ergonomic investigation of hand tools (case study: bottle...
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UNIVERSITI TEKNIKAL MALAYSIA MELAKA
Ergonomic Investigation of Hand Tools
(Case Study: Bottle Opener)
Thesis submitted in accordance with the partial requirements of the
Universiti Teknikal Malaysia Melaka for the
Bachelor of Manufacturing Engineering (Manufacturing Design)
By
Noor Rahimi binti Idiris
Faculty of Manufacturing Engineering
May 2007
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APPROVAL
This thesis submitted to the senate of UTeM and has been accepted as partial
fulfillment of the requirement for the degree of Bachelor of Manufacturing Engineering
(Manufacturing Design). The members of the supervisory committee are as follows:
…………………………………………
Main supervisor
Faculty of Manufacturing Engineering
………………………………………….
Co-supervisor
Faculty of Manufacturing Engineering
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DECLARATION
I hereby, declare this thesis entitled “Analysis of Plastic Flow inside the Three Plate
Mould” is the result of my own research
except as cited in the references.
Signature :.............................................................................
Author’s Name :………………………………………………….
Date :………………………………………………….
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ABSTRACT
Hand and finger force data are used in many settings, including industrial design and
indicating progress during rehabilitation. Forceful exertion of the hand is considerable
stress endured by users of hand tools that may also be one of the factors that lead to the
development of work-related musculoskeletal disorders (WRMSDs). The application of
appropriate work design principles, during the design of tools and workstations that
involve the use of the hand and fingers, may minimize upper extremity injuries within
the workplace. Whether ergonomics is handled by plant teams, safety professionals, or
trained ergonomists, there is often a need for systematic assessments to identify and
quantify injury risk and opportunity potential. Ergonomic analysis tools are designed to
meet these needs. This study is about ergonomic investigation of hand tools which
focusing on bottle opener. The investigation concentrates on ergonomic analysis tools
that are RULA analysis, ACGIH TLV and Strain Index. This study examined whether
exerted finger force could be analyze using the ergonomic analysis tools. Following the
methodology, firstly ergonomic analysis tools were investigated by analyzing the
activity of opening bottle. The data of pinching and gripping strength were taken among
Malaysian population. Data of grip strength and pinch strength are crucial in designing
hand tools. Hand tools design that properly fit the user will help reduce cumulative
trauma disorders (CTDs) and carpal tunnel syndrome in tasks that involve gripping and
pinching. Hopefully in the future there will be ergonomic analysis tools to analyze finger
force and prevent any injuries.
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ABSTRAK
Data untuk kekuatan daya tangan dan jari digunakan dalam banyak perkara, termasuk
dalam rekabentuk industi dan dalam menetukan perkembangan sesuatu pemulihan. Daya
yang dikeluakan oleh tangan boleh dianggap tekanan yg ditahan oleh pengguna
peralatan tangan yang boleh membawa kepada berlakunya penyakit work-related
musculoskeletal disorders (WRMSDs). Penggunaan prinsip rekabentuk kerja yang
sesuai ketika merekabentuk peralatan dan tempat kerja yang melibatkan penggunaan
tangan dan jari boleh mengurangkan kecederaan bahagian atas badan dalam tempat
kerja. Sama ada ergonomik dikendalikan oleh kumpulan perancang, pekerja keselamatan
yang professional atau pelatih ergonomik, selalunya akan terdapat keperluan untuk
penilaian sistematik bagi mengenalpasti dan menjumlahkan potensi serta risiko
kecederaan. Alat-alat analisis ergonomik direka untuk memenuhi keperluan ini. Kajian
ini adalah berkaitan dengan penyiasatan peralatan tangan yang ergonomik yang
memfokuskan kepada pembuka botol. Penyiasatan bertumpu kepada peralatan analisis
ergonomik iaitu analisis RULA, ACGIH TLV dan Strain Index. Kajian ini memeriksa
cara alat-alat ergonomik digunakan. Berpandukan kepada kaedah kajian, peralatan
analisis ergonomik disiasat dengan menganalisis aktiviti membuka botol. Data kekuatan
mencubit dan menggenggam diambil di kalangan orang Malaysia. Data kekuatan
mencubit dan menggenggam sangat penting dalam merekabentuk peralatan tangan.
Rekabentuk peralatan tangan yang sesuai dengan tangan pengguna akan menolong
mengurangkan Cumulative Trauma Disorders (CTDs) dan Carpal Tunnel Syndrome
(CTS) dalam melakukan aktiviti mencubit dan menggenggam. Semoga pada masa
hadapan terdapat peralatan analisis ergonomik bagi menganalisis daya jari dan
mengelakkan sebarang kecederaan.
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DEDICATION
To my lovely parents:
Idiris bin Abdullah
Siti Aeshah binti Yusoff
For your love and demonstration the values of education since I’m still a kid.
To my siblings:
Siti Norzuraini binti Idiris
Mohd Sobri bin Idiris
Zulkifli Bin Idiris
Afuza Abdullah bin Idiris
For your love, encouragement, and support on this project was absolutely invaluable.
To my special Lecturer:
Puan Seri Rahayu binti Kamat
Mr. Norakramin bin Mohamad
For your guidance and helping in finishing this project.
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ACKNOWLEDGEMENT
In the name of Allah, Most Gracious, Most Merciful.
All praises to the Almighty Allah for giving me the strength, patience and
guidance throughout the process of completing this research study. I am grateful to have
the support and motivation from many people throughout completing this study and I
would love to take this opportunity to thank those who are either directly or indirectly
involved during this study is conducted.
Most immediately, a special gratitude goes to my respective supervisor, Puan
Seri Rahayu binti Kamat for her precious advices, time, contributions, comments, and
guidance in every stage of this study. Mt utmost gratitude also goes out to all lecturers
From the Faculty of Manufacturing Engineering for being a very nice and effective
lecturer to me and thus, making this study easier to be completed.
My token of appreciation also goes to my beloved family members who never failed to
be there for their love, supports and prayers. Last but not least, I would like to thank to
all my friends, especially my classmates for their never ending supports.
May Allah bless to all of you.
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TABLE OF CONTENTS
Abstract i
Dedication ii
Acknowledgements iii
Table of contents v
List of Tables viii
List of Figures x
List of Abbreviations xi
1.0 INTRODUCTION
1.1 Introduction 1
1.2 Objectives 2
1.3 Project Scope 2
1.4 Problem Statements 3
2.0 LITERATURE REVIEW
2.1 Introduction 4
2.2 Common ergonomic analysis tools 4
2.3 RULA analysis 6
2.4 ACGIH HALTV 7
2.4.1 Assessment of Hand Activity Level 8
2.4.2 Assessment of Normalize Peak Force 10
2.4.3 How the tool work 11
2.5 Strain Index 12
2.6 Human Hand 17
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2.7 Functional anatomy of the hand 18
2.8 Hand strength 19
2.9 Injuries of hand 21
2.10 Measurement devices 22
2.10.1 Jamar Hydraulic Hand Dynamometer 23
2.10.2 Recommend testing position 24
2.10.3 Normative data 26
2.10.4 Jamar Hydraulic Pinch Gauge 26
2.11 Summary of literature review 28
3.0 METHODOLOGY
3.1 Introduction 30
3.2 Methodology 30
3.3 Methodology of project 36
4.0 RESULTS 37
4.1 Introduction
4.2 RULA analysis 37
4.3 ACGIH HALTLV 41
4.3.1 Hand activity level 41
4.3.2 Normalized Peak Forces 43
4.4 Strain Index Analysis 47
4.4.1 Intensity of exertion 47
4.4.2 Duration of exertion 48
4.4.3 Efforts per minute 50
4.4.4 Hand/Wrist posture 50
4.4.5 Speed of work 51
4.4.6 Duration of task per day 52
4.4.7 Calculation of the Strain Index Score 53
4.4.8 The result of strain index 54
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4.4.9 Interpretation of the Strain Index Score 55
4.5 Data Collection 56
4.5.1 Results of pinching strength 56
4.5.2 Results of gripping strength 60
4.5.3 The Results of Maximum and Minimum value 64
5.0 DISCUSSIONS 67
5.1 Introduction 67
5.2 RULA analysis 67
5.3 ACGIH HALTLV 68
5.4 Strain Index Analysis 69
5.5 Data Collection 70
6.0 CONCLUSIONS 71
7.0 REFERENCES 73
8.0 APPENDICES
A. PROJECT SCHEDULE
B. DATA COLLECTION
C. FREQUENCIES OF PINCHING AND GRIPPING STRENGTH
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LIST OF TABLES
Table Page
2.1 Most commonly used ergonomic tools 5
2.2 Relationship between verbal descriptor 8
2.3 Approximate correspondence between the 10 verbal descriptor 10
2.4 The evaluation and numerical value of intensity of exertion 13
2.5 The values of the duration of exertion task variable 14
2.6 The values of the efforts per minute task variable 14
2.7 The evaluation and numerical values of the posture task variable 15
2.8 The evaluation and numerical values of the speed of work task variable 16
2.9 The values of the task duration per day variable 16
2.10 Summary of literature review 28
3.1 Sample of table to fill up by researcher 34
4.1 Relationship between the verbal descriptors 42
4.2 Hand activity level 43
4.3 Approximate correspondence between the 10 verbal descriptors 44
4.4 Normalize Peak Force 45
4.5 Evaluation and numerical values of intensity of exertion task variable 48
4.6 The values of the duration of exertion task variable 49
4.7 The values of the efforts per minute task variable 50
4.8 The evaluation and numerical values of the posture task variable 51
4.9 The evaluation and numerical values of the speed of work task variable 52
4.10 The values of the task duration per day variable 53
4.11 The value of SI Score 55
4.12 Performance of Malay population on Pinching Strength 56
4.13 Performance of Chinese population on Pinching Strength 57
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4.14 Performance of Indian population on Pinching Strength 58
4.15 Performance of Malay population on Grip Strength 60
4.16 Performance of Chinese population on Grip Strength 60
4.17 Performance of Indian population on Grip Strength 61
4.18 Performance of all subjects on Grip Strength 61
4.19 Maximum and minimum value of pinching strength for Malay 64
4.20 Maximum and minimum value of gripping strength for Malay 64
4.21 Maximum and minimum value of pinching strength for Chinese 64
4.22 Maximum and minimum value of gripping strength for Chinese 65
4.23 Maximum and minimum value of pinching strength for Indian 65
4.24 Maximum and minimum value of gripping strength for Indian 65
4.25 Maximum and minimum value of pinching strength for all races 66
4.26 Maximum and minimum value of gripping strength for all races 66
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LIST OF FIGURES
Figure Page
2.1 Chart of the Threshold Limit Value and Action Level line 12
2.1 Jamar Hydraulic Hand Dynamometer 24
2.2 Jamar Hydraulic Hand Dynamometer 24
2.3 Recommended Testing Position (Side view) 25
2.4 Recommended Testing Position (Front view) 25
2.5 Jamar Hydraulic Pinch Gauge 27
2.6 Analogue Display 27
3.1 Gripping Strength Test 32
3.2 Pinching Strength Test 33
4.1 Opening bottle activity in RULA analysis 38
4.2 The result on RULA analysis (RH) 39
4.3 The result on RULA analysis (LH) 40
4.4 The Hand Activity Level was calculated 45
4.5 The result of Hand Activity Level 46
4.6 The data calculated 54
4.7 The data inputs 54
4.8 The results of data calculated 54
4.9 Graph of pinching performance for male 58
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4.10 Graph of pinching performance of female 59
4.11 Graph of gripping performance of male 62
4.12 Graph of gripping performance of female 63
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LIST OF ABBREVIATIONS
PSM - Projek Sarjana Muda
CTDs - Cumulative Trauma Disorders
WRMSDs - Work-Related Musculoskeletal Disorders
CTS - Carpal Tunnel Syndrome
RH - Right Hand
LH - Left Hand
SPSS - Statistical Package for the Social Science
TLVs - Threshold limit values
AL - Action Limit
ACGIH - American Conference of Governmental Industrial Hygienists
HAL - Hand Activity Level
NPF - Normalized Peak Force
RULA - Rapid Upper Limb Analysis
REBA - Rapid Entire Body Assessment)
MVC - Maximum Voluntary Contraction
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CHAPTER 1
INTRODUCTION
1.1 INTRODUCTION
One issue facing many safety professionals and ergonomics is selecting ergonomic
analysis tools. Selecting ergonomic tools warrants careful study and consideration.
Choosing inappropriate tools can frustrate teams, confuse managers, and yield data that
do not adequately assess risk. This can compromise the entire ergonomics process and
its credibility. For these reason, the investigation of ergonomics analysis tools is really
essential in order to identify and quantify injury risk and opportunity potential.
Every year more people are injured between the ages of 18-64 from repetitive motion
injuries to the human musculoskeletal system than any other category of disorder. The
average employee loses nearly two days of work each year as a result of these disorders
(Putz-Anderson, 1988). Work-related musculoskeletal disorders occur when there is an
interface problem between the physical environment of a job and the physical capacity
of the human body (OSHA, 2002). Unfortunately, workers often overlook ergonomic
illnesses until symptoms become permanent or chronic due to the fact that usually are
not a result of a single incident.
This study investigate an ergonomic analysis tools which focusing on hand tools that is
bottle opener. In this research, the data of pinching and gripping strength were taken
among Malaysian population. The data of pinching and gripping are really important in
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designing properly hand tools. There are few past research about pinching and gripping
strength, but there is no research in investigate Malaysian hand strength.
1.2 Objectives
1) To study the ergonomic hands tools analysis software available in Malaysia’s
market.
2) To gain knowledge of human limitation of their strength of pinching and
gripping for Malaysian population.
3) To find out the distribution of Malaysian population capability in pinching and
gripping for the left and right hand based on age, gender and races.
1.3 Project Scope
1) Investigate the suitable ergonomic hands tools analysis software to analysis hand
activity level which focusing on opening bottle activity in everyday task which
are RULA analysis, ACGIH Hand Activity Level Threshold Limit Value
(HALTLV) and Strain Index that are available in Universiti Teknikal Malaysia
Melaka (UTeM).
2) This project involves ergonomics assessment on strength/power in gripping and
pinching in Malaysian populations from various of aspect :
a) Age (Years)
i. Child ( 7 - 12 )
ii. Teenagers ( 17 - 19 )
iii. Adult ( 20 - 40)
iv. Older People (40 - 70).
b) Race
i. Malay
ii. Chinese
iii. Indian
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c) Gender
i. Male
ii. Female
d) Left and right hand
3) Analysis the data from the survey to find out the human limitation in pinching
and gripping activity.
1.4 Problem Statement
The goal of this study is to investigate ergonomic hand tools analysis software that
available in Malaysia’s market which focusing on hand activity level such as opening
bottle activity. Ergonomic hand tools analysis software involves in this research are
RULA analysis, ACGIH Hand Activity Level Threshold Limit Value (HALTLV) and
Strain Index. Many ergonomic analysis tools are available today which can analyze
many parts of body but there are no tools that can evaluate finger force. This research
also provides the data of pinching and gripping strength for Malaysian population. Data
of grip strength and pinch strength are crucial in designing hand tools. Hand tools design
that properly fit the user will help reduce cumulative trauma disorders (CTDs) and
Carpal Tunnel Syndrome (CTS) in tasks that involve gripping and pinching. The design
of safe and comfortable hand tools is critical to avoid any injuries. In Malaysian
industries, many hand tools are not designed for Malaysian dimensions both in terms of
strength and physical dimensions.
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CHAPTER 2
LITERATURE REVIEW
2.1 Introduction
This chapter discuss about the relevant literature with the title of project. The literature
review highlight past studies related to the subject of this project. It contains a literature
review about the investigations of ergonomics analysis of hand tools and other
information about gripping and pinching strength that are related with the title of thesis.
There were many studies about ergonomics analysis tools. This present study is to
investigate ergonomic hands tool analysis tools during opening bottle activity which
involve of pinching and gripping strength. The ergonomic hands tool analysis involves
in this research are RULA analysis from CATIA software, ACGIH Hand Activity Level
Threshold Limit Value (HALTLV) and Strain Index from Ergoweb software. This study
also provides the data of pinching and gripping strength for Malaysian population. The
purpose of literature review is to be as guidance in writing thesis with related subject.
Source of information were obtained from journals, handbooks, reports and electronics
media publications.
2.2 Common Ergonomics Analysis Tools
Whether ergonomics is handled by plant teams, safety professionals, or trained
ergonomists, there is often a need for systematic assessments to identify and quantify
injury risk and opportunity potential. Ergonomic analysis tools are designed to meet
these needs. Selecting ergonomic analysis tools requires an understanding of the users or
analysts, the types of tasks being analyzed, the characteristics of the tools themselves,
and the intended use of collected data. Table 2.1 is several of the most commonly used
ergonomic hand tools analysis.
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Table 2.1: The most commonly used ergonomic hand tools analysis
Analysis tool Risk factors
evaluated
Areas of body
addressed
Sample applications
RULA
(Rapid Upper
Limb Analysis)
- Repetition
- Force
- Awkward postures
- Wrists
- Forearms
- Elbows
- Shoulders
- Neck
- Trunk
- Assembly work
- Sewing
- Meatpacking
- Grocery cashier
- Dentists and dental
technicians
REBA
(Rapid Entire
Body
Assessment)
- Repetition
- Force
- Awkward postures
- Wrists
- Forearms
- Elbows
- Neck
- Trunk
- Back
- Legs
- Knees
- Patient lifting &
transfer
- Nurses
- Janitors
- Grocery warehouse
- Telephone operators
- Dentists and dental
technicians
- Ultrasound technicians
- Production workers
Strain Index
- Repetition
- Force
- Awkward postures
- Hands
- Wrists
- Small parts assembly
- Meatpacking
- Sewing
- Packaging
- Keyboarding
- Jobs involving highly
repetitive hand motions
Hand Activity
Level (Hand Activity
Level)
- Repetition
- Force
- Hands
- Wrists
- Small parts assembly
- Meatpacking
- Sewing
- Packaging
- Keyboarding
- Jobs involving
repetitive or frequent
hand motions
ACGIH
Hand/Arm
Vibration TLV
- Vibration
- Hands
- Arms
- Shoulders
- Grinding
- Chipping
- Drilling
- Sawing
- Chainsaw operation
- Production work using
vibrating
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The design of safe and comfortable hand tools is critical to avoid CTDs such as carpal
tunnel syndrome. In Malaysian industries, many hand tools are not designed for
Malaysian dimensions both in terms of strength and physical dimensions.
2.3 RULA (Rapid Upper Limb Assessment)
RULA is an ergonomic tool that is used to evaluate exposure to postures, repetition,
force, and muscle activity that contribute to CTDs. This tool is not designed to be a
comprehensive analysis, but rather a quick and easy screening instrument. The focus of
RULA is to help in determining the root cause of cumulative trauma injuries in the
hands, neck, arms, and shoulders. A RULA analysis can be broken up into three steps
that include observation, scoring and recording, and determining an action level. The
observation process of RULA includes determining the part of a task that poses the
highest risk of postural loading. Some factors that may be taken into consideration
include duration of the posture and degree of deviation. Also, while observing, it is
possible to score each side of the body independently if desired. The second step of a
RULA analysis is scoring the posture. In this step, scores are assigned to movements
associated with different parts of the upper extremity. Tables are provided on the RULA
work sheet that allows calculation of a grand score. The final step includes comparing
the grand score to the four action levels in order to determine the degree of risk. The
four action levels include:
a) Action level 1
Scores of 1 or 2 indicate acceptable postures if not repeated for
long periods.
b) Action level 2
Scores of 3 or 4 indicate a need for further investigation and
possible changes.
c) Action level 3
Scores of 5 or 6 indicate changes are required soon.
d) Action level 4
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A score of 7 indicates investigation and changes are required
immediately.
2.4 ACGIH Hand Activity Level Threshold Limit Value (HALTLV)
Authored by the American Conference of Governmental Industrial Hygienists (ACGIH),
the Hand Activity Level is a semi-quantitative analysis that identifies injury risk of the
forearm/wrist/hand in cyclical-short cycle, hand intensive tasks. The tool assesses two
variables hand activity level (HAL) and hand normalized peak force (NPF) and
compares the outcome to a threshold limit value (an exposure level up to which nearly
all workers may be repeatedly exposed without adverse health effects) and action limit
(level of intermediate risk). HAL analysis is intended for mono-task jobs performed for
four or more hours per day. A mono-task job may be defined as a job that requires
performing the same set of motions and/or exertions repeatedly (ACGIH 2003).
Examples include assembly line work or data entry on a keyboard. This method is
applicable to determine the risk of forearm/wrist/hand injury for repetitive short-cycle
tasks performed for four or more hours per day. This analysis primarily evaluates
repetition and force. Other risk factors such as awkward posture, contact stress,
temperature, vibration, and job duration are not directly addressed.
ACGIH is a professional, scientific society composed of industrial hygienists and other
occupational health professionals dedicated to the development and improvement of
worker health protection. Among other activities, they establish threshold limit values
for chemical substances and physical agents. Threshold limit values (TLVs) are
guideline criteria set after review of significant, published, peer-reviewed scientific
literature by ACGIH committees composed of experts in public health and related
sciences. TLVs are health-based values that are established without consideration of
economic factors and technical feasibility.
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TLVs are not standards. They have not been generated by a consensus of various
stakeholders such as what occurs with government regulations or standards from
organizations like the American National Standards Institute. However, ACGIH feels
TLVs are valuable scientific opinion that regulatory bodies should consider in the risk
characterization process of physical agents and chemical substances.
2.4.1 Assessment of Hand Activity Level
The ACGIH TLV addresses mono-task jobs that take place longer than 4 hours a day. A
monotask job may be defined as a job that requires performing the same set of motions
and/or exertions repeatedly (ACGIH 2003). The two independent variables used in the
ACGIH TLV are the Hand Activity Level and the Normalized Peak Force.
The Hand Activity Level (HAL) characterizes repetition on a scale from 0 to 10. Where
0 is completely idle and 10 is the greatest level of repetition imaginable. This scale was
proposed by Latko et al. (Latko 1997; Latko, Armstrong et al. 1997) HAL is a function
of both frequency and speed of work. It can be determined by assessment from a trained
observer or through direct time measurement. This software allows inputting only
considering the trained observer method. Table 2.2 shows the relationship in
determining the Hand Activity Level.
Table 2.2: Table for determining Hand Activity Level (www.ergoweb.com)
Tool Menu Choice (also
the trained observer
method)
Calculated Method
HAL
Numeric
Level Frequency
(exertions/second)
Duty Cycle (% of
work cycle where
force is greater than
5% of maximum)
0.125 40 to 100
-- 0.25 60 to 100
Hand idle most of the
time; no regular exertions 0.125 0 to 40 1
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Consistent conspicuous,
long pauses; or very slow
motions
0.25 0 to 40 2
0.25 40 to 60
3 0.5 0 to 20
Slow, steady
motion/exertions;
frequent brief pauses
0.5 20 to 40
4 1.0 0 to 20
0.5 40 to 80
5 1.0 20 to 60
2.0 20 to 40
Steady motion/exertions;
infrequent pause
0.5 80 to 100
6 1.0 60 to 80
2.0 40 to 60
1.0 80 to 100
7 2.0 60 to 80
Rapid, steady
motion/exertions; no
regular pauses
2.0 80 to 100 8
-- -- 9
Rapid, steady
motion/difficulty keeping
up or continuous exertion
-- - 10