Chapter 2 Flashcards

1
Q

biomechanics

A

the study of how musculoskeletal systems interact to make movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

muscle origin

A

a muscle’s proximal attachment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

muscle insertion

A

a muscle’s distal attachment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

fleshy attachment of muscle

characteristics, location

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Fibrous attachments of muscle

characteristics

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

agonist

A

the “prime mover”

the muscle most responsible for causing movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

antagonist

A

the muscle that can slow down or stop a movement.

this protects the structure of joints

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

synergist

A

the muscle that assists indirectly in a movement

especially important when an agonist crosses 2 joints

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

first class lever

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

fulcrum

A

the pivot point of a lever

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

lever

A

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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

mechanical advantage

A

the muscle force moment arm > the resistive force moment arm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

muscle force

A

the force generated by muscle tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

resistive force

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

second class lever

A

a lever type in which:

  • muscle force and resistive force are on same side of fulcrum
  • mechanical advantage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

moment arm

aka force arm, torque arm, lever arm

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

third class lever

A

a lever type in which:

  • muscle force and resistive force are on same side of fulcrum
  • mechanical disadvantage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

torque

definition, formula, unit

A

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

Formula: force * length of moment arm

measured in Newtons * meters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

work

A

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

F * D =

measured in joules or Newtons * meters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

power

formula(s), unit, definition

A

the time rate of doing work

P = W/t
P = F * v

measured in Watts or Joules/seconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

angular displacement

definition, unit

A

the angle through which an object rotates

measured in radians

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

angular velocity

definition, unit/measurement

A

an objects rotational speed

measured in radians/sec

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

rotational work

formula, unit, definition

A

the work done in rotating an object

measured in Joules

rotational work = Torque * angular displacement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

rotational power (formula)

A

rotational work / time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

recruitment

A

the involvement of motor units into a contraction

26
Q

rate coding

A

the rate motor units are fired

27
Q

pennate muscle

A

fibers align obliquely with tendon. featherlike arrangement

28
Q

angle of pennation

A

angle between muscle fibers and imaginary line connecting origin to insertion

(rare to see pennation greater than 15 degrees)

29
Q

classic formula

A

used to equate loads lifted between athletes

= load/bodyweight^2/3

30
Q

bracketing technique

A

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

31
Q

friction

A

resistive force from one object pressed against another

32
Q

fluid resistance

A

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

33
Q

surface drag

A

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

34
Q

form drag

A

1 of 2 forms of fluid resistance produced from fluid meeting front or rear of object.

(cross sectional area affects this)

35
Q

lordotic spine position

A

neutral spine position in which the lumbar region is arched ventral

36
Q

ventral

A

towards the front - anterior

37
Q

dorsal

A

towards the back - posterior

38
Q

Valsalva maneuver

A

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

39
Q

Factors in muscle force

A
  • 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
40
Q

factors of neural control component on muscle force production

A

more force when

  • more motor units involved (recruitment)
  • bigger motor units involved
  • higher firing rate (rate coding)
41
Q

effect of cross sectional area on muscle force

A

higher cross-sectional area indicates more strength

42
Q

effect of fiber arrangement (pennation) on muscle force

A

more pennation means more force potential, but less velocity potential

43
Q

effect of muscle length on muscle force

A

resting length = most potential crossbridge sites = most force potential

44
Q

factors contributing to effect of joint angle on muscle force

A

dependent on

  • moment arms
  • type of exercise
  • joint in question
45
Q

effect of contraction velocity on muscle force

A

force capability declines as velocity increases

46
Q

effect of joint angular velocity on muscle force

A

higher for eccentric actions vs. concentric

lower speeds = greater force capabilities

47
Q

importance of strength:mass ratio

A

important for sports with weight classes

48
Q

body size effect on strength

A

body mass increases faster than strength

the classic formula can equate lifts from different body sizes

49
Q

sources of resistance to muscle contraction

A
  • gravity
  • inertia
  • friction
  • fluid resistance
  • elasticity
50
Q

gravity as resistance

things to know

A

F (weight) = mass * acceleration of gravity

gravity’s effect differs due to moment arms

51
Q

inertia

A

inertia reduces resistance at the end of a movement

heaver weights can be used in high acceleration movements than in slow movements

52
Q

back injury

location, how, avoidance

A

common location : L4 - S1

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

53
Q

kyphotic

A

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

54
Q

shoulder injury

why prone, avoidance

A

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

55
Q

knees

how do the get injured

A

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

56
Q

elbows/wrists (how)

A

how: overhand sports and overhead lifts

57
Q

effects of tendon insertion location

A
  • moment arm

- velocity

58
Q

eccentric muscle action

A

F(m) > F(r)

muscle shortens

59
Q

concentric muscle action

A

F(r) > F(m)

muscle shortens

60
Q

isometric muscle action

A

Fm = Fr

muscle length unchanged

61
Q

3 ways to create intra-abdominal pressure

A
  • valsalva maneuver
  • contract diaphragm with open glottis
  • weight belt