Download Biomechanics of the Upper Limbs - A. Freivalds (CRC, 2004) WW PDF

TitleBiomechanics of the Upper Limbs - A. Freivalds (CRC, 2004) WW
TagsMedical
LanguageEnglish
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Total Pages625
Table of Contents
                            Preface
The Author
Acknowledgements
Contents
1
	Introduction to Biomechanics
		1.1 What Is Biomechanics?
		1.2 Basic Concepts
		1.3 Coordinate Systems
		1.4 Force Vector Algebra
		1.5 Static Equilibrium
		1.6 Anthropometry and Center of Mass Determination
		1.7 Friction
		1.8 Dynamics
		Questions
		Problems
		References
2
	Structure of the Musculoskeletal System
		2.1 Gross Overview of Movements
		2.2 The Skeletal System
		2.3 Mechanical Properties of Bone
		2.4 Soft Connective Tissue
		2.5 Joints
			2.5.1 Articular Joints
			2.5.2 Joint Lubrication
			2.5.3 Wear and Osteoarthritis
			2.5.4 Cartilaginous Joints
		Questions
		Problems
		References
3
	Neuromuscular Physiology and Motor Control
		3.1 Introduction to Musculature
		3.2 Structure of Muscle
		3.3 Basic Cell Physiology
		3.4 The Nervous System
		3.5 The Excitation-Contraction Sequence
		3.6 Motor Units
			3.6.1 Types of Motor Units
			3.6.2 Motor Unit Twitch
		3.7 Basic Muscle Properties (Mechanics)
			3.7.1 Active Length-Tension Relationship
			3.7.2 Passive Length-Tension Relationship
			3.7.3 Velocity-Tension Relationship
			3.7.4 Active State Properties
			3.7.5 Developments Leading to Hill’s Muscle Model
			3.7.6 Fatigue and Endurance
		3.8 Energy, Metabolism, and Heat Production
		3.9 Receptors
			3.9.1 Muscle Spindles
			3.9.2 Golgi Tendon Organs
			3.9.3 Other Receptors
		3.10 Reflexes and Motor Control
			3.10.1 Stretch Reflex
			3.10.2 g-Loop Control
			3.10.3 a-g Coactivation
			3.10.4 Reciprocal Inhibition
			3.10.5 Clasp-Knife Reflex
			3.10.6 Other Polysynaptic Reflexes
		Questions
		Problems
		References
4
	Modeling of Muscle Mechanics
		4.1 Laplace Transforms and Transfer Functions
			4.1.1 Partial Fraction Expansion
			4.1.2 Transfer Functions
		4.2 Viscoelastic Theory
		4.3 Hill’s Muscle Models
			4.3.1 Active Muscle Response
			4.3.2 Tension Buildup
			4.3.3 Stress Relaxation
			4.3.4 Creep
			4.3.5 Time Constant
		4.4 Frequency Analysis
			4.4.1 Generalized Approach
			4.4.2 Magnitude and Phase Angle in the Frequency Domain
			4.4.3 Magnitude and Phase Angle in the Laplace Domain
		4.5 Frequency Analysis of Passive Muscle
		4.6 Hatze’s Multielement Model
		4.7 Applications of the Hatze Muscle Model
		4.8 Control Theory and Motor Control
			4.8.1 Basic Concepts
			4.8.2 First-Order System
			4.8.3 Second-Order System
			4.8.4 Human Information Processing and Control of Movements
		4.9 Root Locus Approach to Muscle Modeling
			4.9.1 The Root Locus Method
			4.9.2 Muscle Spindle Model
			4.9.3 Time Delays
			4.9.4 Velocity Control
			4.9.5 Reflex Stiffness
		Questions
		Problems
		References
5
	Models of the Upper Limbs
		5.1 Anatomy of the Hand and Wrist
			5.1.1 Bones of the Hand and Wrist
			5.1.2 Joints of the Hand
			5.1.3 Muscle of the Forearm, Wrist, and Hand
			5.1.4 Flexor Digitorum Profundus and Flexor Digitorum Superficialis
			5.1.5 Flexor Tendon Sheath Pulley Systems
			5.1.6 Wrist Mechanics
			5.1.7 Select Finger Anthropometry Data
		5.2 Static Tendon-Pulley Models
		5.3 Dynamic Tendon-Pulley Models
		5.4 Complex Tendon Models
			5.4.1 Reduction Methods
			5.4.2 Optimization Methods
			5.4.3 Combined Approaches
		5.5 A Two-Dimensional Hand Model
		5.6 Direct Measurement Validation Studies
		5.7 Critical Evaluation of Modeling Approaches
		Questions
		Problems
		References
6
	Musculoskeletal Disorders and Risk Factors
		6.1 The Extent of the Problem
		6.2 Common MSDs and Their Etiology
			6.2.1 Tendon Disorders
			6.2.2 Muscle Disorders
			6.2.3 Nerve Disorders
			6.2.4 Vascular Disorders
			6.2.5 Bursa Disorders
			6.2.6 Bone and Cartilage Disorders
		6.3 Medical Diagnosis and Treatment of MSDs
		6.4 Epidemiologic Approach to MSDs
			6.4.1 Introduction to Epidemiology
			6.4.2 Statistical analyses
			6.4.3 Multivariate Modeling
			6.4.4 Quality of Epidemiological Research
		6.5 The Scientific Research and Evidence for Occupational Risk Factors
			6.5.1 Neck Disorders
			6.5.2 Shoulder Disorders
			6.5.3 Elbow Disorders
			6.5.4 Hand/Wrist - Carpal Tunnel Syndrome
			6.5.5 Hand/Wrist - Tendinitis
			6.5.6 Hand/Arm - Vibration Syndrome
		6.6 The Scientific Research and Evidence for Psychosocial Risk Factors
		6.7 Iatrogenesis - A Contrarian View
		Questions
		Problems
		References
7
	Instrumentation
		7.1 Introduction
		7.2 Wrist and Finger Motion Measurement
			7.2.1 Types of Measurement Devices
			7.2.2 Calibration Methods
			7.2.3 Static Measurements - Range of Motion
			7.2.4 Dynamic Measurements - Angular Velocity and Acceleration
		7.3 Pressure and Force Distribution Measurements
			7.3.1 Early Pressure Devices
			7.3.2 Force Sensing Electronic Components
			7.3.3 Integrated Touch Glove System
		7.4 Nerve Conduction Measurements
			7.4.1 Basic Concepts
			7.4.2 Nerve Stimulation and Recording
			7.4.3 Response Measures
			7.4.4 Limitations
		7.5 Electromyography
			7.5.1 EMG Instrumentation
			7.5.2 EMG Analysis
		Questions
		Problems
		References
8
	Job and Worksite Analysis
		8.1 The Need for Job Analysis
		8.2 Reliability and Validity of Assessment Tools
			8.2.1 Basic Concepts
			8.2.2 Reliability of Assessments
			8.2.3 Reliability of Analysts
			8.2.4 Accuracy and Precision
			8.2.5 Applications
		8.3 Initial Identification of Musculoskeletal Injury Problems
			8.3.1 Initial Steps
			8.3.2 Surveys and Subjective Ratings
				8.3.2.1 Symptom Surveys
				8.3.2.2 Body Discomfort Maps
				8.3.2.3 Subjective Ratings
				8.3.2.4 Nordic Questionnaire
			8.3.3 Limitations of Surveys
		8.4 Gross Posture and Task Analyses
			8.4.1 Early Recording of Postures
			8.4.2 OWAS
			8.4.3 Posture Targeting
			8.4.4 RULA
			8.4.5 Video Posture Analyses
			8.4.6 Task Analyses
		8.5 Quantitative Upper Limb WRMSD Risk Assessment Tools
			8.5.1 Checklists
			8.5.2 Strain Index
			8.5.3 OCRA
			8.5.4 Recent Developments
		8.6 Data-Driven Upper Limb WRMSD Risk Index
		Questions
		Problems
		References
9
	Hand Tools
		9.1 Introduction
			9.1.1 Historical Development of Tools
			9.1.2 Tools and Musculoskeletal Injuries
			9.1.3 General Tool Principles
		9.2 General Biomechanical Considerations of Tools
			9.2.1 Anatomy and Types of Grip
			9.2.2 The Biomechanics of a Power Grip
			9.2.3 The Biomechanics of a Precision Grip
			9.2.4 Measurement of Skin Coefficient of Friction
			9.2.5 Grip Force Coordination
			9.2.6 Static Muscle Loading
			9.2.7 Awkward Wrist Position
			9.2.8 Tissue Compression
			9.2.9 Repetitive Finger Action
		9.3 Handles for Single-Handled Tools
			9.3.1 Handle Length
			9.3.2 Handle Diameter
			9.3.3 Handle Shape
			9.3.4 Texture and Materials
			9.3.5 Angulation of Handle
		9.4 Handles for Two-Handled Tools
			9.4.1 Grip Span
			9.4.2 Gender
			9.4.3 Handedness
		9.5 Other Tool Considerations
			9.5.1 Posture
			9.5.2 Weight
			9.5.3 Gloves
			9.5.4 Vibration
			9.5.5 Rhythm
			9.5.6 Miscellaneous
		9.6 Agricultural and Forestry Tools
			9.6.1 Shovels and Spades
				9.6.1.1 Shoveling Rate
				9.6.1.2 Shovel Load
				9.6.1.3 Throw Height
				9.6.1.4 Throw Distance
				9.6.1.5 Posture
				9.6.1.6 Technique
				9.6.1.7 Lift Angle
				9.6.1.8 Length of Handle
				9.6.1.9 Handle Material
				9.6.1.10 Shovel Weight
				9.6.1.11 Blade Size, Shape, and Thickness
			9.6.2 Axes and Hammers
				9.6.2.1 Length and Striking Efficiency
				9.6.2.2 Weight and Striking Efficiency
				9.6.2.3 Other Considerations
			9.6.3 Saws
				9.6.3.1 General Considerations
				9.6.3.2 Pulling vs. Pushing
			9.6.4 Other Agricultural Tools
				9.6.4.1 Hoes
				9.6.4.2 Wheelbarrows
		9.7 Industrial Tools
			9.7.1 Pliers
			9.7.2 Screwdrivers
			9.7.3 Knives
			9.7.4 Meat Hooks
			9.7.5 Power Tools
				9.7.5.1 Power Drills
				9.7.5.2 Nutrunners
				9.7.5.3 Handle Sizes
			9.7.6 Railroad Tools
			9.7.7 Mining Tools
			9.7.8 Miscellaneous Tools
				9.7.8.1 Soldering Irons
				9.7.8.2 Surgical Instruments
				9.7.8.3 Dental Instruments
				9.7.8.4 Food Scoops
				9.7.8.5 Writing Instruments
				9.7.8.6 Scissors
				9.7.8.7 Toothbrushes
		Questions
		Problems
		References
10
	The Office Environment
		10.1 General Musculoskeletal Problems
		10.2 The Seated Workplace
			10.2.1 Seated Posture
				10.2.1.1 The Spine
				10.2.1.2 Disc Compression Forces
				10.2.1.3 Electromyography
			10.2.2 Seated Posture at a Computer Workstation
				10.2.2.1 Standard Posture
				10.2.2.2 Screen Height
				10.2.2.3 Screen Distance
				10.2.2.4 Arm Support
				10.2.2.5 Alternate Posture
			10.2.3 Determination of Seated Comfort
				10.2.3.1 Fitting Trials
				10.2.3.2 Postural Changes
				10.2.3.3 Task Performance
				10.2.3.4 Subjective Assessment
				10.2.3.5 Physical Measures
			10.2.4 Seat Pressure
				10.2.4.1 Seat Pressure Distribution
				10.2.4.2 Sores and Ulcers
				10.2.4.3 Adaptive Seats
				10.2.4.4 Cushioning
				10.2.4.5 Two-Stage Seats
				10.2.4.6 Foot Pressure
			10.2.5 Sit-Stand, Forward-Sloping, and Saddle Chairs
				10.2.5.1 Sit-Stand Chairs
				10.2.5.2 Trunk-Thigh Angle
				10.2.5.3 Forward-Sloping Chairs
				10.2.5.4 Saddle Chairs
				10.2.5.5 Compromise Seat Pan
			10.2.6 Work Surface and Line of Sight
				10.2.6.1 Work Surface Height
				10.2.6.2 Line of Sight
				10.2.6.3 Tilted Work Surface
				10.2.6.4 Working Area
				10.2.6.5 Workspace Envelope
		10.3 The Keyboard
			10.3.1 Standard Keyboard Features
				10.3.1.1 Keyboard Slope
				10.3.1.2 Keyboard Profile
				10.3.1.3 Key Size, Displacement, and Resistance
				10.3.1.4 Key Feedback
				10.3.1.5 Keying Forces
			10.3.2 Split and Sloped Keyboards
				10.3.2.1 Standard Keyboard Problems
				10.3.2.2 Optimum Split Angles
				10.3.2.3 Performance Effects
				10.3.2.4 Negative-Slope Keyboards
			10.3.3 Layout of Keys
				10.3.3.1 Standard QWERTY Layout
				10.3.3.2 Dvorak Layout
				10.3.3.3 Other Layouts
			10.3.4 Chord Keyboards
			10.3.5 Numeric Keypads
		10.4 The Mouse and Other Cursor-Positioning Devices
			10.4.1 Cursor Positioning
			10.4.2 The Mouse
			10.4.3 Mouse Alternatives
		10.5 Notebooks and Handheld PCs
		10.6 Control Measures
			10.6.1 Rest Pauses
			10.6.2 Exercises
		Questions
		References
Glossary
Name Index
Subject Index
                        
Document Text Contents
Page 2

BIOMECHANICS OF
THE UPPER LIMBS
Mechanics, Modeling, and
Musculoskeletal Injuries

Page 312

Musculoskeletal Disorders and Risk Factors 293
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294 Biomechanics of the Upper Limbs

also be the case for back pain; Hadler, 1986; Frank et al., 1995). It is also an
adversarial system, in which if the condition is not improving rapidly, claim-
ants cannot back out easily without casting doubt on their original claims
and symptoms. The worker is indicted partially for being gullible and suc-
cumbing to general rumors or media alarms and partially for being greedy
and seeking easy compensation. Ergonomists and other researchers are
faulted for methodological problems in cross-sectional studies (which are
the vast majority in the epidemiological studies cited in Section 6.5) in which
prevalence or morbidity depends on reporting recall, volunteer biases, and
difficulty in distinguishing between etiological and forecasting factors (Sack-
ett, 1979). There are also sociological aspects such as sustained media interest
and sensationalism, strong union support for “empowering the dispos-
sessed,” and, sometimes, an almost Luddite reaction to high-technology
advancements (Arksey, 1998).

Similar to the “nature vs. nurture” concept in child development, there is
probably some truth to the iatrogenic concept. Many of the above arguments
can be found to occur, especially in extreme cases. Also, anecdotally (and
from personal experience) there seems to be an increase in the reporting of
MSDs upon completion of a symptom survey or participation in an ergo-
nomics awareness program. This is only natural. Worker awareness has been
increased and the person realizes there is a cause for the discomfort or pain
that the person is already experiencing, making it easier to go to the plant
nurse and report the problem. However, this increase in incidence rates is
typically only a spike, which then should decrease below previous levels,
once an ergonomics program has been implemented or, in the worst case,
return to preexisting levels, once work returns to the status quo.

There are undoubtedly overlapping and confounding psychosocial and
individual factors that exacerbate the development of MSDs by amplifying
already existing strains and pains that normally result with many jobs.
Unhappiness with the job, the supervision, pay, etc. were all shown to be
contributory factors to MSDs. The key, however, is existing strains and pains.
It would be unreasonable to expect that job unhappiness in itself would lead
to MSDs. There has to be some underlying physical cause first. To completely
eliminate the physical occupational stressors seems foolhardy at the least
and potentially very costly, both to the company and to the individual
workers. On the other hand, equal attention should also be given to the
mental well-being of the worker. The company may be pleasantly surprised
by increased productivity through increased worker motivation and the
Hawthorne effect (Niebel and Freivalds, 2003).

Questions
1. Describe the etiology of tendon-related disorders.
2. What are some of the common tendon-related disorders?

Page 624

605

ulnar nerve 239, 241, 247–248, 336
ultimate tensile strength 40–41, 568
undamped 156, 158–159, 568
underdamped 156, 157–159, 184, 568
unipennate 568
unipolar 343, 569
unit impulse 108, 569
unit membrane theory 60, 569
unit step function 101, 123–124, 179, 569

V

validity 362, 569
construct 362
criterion 362
face/content 362
predictive 362

vector 5–8, 569
angle 7
cross product 8
dot product 8
magnitude 7
resultant 7
right-hand rule 8

velocity 23–24
velocity control 184–185
velocity-tension relationship 74–76
vertebrae 25, 63
vibration 241–242, 247, 440
viscoelastic theory 109–116, 569

creep 114–115
dashpot 109–110
elasticity 109
final value theorem 116
initial value theorem 116
Kelvin body 112–113
Maxwell fluid 110–111
spring 109
strain retardation 113–115
stress relaxation 113–116
viscosity 109
Voigt solid 110, 112

viscosity 109

visual analogue scale 377, 569
Voigt solid 110, 112

W

Wald statistic 268, 569
whiplash 92
white finger syndrome 242, 569
white matter 89, 569
Wolff’s Law 36, 43, 569
work surface 495–502

height 495
normal line of sight 497–500
normal working area 500–501
tilted 499–500
workspace envelope 500–502

work-related musculoskeletal disorders
(WRMSDs, see musculoskeletal
disorders)

work-rest cycles 79, 81–83, 519–520
work-space envelope 500, 502, 570
woven bone 570
wrist joint 16, 27, 419
wrist motion measurement 311–320

acceleration 317–320
angular velocity 317–320
calibration 313–316
range of motion 316–317

writer’s cramp 238, 473, 570

Y

yield point 40–41, 570
Young’s modulus 41

Z

z-discs 59, 570
zero 163, 167, 570
zero drift 313, 570

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