WORKPLACE ENVIRONMENT & ERGONOMICS

1. WORKPLACE ENVIRONMENT & ERGONOMICS CHAPTER 4

2. ERGONOMICS-What is it? • Derived from two Greek words: • “Nomoi” meaning natural laws • “Ergon” meaning work • Hence, ergonomists study human capabilities in relationship to work demands

3. History • As early as 18th century doctors noted that workers who required to maintain body positions for long periods of time developed musculoskeletal problems. • Within last 20 years research has clearly established connections between certain job tasks and RSI or MSD.

4. Focus and Objectives of Ergonomics cont… • The focus is that people (their abilities and limitations) and their requirements are considered when: • Objects, systems which people use and operate within are being designed and developed; • Procedures to carry out work are being developed; • Facilities which involve and affect people are being evaluated.

5. Focus and Objectives of Ergonomics • The objectives of Ergonomics are: • Enhance and optimize the effectiveness with which work and other human activities are carried out; • Also to maintain certain desirable human values in the process, e.g. health, safety; • Stimulate work interest and satisfaction.

6. Effects of poor Ergonomics • Discomfort • Accidents and injuries • Fatigue • Errors • Illness • Annoyance • Productivity down

7. What two elements are at work? • Static work: musculoskeletal effort required to hold a certain position, even a comfortable one. Example: sit & work at computers; keeping head and torso upright requires small or great amounts of static work depending on the efficiency of the body positions we chose.

8. Elements at work (cont) • Force: amount of tension our muscles generate Example: tilting your head forward or backward from a neutral, vertical position quadruples the amount of force acting on your lower neck vertebrae • Increased force is due to increase in muscular tension needed to support head in a tilted position

9. 3 Main Ergonomic Principles: • Work activities should permit worker to adopt several different healthy and safe postures. • Muscle forces should be done by the largest appropriate muscle groups available • Work activities should be performed with joints at about mid-point of their ROM (esp. head,trunk,UE)

10. FACTS • The average person working at a keyboard can perform 50,000 to 200,000 keystrokes a day • Overexertion, falls & RMI are the most common cause of workplace injury • An average of 125,000 back injuries due to improper lifting each year. • Muscles overuse results in tiny tears in the muscles and scarring; these contribute to inflammation and muscle stiffness

11. A Bit of Anatomy !! • Overuse and small repetitive movements ie: cumulative trauma disorder (CTD), repetitive stress injury (RSI), musculoskeletal disorder (MSD) disturb balance of muscles, tendons, ligaments and nerves

12. What causes Nerve Compression or Entrapment? • Repeated motions • Tight muscles • Inflammation of surrounding tissues • Misalignment of the nerve

13. What are 4 Common Nerve injuries? • Thoracic Outlet Syndrome: brachial plexus compression due to muscle tightness side of neck from poor head position or slumped posture. signs and symptoms (S/Sx): numbness/tingling in hand, made worse w/overhead activities or cradling phone between ear and shoulder

14. Nerve injuries (cont) • Radial tunnel syndrome: compressed radial nerve @ outside of elbow d/t repetitive wrist & finger extension or turning of forearm S/Sx: Sensations from elbow to base of thumb w/ wrist weakness a common sx

15. Nerve injuries (cont) • Cubital tunnel syndrome: ulnar nerve compression inside of the elbow d/t repetitive bending of elbow or resting your elbow on a hard surface S/Sx: numbness or tingling and inside of arm w/ tingling to ring & little fingers

16. Nerve injuries (cont) • Carpal tunnel syndrome: compression of median nerve at level of carpal tunnel Where is carpal tunnel? Formed @ wrist by ligament over the carpal bones in hand S/Sx: numbness or tingling in thumb, index, or middle finger & ½ of ring finger; often awakened @ night by hand “falling asleep” Sx increased by driving or attempting to hold objects; dropping objects is a common complaint

17. Tendons and Tendonitis • Tendons are connective tissue that attach muscle to bone; have little stretch or rebound • Tendon overuse, static or prolonged position=inflammation or tendonitis • Tendons of wrist & hand very small; @ high risk for injury w/ overuse • “Tennis elbow” or lateral epicondylitis affects finger extensor tendons outside of elbow • “Golfer’s elbow” or medical epicondylitis affects finger flexor tendons inside of elbow

18. What to do ?? • Warm up & stretch before activities that are repetitive, static or prolonged • Take frequent breaks from ANY sustained posture every 20-30 minutes • Respect pain- positions or stop painful activity • Recognize early signs of inflammatory process, & tx early PREVENT, PREVENT, PREVENT !!!

19. Maintain Neutral Posture • Maintain erect position of back& neck w/ shoulders relaxed • Position equipment & work directly in front of and close to your major tasks • Keep upper arms close to the body, elbows 90-100 degrees • Keep feet flat on floor, upper body weight resting on “sits bones” • Wrists as neutral as possible; safe zone for wrist movement is 15 degrees in all directions

20. You talking to me? • Avoid bending neck forward for prolonged periods of time (*remember quadruple the force); use a copy holder • Avoid static positions for prolonged time; muscles fatigue---MOVE to circulation!

21. Modify Tasks: • Alternate activities frequently; rotate heavy &/or repetitive tasks w/ lighter less repetitive ones. • If sx become worse REASSESS task setup & look for alternative methods • Avoid repetitive or prolonged grip activities • Avoid pinching w/ wrist in flexion or wrist deviation (bending to side) • Take frequent breaks to stretch & rest hands

22. Body Mechanics • Use the largest joints & muscles to do the job • Use 2 hands to lift rather than one, even with light objects and tasks. • Avoid lifting w/ the forearm in full pronation (palm down) or supination (palm up) • Slide or push & pull objects instead of lifting • Keep reaching to a minimum • Carry objects close to body at waist level

23. Correct & Incorrect Techniques

24. Good and Bad of “ TILT”

25. Recommended Position FOR Computer user

26. ERGO REMINDERS from Stretchbreak.com

27. Practice Wellness at Work and Home ! Exercise Relaxation Nutrition Spirit Mind Body

28. MOVE STRETCH BREATHE

29. An ounce of Prevention is worth a pound of cure !

30. Ergonomics in occupational health and safety 1. User

31. 2. Machine

32. 3. Workplace

33. 3. Environment

34. 4. Special questions

35. Indoor Air Quality • Indoor air quality (IAQ) is a term referring to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants

36. Indoor Air Pollution • The National Health and Medical Research Council (NHMRC- Australia) defines indoor air as air within a building occupied for at least one hour by people of varying states of health. This can include the office, classroom, transport facility, shopping centre, hospital and home. • Indoor air quality can be defined as the totality of attributes of indoor air that affect a person's health and well being.

37. Sick building syndrome Condition associated with complaints of discomfort including headache; nausea; dizziness; dermatitis; eye, nose, throat, and respiratory irritation; coughing; difficulty concentrating; sensitivity to odors; muscle pain; and fatigue.

38. Sick building syndrome • The specific causes of the symptoms are often not known but sometimes are attributed to the effects of a combination of substances or individual susceptibility to low concentrations of contaminants. • The symptoms are associated with periods of occupancy and often disappear after the worker leaves the worksite.

39. Cause of SBS • Inadequate ventilation 52% • Contamination from inside building 16% • Contamination from outside building 10% •  Microbial contamination  5% •  Contamination from building fabric  4% • Unknown sources 13%

40. Thermal Comfort • Personal factors (health, psychology, sociology & situational factors) • Air temperature • Mean radiant temperature • Air movement / velocity (see wind chill factor) • Relative humidity (see also perspiration) • Insulative clothing • Activity levels.

42. Sources of Indoor Pollutants Base on Specific Building Combustion activity Furniture Chemical Building materials Food Water Smoking activity Outdoor air pollution

43. Walkaround Inspection • Potential Problem Areas • Sample Collection