Biomechanics Flashcards

1
Q

what does “bio” refer to?

A

life/living organisms

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2
Q

what does “mechanics” refer to?

A

study of physical actions of forces

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3
Q

define statics

A

the study of systems in a constant state of motion

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4
Q

define dynamics

A

the study of systems in motion with acceleration

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5
Q

define kinematics

A

description of a systems motion

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6
Q

define kinetics

A

study of forces associated with a body’s motion

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7
Q

what are the key functions of machines?

A
  • increase mechanical advantage
  • balances multiple forces
  • enhances forces to decrease the total force required to overcome resistance
  • enhance ROM and speed of movement to move resistance further or faster than the applied force
  • alter the resulting direction of the applied force
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8
Q

what are the different kinds of machines?

A
  • levers
  • wheel and axle
  • pulleys
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9
Q

describe what a lever machine is

A

most common type of machine that allows the body to move and apply force.
- 1st, 2nd, and 3rd classes

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10
Q

define 1st class levers

A

effort and load are on opposite sides of the fulcrum - ex: triceps extension

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10
Q

define 2nd class levers

A

effort and load are on the same side of the fulcrum; effort is farther from fulcrum and load is closer
- ex: calf raise

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11
Q

define 3rd class levers

A

effort and load are on the same side of the fulcrum; effort is closer to the fulcrum and load is farther
- ex: elbow flexion

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12
Q

define torque

A

an eccentric force that causes rotation
- Eccentric force: muscle contraction pulling on bones at attachment sites causing bones to rotate at joint axis

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13
Q

describe what a wheel and axle machine is

A
  • Purpose: enhance ROM and speed
  • Function: 1st class lever; wheel and axle complete turn at the same time
  • Mechanical advantage: determined by the radius of the wheel compared to the radius of the axle
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14
Q

describe what a pulley machine is

A
  • Purpose: change effective direction of force application
  • Function: single, compound
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15
Q

what is an example of a wheel and axle machine in the body?

A

axle = humerus
Outside of wheel = hand/wrist
Movement = internal rotation
Results = increased speed to throw objects

16
Q

what is an example of a pulley machine in the body?

A

Pulley = lateral malleolus
Tendon = peroneus longus
Movement = ankle PF, eversion

17
Q

describe Newton’s 1st law of motion: Inertia

A

an object at rest remains at rest and an object in motion remains in motion at a constant speed and in a straight line unless acted on by an unbalanced force

18
Q

describe Newton’s 2nd law of motion: Force

A

acceleration of an object depends on its mass and the amount of force applied; F=MA

19
Q

describe Newton’s 3rd law of motion: Action/reaction

A

for every action, there is an equal and opposite reaction

20
Q

define static friction

A

resultant force from resistance between 2 object surfaces coming into contact AT REST

21
Q

define kinetic friction

A

resultant force from resistance between 2 object surfaces coming into contact
SLIDING against each other

22
Q

define rolling friction

A

resultant force from resistance between 2 object surfaces coming into contact
ROLLING across a surface

23
Q

define balance

A

ability to control equilibrium
- Equilibrium: state of 0 acceleration
- Stability: needed to control equilibrium and achieve balance

24
how is stability achieved?
- enhanced by altering COG as needed - COG: the point at which all of the body’s mass and weight are equally distributed - Response to perturbation: lower COG, COG within BOS, and enlarged BOS
25
what is the number 1 source of force?
- Muscle contraction is the number 1 source of force - Without forces there is no movement - F=MA (force = mass times acceleration)
26
what is the momentum equation?
M=MV (momentum = mass times velocity) - Impulse = force x time (can alter momentum)
27
describe what a mechanical load is
physical stress on a mechanical system or component
28
what are some internal and external forces effecting mechanical load?
Internal forces: - Active: muscle contraction - Passive: tension in tendons, connective tissues, ligaments, and joint capsules External forces: - Gravity - Inertia - Direct contact
29
what are the different types of mechanical load?
- Tension (stretch/strain) - Compression - Shear - Bending - Torsion (twist) - Combined (compression + rotation)
30
describe some injuries and prevention associated with mechanical loads
injury/damage: - Fracture bones - Dislocate joints - Disrupt muscles and connective tissues Injury prevention - The body can absorb energy from internal and external forces - Absorb force over larger aspects - Spread absorption rate over a greater time period - Stronger and healthier tissue can withstand greater mechanical loading