Biomechanics Exam 1 Flashcards
(53 cards)
1
Q
Anatomical Position
A
- erect standing position with all body parts forward
- starting point for movement
- palms supinated, feet + hips shoulder width apart, erect
- problem: doesn’t represent majority of how we start movement
2
Q
Superior
A
Close to the head
3
Q
Inferior
A
Farther from head
4
Q
Anterior
A
Toward front of body
5
Q
Posterior
A
Toward back of body
6
Q
Medial
A
Toward midline
7
Q
Lateral
A
Away from midline
8
Q
Proximal
A
Closer to trunk
9
Q
Distal
A
Farther from trunk
10
Q
Superficial
A
Toward surface of body
11
Q
Deep
A
Inside body
12
Q
Sagittal Plane
A
- forward of backward movement
- flexion, extension, hyperextension, dorsiflexion, plantarflexion
13
Q
Frontal plane
A
- abduction, adduction, lateral flexion, elevation, depression, inversion, eversion, radial + ulnar deviation
14
Q
Transverse plane
A
- left + right rotation, horizontal abduction + adduction, medial + lateral rotation, internal + external rotation, supination + pronation
15
Q
Linear Motion
A
motion along a line
16
Q
Rectilinear
A
motion along a straight line; sprint
17
Q
Curvilinear
A
motion along a curved line; running around a track
18
Q
Angular motion
A
rotation around an axis; discus, hammer throw
19
Q
General motion
A
combination of linear and angular motion; includes most human motion
ie: walking across room in straight line = rectilinear (pathway) + angular (joint movement)
20
Q
Mechanical system
A
- body or portion of body that is deliberately chosen by analyst
21
Q
Mass (m)
A
- quantity of matter composing a body
- kg
22
Q
Inertia
A
- tendancy to resist change in state of motion
- stationary or dynamic
- proportional to mass
- no units
23
Q
Force
A
- push or pull; internal or external
- linear
- characterized by magnitude, direction, and point of application
- F = ma (mass x acceleration)
- Newton (N)
24
Q
Free body diagram
A
- diagram showing vector representations of all forces acting in a defined system
- magnitude = length of vectors
- direction = way arrow points
- point of application = arrow points to
- ball example: see notes
25
Net Force
- single resultant force derived from the vector composition of all the acting forces
- the force that demonstrates the net effect of all acting forces on a body
- the answer
26
Torque
- the rotary effect of a force
- it is a force
- angular equivalent of force
- aka moment of force
- torque = force (rotational = linear)
- T = Fd (force x perpendicular distance)
- Nm
- what joint is rotating? the, what muscle generates that force?
27
Center of gravity
- point around which a body's weight is equally balanced in all directions
- serves as index of total body motion
- point at which the weight vector acts
- dictates where body goes
28
Weight
- attractive forces the earth exerts on body
- weight = mag (product of mass x acceleration of gravity)
- N
- weight is a force
29
Pressure
- force per unit of area over which the force acts
- gasses or liquids
- commonly used to describe force distribution w/in a fluid or gas (bp, water pressure)
- N/m2 (Newton's per meters squared)
30
Stress
- force per unit of area over which the force acts
- commonly used to describe force distribution w/in a solid
- N/m2
- ie: high heels vs. tennis shoes
31
Volume
- space required by a body
- has 3 dimensions: width, height, depth
- m3 and cm3
32
Density
- mass per unit of volume
- represented by greek letter rho (p)
- kg/m3
- ie: softball vs wiffleball - same volume, but masses different
33
Specific weight
- weight per unit of volume
- represented by greek letter gamma (y)
- N/m3
34
Impulse
- product of force and the time over which the force acts
| - Ns
35
Compression
- pressing or squeezing force directed axially through a body
36
Tension
- pulling or stretching force directed axially through body
37
Shear
- force directed parallel to a surface
| - sliding
38
Bending
- asymmetric loading that produces tension on one side of a body's longitudinal axis and compression on the other
39
Torsion
- load producing twisting of a body around its longitudinal axis
40
Deformation
- change in shape
- get this through loading:
- elastic region: low load; structure goes back to natural shape
- yield point: more permanent deformation; not completely irreversible
- ultimate failure point: structure lost all structural integrity
- yield point and ultimate failure point apart of plastic region
41
Repetitive loading
- repeated application of a subacute load that is usually low magnitude
- ie: marathon runners; stress fx
42
Acute loading
- application of a single force of a sufficient magnitude to cause injury to a tissue
43
Loading
- likelihood of injury shrinks with very high loads and highly frequent low level loads
- likelihood of injury highest w/ medium loading at medium frequency
- includes: compression, tension, shear, bending, torsion, deformation
44
Vector algebra
- vector composition: process of determining a single vector from two or more vectors by addition
- 2 vectors in same direction added
- 2 vectors in opposite direction are subtracted
- tip-to-tail method
vector resolution: operation that produces a single vector w/ two perpendicular vectors such that the vector composition of the two perpendicular vectors yields the original vectors
45
Linear Kinematics
- form, pattern, or sequencing of movement w/ respect to time
- the appearance of motion
46
Linear displacement
- change in location
- directed distance from initial to final location
- the vector equivalent of linear distance ( even if path is nonlinear)
- cm,m,km
- can be the same or di from distance
47
Linear velocity
- rate of change in location
- velocity = displacement/time or v=d/t
- vector equivalent of linear speed
- m/s
- see diagram in notes (velocity on y axis) (uses tip to tail method)
48
Acceleration
- rate of change in linear velocity
- acceleration = change in velocity/time or a=v2-v1/t
- m/s
- may be positive, negative, or equal to 0 based on the direction of change in velocity
49
Projectile
- a body in free fall that is subject only to gravity and air resistance forces
- external (ball) or body (jumping)
- vertical component influenced by gravity and the horizontal is not
- affected by flight path (ball that is dropped vs rolled)
- pattern of change in vertical velocity of projectile is symmetrical about the apex
- other affecting factors: projection angle, mass, force
50
Gravity
- produces a constant acceleration of -9.81 m/s2
51
Projection angle
- direction of projection w/ respect to the horizontal
- depends on distance you want object to go
- max height will decrease w/ increased projectile distance at same projection speed
52
Projection speed
- magnitude of projection velocity
53
Relative projection height
- the difference between projection height and landing height
- ie: pole vaulting, uneven bars, vault
