1 / 19

IE 553 Engineering of Human Work Dr. Andris Freivalds Class #26

IE 553 Engineering of Human Work Dr. Andris Freivalds Class #26. IE 553 Engineering of Human Work Dr. Andris Freivalds Class #26. Anaerobic. Aerobic. Physical Work Capacity ( Å&R, Ch.7,8,11). Work Capacities (Demands) Aerobic (with oxygen)

kylene
Télécharger la présentation

IE 553 Engineering of Human Work Dr. Andris Freivalds Class #26

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. IE 553 Engineering of Human Work Dr. Andris Freivalds Class #26 IE 553

  2. IE 553 Engineering of Human Work Dr. Andris Freivalds Class #26 IE 553

  3. Anaerobic Aerobic Physical Work Capacity (Å&R, Ch.7,8,11) Work Capacities (Demands) • Aerobic (with oxygen) • C6H12O6 + 6O2 ⇒ 6CO2 + 6H2O + 38ATP • Anaerobic (no oxygen) • C6H12O6 ⇒ 2C3H6O3 + 2ATP (Myoglobin) IE 553

  4. Intensity of Work • Submaximal tasks, as measured by: • VO2 • Lactate IE 553

  5. Energy Sources & Duration of Work IE 553

  6. Energy Sources & Duration of Work Myoglobin = quick, replenishable supplier of O2 IE 553

  7. Intermittent Work(Work/Rest Cycles) • Short, frequent W/R cycles are best • Self-paced work with spontaneous pauses • For prolonged work, VO2 should be at steady state 412 W IE 553

  8. Individual Differencesin Physical Work Capacity • Peaks at 25 then ↓ • Males > females • Due to body size IE 553

  9. Physical Fitness (Males 20-29, in ml/min/kg) Average = 3 l/min IE 553

  10. Measurement of Energy Expenditure • Direct calorimetry • Indirect calorimetry • Predict from oxygen uptake V02 (l/min)     = VE [I02 - EO2] VC02 (l/min)   = VE ECO2 E (kcal/min) = 3.94 V02 + 1.106 VC02 - 2.17 Neq      E (kcal/min)    = 3.9 V02 + 1.1 VC02      E (kcal/min)    = 4.9 V02 (if RQ = 0.9) RQ = VC02 / V02 IE 553

  11. Respiratory Quotient RQ = VC02 / V02 IE 553

  12. Measurement of Aerobic Capacity • Direct – supramax-imal task • Submaximal task, extrapolate with HR 1) Step levels of 5 min 2) Reproducible workload 3) Large muscle groups, 4) Not too much skill IE 553

  13. Task/Work Analysis • Basic requirements for a job/task: • Energy exp < VO2max • Fatigue threshold (?) • Repeatable task • Eave = (Ew×Tw + Er×Tr)/(Tw+Tr) • Ew = [Eave(Tw+Tr) - Er×Tr]/Tw IE 553

  14. ENERGY COST OF WORK IE 553

  15. Acceptable Job Energy Expenditure • Recommended physical work capacity: • ERPWC = VO2max/3             • uniform work best, • excursions make worse • static worse than dynamic • large muscles better than localized loading • For jobs exceeding RPWC: • Rest allocation or work/rest cycling • Tr = T(Ew - ERPWC) (Ew - Er) IE 553

  16. Monitoring Fatigue Heart Rate Recovery • Brouha guidelines • Measure HR at: • 0.5→1 min (HR1) • 2.5→3 min (HR2) • Acceptable work if: • HR1 < 110/min • HR2 - HR1 ≥ 20/min • Work pulse < 40 /min • Avoid heart rate creep • Short, frequent work-rest cycles IE 553

  17. Subjective ratings of perceived exertion (RPE) (Borg, 1960) IE 553

  18. Ratings for Work IE 553

  19. Work Efficiency • Gross efficiency (%) = WorkOut/E × 100 • Net eff. (%) = WorkOut/(E-BMR) × 100 • Ex. IE 553

More Related