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Qualitative Non-numerical Based on direct observation Equipment not necessary Focus on time and space Examples: Rotation of femur during golf swing Adduction of humerus during freestyle swim. Quantitative Numerical Based on data collected Equipment necessary Focus on forces
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Qualitative Non-numerical Based on direct observation Equipment not necessary Focus on time and space Examples: Rotation of femur during golf swing Adduction of humerus during freestyle swim Quantitative Numerical Based on data collected Equipment necessary Focus on forces Examples: Stress on shoulder during baseball pitch Compression force on femur during landing Basic Terminology
Areas of Study • 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 • Examines systems not moving or moving at a constant speed • Equilibrium: no acceleration • Example: Spaceship gliding through space • Dynamics • Examines systems that are being accelerated • Example: Softball pitch
Stress-Strain Curve • Stress (σ) • Force applied to deform a structure • Force per unit area • Measured in N/m2 or pascals • σ=F/A • Strain (ε) • Deformation caused by applied stress • ε=ΔL/L
Stress-Strain Curve(cont.) • 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 Insert figure 1-9.
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 • 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(cont.) • Anterior – front, ventral • Posterior – back, dorsal • Ipsilateral – on the same side • Contralateral – on opposite sides
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
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