Ergonomics: Why do workers get injured? Presented by: Steve Bilan Ergonomic Specialist

What do you know about Ergonomics?

• Ergonomics is the study of designing equipment and devices that fit the human body, its movements, and its cognitive abilities.

What do you know about Ergonomics?

• Equipment: Anything that requires any sort of human input to make it work

• Movements: Any body movement required for the task

• Cognitive Abilities: Intelligence and behavior, especially focusing on how information is

represented, processed, and transformed (in faculties such as perception, language, memory, reasoning, and emotion) within nervous systems

Cognitive Ability

Factors that will impact Cognitive perception: • Sleep Deprivation • Noise • Medications • Work Scheduling • Stress • Research is also finding diseases such as Hypertension

have a major role in cognitive ability. • What does this means in regards to ergonomics?

Riddle

• What goes up but does not come down?

Answer

•AGE

How does this contribute to a Musculoskeletal injury/Disorder?

Safe Workload • IF WE CAN CONTROL FATIGUE, WE CAN

TAKE AWAY MSD’S • Under regular good working conditions with

sufficient rest breaks injury is not as likely occur

• Miniature rest breaks are essential throughout the day to prevent injury

Safe Workload

Time

Forc

e

Workload Tissue Tolerance

Rest Periods

Workday

520

520

520

520

520

620

719

818

916

1013

911

810

711

613

514

615

716

815

914

1012

911

810

711

613

514

615

716

815

914

1012

911

810

711

613

514

615

716

815

914

1012

Workload

Tissue Tolerance

Time

Force

Workday

Actue Injury

520

520

520

520

520

3020

56

56

56

56

56

57

57

57

58

58

59

59

109

56

56

56

Workload

Tissue Tolerance

Time

Force

Acute Injury

Chronic Injury

518

518

518

518

518

1017

1016

1015

1013

1011

512

513

514

516

517

1017

1016

1014

1012

1011

512

513

514

515

516

1016

1015

1013

1012

1010.5

511

512

513

514

515

1014

1013

1011

1010

105

56

56

56

57

58

Workload

Tissue Tolerance

Time

Force

Chronic Injury

Stats

WorkdaySafe WorkloadToo Many HoursAcute InjuryChronic Injury

520520520520518

520520520520518

520520520520518

520520520520518

520520520520518

6201019101930201017

71910171017561016

81810151015561015

91610131013561013

101310111011561011

91151251256512

81051451457513

71151651657514

61351851857516

51452052058517

61510191019581017

71610171017591016

81510151015591014

914101310131091012

101210111011561011

91151251256512

81051451456513

711516516514

613518518515

514520520516

615101910191016

716101710171015

815101510151013

914101310131012

1012101110111010.5

911512109511

810514107512

711516105513

613518514

514520515

61510191014

71610171013

81510151011

91410131010

10121011105

56

56

56

57

58

Safe Workload

520

520

520

520

520

1019

1017

1015

1013

1011

512

514

516

518

520

1019

1017

1015

1013

1011

512

514

516

518

520

1019

1017

1015

1013

1011

512

514

516

518

520

1019

1017

1015

1013

1011

Workload

Tissue Tolerance

Time

Force

Too many hours

520

520

520

520

520

1019

1017

1015

1013

1011

512

514

516

518

520

1019

1017

1015

1013

1011

512

514

516

518

520

1019

1017

1015

1013

1011

109

107

105

Workload

Tissue Tolerance

Time

Force

Working too many hours

Forc

e

Time

Workload Tissue Tolerance

Chronic Injury

Workday

520

520

520

520

520

620

719

818

916

1013

911

810

711

613

514

615

716

815

914

1012

911

810

711

613

514

615

716

815

914

1012

911

810

711

613

514

615

716

815

914

1012

Workload

Tissue Tolerance

Time

Force

Workday

Actue Injury

520

520

520

520

520

3020

56

56

56

56

56

57

57

57

58

58

59

59

109

56

56

56

Workload

Tissue Tolerance

Time

Force

Acute Injury

Chronic Injury

518

518

518

518

518

1017

1016

1015

1013

1011

512

513

514

516

517

1017

1016

1014

1012

1011

512

513

514

515

516

1016

1015

1013

1012

1010.5

511

512

513

514

515

1014

1013

1011

1010

105

56

56

56

57

58

Workload

Tissue Tolerance

Time

Force

Stats

WorkdaySafe WorkloadToo Many HoursAcute InjuryChronic Injury

520520520520518

520520520520518

520520520520518

520520520520518

520520520520518

6201019101930201017

71910171017561016

81810151015561015

91610131013561013

101310111011561011

91151251256512

81051451457513

71151651657514

61351851857516

51452052058517

61510191019581017

71610171017591016

81510151015591014

914101310131091012

101210111011561011

91151251256512

81051451456513

711516516514

613518518515

514520520516

615101910191016

716101710171015

815101510151013

914101310131012

1012101110111010.5

911512109511

810514107512

711516105513

613518514

514520515

61510191014

71610171013

81510151011

91410131010

10121011105

56

56

56

57

58

Safe Workload

520

520

520

520

520

1019

1017

1015

1013

1011

512

514

516

518

520

1019

1017

1015

1013

1011

512

514

516

518

520

1019

1017

1015

1013

1011

512

514

516

518

520

1019

1017

1015

1013

1011

Workload

Tissue Tolerance

Time

Force

Safe Workload

Too many hours

520

520

520

520

520

1019

1017

1015

1013

1011

512

514

516

518

520

1019

1017

1015

1013

1011

512

514

516

518

520

1019

1017

1015

1013

1011

109

107

105

Workload

Tissue Tolerance

Time

Force

Working too many hours

Rest and Recovery

• During the rest phase, physiologically your body is seizing the opportunity to repair itself to become stronger in preparation for the next stresses placed upon it

• Not surprisingly, as you get older, the more your body relies on rest and recovery time.

Rest and Recovery

• The recovery rate closely relates to how fast the body can grow new cells to repair itself.

• Studies show that injured athletes 45 and older recover between 15 to 18 percent more slowly than a similarly injured 30-year-old.

Rest and Recovery of individuals later in life

Fool Proof Prevention • To ensure that your design will not cause injury

the most important factor of your design is to ensure that REST and RECOVERY periods are sufficient to recover from the demands of the tasks workers perform

• The body is self repairing and can repair itself throughout the day

• This does not mean coffee breaks. This is the application of work at the right times for employee

TRUE or FALSE

• If all your muscles could pull in one direction you could create a force of 1000 lbs!

FALSE • If all your muscles could pull in one direction

you could create a force of 25 tons!

How to identify risk factors for MSI/MSDs (poor ergonomics)

Ergonomics 5 W’s and a H (A Task analysis)

• Who • What • Where • When • Why • How

Who

• Workers • Age (as mentioned earlier) • Height • Capabilities • Previous Injuries/General Health • Anthropometrics • Training History • Job Experience

What

• Tasks are being performed, workstation, environment, work structure

• Necessary and unnecessary movements, motions, lifts, etc

(What) Work System

Employee

Task

Work Structure

Workstation

Environment

Task – What is the job description – What are the essential steps – Physical Demand Description (PDD) – Safety – Skill requirement

Workstation – Equipment and Tools – Machinery – Workstation layout – Measurements such as height, width, depth – Weights of objects

Environment – Light levels – Noise levels – Vibration levels – Temperature – Air Quality

Work Structure

• Production Rate • Training • Supervisor • Management Style • Policies and Procedures • Workload

Where

• Areas that are at the greatest risk • How do you determine where?

Tools that can be used to identify tasks for potential injury

• MSI survey • Risk Analysis Checklist • Injury History • WCB information • Talking with employees • Reviewing OHC committee minutes and first

aid kit logs

MSI Survey MSI SURVEY FORM 1. What department do you work in? ________________ What is your job title? _____________________________ 2. In the last year, have you had any pains, aches, soreness, numbness, tingling, swelling, burning feelings, muscle

weakness, muscle tightness, changes in skin colour or difficulty in grasping or holding objects, that have lasted for more than a week, that you believe are mainly caused by your work? YES NO. If YES, please complete the remainder of this survey. If NO, you do not have to complete the rest of the survey.

3. How long have you worked in your present job? Less than 1 year 1 – 5 years More than 5 years 4. How many hours do you work at your job each week, not including lunch and coffee breaks? __________________ 5. How long are your daily breaks at work?____________________________________________________________ 6. List the 2 most physically demanding (forceful, awkward or repetitive, etc.) tasks that you do at work? _________ ______________________________________________________________________________________________ 7. How often do you perform these tasks?_____________________________________________________________ 8. Please put an X in the boxes in the table below that apply to you.

In the last 2 months I have had symptoms (such as aches, pains, discomfort, or numbness) in my:

In the last 7 days I have had symptoms (such as aches, pains, discomfort, or numbness) in my:

Neck No Yes

Neck No Yes

Shoulders No Yes

in the right shoulder in the left shoulder

Shoulders No Yes

in the right shoulder in the left shoulder

Elbows No Yes

in the right elbow in the left elbow

Elbows No Yes

in the right elbow in the left elbow

Wrist / Hands No Yes

in the right Wrist / Hand in the left Wrist / Hand

Wrist / Hands No Yes

in the right Wrist / Hand in the left Wrist / Hand

Upper Back No Yes

Upper Back No Yes

Lower Back (Small of Back) No Yes

Lower Back (Small of Back) No Yes

One or both hips/thighs/buttocks No Yes

One or both hips/thighs/buttocks No Yes

One or both Knees No Yes

One or both Knees No Yes

One or both Ankles / Feet No Yes

One or both Ankles / Feet No Yes

Risk Analysis Checklist Risk Analysis Checklist

Department:

Position:

Comments: Comments:

Comments:

Comments:

Comments:

Comments:

Comments:

TravellingBreaks extending past normal durationsNo rotation schedule

Risk Level = 0.00

MonotonyInformation handling demandsComplex decision makingDeadline pressures

Othat Factors:Shift work

High skill requirementMental Load:

Multiple tasks done simultaneouslyTactile requirementsTraining time highHigh concentration requirements

VibrationPoor handles / grips (pressure points, sharp edges, etc.)

Hand Tool Use:Heavy hand tools (>10 lb.)Bent wrist postures with tool usage

Lack of handling aids

Controls and Displays:Poor compatabilityNo display lightingFrequent used controls not centrally locatedControls are confusing or not easily identifiedControls are too smallFrequent operation of controls appears rushedControls labeled and marked

Static holding or carryingFrequent stair or ladder climbing

Physical Demands:

Load above 40 lb.Sudden or jerky movementsEndurance requirementsPoor grips

Frequent heavy liftingLifting from overhead or below the waistObstructed pathwayTwisting while lifting

Glare (direct of reflected)Hot surfacesSlippery floor surfaces

Awkward objects to lift (bulky, large)

Humid

High noise levelsPoor task lightingPoor ambient lightingCold temperatures (require PPE)

Environment:

Hot temperaturesFumes and vaporsPoor air circulation

Controls / parts require reachingPoor working heights (bending required to perform)CrowdingComponents beyond normal reachesPoor chairs (not adjustable, no back support, no foot rest)No adjustability in workstation

Awkward Postures (bending, twisting, above shoulder, etc.)Workplace Characteristics:

Static / Sustained muscle workNo sitting while performing the job

Injury History- Injury Log Log of Work-Related Injuries & Illnesses Resulting in Lost Time or Medical Treatment

Department: __________________ Year: _________

Date Body Part Injured

*Type of Injury

*Direct Cause of Injury

**Systemic Cause of Injury

Work Area

Occupation Shift/Time of Day

Steps Taken to Prevent Similar Injuries

Example 1 May 1/11

Back Strain Lifting

No mechanical lifting devices

Bin assembly

Labourer Days/No specific time

Purchased gantry crane. Managers and supervisors must ensure that all safety policies are enforced.

Example 2 June 6/11

Eye

Scratch Metal chip in eye

Eye protection not worn; did not fit.

Bracket making

area.

Welder Evening Shift/

7:00 PM

Purchased various sizes & types of eye protection. Eye protection program established. Supervisors annual pay increments tied to enforcement of health & safety policies and injury statistics for their area of responsibility.

Example 3 Aug 7/11

Wrist Carpal Tunnel

Repetitive Motions

No job rotation Data Entry Data Entry Clerk

Daytime/ Cumulative

Data entry clerks and file clerks rotate jobs every 2 hours.

* For type of injury and cause of injury use only 1 or 2 words whenever possible such as fall, trip, knife cut, lifting, repetition, fracture, hit thumb, pushing, pulling, etc. ** Example: Direct Cause of Injury - Employee didn’t have guard on saw Systemic Cause of Injury – Inadequate training provided to employee or safety policies not being enforced by manager/supervisor. *** Modified work is also called light duty work etc., (All modified/light duty work needs to be purposeful, productive work.)

Committee Minutes

Talking with Employees

Early warning signs of MSIs • Numbness • Pain • Tingling • Swelling and Inflammation • Burning sensations • Weakness • Red skin

When

• Proactive is the best, prevent injuries from happening before they happen

• Immediately after incident

Why

• Reduced risk of PAIN or INJURY • Positive feelings about work • Ability to work at full potential. • Higher quality of life when at work and

when away from work

How How do you know what to look for? 1. Amount of FORCE needed to perform all or

part of job task 2. AWKWARD POSTURE (arm, wrist, neck,

leg, back, etc.) required by the job or job task

3. Amount of REPETITION in the job

EMG

• Electromyography (EMG) is an electro diagnostic medicine technique for evaluating and recording the electrical activity produced by skeletal muscles

FORCE

• Force is not weight. • Force is defined as a push, pull, or lift acting

upon an object. • Force required to do a certain task depends

on several factors. • Force can be measured using a force gauge

dynamometer.

Force

AWKWARD POSTURES • Awkward postures can be defined as any posture

where any joint deviates from its natural neutral position.

• This could be a bent wrist, back, neck, raised shoulders, etc.

• When any joint is in an awkward posture the muscles are stretched and the joint becomes weak and susceptible to injury.

• Ideally joint deviation should be 0, this will minimize the torque about a joint

How

• Examples of Awkward Postures

Examples of Awkward Postures

REPETITION

• Definitions: 1) Cycle time of less than 30secs; where the cycle

time is the time to do one operation (Silverstein et al, 1986). This is a definition from the automotive industry

2) Cycle time less than 1 minute is monotonous (Kivi, 1984)

3) Over 120 cycles/hour (Sjogaard et al, 1987)

Repetition

• We can look at repetition several ways, for example: – Parts/hour – Movements/hour – Pauses in a cycle – Periodization of rest breaks

• Repetitive Motions

Examples of Repetition

Combining Risk Factors

Force and Posture

Height of object being lifted: – 36”

Distance of object from body – 15”

Back compression force – 453.51lbs

Weight of object – 25 lbs

The NIOSH Action limit is 770lbs of back compressive force (at L5/S1)

Force and Posture

Height of object being lifted: – 36”

Distance of object from body – 33”

Back compression force – 1027.33lbs

Weight of object – 25 lbs

The NIOSH Action limit is 770lbs of back compressive force (at L5/S1)

Lifting a relatively light object can cause large compressive forces in the spine.

Height of object being lifted: – 6” Distance of object from body – 17” Back compression force – 860.75 lbs Weight of object – 25 lbs The NIOSH Action limit is 770lbs of back compressive force (at L5/S1) This means that even this task of lifting 25lbs once is potentially unsafe

Force and Posture

To Summarize

• Reducing or eliminating unnecessary movements (Repetition) and/or awkward postures and/or excessive force will greatly reduce musculoskeletal injuries, because it will decrease the workers fatigue.

• When workers are fatigued they are at greater risk to become injured both chronically and Acute.

Questions?

Slide Number 1What do you know about Ergonomics?What do you know about Ergonomics?Cognitive AbilityRiddleAnswer�How does this contribute to a Musculoskeletal injury/Disorder?Safe WorkloadSafe Workload Chronic Injury Rest and RecoveryRest and RecoveryRest and Recovery of individuals later in lifeFool Proof PreventionTRUE or FALSESlide Number 16How to identify risk factors for MSI/MSDs (poor ergonomics)Ergonomics 5 W’s and a H� (A Task analysis)WhoWhat(What) Work SystemTaskWorkstationEnvironmentWork StructureWhere Tools that can be used to identify tasks for potential injuryMSI SurveyRisk Analysis ChecklistInjury History-Injury LogCommittee MinutesTalking with Employees�WhenWhyHowEMGFORCEForceAWKWARD POSTURESHowSlide Number 41Slide Number 42REPETITIONRepetitionSlide Number 45Examples of RepetitionCombining Risk FactorsForce and PostureForce and PostureForce and PostureTo SummarizeQuestions?