Reading 1
Biomechanics- how the systems and structure of biological organisms react to various forces
and external stimuli
Anthropometry- the systematic measurement of the physical properties of the human body
- Size
- Shape
- Composition
- Length
- Volume
- Height
Qualitative analysis- analysis without the use of numbers
Quantitative analysis- numeric description of the characterization of the movements
Motion- action of changing location or position
Translational motion- body linearly moves but doesn't rotate from one point to another
Rotational motion- rotation of the body around a fixed axis
Oscillatory motion- object repeats the same movement over and over
Periodic motion- regular and repeating motion
One repetition= cycle
Duration of cycle= period
frequency= cycles in a unit of time
Newton's laws of mechanics
Inertia: the natural tendency of objects to resist changes in their state of motion
Force: any influence which changes the motion of an object (unit: SI)
Balanced force: forces are in equal magnitude in opposite directions
Unbalanced force: their is an individual force not being balanced by a force of equal magnitude
in the opposite direction
Vector: used to calculate the magnitude and the direction of the sum of several forces
Net force: the vector sum of all forces that act upon an object
Mass: that quantity that is solely dependent upon the inertia of an object
Acceleration: the rate of change of velocity of an object with respect to time
Pair of forces: a set of two forces that are in opposite direction, with equal magnitudes that act
on different object
Resistance force: a force that operates opposite the direction of motion of a body and tends to
prevent or slow down the body's motion
Effort force: the force used to move an object over a distance
Mechanical load on the human musculoskeletal system
Weight: the attractive force that earth exerts on a body
Density: the relationship between the mass of the substance and how much space it takes up
,Center of mass: the unique position at which the weighted position vectors of all the parts of a
system add up to zero- the properties of elements the body is made up of
Center of gravity: the point around which a body's weight and mass are equally balanced in all
directions- hows and where gravitational forces act on the body
Levers
Levers: bar that pivots around fulcrum
First class lever: fulcrum located between resistance force and effort force ex: scissors, plier
Second class lever: the resistance force is located between fulcrum and effort force ex: stapler
Third class lever: effort force is applied between resistance force and fulcrum Ex: tweezer, ice
tongs
Internal and external loads on the human body
External forces- gravitational forces, friction, contact pressure
Internal forces- muscle forces, passive action of connective tissues, joint contact force
Torque- the ability of a force to produce rotation around an axis (unit: Nm)
Amount of torque depends on
1. The amount of force
2. The distance between the force and the axis of motion, moment arm
Collagen
Structural basis for tissues
Collagen- macromolecule- linked to each other to build collagen fibrils
More than 12 types of collagen
Most common- type 1- can be isolated from any tissue- can be found in dermis, tendon,
ligaments, bone
Type 2- located in articular cartilage, nucleus pulposus of intervertebral discs
Collagen
- Intra and interchain bonding- cross linking- give the strength and tensile stiffness to
connective tissues
Reading 2- biomechanical behavior of bone tissue
Viscoelastic behavior of connective tissues
2 subtypes of connective tissue- soft and specialized
Mechanical properties of the connective tissues- viscoelastic or poroelastic behavior
Viscoelastic materials- relationship between stress and strain depends on time or frequency-
time- dependent mechanical behavior and specific characteristics
Viscoelasticity: aspect of fluid behavior (viscous) and solid behavior (elastic)
, Viscosity: resistance of fluid to change in shape of motion state
Resist flow- high viscosity ex: honey
Elasticity: tendency of solid materials to return to their original shape after forces are applied to
them
Plasticity: the deformation of solid materials undergoing non-reversible changes of shape in
response to applied forces
Elastic materials store 100% due to deformation
Viscoelastic materials do not store 100% but actually lose/dissipate some of the energy
dissipation= hysteresis
Strength: the ability to withstand an applied load without failure or plastic deformation- defined
by the point of failure or load sustained before failure
Stiffness: rigidity of a material
Stress: a load is applied to a material, the material develops internal resistance to applied load
Strain: percentage of change in length of a material in relation to original length
Yield point: the maximum amount of deformation a material can withstand and still return to
original shape
Failure point: the material is loaded beyond the yield point and permanent damage occurs to the
material- the material may break into 2+ pieces
Elastic region: the region of stress- the strain curve up to and including the yield point
Plastic region: strain curve beyond yield point
Plastic deformation: a permanent change of a material
Rate dependence: the deformation of the material depends on the rate at which loads are
applied
Creep: tendency of solid material to move slowly or deform permanently under the influence of
mechanical stresses
Stress relaxation: the behavior of stress reaching a peak and then decreasing or relaxing over
time until a fixed level of strain
Primary mechanical function of the skeletal system
Skeletal system performs critical functions for human body
- Supports body
- Facilitates movement
- Protects internal organs
- Produces blood cells
- Stores and releases minerals and fat
Type, composition and structure of bone tissue
Type
Bone classification Features Function Example
based on shape
Long Longer than wide Support the weight of Humerus, ulna,
Biomechanics- how the systems and structure of biological organisms react to various forces
and external stimuli
Anthropometry- the systematic measurement of the physical properties of the human body
- Size
- Shape
- Composition
- Length
- Volume
- Height
Qualitative analysis- analysis without the use of numbers
Quantitative analysis- numeric description of the characterization of the movements
Motion- action of changing location or position
Translational motion- body linearly moves but doesn't rotate from one point to another
Rotational motion- rotation of the body around a fixed axis
Oscillatory motion- object repeats the same movement over and over
Periodic motion- regular and repeating motion
One repetition= cycle
Duration of cycle= period
frequency= cycles in a unit of time
Newton's laws of mechanics
Inertia: the natural tendency of objects to resist changes in their state of motion
Force: any influence which changes the motion of an object (unit: SI)
Balanced force: forces are in equal magnitude in opposite directions
Unbalanced force: their is an individual force not being balanced by a force of equal magnitude
in the opposite direction
Vector: used to calculate the magnitude and the direction of the sum of several forces
Net force: the vector sum of all forces that act upon an object
Mass: that quantity that is solely dependent upon the inertia of an object
Acceleration: the rate of change of velocity of an object with respect to time
Pair of forces: a set of two forces that are in opposite direction, with equal magnitudes that act
on different object
Resistance force: a force that operates opposite the direction of motion of a body and tends to
prevent or slow down the body's motion
Effort force: the force used to move an object over a distance
Mechanical load on the human musculoskeletal system
Weight: the attractive force that earth exerts on a body
Density: the relationship between the mass of the substance and how much space it takes up
,Center of mass: the unique position at which the weighted position vectors of all the parts of a
system add up to zero- the properties of elements the body is made up of
Center of gravity: the point around which a body's weight and mass are equally balanced in all
directions- hows and where gravitational forces act on the body
Levers
Levers: bar that pivots around fulcrum
First class lever: fulcrum located between resistance force and effort force ex: scissors, plier
Second class lever: the resistance force is located between fulcrum and effort force ex: stapler
Third class lever: effort force is applied between resistance force and fulcrum Ex: tweezer, ice
tongs
Internal and external loads on the human body
External forces- gravitational forces, friction, contact pressure
Internal forces- muscle forces, passive action of connective tissues, joint contact force
Torque- the ability of a force to produce rotation around an axis (unit: Nm)
Amount of torque depends on
1. The amount of force
2. The distance between the force and the axis of motion, moment arm
Collagen
Structural basis for tissues
Collagen- macromolecule- linked to each other to build collagen fibrils
More than 12 types of collagen
Most common- type 1- can be isolated from any tissue- can be found in dermis, tendon,
ligaments, bone
Type 2- located in articular cartilage, nucleus pulposus of intervertebral discs
Collagen
- Intra and interchain bonding- cross linking- give the strength and tensile stiffness to
connective tissues
Reading 2- biomechanical behavior of bone tissue
Viscoelastic behavior of connective tissues
2 subtypes of connective tissue- soft and specialized
Mechanical properties of the connective tissues- viscoelastic or poroelastic behavior
Viscoelastic materials- relationship between stress and strain depends on time or frequency-
time- dependent mechanical behavior and specific characteristics
Viscoelasticity: aspect of fluid behavior (viscous) and solid behavior (elastic)
, Viscosity: resistance of fluid to change in shape of motion state
Resist flow- high viscosity ex: honey
Elasticity: tendency of solid materials to return to their original shape after forces are applied to
them
Plasticity: the deformation of solid materials undergoing non-reversible changes of shape in
response to applied forces
Elastic materials store 100% due to deformation
Viscoelastic materials do not store 100% but actually lose/dissipate some of the energy
dissipation= hysteresis
Strength: the ability to withstand an applied load without failure or plastic deformation- defined
by the point of failure or load sustained before failure
Stiffness: rigidity of a material
Stress: a load is applied to a material, the material develops internal resistance to applied load
Strain: percentage of change in length of a material in relation to original length
Yield point: the maximum amount of deformation a material can withstand and still return to
original shape
Failure point: the material is loaded beyond the yield point and permanent damage occurs to the
material- the material may break into 2+ pieces
Elastic region: the region of stress- the strain curve up to and including the yield point
Plastic region: strain curve beyond yield point
Plastic deformation: a permanent change of a material
Rate dependence: the deformation of the material depends on the rate at which loads are
applied
Creep: tendency of solid material to move slowly or deform permanently under the influence of
mechanical stresses
Stress relaxation: the behavior of stress reaching a peak and then decreasing or relaxing over
time until a fixed level of strain
Primary mechanical function of the skeletal system
Skeletal system performs critical functions for human body
- Supports body
- Facilitates movement
- Protects internal organs
- Produces blood cells
- Stores and releases minerals and fat
Type, composition and structure of bone tissue
Type
Bone classification Features Function Example
based on shape
Long Longer than wide Support the weight of Humerus, ulna,
