Basic Terminology
Qualitative
 Non-numerical
 Based on direct
observation
 Equipment not necessary
 Focus on time and space
 Examples:
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Rotation of femur during
golf swing
Adduction of humerus
during freestyle swim
Quantitative
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Numerical
Based on data collected
Equipment necessary
Focus on forces
Examples:
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Stress on shoulder during
baseball pitch
Compression force on
femur during landing
Areas of Study
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Biomechanics vs. Kinesiology
Anatomy vs. Functional Anatomy
Linear vs. Angular Motion
Kinematics vs. Kinetics
Biomechanics vs. Kinesiology
 Kinesiology:
 Scientific study of human movement
 Anatomical, physiological, psychological,
biomechanical
 Biomechanics:
 Application of mechanics to biological
systems
 More specific than kinesiology
Anatomy vs. Functional
Anatomy
 Anatomy
 Structure of the body
 Focus on structure
 Example: Study of biceps brachii
 Functional Anatomy
 Body components necessary to achieve
goal
 Focus on function
 Example: Analysis of bicep curl
Linear vs. Angular Motion
 Linear Motion
 AKA translation or translational motion
 Movement on straight or curved pathway
 All points move same distance, same time
 Angular Motion
 Motion around some point
Kinematics vs. Kinetics
 Both are biomechanical analyses
 Kinematics
 Examines space and time
 Kinetics
 Examines forces
Statics vs. Dynamics
 Statics
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Examines systems not moving or moving at a
constant speed
Equilibrium: no acceleration
Example: Spaceship gliding through space
 Dynamics
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Examines systems that are being accelerated
Example: Softball pitch
Stress-Strain Curve
 Stress (σ)
 Force applied to deform a structure
 Force per unit area
2
 Measured in N/m or pascals
 σ=F/A
 Strain (ε)
 Deformation caused by applied stress
 ε=ΔL/L
Stress-Strain Curve
(cont.)
Insert figure 1-9.
 Elastic modulus (k)
 Stiffness of a material
 k=stress/strain=σ/ε
 Residual strain
 Difference between original length and length
resulting from stress into the plastic region
 Safety factor
 5–10x typical stress on structure
Stored Mechanical Energy
 Proportional to area under stress-strain curve
 ME=½σε
 Spring, rubber band, trampoline
Insert figure 1-12.
Types of Materials
 Elastic
 Linear relationship between stress and strain
 Viscoelastic
 Non-linear relationship between stress and strain
 Hysteresis: energy lost in a viscoelastic material
Skeleton
 Axial
 Head
 Neck
 Trunk
 Appendicular
 Upper extremities
 Lower extremities
Insert figure 1-16, only the
part labeled with the
segments of the axial and
appendicular skeleton.
Reference Positions
 Anatomical position
 Standard reference point
 Palms face front
 Fundamental position
 Similar to anatomical position
 Arms more relaxed
 Palms face inward
 Relative angle
 Included angle between two segments
Relative Position
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Medial – toward midline of the body
Lateral – away from midline of the body
Proximal – toward point of attachment
Distal – away from point of attachment
Superior – toward the top of the head
Inferior – toward the bottom of the feet
Relative Position
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Anterior – front, ventral
Posterior – back, dorsal
Ipsilateral – on the same side
Contralateral – on opposite sides
(cont.)
Flexion & Extension
 Flexion
 Decreasing joint angle
 Extension
 Increasing joint angle
 Hyperflexion
 Flexion beyond normal range
 Hyperextension
 Extension beyond normal range
Abduction & Adduction
 Abduction
 Moving away from midline
 Adduction
 Moving toward midline
 Hyperabduction
 Abduction past 180° point
 Hyperadduction
 Adduction past 0° point
Other Movement Descriptors
 Rotation
 Medial (internal) or lateral (external)
 Right/left for head & trunk
 Lateral flexion
 Head or trunk only
 Example: head tilts sideways
 Circumduction
 Movement in a conic fashion
Movement of the Scapulae
Elevation – raising the scapula (shrug)
Depression – lowering the scapula
Protraction – move scapulae apart
Retraction – move scapulae together
Upward rotation – bottom of scapula
moves away from trunk, top moves toward
 Downward rotation – return to normal
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Specialized Movement Descriptors
 Horizontal adduction
 Combination of flexion & adduction
 Horizontal abduction
 Combination of extension & abduction
 Supination – turn palms frontward
 Pronation – turn palms backward
 Radial flexion – hand toward thumb
 Ulnar flexion – hand toward little finger
Movement Descriptors of the Foot
 Plantarflexion
 Increase angle between foot and shank
 Dorsiflexion
 Decrease angle between foot and shank
 Inversion
 Lift medial edge of foot
 Eversion
 Lift lateral edge of foot
Pronation & Supination
of the Foot
 Pronation & supination of the feet are not the same as inversion
& eversion
 Pronation of the foot
 Dorsiflexion at the ankle
 Eversion in the tarsals
 Abduction of the forefoot
 Supination of the foot
 Plantarflexion at the ankle
 Inversion in the tarsals
 Adduction of the forefoot
Reference Systems
 Necessary for accurate observation & description
 Fundamental & anatomical positions
 Axes
 Imaginary lines that intersect at right angles
 Origin
 Point of intersection of axes
Absolute vs. Relative
 Relative
 Segment movement described relative to
the adjacent segment
 Absolute
 Axes intersect in the center of a joint
Planes & Axes
 Plane
 Flat, two-dimensional surface
 Cardinal planes
 Planes positioned at right angles and intersecting the
center of mass
 Axis of rotation
 Point about which movement occurs
 Perpendicular to plane of motion
Cardinal Planes
 Sagittal
 Left & right halves
 Mediolateral axis
 Frontal (coronal)
 Front & back halves
 Anteroposterior axis
 Transverse (horizontal)
 Upper & lower halves
 Longitudinal axis
 Many other planes exist
Degrees of Freedom
 Degree of freedom
 Number of planes in which a joint has the ability to
move
 1 degree of freedom
 Uniaxial
 Example: Elbow
 2 degrees of freedom
 Biaxial
 Example: Wrist
 3 degrees of freedom
 Triaxial
 Example: Shoulder
Summary
 Human movement analyzed using…
 Qualitative analysis
 Quantitative analysis
 Materials & structures analyzed using…
 Stress-strain curve
 Movement described…
 Using anatomical movement descriptors
 In relation to planes of motion