Angular kinematics

What is angular kinematics?

Deals with angular motion.

Nearly all human movement involves rotation of body segments.

Units of angular angle measures

Degrees

Radians (1rad =  57.3°)

Revolutions (1rev = 360°)

Conversions of angular measurements

-Radians to degrees = x180 and /π

-Degrees to radians = xπ and /180

-Degrees to revolutions = /360

How to determine direction in angular kinematics

Is the movement clockwise or anti-clockwise?

Is it positive or negative? (right hand thumb rule)

What’s the right hand thumb rule?

Curl your finger in the direction of rotation and then see whether your thumb points up (positive) or down (negative).

What’s an absolute angle?

Measured from an external frame of reference.

Can be a vertical line from the centre of rotation or a horizontal line.

What is a relative angle?

The degrees of flexion or angle formed at the centre of rotation.

Formed between to limb segments.

What is angular displacement?

Angle between the final and initial position.

Final position - initial position

(Is a vector)

What is angular velocity?

Change in angular displacement per unit time.

Angular displacement / change in time

(Deg/s or Rad/s)

What’s angular acceleration?

Change in angular velocity per unit time.

Angular velocity / change in time (s)

Angle degrees of joint movement

Hip - flexion = positive and extension = negative.

Knee - flexion = high positive degrees and extension = low positive degrees.

Ankle- dorsiflexion = positive and plantar flexion = negative