This document discusses angular kinematics of human movement. It defines relative and absolute angles and describes tools used to measure body angles like goniometers, electrogoniometers, and inclinometers. It also discusses instant centers of rotation and angular kinematic relationships like angular distance, displacement, speed, velocity, and acceleration. Additionally, it covers the relationships between linear and angular motion and velocity.

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

4. 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 00
• Other arm free to rotate
• Center of goniometer over joint center
• Arms aligned over longitudinal axes

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

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

8. 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

9. 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

10. 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

11. Angular Kinematic Relationships
Angular Acceleration
Angular acceleration = change in angular
velocity/ change in time
 =  /t
Units – deg/s2, rad/s2, & rev/s2

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

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