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  3. ERGONOMICS WHAT IS IT DEF: “ FITTING THE JOB TO THE WORKER” WORD Ergonomics – derived from Greeck ergon : work nomos : Natural laws Ergonomists study human capabilities in relationship to work demands.

  4. POSTURE • In recent years, ergonomists have attempted to define postures which minimize unnecessary static work and reduce the forces acting on the body. All of us could significantly reduce our risk of injury if we could adhere to the following ergonomic principles: • All work activities should permit the worker to adopt several different, but equally healthy and safe postures • Where muscular force has to be exerted it should be done by the largest appropriate muscle groups available. • Work activities should be performed with the joints at about mid-point of their range of movement. This applies particularly to the head, trunk, and upper limbs.

  5. THE PROBLEM • Here, however, we arrive at a serious problem - and a challenge to conventional ergonomic thinking: In order to put these recommendations into practice, a person would have to be a skilled observer of his or her own joint and muscle functioning and would have to be able to change his or her posture to a healthier one at will. No one develops this sort of highly refined sensory awareness without special training. Therefore, in order to derive the benefits of ergonomic research, we must learn how to observe our bodies in a new way.* Any attempt to improve workplace conditions can have only limited success if this issue is ignored.

  6. A SOLUTION • One training program that cultivates precisely these skills is the Alexander Technique. It has a long history of helping people develop the subtle coordination of thought and physical action required to monitor and alter harmful patterns of posture and movement. In short, it enables its students to put ergonomic principles into practice, and thus helps them reduce their risk of developing a repetitive strain injury.

  7. Ergonomics: Training in ergonomics involves; • Designing of machines. • Tools • Equipment • Manufacturing process. • Lay out of the places of work. • Methods of work. • Environment in order to achieve greater efficiency of both man & machine.

  8. Objective of Ergonomics “ to achieve the best mutual adjustment of man and his work, for the improvement of human efficiency and well being”

  9. uses of computer What not

  10. COMPUTERS Working for hours on end with a computer is now a fact of life. simple 7 point checklist will help you recognize and avoid the most common problems: C ontact stress O rganisationM onotonyP ostureU ncomfortable environmentT etchinessE xercise

  11. Role of a DOCTOR “ Occupational health should aim at • Promotion & Maintenance of highest degree of Physical Mental Social well – being of workers of all occupations • Prevention among workers of departures from health caused by their working conditions. • Protection of workers in their employment from risks resulting from factors adverse to health • Placing & Maintenance of the worker in an occupational environment adopted to his physiological & psychological equipment SUMMARY: “ THE ADOPTATION OF WORK TO MAN & EACH MAN TO HIS JOB”

  12. OCCUPATIONAL HEALTH LEVELS OF APPLICATION: • Health promotion. • Specific protection. • Early Diagnosis. • Treatment. • Disability limitation • Rehabilitation • TOOLS: • Epidemological approach • Statistics • Health screening • Health education

  13. ERGONOMICS-COMPUTERS Computers are, of course, here to stay:. Ergonomic considerations, eg furniture, heights, angles, etc. have a bearing and it is important to get these easily adjustable external elements correctly organised. Rather than looking at the problem from the outside, in terms of "good chairs", the "right position", or the "correct way to lift", what about considering the more fundamental internal aspects of how we organise our balance and co-ordination? These are the things which influence how comfortable we stay, how tired we get, how alert or mentally "sharp" we are and how prone to injury or stress we become. They are also the elements over which we can learn to have a direct and instant personal control.

  14. QUESTIONS ASKED • correct type of chair, stool, desk, or table to be used in order to prevent the bad habits which these pieces of furniture are supposed to have caused • TO AVOD; • basic patterns of good "Use of the Self"; that is, how to optimise performance and minimise the risk of suffering a range of musculo-skeletal injuries

  15. INTRODUCTION to Computers Computers has become an integral part of life. We come across it at every stage of life, right from banking to gaming to education , infact this presentation is also a gift of computers, but every good thing comes with a price. Bad Form Lead To Painful Computing, Ergonomic Injuries New studies show that if you don't use the proper form when working on a computer, there is every chance of getting discomfort, pain and even injury. New research shows it takes more than just an ergonomic desk chair or a split keyboard to prevent health problems affecting millions of computer users. But that doesn't mean computer users should resign themselves to a life of chronic pain, said Dr. Erik Peper and Katherine Hughes Gibney of San Francisco State University's (SFSU) Institute for Holistic Healing Studies.

  16. INTRO CONTD … • Much like developing a golf swing or a tennis serve, if you don't use the proper form when working on a computer, you chance discomfort, pain and even injury. • Therefore the need for people to develop healthy computing habits extends beyond those working in positions such as data entry, which are normally associated with repetitive motion injury. • However, Peper and Hughes Gibney resist the common descriptor "repetitive motion injury," noting that muscle groups are used repetitively all the time without injury. • Instead, they see repetitive motion as one factor among many that contribute to a cluster of symptoms they call "computer-related disorder" (CRD). • "Because computer use is pervasive in modern society, by the time people hit the corporate market, they have unwittingly learned bad computing habits and so they are already at risk for CRD."Businesses spend millions of dollars teaching employees how to use software, but they neglect training on how to work on computers productively while maintaining health.“ • Ergonomics doesn't provide all the answers. You can be working in the 'optimum ergonomic position' and still be tense." • The problem is "dysponesis" -- inappropriate muscle tension.

  17. HISTORY • ENIAC, short for Electronic Numerical Integrator And Computer, was the first all-electronic computer designed to be capable of being reprogrammed by rewiring to solve a full range of computing problems. • ENIAC was developed and built by the U.S. Army for their Ballistics Research Laboratory with the purpose of calculating ballistic firing tables. ENIAC was conceived of and designed by J. Presper Eckert and John William Mauchly of the University of Pennsylvania. The computer was commissioned on May 17, 1943 as Project PX, constructed at the Moore School of Electrical Engineering from mid-1944, and formally operational from February 1946 having cost almost $500,000. • Physically ENIAC was a monster—it contained 17,468 vacuum tubes, 7,200 crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors and around 5 million hand-soldered joints. It weighed 30 short tons (27 t), was roughly 2.4 m by 0.9 m by 30 m, took up 167 m² and consumed 160 kW of power. • These computers itself were a big hazards • Computers have evolved in these decades from this monster to slim gadget like laptops


  19. ENIAC ENIAC Transistors size variation


  21. PROBLEMS Awkward Postures, which might include: prolonged work with hands above the head or with the elbows above the shoulders; prolonged work with the neck bent; squatting, kneeling, or lifting; handling objects with back bent or twisted; repeated or sustained bending or twisting of wrists, knees, hips or shoulders; forceful and repeated gripping or pinching.Forceful Lifting, Pushing Or Pulling, which might include: handling heavy objects; moving bulky or slippery objects; assuming awkward postures while moving objects. Prolonged Repetitive Motion, which might include: keying; using tools or knives; packaging, handling, or manipulating objects.Contact Stress, which might include: repeated contact with hard or sharp objects, like desk or table edges.Vibration, which might include: overuse of power hand tools.

  22. Ergonomics and Health Issues • Ergonomics Defined • Repetitive Stress Injuries • Avoiding Repetitive Stress Injuries • Eyestrain • Electromagnetic Fields

  23. Ergonomics and Health Issues - Ergonomics Defined • Ergonomics is the study of the physical relationship between people and their tools – such as computers. • Extended or improper computer use may result in a number of ailments, such as: • Repetitive injuries • Carpal tunnel syndrome • Eyestrain • Exposure to electromagnetic fields

  24. Ergonomics and Health Issues - Repetitive Stress Injuries • Repetitive stress injuries (RSIs) result from using the body continuously in ways it was not designed to work. • RSIs have appeared in office workers who spend a lot of time using the computer keyboard and mouse. • Carpal tunnel syndrome is a common type of repetitive stress injury, which may be caused by extended or improper use of a computer keyboard.

  25. Ergonomics and Health Issues - Avoiding Repetitive Stress Injuries • One of the easiest ways to avoid RSIs is to use ergonomically correct furniture, including an ergonomically designed chair and keyboard. • An ergonomically correct chair features adjustable height, lower-back support, and armrests. It should allow you to type with your forearms parallel to the floor. • An ergonomically correct keyboard is designed to allow the hands to rest in a natural, comfortable position so you can type without overreaching or getting fatigued.

  26. Lower back support Armrests Adjustable height Angles place hands in a natural position

  27. Ergonomics and Health Issues - Eyestrain • Many computer users find their vision deteriorating after a while. This is caused by using the PC too long, poor positioning, or other factors. • To avoid eyestrain, don't stare at the screen too long, place the monitor from 2 to 2 ½ feet away, avoid glare, and keep the screen clean. • Use a monitor that holds a steady image without flickering. Look for a dot pitch no greater than .28 mm and a refresh rate of at least 72 Hz.

  28. Ergonomics and Health Issues - Electromagnetic Fields • Electromagnetic fields (EMFs) occur during the generation, transmission, and use of low-frequency electrical power. Some people are concerned that EMFs are linked to cancer. • To reduce your risks from EMF exposure: • Take frequent breaks away from the computer. • Sit at arm's length from the system unit and monitor. • Use a flat-panel display (which does not produce EMFs).

  29. OCCUPATIONAL HAZARDS IN USING COMPUTERS • Cumulative trauma disorder (CTD), and Repetitive stress injury (RSI) Work-related musculo skeletal system disorders (WMSDs) carpal tunnel syndrome back pain Osteoarthritis tendonitis tenosynovitis "pitcher," "golfer" or "tennis" elbow • Computer Electromagnetic Radiation and Its Health Effects • COMPUTER VISION SYNDROME sore and tired eyes, blurred vision and eye fatigue after prolonged use of their terminals.

  30. CARPAL TUNNEL SYNDROME • According to the Bureau of Labor Statistics, “disorders associated with R.T.D” account for about 60% of all occupational illnesses. Of all these disorders, carpal tunnel syndrome is the condition most frequently reported. • The carpal tunnel receives its name from the 8 bones in the wrist, called carpals, that form a tunnel like structure. The tunnel is filled with flexor tendons which control finger movement. It also provides a pathway for the MEDIAN NERVE to reach sensory cells in the hand. Repetitive flexing and extension of the wrist may cause a thickening of the protective sheaths which surround each of the tendons. • The swollen tendon sheaths, or tenosynovitis, apply increased pressure on the median nerve and produce Carpal Tunnel Syndrome • MOTOR-thenar muscle at the base of the thumb atrophies, and strength is lost . • SENSORY- subjective or objective hypoesthesia coinciding with median nerve distribution, heat and cold sensation lost . • Tinel’s Sign (i.e. distal tingling resulting from proximal nerve percussion);


  32. Phalen's sign • Test for Carpel Tunnel Syndrome (CTS). Hold the position for one minute; if pain or numbness and tingling are felt this is highly suggestive of CTS positive wrist flexion test

  33. CTS ctd.. • Paresthesias, unusual tingling and the sensation of numbness, paralleling the nerve’s path, are prime complaints. • Diagnosis : Clinical Electromyogram and a nerve conduction study gives quantitative support for nerve compression. • Prevention: modified layouts of work stations maintain wrist in a more natural position during work exercise breaks.

  34. CTS :Rx • Treatment of CTS may involve surgery to release the compression on the median nerve and/or use of antiinflammatory drugs and hand splinting to reduce tendon swelling in the carpal tunnel. Such medical interventions have met with mixed success, especially when an affected person must return to the same working conditions. • Effective conservative treatment of CTS should include: • Chiropractic manipulation of the wrist, forearm and hand • Ice massage (10 to 12 minutes) several times a day • minimizing any irritating activities • wrist strengthening exercises • wrist stretching exercises • possible use of wrist brace or splint while sleeping • applying sound ergonomic principles

  35. COMPUTER VISION SYNDROME Some visual display users have reported • sore and tired eyes, • blurred vision and • eye fatigue after prolonged use of their terminals. It is natural for some people to experience visual discomfort if they've been using their eyes intensively over a long period of time, whether it is working at a display, studying for an exam or doing close work. While eye fatigue may be uncomfortable, it is not damaging to the eye. It also is a temporary condition and goes away with rest.

  36. Computer Electromagnetic Radiation and Its Health Effects • The safety of users is a primary consideration when VDTs (Vedeo display terminals)are introduced into the work environment. VDTs are essentially electrically identical to television sets. Both VDTs and television sets produce electromagnetic emissions (sometimes called radiation) from CRT (Cathode ray tube); the phosphor, which is the chemical composition that coats the inside of the CRT screen; and from associated electronic components. • Although OSHA has no specific standards that apply to computer workstations or extremely low frequency electric and magnetic field exposure, there are standards on radiation, noise, and electrical hazards. • The radiation levels emitted by video displya terminals are below the occpuational exposure standards. in many cases ,the levels are below the dectection capabality of survey instrumentation used.considering the radiation measurments, biological injury thresholds, and occupational exposure standards, the VDT does not present a radiation hazards to VDT operator. • There is no significant evidence that the occurence of catract, birth defects , miscarriages, or skin rashes is related to radiation exposure from VDTs. Thus, there is no justification for providing additional (RADIATION ) shielding of the VDT or lead aprons for the operators or for transferring pregnant women to other jobs to reduce the irradiation exposure.

  37. Millions of people work with computers every day. There is no single “correct” posture or arrangement of components that will fit everyone. However, there are basic design goals to consider when setting up a computer workstation or performing computer-related tasks. • Ergonomics is the vital link between safety, quality, and production. The improved worker performance and well-being generated through ergonomic implementation can help management meet their goals of quality and corporate excellence. • Creating the Ideal Computer Workstation: plan to create an ergonomically sound workstation for computer users, including: • Illustrated guidelines on how to adjust your furniture, computer equipment, and work aids. • Information on how to organize your work area and tasks. • Checklists to evaluate the ergonomics of your current workstation and for use as specification lists when purchasing new equipment. • This guide seeks to accommodate most, not all, office workers. If you are very small, very large, or are visually impaired, you may require accommodations different than those included in this guide. If that is the case, refer to your safety or occupational health office.

  38. The Work Area

  39. Upright sitting posture The user's torso and neck are approximately vertical and in-line, the thighs are approximately horizontal, and the lower legs are vertical.

  40. Standing posture The user's legs, torso, neck, and head are approximately in-line and vertical. The user may also elevate one foot on a rest while in this posture.

  41. Declined sitting posture The user's thighs are inclined with the buttocks higher than the knee and the angle between the thighs and the torso is greater than 90 degrees. The torso is vertical or slightly reclined and the legs are vertical.

  42. Reclined sitting posture. The user's torso and neck are straight and recline between 105 and 120 degrees from the thighs.


  44. MONITORS QUICK TIPS • Put monitor directly in front of you and at least 20 inches away. • Place monitor so top line of screen is at or below eye level. • Place monitor perpendicular to window. Choosing a suitable monitor and placing it in an appropriate position helps reduce exposure to forceful exertions, awkward postures, and overhead glare. This helps prevent possible health effects such as excessive fatigue, eye strain, and neck and back pain.

  45. MONITORS • Consider the following issues to help improve your computer workstation: • Viewing distance • Viewing angle (height and side-to-side) • Viewing time • Viewing clarity • You should choose a monitor and consider its placement in conjunction with other components of the computer workstation, including the keyboard, desk, and chair.

  46. MONITORS • Potential Hazards • Monitors placed too close or too far away may cause you to assume awkward body positions that can lead to eyestrain. • Viewing distances that are too long can cause you to lean forward and strain to see small text. This can fatigue the eyes and place stress on the torso because the backrest is no longer providing support. • Viewing distances that are too short may cause your eyes to work harder to focus (convergence problems) and may require you to sit in awkward postures. For instance, you may tilt your head backward or push your chair away from the screen, causing you to type with outstretched arms.

  47. Monitors Sit at a comfortable distance from the monitor where you can easily read all text with your head and torso in an upright posture and your back supported by your chair. Generally, the preferred viewing distance is between 20 and 40 inches (50 and 100 cm) from the eye to the front surface of the computer screen. Note: text size may need to be increased for smaller monitors. Put monitor directly in front of you and at least 20 inches away. Place monitor so top line of screen is at or below eye level. Place monitor perpendicular to window

  48. Monitors Provide adequate desk space between the user and the monitor (table depth). If there is not enough desk space, consider doing the following:Make more room for the back of the monitor by pulling the desk away from the wall or divider; orProvide a flat-panel display, which is not as deep as a conventional monitor and requires less desk space); orMove back and install an adjustable keyboard tray to create a deeper working surface. Flat-panel displays take up less roomthan conventional monitors

  49. Monitors • Potential Hazard Working with your head and neck turned to the side for a prolonged period loads neck muscles unevenly and increases fatigue and pain Position your computer monitor directly in front of you so your head, neck and torso face forward when viewing the screen.  Monitors should not be farther than 35 degrees to the left or right If you work primarily from printed material, place the monitor slightly to the side and keep the printed material directly in front. Keep printed material and monitors as close as possible to each other.

  50. Monitors Display screen is too high Potential Hazard A display screen that is too high or low will cause you to work with your head, neck, shoulders, and even your back in awkward postures. When the monitor is too high, for example, you have to work with your head and neck tilted back. Working in these awkward postures for a prolonged period fatigues the muscles that support the head. Possible Solutions The top of the monitor should be at or slightly below eye level. The center of the computer monitor should normally be located 15 to 20 degrees below horizontal eye level .The entire visual area of the display screen should be located so the downward viewing angle is never greater than 60 degrees when you are in any of the four reference postures.  In the reclining posture the straight forward line of sight will not be parallel with the floor, which may increase the downward viewing angle. Using very large monitors also may increase the angle.Remove some or all of the equipment (CPU, surge protector, etc.) on which the monitor may be placed. Generally, placing the monitor on top of the CPU will raise it too high for all but the tallest users.Elevate your line of site by raising your chair. Be sure that you have adequate space for your thighs under the desk and that your feet are supported. Comfortable viewing angle