My Class

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MWA presents Ergonomics and the Aging
Workforce Dr. Andris Freivalds Dept. of
Industrial Manufacturing Engineering Penn State
University Email axf_at_psu.edu
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Why Study Aging Worker? - 1
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Why Study Aging Worker? - 2

• 1) Increase in older workers

• 2) Shift from part- to full-time

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Bodily Changes with Aging

• Anthropometric size, range of motion
• Physiological physical work capacity
• Physical muscle strength
• Physical biomechanical integrity
• Perceptual visual, auditory senses
• Cognitive information processing

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Anthropometric ChangesHeight and Weight vs.
Age(NHS on 6672 adults, McCormick, 1970)
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Anthropometric ChangesRange of Motion

• Overall decrease in all joints
• ? in 13 joints - neck, trunk worst (Doriot, 2006)
• ? in 17 joints upper limbs least (Bill, 1981)
• Decrease in task effectiveness
• ? shoulder ROM (reach) (Barnes, 2001 Kibler,
  1976)
• ? 8/decade in cervical ROM (Simpson, 2008)
• Decrease in mobility
• ? 8 both dorsi plantar flexion (Nigg, 1992)
• ? 20 in hip extension (Roach, 1991)

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Physiological Changes
Every variable shows change for the worse!
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Measurement of Aerobic Capacity

• V02  VE I02 - EO2
• V02  HRxSV AV-O2
• But HR, SV, VE ?
• Submaximal task
• Extrapolate - max HR
• Max HR also ?
• (Astrand Rodahl, 1986)

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Max Heart Rate vs. Age(Astrand Christensen,
1964)
HR 220 Age (AHA) HR 209 0.7 Age (Tanaka,
2001) HR 217 0.876 Age (AR, 1986)
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Aerobic Capacity vs. Age

• Absolute Aerobic Capacity (Astrand, Astrand, 1973)

• 2) Normalized to body weight (Astrand
  Rodahl, 1986)

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Physical ChangesMuscle Strength vs. Age
(Viitasalo, Era, 1985)
(Astrand Rodahl, 1986)
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Physical ChangesBiomechanical Integrity
(Injuries-1)

• 1) 60 lb radiator cores

• 2) Analysis with UM3D model

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Physical ChangesBiomechanical Integrity
(Injuries-2)

• 3) Low-back force 1148 lbs

• 4) Low-back disc failure

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Physical ChangesBiomechanical Integrity
(Injuries)

• 2) Tendinitis, tenosynovitis, carpal tunnel
  syndrome

• 1) Work-related musculo-skeletal disorders (CTD,
  RSI)

Prevalence 14 overall population 17 50-59 year
olds 24 60-65 year olds
Due to high forces, high repetition, extreme
joint motions, lack of rest
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Ex Garment industry
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Perceptual Visual Ability

• Changes start at age 40
• Lens thickens?farsightedness
• and ? in pupil size
• Lens becomes opaque
• 66 ? retinal illumination by 60
• Requires greater contrast
• Increase in disability glare
• ? in visual acuity (1?0.6)
• ? contrast sensitivity (gt2 c/deg)

(from Blackwell, 1971)
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Perceptual Hearing Ability

• 1) Loss in high frequencies
  (Kryter, 1983)

• 2) ? in speech intelligibility (Bergman, 1976)

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Cognitive Changes

• Become noticeable after age 65
• Decreased performance
• Retrieval of info from long-term memory
• Choosing among response alternatives
• Executing response
• Disruptions to short-term memory
• Difficulties handling incompatibilities
• Decrements in perceptual coding of ambiguous
  stimuli

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Perceptual and Cognitive Fixes

• Strengthen stimuli (louder, brighter)
• Reduce irrelevant details
• Maintain high compatibility
• Reduce time-sharing demands
• Allow self-pacing
• Allow more time and practice to learn new material

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Other Changes and Factors

• Harder to maintain posture and balance
• More sleep disturbances
• Length and depth of sleep
• Especially critical for shift workers
• Less able to maintain normal temperature
• Start sweating later
• Decreased peripheral blood flow
• Increased risk for heat stroke

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Americans with Disabilities Act (ADA 1990)

• Outlaws discrimination against disability
• Aging may fall into this category
• Substantially limits a major life activity
• Employer must provide reasonable accommodation
• Should not be undue hardship on employer

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Summary

• Anthropometric change not a big factor
• Few jobs with physiological considerations
• Strength considerations may be important
• Perceptual factors may be important
• Cognitive factors typically become important only
  in gt65 year olds
• Biomechanical factors probably most important,
  especially in injury causation

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Solution Ergonomic Job Redesign

• Reduce static work and muscle loading
• Keep work in neutral zones
• Avoid twisting of the torso
• Minimize lifting use hoists and lifts
• Stretching throughout the day
• Regular exercise programs
• Good for older workers, females, everybody

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Aging Worker Coping Mechanisms(My observations
from industry)

• Steady, self pacing
• Take regular breaks
• Stronger worker ethic
• Immigrant stock
• Different ethnic background
• Work through injuries
• Seniority, bid out of job

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Overall Summary (My perspective from industry)

• Aging worker is at a disadvantage!
• Does industry really care??
• 55-64 year-olds are 11 of the workforce
• gt 65 year-olds are only 2.5 of the workforce
• Quite a bit of self-selection (survivor effect)
• Probably need federal legislation to specifically
  focus on elderly workers
• Injury costs biggest driving force