chapter 2 kinematic concepts for analyzing human motion basic biomechanics, 6 th edition by susan j....

Chapter 2

Kinematic Concepts for Analyzing Human

MotionBasic Biomechanics, 6th edition

By Susan J. Hall, Ph.D.

© 2012 The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill/Irwin

2-2

What is anatomical reference position?

• erect standing position with all body parts facing forward• considered the starting point for all body segment movements

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

2-3

posterior: toward the back of the body

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

Directional terms:

inferior: farther away from the head

anterior: toward the front of the body

superior: closer to the head

medial: toward the midline of the bodylateral: away from the midline of the body

proximal: closer to the trunk

distal: away from the trunk

superficial: toward the surface of the body

deep: inside the body away from the surface

2-4

Reference planes:

• sagittal plane - in which forward and backward movements occur

• frontal plane - in which lateral movements occur

• transverse plane - in which rotational movements occur

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

2-5

Reference axes:

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

Longitudinal axis - directed vertically and around which rotational movements occur

Anteroposterior axis – directed along the sagittal plane and around which rotations in the frontal plane occur

Mediolateral axis – directed along the frontal plane and around which rotations in the sagittal plane occur

2-6

Forms of motion:

Linear motion: motion along a line

• Rectilinear motion: (along a straight line)

• Curvilinear motion: (along a curved line)

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

2-7

Forms of motion:

Angular motion: rotation around an axis

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

2-8

Forms of motion:

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

Rectilinear motion

Curvilinear motion

Angular motion

2-9

Forms of motion:

General motion: a combination of linear and angular motion (includes most human motion)

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

2-10

What is a mechanical system?

• a body or portion of a body that is deliberately chosen by the analyst• examples: throwing arm, kicking leg, the trunk during performance of a lift, the entire body during performance of a maximal vertical jump

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

2-11

Flexion Extension Hyperextension

Dorsiflexion Plantar flexion

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

What movements occur in the sagittal plane?

2-12

What movements occur in the frontal plane?

Abduction Adduction

Lateral flexion

Elevation Depression

Radial deviation

Ulnar deviation

Eversion Inversion

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

2-13

What movements occur in the transverse plane?

Medial rotation

Lateral rotation

Pronation Supination

Horizontal adduction

Horizontal abduction

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

2-14

Spatial Reference Systems

• useful for standardizing descriptions of human motion• most commonly used is the Cartesian coordinate system• human body joint centers are labeled with numerical x and y coordinates

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

2-15

Spatial Reference Systems

(0,0)X

Y

(x,y) = (3,7)

Cartesian coordinates of the hip

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

2-16

Spatial Reference Systems

Coordinates can be both positive and negative.

x

y

(0,0)

x = +y = +

x = -y = +

x = -y = -

x = +y = -

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

2-17

Qualitative Analysis:

Prerequisite Knowledge

• What is the purpose of the skill?• What are the causes of performance errors? • How can knowledge be gained?

• experience in performing the skill• reading available literature• attending conferences and workshops

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

2-18

Qualitative Analysis:

Planning

• What is the question to be answered?

• From what perspectives (angle and viewing distance) should the movement be viewed?

• How many observations should be taken?

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

2-19

Qualitative Analysis:

Planning

• What plans should be made for:

• performer attire

• lighting conditions

• background

• use of video

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.

2-20

Qualitative Analysis:

Conducting the Analysis

IdentifyQuestion/Problem

Make Decisions

Interpret Observations

Viewing Angle

Viewing Distance

Performer Attire

EnvironmentalModifications

Use of Video

Auditory

From Performer

From Other Analysts

CollectObservations

Communicatewith Performer

End Analysis

Visual

Refine Question

Basic Biomechanics, 6th editionBy Susan J. Hall, Ph.D.