APPENDIX B Report of the Physical Demands Subcommittee

Physical Demands Subcommittee

Content Model and Classification Recommendations

APPENDIX B

Report of the

Physical Demands Subcommittee

Content Model and Classification Recommendations

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Physical Demands Subcommittee

Content Model and Classification Recommendations

Physical Demands Subcommittee

Subcommittee Chair

Deborah E. Lechner, PT, MS

Subcommittee Members

Gunnar Andersson, MD, Ph.D.

Mary Barros-Bailey, Ph.D.

Sylvia E. Karman, Project Director

Occupational Information Development

Social Security Administration

September 1, 2009

Physical Demands Subcommittee

Content Model and Classification Recommendations

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TABLE OF CONTENTS

Introduction...........................................................................................................1

Methodology and Procedures...............................................................................3

Physical Demands Subcommittee Recommendations..........................................7

Definition of Terms..............................................................................................21

References .........................................................................................................25

Appendix A .........................................................................................................29

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Introduction

Purpose/Mission and the Role of Subcommittee: The purpose/mission of the

Physical Demands Subcommittee is to provide recommendations to the OIDAP

regarding the development of the physical demands content model and

components of a new Occupational Information System (OIS). This new OIS will

serve as a long-term replacement for the Dictionary of Occupational Titles (DOT),

the Selected Characteristics of Occupations (SCO), and the Revised Handbook

for Analyzing Jobs (RHAJ).

Each occupation in the new OIS will be described to some extent by the physical

demands and requirements of the occupation. Our recommendations will focus

on the following categories of physical demands:

I. Manual Materials Handling/Strength;

II. Postures and Positions;

III. Mobility and Movement;

IV. Psychomotor;

V. Sensory; and,

VI. Environmental.

Each of these categories will have a list of physical demands. For example, the

Manual Materials Handling/Strength would have:

 Lifting;

 Carrying;

 Pushing; and,

 Pulling.

Many of these physical demands would have further qualifiers such as one-handed

vs. two-handed lifting, carrying pushing and pulling, and would be rated according

to duration and repetition.

The Physical Demands Subcommittee will also discuss the issues with the present

“level of gross physical activity” (i.e., Sedentary, Light, Medium, etc.) that is

consistent with an individual’s overall physical residual functional capacity (RFC).

SSA needs such a schema at Steps Four and Five of their sequential disability

determination process.

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Methodology and Procedures

The Physical Demands Subcommittee investigated and deliberated on the

physical demands components of the OIS to inform its recommendations in the

following manner:

Panel Meetings Involving Relevant Presentations: Members of the Physical

Demands Subcommittee attended all meetings held by the Occupational

Information Development Advisory Panel (Panel) on the following dates:

 February 23-25, 2009—Washington, DC

 April 27-29, 2009—Atlanta, GA

 June 9-11, 2009—Chicago, IL

During each of these Panel meetings, the Physical Demands Subcommittee

heard testimony from a variety of stakeholders (within and outside the Social

Security Administration (SSA)) regarding desired changes to the physical

demands in the current DOT, SCO and RHAJ. The Chair of the Physical

Demands Subcommittee presented a preliminary literature review at the June

2009 Panel meeting.

Formation of Subcommittees: The Physical Demands Subcommittee was

formed on February 25, 2009 and consisted of Deborah Lechner, PT, MS, Chair;

PhD, Gunnar Andersson, MD, PhD; Mary Barros-Bailey; and, Sylvia Karman,

Project Director, Occupational Information Development, Social Security

Administration.

Activities of Subcommittees: The Physical Demands Subcommittee met five

times:

 April 2009—Panel meeting in Atlanta, GA

 Via teleconference—May 2009

 June 2009—Panel meeting in Chicago, IL

 Via teleconference—July 29, 2009

 Via teleconference—August 31, 2009

We have also exchanged information and research articles via email in

preparation for our subcommittee meetings.

Studies: A preliminary feasibility study was conducted in June 2009, pulling

data from Functional Capacity Evaluations (FCEs) that have been performed for

the purpose of long term private disability determination. The purpose of this

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feasibility study is to determine the time required to perform a data transfer from

existing .tif files into a Microsoft Excel spreadsheet which would permit the data

to be analyzed. It was determined that sanitizing the records would involve five

minutes per record. Entering data into a spreadsheet or database would take

approximately 10 minutes per record. Over 900 records in which a

comprehensive set of tasks was evaluated are available. Accessing these

records would allow SSA to perform an exploratory factor analysis of physical

demands and is being considered.

Sources Consulted: Members of the Physical Demands Subcommittee

reviewed the physical components of existing general work taxonomies as well

as taxonomies used in the ergonomics literature for the purposes of classifying

the physical demands of work. See the bibliography and the Excel spreadsheet

in Appendix A of this report for details.

DDS/ODAR/Appellate Council Visits: Members of the Physical Demands

Subcommittee visited their local Disability Determination Services (DDS) offices

and the Maryland Office of Disability Adjudication and Review (ODAR), and

Appellate Councils to observe the current DOT/SCO taxonomy being utilized in

SSA’s disability determination process and the adjudication of appeals.

Review of Recommended Documents and SSA Working Papers: Members

of the Physical Demands Subcommittee reviewed the following presentations

and SSA-prepared and recommended papers;

 Working Paper: What is a Content Model?

 Working Paper: Developing an Initial Classification System

 Working Paper: Social Security Administration’s Legal,

Program and Technical/Data Occupational Information

Requirements

 Working Paper: SSA Plans and Methods for Developing a

Content Model: Key Questions to Be Addressed

 Presentation: A History of Job Analysis (Mark A. Wilson,

Ph.D.)

In addition, the subcommittee reviewed user input from the following sources:

 A Call to Update the DOT: Findings of the International

Association of Rehabilitation Professionals (IARP),

Occupational Database Committee (Authors: Angela

Heitzman et al), The Rehab Professional, 17(2)

 IARP OIDAP Survey Summary, July 2009, Final

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 Occupational Information System Survey Comments: IARP,

August 3, 2009

 Comments from National Organization of Social Security

Claimants’ Representatives (NOSSCR)

 User Needs Analysis: Office of Disability Adjudication and

Review; Office of Appellate Operations: (Authors: Roth &

Dunn, SSA, OPDR).

 User Needs Analysis: Maryland Disability Determination

Services (DDS) (Authors: Roth & Dunn, SSA, OPDR).

 National Association of Disability Representatives (NADR)

OIDAP Committee – Collaborative Opinion: July 2009

 Comments from the American Board of Vocational Experts

(ABVE)*

 Comments from the American Physical Therapy

Association*

 Comments from the American Occupational Therapy

Association*

 Presentation by Georgina B. Huskey, President, National

Association of Disability Examiners

 Presentation by Trudy Lyon-Hart, Secretary of the National

Council of Disability Determination Directors

*Included in Appendix F—Report of the User Needs and Relations Subcommittee

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Physical Demands Subcommittee Recommendations

Issues Considered

In its deliberations, the Physical Demands Subcommittee considered the

following:

1) The application of the physical demands taxonomy within the

context of the Social Security Administration’s Five-Step process

for disability determination.

2) The efficacy or lack thereof of the current DOT/SCO physical

demands classification system.

3) The effects of a change of the current DOT/SCO physical demands

classification system on the medical and rehabilitation community

that also currently utilizes the DOT for private disability

determination and for workers’ compensation cases, and the extent

to which SSA and external users share requirements.

4) The input provided from stakeholders at the various Panel meetings

from February through June of 2009.

5) The input provided from stakeholders in the 2002 job analysis

research sponsored by the Department of Labor.

Specific Physical Elements (Demands)/ Recommended Level of Detail

In general, we feel that with the exception of a few areas, the current categories

of physical demands provided in the DOT/SCO provide a fairly adequate level of

detail. The physical demands that are not adequately covered are as follows:

1) Above v. below-waist lifting. There is currently no distinction

between above and below-waist lifting. We consider this to be a

problem when documenting the lifting requirements of various

occupations and comparing those requirements to individuals with

varying physical dysfunctions. For example, an individual who has

sustained an upper extremity dysfunction could possibly handle 30

lb lifting below waist but only able to sustain 10 lb of lifting above

waist. Conversely an individual with a lower extremity or back

dysfunction would likely be able to lift much better above waist than

below waist. Since there is such a high prevalence of applicants

who apply for Social Security disability with a low back

dysfunction/diagnosis, we believe that distinguishing between these

two types of lifting is important for SSA.

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2) Reaching levels and types defined. The current DOT defines

reaching as a physical demand of work. Claimants with shoulder

dysfunction can tolerate reaching at shoulder height and below

fairly well. However reaching above shoulder height is typically

problematic. Claimants with hand injuries and resulting swelling in

a dependent position, tolerate low reaching poorly. For these

reasons, we recommend that reaching be subcategorized into three

different heights a) Above shoulder; b) Shoulder to waist height;

and, c) Below waist. In addition, the reaching required should be

designated as either one-handed or two-handed reaching as noted

below.

3) Addition of keyboarding and use of mouse/touchpad. Given the

frequency of computer use in today’s work environment, we feel

that the addition of keyboarding and use of pointing devices is

warranted. We feel that keyboarding involves a specialized type of

finger dexterity that justifies identifying it as a separate physical

demand. The use of the mouse requires reaching and handling.

The use of the touchpad requires fingering and sensation.

4) Addition of forceful gripping and forceful pinching. The current DOT

taxonomy addresses Handling and Fingering. Handling is

described as hand function that includes contact of the palm of the

hand with the object being handled. Fingering is described as

contact of the fingers only (not palm of hand) with the object being

handled. Neither of these descriptions address squeezing and

pinching motions of the hands and fingers respectively. In SSA

claimants with hand dysfunction resulting in weak or painful

gripping and pinching this hand function is not appropriately

addressed within the parameters of handling and fingering.

5) Documenting the uni- and bi-lateral requirements of occupations

Currently there are no classification options to address the

requirements of one hand in manual materials handling and forceful

exertions in the DOT/SCO. If an applicant with an injury or disease

affecting one arm applies for disability, there currently is no way to

compare the remaining residual functional capacity of his/her

unaffected arm to the one-handed requirements of the job. By

adding the following to the classification system, we feel that this

issue could be addressed:

 One-handed lifting

 One-handed carrying

 One-handed push and pull

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 One-handed reaching

 One-handed fingering

 One-handed handling

6) Addition of trunk (body) rotation/twisting/lateral bending. The

current taxonomy in the DOT does not mention trunk/body rotation.

For claimants who have low back dysfunction, trunk rotation is often

a challenge and is required for many jobs. The trunk rotation can

be repetitive or it can be statically held while a hand and positional

task is performed.

7) Addition of neck rotation/twisting, bending and extension. The

current DOT taxonomy does not address neck rotation and

bending. For claimants with neck dysfunction (i.e., arthritis, cervical

disc disease, and cervical stenosis) the extent of neck rotation and

bending required for work is an important issue. The neck

movements can occur repetitively or held statically while an eye-

hand task is performed.

8) Addition of forward bending from sitting. The current DOT

taxonomy addresses only forward bending from a standing position.

However, some occupations require forward bending from a sitting

position as well. Occupations such as mechanics, electricians,

plumbers, painters are a few examples. Claimants with low back

dysfunction may have difficulty with this position.

9) Increased specificity for climbing. Currently the DOT taxonomy

addresses climbing. In the definition this can include climbing

stairs, ladders, poles, ropes, or scaffolding. The physical ability

required for each type of climbing is significantly different. Stair

climbing is the least demanding of all types of climbing because it

requires less hip and knee motion and strength. Ladder climbing

requires significantly more hip and knee motion and strength and

some use of the upper extremities. The physical demands of a

vertical ladder are greater than an A-frame ladder. Pole and rope

climbing requires similar hip and knee motion as ladder climbing

but significantly more arm strength than ladder climbing. Stair

climbing and climbing an A-frame ladder can typically be performed

with one hand or arm. The other types of climbing require bilateral

hand use. Climbing ramps may also need to be included.

10) Addition of Running. Not many professions require running. For

those that require running, however, the demand is an important

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challenging occupational requirement. The current DOT does not

address running as a physical requirement.

11) Categories for Balance. The current DOT has a single

classification of balance. However, the balance required varies

greatly depending on the surface on which the worker must work.

For example, the balance required for walking on even surfaces is

much less than that required for uneven surfaces. The balance

required for ladder climbing, and beam and scaffold walking, is

much greater than that for level walking. For these reasons, we

recommend classifying balance into at least four categories: a)

Even/Level surfaces; b) Uneven/Irregular surfaces; c) Ladder

climbing; d) Beam and scaffold walking; and, e) Balancing by

walking on an incline.

12) Separate Classification of Sitting, Standing, and Walking. The

current DOT classifies sitting, standing, and walking as part of the

General Physical Category. We recommend that each of these

variables be classified separately and categorized according to

duration or percent of day spent in these activities.

13) Ability to Alternate Position. There are some sedentary jobs where

a sit-stand option is available. This identification borders on

accommodation. However, if the sit-stand option is available, it

opens up opportunities for employment that would otherwise be

unavailable.

14) Ability to Use Assistive Devices: In some work environments the

use of physical assistive devices is permitted and the work

environment lends itself to the use of these devices. In other

environments the use of assistive devices is not feasible. Notation

of the occupations that allow these devices would be helpful.

15) Operation of Foot Controls

: Needs to be added. Documentation of

whether one or two feet are required would be helpful in cases

where the applicant has use of only one foot such as the case if

applicants with an amputation or with paralysis or loss of sensation

of one foot.

16) Repetitive Twisting of Wrist: Needs to be added. Documentation

of the presence of this activity in an occupation would be important

to applicants with carpal tunnel, chronic tendonitis, and arthritis.

Individuals with these diagnoses tolerate repetitive turning of the

wrist and forearm poorly. These motions are present to some

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degree in many manufacturing jobs and in the food processing

industry.

17) Handwriting. Needs to be added. Most occupations in today’s

environment required handwriting to some extent. The duration of

writing can affect the work tolerance of those with carpal tunnel and

arthritis.

Comprehensiveness: The Physical Demands Subcommittee believes that the

physical demands taxonomy should be as comprehensive as possible, covering

all physical demands that are required for work.

Specificity: The Physical Demands Subcommittee believes that the level of

specificity or detail of the content model and taxonomy should be carefully

balanced with practicality and feasibility in mind. Too little detail will result in the

frustration that has occurred with the current DOT expressed by many of the user

needs analyses and stakeholder presentations. Alternatively, too much detail will

render the system impractical and cumbersome to use. We believe that the level

of detail contained in many of the ergonomic taxonomies and assessment tools is

more detail that would be feasible or practical for SSA. However, we believe that

these tools can provide information that will be instructive for SSA in establishing

certain parameters for operational definitions. For example, we recommend that

SSA conduct a formal literature review of the topic of repetition to determine an

appropriate operational definition for repetitive.

Operational Definitions: Operational definitions are extremely important to the

reliability and validity of any data collection method for job analysis. The

definitions must be written in sufficient detail to allow job analysts to correctly

classify the physical demands. Our field experience in job analysis has shown

that positions such as bending/stooping are difficult to classify correctly and to

distinguish from standing or squatting/crouching without specific operational

definitions. Questions arise such as: How much forward bending has to occur in

order for the physical demand to be classified as stooping? Is it 10 degrees, 20

degrees, 30 degrees or more? Our experience indicates that it must be a visible

angle that can be clearly distinguished. We have come to appreciate that there is

no one magical number. However, an arbitrary cut point at least allows the

analysts to be consistent with one another and with themselves on a re-test

situation. The following provide a few examples:

 Trunk angle required to distinguish stooping from

standing;

 Knee angle required to separate squatting from

stooping;

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 Shoulder angle for reaching high, low, medium;

 Force for forceful gripping as distinct from handling;

and,

 Number of consecutive steps to be considered

walking vs. standing.

Recommended Rating System for Specific Demands

Significant controversy surrounds the issue of measurement parameters of the

physical demands. However, most agree that some sort of classification system

of the extent of repetition as well as duration should be included.

Repetition:

 Low Repetition:1-12 times per hour

 Moderate: 13-30 times per hour

 High: 31 to 60 times per hour

While we agree that repetition should be addressed, we are not confident that

this should be the classification system. It may be that the number of repetitions

would vary depending on whether one is classifying upper extremity vs. trunk

repetition. In our brief review of the ergonomics literature, we noted a wide

variation in what is considered “repetitive.”

We feel that this subject deserves very close attention. As such we recommend

a thorough analysis of the literature on repetitive work to determine the most

appropriate classification system for repetition.

Duration

: Several groups have mentioned that a scale for duration for

physical demands is very important. However, most feel that the current

categories of Never, Occasional (1-33% of the day), Frequent 34 – 66% of

the day, and Constant > 66% of the day, are too broad. Most user needs

groups and individuals requested a seldom or rarely category and IARP

requested that the OIS classify jobs that require more than an 8-hour day.

The length of time a physical demand is performed and the length of a

workday should be captured in the data gathering process. Once the

data is analyzed, future recommendations could address how best to

address this issue.

Maximum Continuous Duration

. In addition to the issue of total duration

throughout the day, the maximum continuous duration a position is

assumed or other physical demand must be performed is important as

well. For example, a physical demand may occur occasionally (up to 1/3

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of the day) and in one occupation. The demand would be interspersed

intermittently throughout the day while in another occupation, this 2.7

hours of activity would occur continuously. Many claimants can tolerate

activity if the physical demand is required intermittently but may not be

able to if it is required continuously for 2.7 hours.

Maximum Continuous Distance: For dynamic movements such as

carrying, pushing, pulling, walking, climbing, running, crawling, etc., the

maximum continuous distance can be a very important occupational

demand. If a claimant can only walk 50 continuous feet and the

occupation requires at least 500 feet of continuous walking, then there is

an obvious mismatch between claimant’s ability and the occupational

demand. The challenge is that each job that is analyzed in an occupation

may vary considerably when it comes to these distances based on the

size of the physical location.

Variations of Physical Demands within Occupations: Each occupation will

be studied by observing and measuring physical demands in multiple

representative jobs. Most certainly there will be a range of demands for

each occupation. Even if demands are similar, the extent to which these

demands are required will vary. The occupational classification will

identify the highest physical demand level in individual job analyses that

will then be used to determine a mean for each occupation.

General Physical Category

The current DOT taxonomy defines general physical demands categories as

Sedentary, Light, Medium, Heavy, Very Heavy. Some frustrations with these

general physical categories of have been expressed by user groups. The

frustrations have mainly centered on several issues:

1) Some of the categories are too broad. For example, the Medium

category contains occupations that require 21-50 lbs of lifting and

Heavy includes materials handling in the 51-100 lbs.

2) The definitions include the extent of sitting, standing, and walking

that are required for each level of work. The specific duration of

sitting, standing and walking are only vaguely defined for the

Sedentary and Light levels and not defined at all for Medium level

and above.

3) Interpretation of the levels vary from organization to organization

and among vocational evaluators, insurance companies and case

managers, making it difficult to report functional testing results in a

way that is consistent and meaningful for all referral sources.

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4) Classification of jobs with multiple levels of material handling.

Recommendations for improvements include:

1) More narrow ranges of material handling.

2) Focus definitions on materials handling only. Classify sitting,

standing and walking as independent physical demands and rate

according to the duration.

3) Standardization of interpretation of the categories and how they

relate to claimant disability or ability is needed in the new OIS.

Once data is captured, recommendations should focus on

suggesting methods to represent this concept. That is, these could

involve assigning ranges to weights that are standardized.

4) Occupations should be classified according to the heaviest level of

material handling required. So that if a job requires lifting of a

variety of materials some of which weigh 10 lb, some 35 lb and

some 53 lb. Then the job would be classified based on the 53 lb

weight. If a job had light lifting but heavier pulling, the job would be

classified according to the pulling.

Recommendation:

1) Create more categories that are not as broad. Perhaps a system

that increases by smaller weight increments may provide a solution.

However, once the data is gathered and analyzed, future

recommendations could suggest a scale that is more applicable

than what users presently have.

Recommend Methods of Data Collection

For the DOT, data was collected using field analysts. However, this data

collection has been criticized for lack of standardization. In fact, standardization

was provided through the Handbook of Analyzing Jobs. But the training and

utilization of this method was not consistent across all field locations. For the

O*NET, the data collection was entirely through self report. The Physical

Demands Subcommittee strongly believes that data collection for the physical

demands of work cannot be done via self-report. There are numerous studies

that demonstrate that self-reported physical demands are neither reliable nor

valid, especially at the level of detail requested by user needs analyses, and

stakeholder comments (Wiktorin, Kariqvist, & Winkel, 1993; Oliveira de Souza &

Gil Coury, 2004).

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Sensory/Motor Category

This category includes feeling, hearing, vision, and tasting/smelling. The

American Occupational Therapy Association identified sensory skill demands as

“actions or behaviors required to locate, identify, and respond to sensations and

to select, interpret, associate, organize, and remember sensory events based on

discriminating experiences through a variety of sensations that include visual,

auditory, proprioceptive, tactile, olfactory, gustatory, and vestibular.” Analysis of

the literature regarding such topics as visual ergonomics, hearing demands of

work, and other related areas found little contemporary research regarding the

sensory demands of work.

User groups comments are summarized in the following sensory categories:

1) Speech: Talking may be a function of the mental/cognitive process

of receptive and expressive speech as is addressed in that

subcommittee’s recommendations with respect to the outcomes of

expressive and receptive language that are measurable and

observable. From a physical standpoint, only speech quality

(sound and frequency) are considered.

2) Feeling:

a. User Recommendation: Tactile perceptions of objects,

environmental conditions, and other sensations felt through

the skin.

b. Measurement needs: refined frequency measures.

3) Vision:

a. User Recommendation: Degree of vision needed to

complete the task (i.e., peripheral, accommodation, near

acuity, far acuity, etc.), including vision in one or both eyes.

b. Measurement needs: level of peripheral vision required to

avoid hazards and distance from visual stimuli represented

the greatest need for data elements to be included the

content model. Scales should use realistic units (e.g.,

distances), such as the use of the Snellen chart, of

measurement rather than frequencies.

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4) Hearing:

a. User Recommendation: Degree of sound discrimination to

safely and adequately carry out a work activity. Specificity in

job requirements with respect to distinguishing different

levels of sound as well as any level of sound regardless of

source.

b. Measurement needs: Decibel and frequency demand scales

rather than frequency scales.

5) Tasting/Smelling:

a. The ability to detect the existence of pleasant or

unpleasant tastes or smells may be essential to certain

occupations, such as first responders (e.g., firefighter,

police officer) and those in the hospitality industry (e.g.,

chef, waitress, child care provider). It should be included

when their impairment alone, or in constellation with other

impairments, may preclude a claimant from performing the

core functions of occupations for which they may have

skills.

Recommendations

1) Defining talking within the physical demands context in terms of

speech quality rather than the receptive or expressive qualities that

are more of the mental/cognitive process.

2) Consider more discrete, appropriate, and functional levels of

measurement for feeling, vision, and hearing.

3) Although not frequently encountered as an impairment

consideration, including taste and smell sensory demands due to

their relevance as essential and core functions of a variety of

occupations.

4) Sensory demands are not a primary expertise of any of the

members of the Physical Demands Subcommittee. For this reason,

we recommend that SSA convene a focus group or roundtable of

experts in the area of vision and hearing for more specific

recommendations and definitions that are contemporary.

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Legal, Technical, and Data Issues

Legal issues in the physical demands area that are important to consider relate

mainly to the accuracy of the data that populates the occupational data base.

The data collection method must be shown to be reliable and valid. The data

should be collected by direct observation using a classification system with well-

defined operational definitions rather than self-report.

Test-retest and inter-rater reliability should be studied. Validity will be more

difficult and costly to establish. We believe that the data collection method could

be compared to a full-day time and motion study in a limited number of

occupations at each of the physical demand levels (Sedentary, Light, Medium,

etc). A less rigorous but alternative method of establishing validity would be to

compare the results of the data analysis method to expert opinion. However, this

method of face validity is the weakest form of validity.

A training course and accompanying manual would need to be developed.

Analysts would need to attend a rigorous training with testing and certification in

the established data collection method. Based on research conducted in 2002

with the US Department of Labor, the training could occur via the internet with

protocol practice using videotaped jobs. Periodic re-certification would be

required.

Suggested Studies

The Physical Demands Subcommittee recommends that SSA undertake the

following studies to inform the overall process:

 Perform an analysis of the literature on repetition to determine the

most appropriate definition of the term repetitive.

 Perform contemporary research regarding the sensory demands of

work, particularly as these relate vision and hearing, the areas most

identified by users that require attention.

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Environmental Category

A complete job description should include information about the environmental

conditions present. Of particular concern are exposures to heat and cold,

humidity, wetness (moisture, rain, water), dust, chemicals, fumes, gases, smoke,

mold or mildew, fibers including asbestos, vibration and general conditions of the

workplace (hazardous environment, heights, noise, animals, etc.). Whether work

is performed outdoors or indoors is important since environmental factors are

more difficult to control outdoors.

Most research on the effect of environmental factors on health and human

performance concerns noise, thermal stress (heat and cold), and vibration. In

areas such as noise and vibration safety standards have been developed which

include level and time of exposure. This is also true for exposure to fibers (such

as asbestos). With respect to thermal stress the best measure would be the core

temperature (about 98.6

F or 37

C), but this is an uncomfortable measure to

obtain. In thermally neutral environments (air temperature 20-23

C for a resting,

comfortably clothed person) the body maintains its heat balance by regulation of

blood flow. When the temperature increases beyond that level or when vigorous

activity is performed increased blood flow in the skin results in sweating. Under

excessive heat stress this mechanism shuts down and the core temperature

rises (hyperthermia) with potential development of heat exhaustion and even

heat stroke. Conversely, in colder temperatures the body restricts this blood

flow, then contracts muscles rapidly (shivering). With extreme cold the regulation

fails and the body starts losing heat to the environment (hypothermia). This can

cause death. A complicating factor is the heat accommodation that naturally

occurs in a hot environment. This process results in increase of sweating,

reduced salt concentration in sweat and reduction in core temperature and heart

rate. To determine heat stress one needs to measure air temperature, humidity,

air velocity and surrounding surface temperatures. Although a number of

measures have been developed to address these interactions the “dry bulb

temperature” thermometer is the simplest and most practical (Hancock &

Vasmatzidis, 1999).

In 1986 NIOSH developed as set of heat stress criteria as requested by OSHA

(Millar 1986). Those are primarily based on effective temperature (which

combines air temperature, humidity and air movement) and exposure time. A

formula has also been developed to convert temperature to “wet bulb glove

temperature” (WBGT) which takes radiant heat and air velocity into account

(Yagloglou & Minard, 1957). Recommended exposure limit curves were

developed by NIOSH taking the environmental heat (WBGT) and metabolic heat

(generated by the worker) into account (NIOSH Publications 86-113). The

simplest way to describe heat stress is to record the temperature, time of

exposure, and frequency of exposure.

Physical Demands Subcommittee

Content Model and Classification Recommendations

B-19

As exemplified in the discussion of heat stress, highly sophisticated analyses can

be performed for most environmental conditions. In the context of a useful job

description, all the discussed exposures should be described, but detailed

measurements of exposures are unpractical. At a minimum the exposure, its

concentration (severity), frequency and the workers ability to address the

exposures (protective equipment, etc.) should be described.

Recommendations:

1) Describe and define environmental conditions as they relate to:

heat and cold, humidity, wetness (moisture, rain, water), dust,

chemicals, fumes, gases, smoke, mold or mildew, fibers including

asbestos, vibration and general conditions of the workplace

(hazardous environment, heights, noise, animals, etc.).

2) Define appropriate measures for each condition where possible

(e.g., for noise and vibration issues provide details of the level and

time of exposure) or, at a minimum, include descriptions of levels of

exposure, concentration or severity, frequency and

accommodations available to address the effects of the exposure

(such as protective equipment).

Physical Demands Subcommittee

Content Model and Classification Recommendations

B-20

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Physical Demands Subcommittee

Content Model and Classification Recommendations

B-21

Definition of Terms

Accommodation: adjustment of lens of eyes to bring an object into sharp focus.

Balancing: maintaining body equilibrium to prevent falling.

 Balancing on level surfaces

 Balancing on Uneven surfaces

 Balancing on Ladders

 Balancing on Beam and Scaffolding

Carrying: Transporting an object over a distance through walking, usually holding

the load in the hands or arms.

 One-handed: using one hand or arm to carry the object

 Two-handed: using both hands or arms to carry the object

Color Vision: ability to identify and distinguish colors.

Crawling: moving about on hands and knees, hands and feet or on the abdomen

Crouching: bending the body downward and forward by bending legs at the hips

and knees with simultaneous forward bending of the spine. This is typically

performed when working with material that is at or near the floor level. Squatting

includes positions where one knee is on the floor or both knees are off the floor.

Depth Perception: ability to judge distances and spatial relations.

Far Acuity: clarity of vision at 20 feet or more.

Feeling: perceiving attributes of items as size, shape, temperature as

experienced through the skin.

Field of Vision

: Observing an area that can be seen up and down and right and

left when eyes are fixed on a given point.

Fingering

: picking, pinching, or otherwise working primarily with the fingers. The

object handled does not contact the palm of the hand.

Physical Demands Subcommittee

Content Model and Classification Recommendations

B-22

Handling: seizing, holding, grasping, turning, or working with hands; using the

hands in such a fashion that the object being handled contacts the palm and

fingers of the hand.

Hearing: perceiving the nature of sounds by the ear.

Kneeling: bending the legs at the knees to come to rest on both knees.

Ladder Climbing: Ascending or descending either A-frame or vertical ladders.

Lifting: Raising or lowering an object from one level to another. Involves

primarily vertical displacement of the load but can also include a component of

horizontal displacement as well. Can involve one or two-handed lifting and can

occur either above waist or below waist.

 One-handed: using one hand or arm to raise or lower the object

 Two-handed: using both hands or arms to raise or lower the object

 Above-waist: lifting that occurs from the waist and above. Typically

performed primarily with the strength of the arms, shoulders, and

upper back.

 Below-waist: lifting that occurs from the floor to approximately

waist height. Typically performed primarily with the strength of the

legs and low back.

Near Acuity

: clarity of vision at 20 inches or less.

Physical Demands

: occupational demands that require movement of the body,

including arms, legs, hands, feet, neck and back.

Pulling

: Exerting force upon an object so that the object moves toward the force.

 One-handed: using one hand or arm to pull the object

 Two-handed: using both hands or arms to pull the object

Pushing

: Exerting force upon an object so that the object moves away from the

force.

 One-handed: using one hand or arm to push the object

 Two-handed: using both hands or arms to push the object

Physical Demands Subcommittee

Content Model and Classification Recommendations

B-23

Reaching: extending arms and hands away from the body in any direction.

Shoulder angle must be 45 degrees from the body to be considered reaching.

Three levels of reaching include:

 Low: below the waist

 Medium: waist to shoulder height

 High: above shoulder

Scaffolding or Pole Climbing: Ascending or descending scaffolding or poles.

Sitting: Remaining in a seated position with knees and hips flexed to some

extent and buttocks resting on surface.

Speech: voice tone, quality, projection, and other physical attributes during

speech production in the communication process.

Stair Climbing: Ascending or descending stairs.

Standing: Remaining on one’s feet in an upright position without walking.

Strength Category: The manual material handling/ demands category of the

work.

Stooping/Forward Bending: bending the body downward and forward from a

standing position by bending the spine at the hips and/or waist. The hips must

be flexed more than 20 degrees and the knees are kept relatively straight (flexed

no more than 35 degrees).

Tasting/Smelling: distinguishing flavors or odors using the tongue and/or nose.

Walking: Moving about on foot. Requires three consecutive steps to be

considered walking.

 Level surfaces: surfaces that are level and do not include ramps or

uneven terrain

 Uneven surfaces: surfaces that include uneven terrain. Includes

walking outside over grass, dirt, gravel, up and down curbs

 Ramps/inclines: surfaces that include an incline of over 15 degrees

Physical Demands Subcommittee

Content Model and Classification Recommendations

B-24

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Physical Demands Subcommittee

Content Model and Classification Recommendations

B-25

References

Breen, R., Pyper, S., Rusk, Y., & Dockrell, S. (2007). An investigation of

children’s posture and discomfort during computer use, Ergonomics, 50,

1582-1592.

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the reliability of OWAS observations, Applied Ergonomics, 29, 281-283.

Buchholz, B., Paquet, V., Punnett, L., Lee, D., & Moir, S. (1996). PATH: A work

sampling-based approach to ergonomic job analysis for construction and

other non-repetitive work, Applied Ergonomics, 27, 177-187.

Buchholz, B., Paquet, V., Wellman, H., & Forde, M. (2003). Quantification of

Ergonomic Hazards for Ironworkers Performing Concrete Reinforcement

Tasks During Heavy Highway Construction, AIHA Journal, 64, 243-250.

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limb postures based on perceived discomfort, International Journal of

Industrial Ergonomics, 31, 17-32.

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Genaidy, A., Barkawi, H., & Christensen, D. (1995). Ranking of static non-

neutral postures around the joints of the upper extremity and the spine,

Ergonomics, 38, 1851-1858.

Physical Demands Subcommittee

Content Model and Classification Recommendations

B-26

Graham, B., Lambe, S. R., & Lambe, N. R. (1996). Working practices in a

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Physical Demands Subcommittee

Content Model and Classification Recommendations

B-27

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1367.

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requested linguistic categories similar to those classified by the recording

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Wiktorin, C., Karlquist, L., & Winkel, J. (1993). Validity of self-reported exposures

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Physical Demands Subcommittee

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Physical Demands Subcommittee

Content Model and Classification Recommendations

B-29

Appendix A

Excel Spreadsheet Comparison of Occupational and

Ergonomic Classification Schemes

Shoulder Reach Ranges

RULA REBA PATH LUBA PEO VIRA TRAC

DOL 2002

Research

Flexion

Level 1 0-20 0-20 0 -90 0-45 0-9

0-3

0-6

0-45

Level 2 20-45 20-45 90 + 45-90 90+ 30-60 >60 45-90

Level 3 45 -90 45 -90 NA 90-150 NA 60-90 NA >90

Level 4 90 + 90 + NA >150 NA NA NA NA

Extensio n

Level 1 NA 0 NA 0-20 NA >0 NA NA

Level 2NA>20NA20-45NANANA NA

Level 3 NA NA NA > 45 NA NA NA NA

Medial Rotation

Level 1NANANA0-30NANANA NA

Level 2 NA NA NA 30-90 NA NA NA NA

Level 3 NA NA NA > 90 NA NA NA NA

Lateral Rotation

Level 1NANANA0-10NANANA NA

Level 2NANANA30-OctNANANA NA

Level 3 NA NA NA >30 NA NA NA NA

Abduction

Level 1 NA NA NA 0-30 NA 0-30 0-60 0-45

Level 2NANANA30-90NA30-60>6045-90

Level 3NANANA>90NA60-90NA >90

Adduction

Level 1NANANA0-10NANANA NA

Level 2NANANA30-OctNANANA NA

Level 3 NA NA NA >30 NA NA NA NA

Elbow Bend Ranges

M inimal NA 60 - 100 NA 0-45 NA NA NA NA

Moderate 45-120NANANA NA

Severe NA <60; > 100 NA >120 NA NA NA NA

Wrist Ranges

Flexion

Minimal 0-15 0-15 NA 0-20 NA NA NA NA

Moderate

20-60NANANA NA

Severe>15>15NA>60NANANA NA

Extensio n

Level 1NANANA0-20NANANA NA

Level 2

NA NA NA 20-40 NA NA NA NA

Level 3 NA NA NA >45 NA NA NA NA

Physical Demands Subcommittee

Content Model and Classification Recommendations

B-30

Appendix A

Excel Spreadsheet Comparison of Occupational and

Ergonomic Classification Schemes

(continued)

Wrist Ranges (cont'd)

RULA REBA PATH LUBA PEO VIRA TRAC

DOL 2002

Research

Twisting/Pronation

Neutral No # No # NA 0-70 NA NA NA NA

Non-Neutral No # No # NA >70 NA NA NA NA

Twisting/Supination

Neutral No # No # NA 0-90 NA NA NA NA

Non-Neutral No # No # NA >90 NA NA NA NA

Radial Deviation

Level 1 No # No # NA 0-10 NA NA NA NA

Level 2 No # No # NA 30-Oct NA NA NA NA

Level 3 NA NA NA >30 NA NA NA NA

Ulnar Deviation

Level 1 No # No # NA 0-10 NA NA NA NA

Level 2 No # No # NA 20-Oct NA NA NA NA

Level 3 NA NA NA >20 NA NA NA NA

Trunk Ranges

Flexion

Level 1 0-20 0-20 0-20 0-20 0-20 NA 0-15 0-35

Level 2 20 - 60 20 - 60 20-45 20 - 60 21-60 NA 15-45 >35

Level 3 60 + 60 + > 45 >60 > 60 NA 45-75 NA

Level 4NANANANANANA>75 NA

Ext

Min NA 0 - 20 NA NA NA NA NA NA

Mod NA > 20 NA NA NA NA NA NA

Twist

Level 1 0 0 0-20 0-20 0-45 NA NA No #

Level 2 > 0 > 0 > 20 20-30 > 45 NA NA No #

Level 3 NA NA NA 30-45 NA NA NA No #

Level 4 NA NA NA >45 NA NA NA No #

Side bend

Level 1 0 0 0-20 0-10 NA NA NA NA

Level 2 > 0 > 0 > 20 10 to 20 NA NA NA NA

Level 3 NA NA NA 20-30 NA NA NA NA

Level 4 NA NA NA >30 NA NA NA NA

Neck Ranges

Flexion

Min 0-10 0-20 0-30 0-20 0-20 0-20 NA No #

Mod 10 to 20 NA 20-45 NA >20 NA No #

Sev 20 + 20+ > 30 >45 > 20 NA N A No #

Ext

MinNA0-20NA0-30NA NA NA No #

Mod NA NA 30-60 NA NA NA No #

SevNA20+NA>60NANANA No #

Physical Demands Subcommittee

Content Model and Classification Recommendations

B-31

APPENDIX A

Excel Spreadsheet Comparison of Occupational and

Ergonomic Classification Schemes

(continued)

Neck Ranges (cont'd)

RULA REBA PATH LUBA PEO VIRA TRAC

DOL 2002

Research

Twist

Level 1 0

0-45 0-30 0-45 NA NA No #

Level 2 > 0 > 0 > 45 30-60 > 45 NA NA No #

Level 3 >60

Side bend

Level 1 0 0 0-30 0-30 NA NA NA No #

Level 2> 0> 0> 3030-45NANANA No #

Level 3 >45 NA NA NA No #

Squat

> 45 knee

flexion

Walk/Climb

3 consecutive

steps

NA = Category not used; joint position not classified

No # = Category/ joint position classified but no specific ROM criteria provided