: neutral posture (lumbar lordotic, thoracic kyphotic), intra-abdominal pressure

Question 53

kyphotic

Answer 53

neutral spine position in which the thoracic vertebrae are arched slightly dorsal

Question 54

shoulder injury | why prone, avoidance

Answer 54

why: high mobility and varying tissue types makes the joint less stable avoidance: warm up with light weights

Question 55

knees | how do the get injured

Answer 55

injured when torque is applied not in normal plane of movement (i.e. lateral/medial rotation) or repetitive high-forces on patellar tendon

Question 56

elbows/wrists (how)

Answer 56

how: overhand sports and overhead lifts

Question 57

effects of tendon insertion location

Answer 57

- moment arm | - velocity

Question 58

eccentric muscle action

Answer 58

F(m) > F(r) | muscle shortens

Question 59

concentric muscle action

Answer 59

F(r) > F(m) | muscle shortens

Question 60

isometric muscle action

Answer 60

Fm = Fr | muscle length unchanged

Question 61

3 ways to create intra-abdominal pressure

Answer 61

- valsalva maneuver - contract diaphragm with open glottis - weight belt