BIOMECHANICAL COURSE ENT 214

Final exam 50% Quizzes and assignments: 10% Mid term: 10% Lab : 30%

BASIC BIOMECHANICS

Define the terms biomechanics, static, dynamics, kinematics, and kinetics and explain the ways in which they are related.

Identify and describe the reference positions, planes, and axes associated with the human body.

Define and appropriately use directional terms and joint movement terminology.

Identify and describe the uses of available instrumentation for measuring kinematics quantities.

What is biomechanics?

Application of mechanical principles in the study of living organisms

mechanicsbio

Biomechanics/Mechanics

Statics : study of systems in constant motion, (including zero motion)

Dynamics : study of systems subject to acceleration

Biomechanics/mechanics

• Kinematics: study of the appearance or description of motion

• Kinetics: study of the actions of forces

Static

Mechanics

Dynamics

KineticsKinematics KineticsKinematics

Movement withconstant velocity

Force acting on the object at rest

and moving with constant velocity

Movement withacceleration

Force acting on the object moving with

acceleration

An area of physics that consists of the study of motion and

the effect of forces on an object

Kinematics

Biomechanics

Kinetics

Linear Angular

PositionVelocity

Acceleration

AngularLinear

PositionVelocity

Acceleration

Force Torque

KINESIOLOGY

Human movement •Identify discrete phases in an activity

•Describe segmental movements in each phases•Identify major muscle contributors to each joint

movement

Rising from chair •Movements of hip extension

•Knee extension•Plantarflexion

KINESIOLOGY The scientific study of human movement.

Human movement •Describing motion characteristics of human movement using parameters such as speed, direction, acceleration.

•Study on how motion is created through application of forces both insides and outside the body.

Rising from chair Measure and identify joint forces acting at the hip,

knee, and ankle along with the force between the foot and the floor (all of which act together to produce

the movement up out of the chair)

BIOMECHANICSThe applications of mechanics to human movement

BIOMECHANICS RESEARCH

DrOS (Housh, Housh and Johnson - 2003)

Developmental biomechanics

Evaluate fundamental movement patterns in performing gross (crawling, walking – involve large muscle group) and fine motor skills (manipulating small objects, transferring object – involve small muscle group).

BIOMECHANICS RESEARCHOccupational Biomechanics

Focuses on providing safe and efficient working environment, both indoors and outdoors.

Better Safety equipment – helmets, shin guards,footwear to protect from any work hazards.

Safe and ergonomic working tools to minimize overuse injuries of both upper and lower limbs

Designing of mass public transportation – airplanes,trains,boats and automobiles for safety and efficiency.

Close allied with the science of ergonomics

BIOMECHANICS RESEARCH

Rehabilitative Biomechanics

Observe movement patterns of individuals who are either injured or/and disabled, provide appropriate interventions which enable injured and disabled person to function as close to, if not normally.

Develop exercise equipment, supplementary aids such as walkers, orthotics and even substitution devices such as prostheses for rehabilitation purposes.

BIOMECHANICS RESEARCHExercise and Sport Biomechanics

Describe technique and movement patterns, quantify the contributions of joint actions to technique and in some cases, to predict and evaluate optimal conditions of performance

Integrate the use of exercise machines for improving strength, endurance, flexibility and speed.

Minimize sport related injuries and enhancing performance

Make improvements on equipment such that it is comfortable, easier to use, and provide a safe and effective resistance for improving training and performance.

Qualitative vs Quantitative Analysis

Qualitative: pertaining to quality (without the use of numbers)

Quantitative: involve numbersBoth are important for biomechanical analysis of human motion. Some rely on quantitative, some on qualitative analysis.

ASSIGNMENTIn a group of two, write a summary of two

activities involving human motion analysis.

Identify the following items:

1. What are the problems that encourage the writers to do such research? (10 marks)

2. What are the parameters involve in such analysis? (5 marks)

3. What are the equipments and method used in conducting the experiments? (5 marks)

4. Brief explanation on the results (15marks)

5. What are the things to be considered in the future related to the experiment? (15 marks)

•The assignment should be submitted within a month from the first lecturer.• Mark will be given according to explanation given (easy to understand, figures and other initiatives) •Please use MICROSOFT WORDS to write the assignment.•Any late report will have penalties on the marks.

ASSIGNMENT 1

Chapter 2

Kinematic Concepts for Analyzing Human Motion

Identify and describe the reference positions, planes, and axes associated with the human body.

Define and appropriately use directional terms and joint movement terminology.

Identify and describe the uses of available instrumentation for measuring kinematics quantities.

What is anatomical reference position?

Erect standing position with all body parts facing forward.Considered the starting point for all body segment movements

BODY SEGMENT NAMES

•AXIAL •Accounting50% of body weight•Moves slower the other parts of the body

APPENDICULAR•The lower and upper extremity•Away from trunk become smaller, •faster and their movement• is difficult to observe

UpperarmForearm Hand

NECK

TRUNK

Head

Thigh

Leg

Foot

Upper E

xtre

mity

Low

er E

xtre

mity

Directional Terms

Superior: closer to the head.

Inferior: farther away from the head.Medial: toward the midline of the body.Lateral: away form the midline of the body.

Directional Terms

Anterior: toward the front of the bodyPosterior: toward the back of the bodyProximal: closer to the trunkDistal: away from the trunk

Directional Terms

Superficial: toward the surface of the body

Deep: inside the body away from the surface

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

Reference Axes

Mediolateral axis - around which rotations in the sagittal plane occur

Anteroposterior axis - around which rotations in the sagittal plane occur

Longitudinal axis - around which rotational movements occur

FORM OF MOTION

LinearMotion

Rectilinear Motion

Curvelinear Motion

AngularMotion

General Motion

+

=

= along a straight line

= along a curved line

= Combination of linear motion and angular motion

= rotation around an axis

Forms of MotionLinear motion: motion along a line

Rectilinear motion: (along a straight line)

Curvilinear motion: (along a curved line)

GENERAL MOTION

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

THE MOVEMENTS DESCRIPTION

The six basic movement descriptorsFlexion, extension,

Abduction, adduction,

Rotation (medial and lateral).

Specialized movement descriptorsHead and trunk only

Lateral flexion

Shoulder girdle movementElevation, depression

Protraction and retraction (adduction and abduction in scapula)

Upward and downward rotation

THE MOVEMENTS DESCRIPTIONSpecialized movement descriptors

Arm and thigh

Horizontal abduction and adduction

Forearm

Pronation and supination

Wrist joint

Radial and ulnar flexion

Foot

Plantar and dorsiflexion

Inversion and eversion

Pronation and supination

MOVEMENTS IN THE SAGITTAL PLANEFlexion

Anteriorly directed sagittal plane rotations of the head, trunk, upper arm, forearm, hand and thigh.

Posteriorly directed sagittal plane rotation of the lower leg.

Bending movement in which the relative angle of the joint between 2 adjacent segements decreases.

Extension

Return the body to the anatomical position.

Straightening movement in which the relative angle of the joint between 2 adjacent segments increases as the joint return to the reference position.

Hyperextension

MOVEMENTS IN THE SAGITTAL PLANE

Hyperflexion (Hyperextension) – movement that goes beyond the normal range of flexion (extension - movement that goes beyond the anatomical reference position and opposite of flexion)

Dorsiflexion Plantar flexion

Dorsiflexion: bringing the top of the foot toward the Tibia, angle between the leg and foot decrease.

Plantarflexion: opposite motion of Dorsiflexion, bottom of the foot moves down and the angle between the leg and foot increase.

SAGGITAL PLANE MOVEMENT

Movements in the frontal plane• Abduction & adduction – move a body segment away from and closer to the midline of the body, respectively.

Abduction Adduction

Lateral flexion Bending to one side.

The term lateral flexion is used to describe motions of the trunk and neck.

Elevation & depression Movement of shoulder

girdle in the superior and inferior direction

Lateral flexion

Elevation Depression

Inversion & eversion Inward and outward

rotation of the sole of the foot, respectively.

What is wrist radial and ulnar deviation?Radial and ulnar deviation is the side-to-side movement of the hand at the wrist, toward or away from the thumb. Radial deviation causes up to a 20% reduction in hand strength with just 25 ° of motion from a neutral position. At 40% Ulnar deviation a similar drop in available strength is observed (see illustration).

                                 

Eversion Inversion

Radial & ulnar deviation Side-to-side movement of the hand at the wrist, toward and away from the thumb, respectively.

Movements in the transverse plane

Left & right rotation (head, neck, trunk)

Medial rotation

Lateral rotation

Medial (internal) & lateral (external) rotation – toward midline and away from midline, respectively.

Supination – Outwards or upwards.

Frontal Plane Rotation of a body part, usually

the hand and forearm so that the palm is down.

Transverse Plane Rotation of the forearm,

outwards and inwards. In the foot (subtalar joint), it is

a combination of motions resulting in a position such that the foot is abducted and everted.

Pronation – Inwards or downwards.

Oppose the supination

Pronation

Supination

**Horizontal abduction & adduction

Horizontal adduction

Horizontal abduction

Adduction - from lateral to anterior position (also called horizontal flexion)

Abduction – from anterior to lateral position (also called horizontal extension)

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.

Spatial Reference Systems

(0,0)X

Y

(x,y) = (3,7)

Cartesian coordinates of the hip

Spatial Reference Systems

Coordinates can be both positive and negative.

x

y

(0,0)

x = +y = +

x = -y = +

x = -y = -

x = +y = -

TOOLS FOR MEASURING KINEMATIC QUANTITIES

Direct Measurement Techniques Goniometers

Special Joint Angle Measuring Systems

Accelerometers

Indirect Measurement (Imaging) TechniquesCinematography

Television

Optoelectric technique

Others indirect measurement

Objective: To determine the coordinates of the marked points as a function of time

TOOL FOR KINEMATICS MEASUREMENT OPTICAL SYSTEM

Cinematography (movie cameras) Type of film use depend on lighting available,

Television

The major difference between Cinematography and Television is the frame rate (The number of images that are shown or sent each second) , where the Television has a fixed frame rate (50 or 60 Hz).

Television has high enough field rate for most movement, but too low for quantitative analysis of rapid athletic movement.

•Standard video camera – reflective marker produces a trailing edge and blurs image when there is a rapid movement.

•CCD cameras – eliminates both blurring and skewing

•Infrared cameras – reflected infrared lights from the markers is the only lights picked up by the camera.

Non Optical techniquesMagnetic System – Sensors are linked

by cables to a computer.Electromagnetic System – the subjects

wear a body suit.Acoustic Systems –Sonar uses

reflected sound waves.

Optoelectric Techniques - optical

Subject wear tiny infrared lights on each desired anatomical landmarks. The lights were flashed sequentially, and detected on a special camera.

Advantages and Disadvantages of Optical SystemsAdvantages

Most systems are not limited to the numbers of markers used.

Encumbrance to movement is minimal (lightweigth reflective markers).

Inexpensive (VCR and TV cameras).

TV and Cine can be replayed for teaching purposes or for qualitative analysis of the total body movement.

Disadvantages

Most multiple cameras are expensive.

Some imaging system cannot be used outdoor.

TUTORIAL FOR NEXT WEEK

In a group of 5, write a five minute presentation on the motion capture system. The presentation will be done during the tutorial session.

The purpose of the presentation is to identify and describe the type of kinematics measuring equipment that are currently available.

Includes:1. Classification (imaging – Cinematography, Television,

Optoelectric technique; Other techniques - Magnetic, electromagnetic, acoustic or any other technique).

2. Advantage and disadvantages of the system (cost, limitation in place, and other factors to be considered)