Basic kinematic concepts

Basic Kinematics

Course Content

I. Introduction to the Course

II. Biomechanical Concepts Related to Human Movement

III. Anatomical Concepts Related to Human Movement

IV. Applications in Human Movement

Biomechanical Concepts

A. Basic Kinematic Concepts

B. Vector Algebra

C. Basic Kinetic Concepts

Basic Kinematic Concepts

1. Variables for Describing Motion

2. Reference Systems for Describing Motion of the Human Body and Its Segments

3. Guidelines for Describing Motion of the Human Body and Its Segments

Rigid Body Mechanics

Rigid BodyMechanics

Statics Dynamics

Constant Velocity Motionless

Kinematics Kinetics

Kinematics Kinetics

What is kinematics?

Spatial and temporal characteristics Qualitative or quantitative Linear & angular motion

Why use kinematics?

Practical: Provides a standard for us in performing, teaching, or evaluating a skill

Research: Once we describe, we can ask why?

Problem with kinematics? Practical: Proper kinematics does not always mean

proper force application



2. Reference Systems for Describing Motion of the Human Body & Its Segments

3. Guidelines for Describing Motion of the Human Body & Its Segments

Kinematic Variables

Time Position Displacement & distance Velocity & speed Acceleration

Time – Temporal Analysis

WHEN? HOW OFTEN? IN WHAT ORDER? HOW LONG?

Most basic analysis Examples:

Cadence Stride time Temporal patterning

Temporal Patterning

Temporal PatterningStance Swing

Absolute vs. Relative Timing

Position

position - location in space relative to some reference point

Linear position (s) x,y,z coordinates

Angular position () Units

WHERE?

Displacement & Distance

Displacement (s, ) Final change in position Vector quantity

Distance (p, ) Sum of all changes in

position Scalar quantity

HOW FAR?

Units (m, °)

Velocity & Acceleration

Velocity (v, ) Vector quantity position time Units (m.s-1, °.s-1)

Acceleration (a, ) Vector quantity velocity time Units (m.s-2, °.s-2) Insight into

forces/torques

HOW FAST?HOW QUICKLY IS VELOCITY CHANGING?


1. Types of Motion




Reference Systems: Linear

+x-x

-y

+y

+z

horizontal

vertical

horizontal

Must define origin of reference system to quantify kinematics.

0°

90°

180°

270°

rad½ rev

3/2 rad ¾ rev

/2 rad ¼ rev

2 rad 1 rev

Absolute Reference Systems: Angular

CCW +

Relative Reference Systems: Angular

Relative Reference Systems

Fundamental Standing Position

Anatomical Standing Position

All Joints @ 0except•Ankle @ 90•Forearm varies

Reference Systems for Measuring Joint Position & Displacement

0

90

140140

0

0 40 9090


1. Types of Motion




1. Distinguish between motion & position of joints & segments.

A B

2. Recognize that either segment can rotate about a joint.

3. Recognize that bones move linearly as well as angularly.

4. Understand that movement generally occurs in oblique planes around oblique axes.

5. When observing motion, look at the plane, down the axis.

Summary

1. Identify the system of interest2. Identify the type(s) of motion of interest3. Identify the reference system for the motion4. Describe precisely the temporal & spatial

characteristics of that motion using appropriate terminology for the situation

Time Position Displacement (ROM) Velocity Acceleration

For the next lecture day:

Lecture Topic #2 Subtopic C – Vector Algebra

Basic kinematic concepts

Documents

Transcript of Basic kinematic concepts