Shared Flashcard Set

Details

Biomechanics
definitions
66
Biology
Undergraduate 2
01/09/2012
Click here to study/print these flashcards.

Create your own flash cards! Sign up here.

Additional Biology Flashcards

 

 

Cards

Term
BIOMECHANICS
 Definition
BIOMECHANICS:
Sub discipline of kinesiology
The study of biological systems from a mechanical perspective
○Science that examines forces acting upon and within a biological structure and the effects produced by these forces.
Describes human movement in mechanical terms, using force, distance, direction of movement etc.
Term
MECHANICS
 Definition
MECHANICS:
A branch of physics involving analysis of the action of forces on particles and mechanical systems
Term
STATICS
 Definition
STATICS:
The study of systems that are in a state of constant motion (at rest or constant velocity)
Term
DYNAMICS
 Definition
DYNAMICS:
The study of systems in which acceleration is present
2 branches: Kinematics and kinetics
Term
KINEMATICS
 Definition
KINEMATICS:
Study of the description of motion, including considerations of space and time
Position, velocity, acceleration
Term
KINETICS
 Definition
KINETICS:
Study of action of forces
Consider anthropometric factors
Term
Anthropometric factors
 Definition
Anthropometric factors
Size, shape, weight of body segments
Term
MOTION
 Definition
MOTION:
Change of place or position
Forms of motion:
a) Linear
b) Angular
Term
Linear Motion
 Definition
Linear Motion
= Motion in a straight or curved line
all parts of the body moving in the same direction at the same speed
Aka. Translation
Rectilinear: if the line is straight
Curvilinear: if the line is curved
Term
Angular Motion
 Definition
Angular Motion
= rotation around a central line or pivot point
- Involved in almost all voluntary human movement
Term
General Motion
 Definition
General Motion
= Linear motion/translation+ Angular/rotation motion
(most human movement)
Term
ANATOMICAL REFERENCE POSITION:
 Definition
ANATOMICAL REFERENCE POSITION:
An erect standing position with the feet slightly separated and the arms hanging relaxed at the sides, with the palms of the hands facing forward.
Considered the starting point
for all body segment movements
Term
Sagittal Plane
 Definition
Sagittal Plane (asso w/MEDIOLATERAL)
Divides right/left sides
Mid- and para-
Movements:
Flexion
Extension
Hyperextension
Dorsiflexion
Plantarflexion
Term
Frontal Plane
 Definition
Frontal Plane (ANTEROPOSTERIOR)
Aka. Coronal plane
Divides body front/back
Movements:
Abduction
Adduction
Radial deviation
Ulnar deviation
Subtalar eversion/pronation
Subtalar inversion/supination
Term
Transverse Plane
 Definition
Transverse Plane (LONGITUDINAL)
Aka. Horizontal plane
Divides the body top/bottom
Movements:
L/R rotation
Medial (internal) rotation
Lateral (external) rotation
Forearm supination
Forearm pronation
Horizontal abduction
Horizontal adduction
Term
Anatomical Reference Axes
 Definition
Anatomical Reference Axes
Axis of rotation = an imaginary line about which rotation occurs
3 reference axes:
1.Mediolateral (right/left) axis
- Associated with sagittal plane
2.Anteroposterior (front/back) axis
- Associated with to frontal plane
3. Longitudinal (vertical)
- Associated with transverse plane
Term
Nonaxial
 Definition
Joints are classified according to the number of axes about which their rotation occurs
or the number of planes in which the segment moves.
Nonaxial: allow only slight gliding movements.
Intercarpal, intertarsal
Term
Uniaxial
 Definition
Uniaxial: allow movement in one plane, around one axis.
Elbow, ankle (TC), interphalangeal
Term
Biaxial
 Definition
Biaxial: allows movement in 2 planes, around 2 axes.
Wrist, knee, thumb
Term
Multiaxial
 Definition
Multiaxial: allows movement in all 3 basic planes, around all 3 axes.
Shoulder, hip
Term
Combined Movement
Circumduction
 Definition
Circumduction:
Circular movement of a body segment
Flexion + Extension + Abduction + Adduction
COMBINED MOVEMENT
Term
Scapular movement
Elevation/Depression
 Definition
Elevation/Depression
AP axis, frontal plane
Term
Scapular movement
Protraction/Retraction
 Definition
Protraction/Retraction
Longitudinal axis, transverse plane

AP
Term
Scapular movement
Upward/Downward Rotation
 Definition
Upward/Downward Rotation
AP axis, frontal plane
Term
Qualitative Kinematic Analysis
types of measuring tools
 Definition
Qualitative Kinematic Analysis
StroMotion
SimulCam
Kinovea
Free open source software for video analysis
Kinematic and kinetic measurement capabilities
Term
Quantitative kinematic analysis
 Definition
dartfish-The positions of the joint centers can be located in space and kinematic variables (displacement, velocity, acell) can be calculated (like stick figures)
Vicon motion capture= Three dimensional representation is produced using reflective markers and a multi camera system (lights on body to make 3d skeleton)
Term
Dynamography
 Definition
Dynamography
Dynamography is the study of the forces at work in a mechanical system.
Examples:
Dynamometer- Used to measure force, torque or power at a joint
Force platform- Transducers are used to measure forces applied to a surface
Term
Electromyography
 Definition
Electromyography
EMG is the technique of recording electrical activity in muscles, or myoelectric activity which is produced during the depolarization and repolarization of the muscle cell membrane that occurs during contraction
Use of electrodes to measure the amount of activity occurring in the muscles contracting under the electrodes
More activity = greater force output
Term
Electrogoniometry
 Definition
Electrogoniometry
A goniometer is a device used to measure joint angles
A protractor with two extended arms in which the axis of the goniometer is placed over the centre of the joint and the arms are attached to the segments under study
Change in joint angle is measured electronically using a potentiometer
Term
Timing Gates
 Definition
Timing Gates
Systems combine photo cells, light beams and timers
Photo cell is electronically connected to timer to measure time interval between disruption of light beam
Calculate velocity of moving body
Term
Accelerometer
 Definition
Accelerometer
Transducer used for direct measurement of acceleration
Device is firmly attached to body segment or object of interest
3-D accelerometers can measure angular accelerations
Term
Inertia
 Definition
Inertia
the tendency of a body to maintain it's state of motion
resistance to action or change
resistance to acceleration
○Proportional to the body’s mass
Greater mass = more it tends to maintain its current state of motion; more difficult to disrupt.
○Applies to motionless objects as well as objects moving at a constant velocity
○No units
Term
Newton’s 1st Law of Motion (Law of Inertia)
 Definition
Newton’s 1st Law of Motion (Law of Inertia):
A body will remain at rest or in a state of constant motion unless acted upon by an outside force.
Term
Mass
 Definition
Mass: quantity of matter contained in an object.
Examples:
○Skater gliding on ice
○Sumo wrestler in ready position
Term
Centre of gravity
 Definition
Centre of gravity: point around which a body’s weight is equally balanced, no matter how the body is positioned.
Not always within the body or object
Determines the way in which the body responds to external forces
Term
Newton’s Second Law of Motion
 Definition
Force = mass x acceleration
Force = m x a F=kg x m/s2
Unit of force is the Newton
 F = m x a is Newton’s Second Law of Motion
Law of Acceleration
○A force applied to a body causes an acceleration of that body of a magnitude proportional to the force, in the direction of force , and inversely proportional to a body’s mass
Term
Force
 Definition
Force
a push or pull
causes a change in the linear motion of an object or person
Characterized by:
○Magnitude
○Direction
○Point of application
Term
Torque
 Definition
Torque: is a measure of the tendency to rotate around an axis of rotation, which causes a change in the angular motion of an athlete or segment.
“rotary force”
Torque = moment
IE. If you push someone on a swing, you are producing torque by applying force to the seat, at a distance from the axis through the support at the top
Torque = F x d┴
○Units: Nm
Term
Mass
 Definition
Mass
The quantity of matter making up a body or object
Metric system unit – kilogram (kg)
Mass of an object is the same no matter where it is
Term
Weight
 Definition
Weight
A measure of the earth’s gravitational force acting on mass
Directed towards the centre of the earth from the CG of an object
Weight = mass times the acceleration due to gravity
○Weight = m x g
Units = Newton
Force of Gravity (g) = downward acceleration due to gravity = 9.81 m/s2
Term
Pressure
 Definition
Pressure
= Force distributed over a given area
P = F/A
Units = N/m2 = Pascal
Can also use N/cm2
Term
volume
 Definition
Volume: space occupied by a body
Width x height x depth
Units: m3
Term
Density
 Definition
Density: mass per unit of volume
Density = ρ (rho) = mass/volume
Units: kg/m3
Term
Specific weight
 Definition
Specific weight: weight per unit of volume (N/m3)
Specific weight = weight/volume
Units: N/m3
Term
Impulse
 Definition
Impulse-- product of force and the time over which the force acts
important because it produces a change in velocity of a person or object
Impulse = Force (N) x time (s)
Units: Ns
Term
Impulse:Momentum Relationship
 Definition
Impulse:Momentum Relationship
Impulse = change in momentum (where momentum = mass x velocity)
Impulse = mvf - mvi= change in momentum
Impulse =  Momentum where  = “change in”
Term
Stress
 Definition
Stress is the distribution of force within a body, or the force divided by the area over which the force acts
Stress = Force (N)/area (m2) = N/m2
Stress represents the force distribution inside a solid body when an external force acts, whereas pressure represents the distribution of force external to a solid body
Term
Strain
 Definition
Strain-deformation, change in shape
 the amount of deformation divided by the original length of the structure
Strain = change in length/original length= % change
10 cm tendon increases in length by 1 cm when stretched:
○Strain = 1/10 = 10% strain
Term
Compression
 Definition
Compression-pressing or squeezing force directed axially through a body
Term
Tension
 Definition
Tension-pulling or stretching force acting axially through a body
Term
Shear
 Definition

Shear - force directed parallel or tangent to a surface; sliding force

Term
Axial forces
 Definition
Axial forces- line of force is directed along the longitudinal axis of the body
compression and tension are axial forces
Term
Bending
 Definition
Bending
asymmetric loading that produces tension on one side of a body's longitudinal axis and compression on the other side
Term
Torsion
 Definition

Torsion load which produces twisting of a body around it's longitudinal axis

Term
Combined Loading
 Definition
Combined Loading
simultaneous action of more than one of the pure forms of loading
○Example: Shear + Tension
(very dangerous to human body)
Term
load-deformation curve
 Definition
The relationship between the amount of force applied to a structure and the structure’s response
Aka. Stress-strain curve
Elastic region: the region on the curve in which the tissue will return to its original shape after loading; no permanent damage has occurred to the tissue
Slope of curve is linear here
Plastic region: the region on the curve in which the deformation is permanent; the tissue has been damaged and will no longer return to its original shape;
The curve may no longer be linear
Term
load-deformation curve 2
 Definition

Load-Deformation Curve Yield point (elastic limit): point on the load deformation curve past which deformation is permanent An inflection point on the curve – slope changes from a linear relationship to a non linear relationship Failure point: Loss of mechanical continuity, the point at which the structure breaks

Term
Stiffness
 Definition
Stiffness
the ratio of stress to strain in a loaded material
slope of the stress-strain curve
the stress divided by the relative amount of change in the structure's shape
Term
Compressive strength
 Definition
Compressive strength
the ability to resist pressing or squeezing forces
○ bone has high compressive strength
Term
Tensile strength
 Definition
Tensile strength
the ability to resist pulling or stretching force
Term
repetitive load
 Definition

Repetitive application of a relatively light load may produce stress injury Running a marathon produces a stress fracture Chronic or stress injury

Term
Acute load
 Definition
Acute loading is the application of a force of sufficient magnitude to cause injury to a biological tissue
hard football tackle breaks a leg
Term
Axis of rotation:
 Definition
Axis of rotation:
Imaginary line perpendicular to the plane of rotation and passing through the centre of rotation.
Term
kinetic vector quantities
 Definition
force, weight, pressure, specific weight, torque
Term
kinematic vector quantities
 Definition
- displacement, velocity, acceleration
Term
scalar quantities
 Definition
magnitude, but no direction= mass, volume, length, speed
Supporting users have an ad free experience!