MWA presents Ergonomics and the Aging Workforce Dr. Andris Freivalds

1. MWA presents Ergonomics and the Aging Workforce Dr. Andris Freivalds Dept. of Industrial & Manufacturing Engineering Penn State University Email: axf@psu.edu Aging:12/10/08

2. Why Study Aging Worker? - 1 Aging:12/10/08

3. Why Study Aging Worker? - 2 1) Increase in older workers 2) Shift from part- to full-time Aging:12/10/08

4. 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 Aging:12/10/08

5. Anthropometric ChangesHeight and Weight vs. Age(NHS on 6672 adults, McCormick, 1970) Aging:12/10/08

6. 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) • ↓ 8⁰/decade in cervical ROM (Simpson, 2008) • Decrease in mobility • ↓ 8⁰ both dorsi & plantar flexion (Nigg, 1992) • ↓ 20% in hip extension (Roach, 1991) Aging:12/10/08

7. Physiological Changes Every variable shows change for the worse! Aging:12/10/08

8. 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) Aging:12/10/08

9. Max Heart Rate vs. Age(Astrand & Christensen, 1964) HR = 220 – Age (AHA) HR = 209 – 0.7 Age (Tanaka, 2001) HR = 217 – 0.876 Age (A&R, 1986) Aging:12/10/08

10. Aerobic Capacity vs. Age Absolute Aerobic Capacity (Astrand, Astrand, 1973) 2) Normalized to body weight (Astrand & Rodahl, 1986) Aging:12/10/08

11. Physical ChangesMuscle Strength vs. Age Aging:12/10/08 (Viitasalo, Era, 1985) (Astrand & Rodahl, 1986)

12. Physical ChangesBiomechanical Integrity (Injuries-1) 1) 60 lb radiator cores 2) Analysis with UM3D model Aging:12/10/08

13. Physical ChangesBiomechanical Integrity (Injuries-2) 3) Low-back force =1148 lbs 4) Low-back disc failure Aging:12/10/08

14. Physical ChangesBiomechanical Integrity (Injuries) 1) Work-related musculo-skeletal disorders (CTD, RSI) 2) Tendinitis, tenosynovitis, carpal tunnel syndrome 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 Aging:12/10/08

15. Ex: Garment industry Aging:12/10/08

16. 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 (>2 c/deg) (from Blackwell, 1971) Aging:12/10/08

17. Perceptual – Hearing Ability 1) Loss in high frequencies (Kryter, 1983) 2) ↓ in speech intelligibility (Bergman, 1976) Aging:12/10/08

18. 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 Aging:12/10/08

19. 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 Aging:12/10/08

20. 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 Aging:12/10/08

21. 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 Aging:12/10/08

22. 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 >65 year olds • Biomechanical factors probably most important, especially in injury causation Aging:12/10/08

23. 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 Aging:12/10/08

24. 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 Aging:12/10/08

25. 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 • > 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 Aging:12/10/08