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BIOMECHANICS > MIDTERM 1 > Flashcards

MIDTERM 1 Flashcards

1
Q

kinematics vs kinetics

A

kinetics: describes motion of body in terms of FORCES i.e. all force, no mvmt

kinematics: describes motion using displacement, velocity, acceleration. NO FORCES

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2
Q

position

A

location of an object relative to a reference

a SCALAR quantity, has magnitude but no direction

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3
Q

scalar vs vector

A

scalar: magnitude, no direction

vector: magnitude and direction

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3
Q

moment of force

A

TORQUE, rotary effect of force

when a force is applied a distance away from the centre

the greater the distance away = bigger force = greater moment of force

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3
Q

spatial-temporal graph

A

time against vertical displacement

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4
Q

spatial-spatial graph

A

horizontal displacement vs vertical displacement

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5
Q

types of contractions

A
  1. concentric
  2. eccentric
  3. isometric
  4. isokinetic
  5. isotonic
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6
Q

isotonic vs isokinetic vs isometric contractions

A

isokinetic: mvmnt where angular velocity of displaced BODY SEGMENT is constant, i.e. equal torque. needs special machinery.

isometric: contraction where load = muscle, and no change in muscle length
- TM/TL = 1
- omega = 0, meaning angular velocity = 0

isotonic: contraction where muscle contracts and does work against a load i.e., concentric, eccentric contractions

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7
Q

concentric vs eccentric contractions

A

eccentric: load > muscle, the muscle cannot move load and muscle lengthens
- TM/TL < 1

concentric: load < muscle, muscle shortens as it moves load
- TM/TL > 1

  • for either, omega = k, a constant
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8
Q

stress vs strain

A

stress: when a load is applied to a cross-sectional area

strain: when bone deformation occurs as a result of stress

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9
Q

types of stress

A
  1. torsion
  2. compression
  3. combined loading
  4. tension
  5. shear
  6. bending
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10
Q

tension stress-strain relation

A

E: elastic region
- quickly increasing, linear relationship
- can return to original shape

plastic modulus
- after elastic region
- SOME damage to the bone, but no fracture
- when in this region, more stress = EVEN MORE strain
- won’t return to exact shape

ultimate point: fracture

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11
Q

compression stress-strain relation

A

entire graph is “elastic region” until ultimate point
- why bones can withstand more compression

minimal strain compared to stress

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12
Q

types of fractures

A
  1. greenstick
  2. comminuated
  3. avulsion
  4. transverse
  5. oblique
  6. impacted
  7. fissure
  8. spiral
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13
Q

fracture caused by compression of bone

A

impacted

occurs in middle when bone buckles into self

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14
Q

common in children bcs bones not ossified

A

greenstick

bone bends rather than breaks

15
Q

trapping of bone while other twists over i.e. foot in rock

A

oblique

fracture at sloped angle or curves

16
Q

caused by force not strong enough to completely break bone

A

fissure/hairline

incomplete bone fracture, lines visible that don’t pass through bone

17
Q

caused by crushing force

A

comminuated

fractures in multiple pieces

18
Q

muscle contraction or stretch that’s stronger than the force that holds the tendon/ligament to the bone

A

avulsion

ligament/tendon pulls away from bone attachment, breaking off piece of bone

19
Q

caused via bending force that snaps bone

A

transverse

fracture at 90 degree angle

20
Q

structure of muscle

large –> small

A
  1. whole muscle
  2. muscle fibres
  3. microfibrils: smallest component of muscle fibres
  4. sarcomeres: repeating units
  5. myofilaments: includes myosin and actin
21
Q

contraction cycle steps

A
  1. ATP hydrolysis: ATP broken down into ADP + Pi, energizes myosin head
  2. formation of cross-bridges. myosin head attaches to binding sites on actin
  3. power stroke: cross-bridge rotates, sliding filaments
  4. detachment of myosin from actin: when a new ATP binds to myosin head, it detaches from binding site to repeat cycle
22
Q

what starts contraction cycle?

A

sarcoplasmic reticulum releases Ca2+ into muscle cell (stored in SR until nerve impulse)

calcium binds to troponin, making it move tropomyosin away from myosin binding sites

23
Q

contractile proteins

A

myosin: converts ATP –> mvmnt –> force

actin: provides site for myosin head to attach

24
Q

regulatory proteins

A

both proteins are on actin

tropomyosin: covers myosin binding site when at rest so head can’t attach

troponin: moves tropomyosin away from site when Ca2+ binds to it

25
Q

structural proteins

A

myomesin: forms m-line

dystrophin: links thin filaments (actin) to sarcolemma

titin: stabilizes position of myosin, allowsing stretching and returning to shape

26
Q

thin vs thick filament

A

thick: myosin

thin: actin

27
Q

I band

A

only contains thin filaments (actin)

28
Q

M line

A

middle of sarcomere

29
Q

A band

A

entire length of thick filament (myosin)

30
Q

H zone

A

one actin to another, only containing thick filaments

31
Q

Wolff’s Law

A

bone will adapt to load under which it’s placed bcs more muscle = more weight = more bone

bone will resemble function

bone is resorbed from places it’s not needed

32
Q

bone remodelling steps

A
  1. osteoclasts resorb old bone
  2. osteoblasts lay down new bone

estrogen induces osteoclast apoptosis
- menopause causes osteoclasts to live longer

33
Q

what does EMG give info on

A
  • what muscles are active/prime mover
  • show rigidity i.e. parkinsons
  • how much tension generated
  • timing of muscle activation (when they are recruited)
  • fatigue state i.e. when muscle gets tired, force production down, electrical activity dec

BIOMECHANICS (3 decks)

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