Angular kinematics of human movement

Basic Biomechanics

1. Angular Kinematics of Human Movement Prepared By: Hazrat Bilal Malakandi DPT (IPM&R, KMU)

2. Relative versus Absolute Angles Relative angle: Angle of a joint formed between the longitudinal axes of adjacent body segments Anatomical reference position Absolute angle: Horizontal reference Vertical reference

3. Tools for Measuring Body Angles Goniometer: A goniometer is a device used in physical therapy to measure the range of motion around a joint in the body. The term goniometry is derived from two Greek words, gonia , meaning angle, and metron , meaning measure One arm fixed to protractor at 0 Other arm free to rotate Center of goniometer over joint center Arms aligned over longitudinal axes

4. Electrogoniometer ( elgon ): a device for measuring angles (usually joint angles) directly, giving an electrical output (often interfaced to a computer ).

5. Inclinometers: An inclinometer or clinometer is an instrument for measuring angles of slope (or tilt), elevation or depression of an object.

6. Instant Center of Rotation The instant center of rotation , also called instantaneous center or instant center , is the point in a body undergoing planar movement that has zero velocity at a particular instant of time

7. Angular Kinematic Relationships Angular Distance & Displacement Assessed as difference of initial & final positions Counterclockwise is positive Clockwise is negative Measured in Degrees, radians, or revolutions

8. Angular Kinematic Relationships Angular Speed & Velocity Angular speed = angular distance /  =  / change in time t Angular velocity = angular displacement /  =  / change in time t Units: deg/s, rad /s, rev/s, & rpm

9. Angular Kinematic Relationships Angular Acceleration Angular acceleration = change in angular velocity / change in time  =   /  t Units – deg/s 2 , rad /s 2 , & rev/s 2

10. Relationship Between Linear and Angular Motion s = r  Radius of rotation : Linear distance & radius of rotation same units Angular distance in radians

11. Linear and Angular Velocity V = r  m/s = (m) ( rad /s)