Ergo Biomech 2008
Transcript of Ergo Biomech 2008
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ERGONOMICSERGONOMICS
DR. SITI ZAWIAH MD. DAWALDR. SITI ZAWIAH MD. DAWAL
DEPT. OF ENGINEERING DESIGNDEPT. OF ENGINEERING DESIGN
AND MANUFACTUREAND MANUFACTUREUNIVERSITY OF MALAYAUNIVERSITY OF MALAYA
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ERGONOMICS
and BIOMECHANICS
Copyright @ 2008 by ERGO
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IntroductionIntroduction
Bio- life or way of life in GreekBio- life or way of life in Greek
Mechanics branch of science dealsMechanics branch of science dealswith forces and effect of forces.with forces and effect of forces.
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Three disciplinesThree disciplines
Mechanics of rigid bodyMechanics of rigid body
Mechanics of solid deformable bodiesMechanics of solid deformable bodies
Fluid mechanicsFluid mechanics
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Mechanics- Forces and MotionMechanics- Forces and Motion
Description and analysis of motion -kinematicsDescription and analysis of motion -kinematics
Description and analysis of forces kineticsDescription and analysis of forces kinetics
Description and analysis of forces tend to causeDescription and analysis of forces tend to cause
motion -staticsmotion -statics
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Kinematic concepts forKinematic concepts for
analyzing human motionanalyzing human motion
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The SkeletonThe Skeleton
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General FunctionsGeneral Functions
Gives the body its basic shape andGives the body its basic shape and
provides a strong , protective andprovides a strong , protective and
supporting framework for all other systemssupporting framework for all other systems
of the body.of the body.
With regards to movement the bones ofWith regards to movement the bones of
the skeleton act as a levers operated bythe skeleton act as a levers operated by
the skeletal muscles.the skeletal muscles.
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Mechanical FunctionsMechanical Functions
At birth 270 bonesAt birth 270 bones
Adults 206 bonesAdults 206 bones
4)4)Acts as a supporting framework for theActs as a supporting framework for the
rest of the bodyrest of the body
5)5)Acts as a lever system muscleActs as a lever system muscle6)6)Protect certain organsProtect certain organs
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Anatomical Reference PlanesAnatomical Reference Planes
Median Plane or Sagittal plane verticalMedian Plane or Sagittal plane vertical
plane that divide the body - left and rightplane that divide the body - left and right
portions.portions.
Coronal plane or Frontial plane verticalCoronal plane or Frontial plane vertical
plane perpendicular to median plane.plane perpendicular to median plane.
( anterior and posterior)( anterior and posterior)
Tranverse Plane horizontal planeTranverse Plane horizontal plane
perpendicular to both median and coronalperpendicular to both median and coronal
planes.planes.
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Types of movementsTypes of movements
See handoutsSee handouts
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Newtons 1Newtons 1stst Law of MotionLaw of Motion
A body which is at rest will remain at restA body which is at rest will remain at rest
unless some external force is applied to itunless some external force is applied to it
and a body which is moving at a constantand a body which is moving at a constant
speed in a straight line will continue to dospeed in a straight line will continue to do
so unless some external force is applied toso unless some external force is applied to
it.it.
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Newtons 2Newtons 2ndnd law of Motionlaw of Motion
Force = mass x accelerationForce = mass x acceleration
F =F = mm x ax a
The relationship between force, theThe relationship between force, the
resulting motion of a body and theresulting motion of a body and the
properties of the body itself.properties of the body itself.
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Newtons 3Newtons 3rdrd Law of motionLaw of motion
To every action force there is always opposed anTo every action force there is always opposed anequal reaction force orequal reaction force or
The mutual action forces of two bodies upon eachThe mutual action forces of two bodies upon each
other are always equal and oppositely directed.other are always equal and oppositely directed.
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Moment of ForceMoment of Force
= W x distance X= W x distance X11
Where W is the magnitude of theWhere W is the magnitude of thegravitational force e.g. weight of the bootgravitational force e.g. weight of the boot
and Xand X11 is the perpendicular distanceis the perpendicular distance
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How would you represent the line ofHow would you represent the line of
gravity of the patient in each of thegravity of the patient in each of thediagrams given. (approximate position)diagrams given. (approximate position)
Tutorial
Copyright @ 2008 by ERGOCopyright @ 2008 by ERGO
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Centre of GravityCentre of Gravity
The centre of gravity (C of G) of an objectThe centre of gravity (C of G) of an object
is the point at which all of the weight of theis the point at which all of the weight of the
object may be considered to beobject may be considered to be
concentrated and about which the objectconcentrated and about which the object( in theory) exactly balance.( in theory) exactly balance.
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Machines and mechanismMachines and mechanism
Rehabilitation machines are devices thatRehabilitation machines are devices that
have been developed to provide specifichave been developed to provide specific
movements for limbs or joints or to providemovements for limbs or joints or to provide
specific resistance to muscle actionspecific resistance to muscle action
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MechanismMechanism
Mechanism such as lever used inMechanism such as lever used in
machines to transform motion and /ormachines to transform motion and /or
force into a desired output.force into a desired output.
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LeverLever
A lever is a rigid beam pivoted at a pointA lever is a rigid beam pivoted at a pointknown as the fulcrum.known as the fulcrum.
There are three classes of leverThere are three classes of lever - First order lever- First order lever
- Second order lever- Second order lever - Third order lever- Third order lever
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Inclined PlaneInclined Plane
Inclined plane is a good example of aInclined plane is a good example of a
method used since ancient times to raisemethod used since ancient times to raise
heavy loads with a relatively small effort.heavy loads with a relatively small effort.
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Tutorial 1Tutorial 1
2) Refer to the 12) Refer to the 1stst Q comment on theQ comment on the
stability of the subject in each position.stability of the subject in each position.
3) Refer to figure 2, assume that the3) Refer to figure 2, assume that the
combined weight of a patient and a wheelcombined weight of a patient and a wheel
chair is 800N and the therapist is requiredchair is 800N and the therapist is required
to push the wheelchair up a ramp that hasto push the wheelchair up a ramp that has
a slope of 1 in 10. Calculate the minimuma slope of 1 in 10. Calculate the minimumforce that the therapist must apply to pushforce that the therapist must apply to push
the chairthe chair