Kinetic Concepts for Analyzing Human Motion

Presentation Created by

Dr. Hazrat Bilal Malakandi. PT

DPT (IPM&R, KMU)

Objectives

• Qualitative analysis• Identify common units of measurement for mass,

force, weight, pressure, volume, density, specific weight, torque, and impulse

• Identify and describe the different types of mechanical loads that act on the human body

• Identify and describe the available instrumentation for measuring kinetic quantities

• Solve quantitative problem involving vector quantities using both graphic and trigonometric procedures

Basic Concepts Related to Kinetics

• Inertia

• Mass

• Force

• Center of Gravity

• Weight

• Pressure

• Volume

• Density

• Specific weight

• Torque

• Impulse

Common Units for Kinetic Quantities

Quantity Symbol Metric Unit English UnitMass m kg slugForce F N lbPressure P Pa psiVolume (solids) V m3 ft3

(liquids) liter gallonDensity kg/m3 lb/ft3

Specific weight N/m3 lb/ft3

Torque T N-m ft-lbImpulse N • s lb • s

Mechanical Loads on the Human Body

• Compression

• Tension

• Shear

• Stress

• Torsion

• Bending

• Combined loading

Repetitive vs. Acute Loads

• Repetitive loading

• Acute loading

• Macrotrauma

• Microtrauma

Tools for Measuring Kinetic Quantities

• Electromyography (EMG)

– To study neuromuscular function

• Dynamography

– Primarily employed in gait research

– Starts, takeoffs, landings, baseball & golf swings, and balance

Vectors & Scalar Quantities

• Kinetic vector quantities

– force weight, pressure, specific weight & torque

• Kinematic vector quantities

– Displacement, velocity & acceleration

• Scalar quantities

– Mass, volume, length & speed

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