بسم الله الرحمن الرحيم 1

Ergonomics

Ergonomics Is the study of the way in which people interact with equipment in their working environment to improve their comfort , safety and productivity Or it is the science of fitting jobs to the people who perform them

Ergonomic Program Benefits Decreased injuries ,illnesses Decreased worker’s compensation costs Increased efficiency at work

Ergonomic Program Benefits Decreased absenteeism and turnover Increased physical well being Improved employee morale

Ergonomics Involves knowledge of three key aspects - Anatomical - Physiological - Psychological

Cumulative Trauma Disorders ( CTDs ) Are Conditions likely to result from lack of attention to ergonomic principles Develop over a long period of time It is impossible to predict who will develop CTDs

Cumulative Trauma Disorders ( CTDs ) Result from the accumulation of stresses over time Many off the-job activities can lead to CTDs Examples are : Tennis , golf , gardening , needle work , etc.

Factors affecting CTDs Contact stress Is caused by any sharp or hard object putting localized pressure on a part of the body. It will irritate local tissues and interfere with circulation and nerve function Excessive heat Can result in increased fatigue and heat stress

Factors affecting CTDs Extreme cold Constricts blood vessels and reduces sensitivity and coordination of body parts Stress and Psycho-social issues can create increased muscle tension and reduce a person’s awareness of work technique

Examples of CTDs Repetitive Strain Injury , RSI Tendinitis Tenosynovitis Bursitis

Examples of CTDs De Quervain’s disease Carpal Tunnel Syndrome Work Related Upper Limb Disorders Lower Back injuries

Factors Behind CTDs Position of the body Force required to perform the task Frequency of the task

Position of the body

Body Position Nobody can work in a perfect position all the time The best position For Tendons & Ligaments are those in which the muscles have the most strength

Body Position Body muscles will have the most strength if - Wrists are straight - Back and neck are as close to their natural alignment as possible - Shoulders are relaxed - Elbows are near the side and bent at about 90 angle to reach the work

Body Position Static posture occurs when one position is held for a prolonged period of time The muscles will become fatigued from a lack of blood flow during a static posture The fatigue can lead to discomfort and even injury

Body Position A neutral body position is safest and most efficient position to work Awkward posture is a deviation from the neutral position & it puts stress on muscles , tendons and joints

Neutral position

MUSCLES TENDONS

LIGAMENTS

Body Position Let us discuss the position of the following body parts : 1 – Neck and shoulders 2 – Back 3 – Elbows 4 – Wrist

Neck and shoulders position

Position of Neck and Shoulders Neck to be in natural alignment with the spine Head should not be tilted to one side or turned to the left or right A good guideline to follow : Ears should be over the shoulders

Position of Neck and Shoulders Shoulders should be relaxed & not raised Arms not raised Tension in the neck & shoulders can result from having to hold the head to work at a work station that is too low or too high

Position of Neck and Shoulders The too high work station is the most common source of tension to neck & shoulders In case of too high work station : Either to lower the work or to raise the employee The second option is more easier

Back position

Back Position If employees do most of their work standing in one position , there should be a rail or other foot support to permit them to prop one foot up This position puts the spine in the best alignment to prevent uneven pressures on the discs

Back Position If you have employees who sit for most of the shift , provide them with ergonomically sound chair Avoid stooping , twisting and over-reaching Try to eliminate the need for manual handling

The Human Spine

Twisting

Twisting

Over - reaching

Stooping while handling

Manual handling

Elbows position

Elbows Position Elbows should be at 90 angle without any rotation of the forearms or bending of the wrists If arms are extended with elbows at angle greater than 90 , arm muscles will be stretched out , become stiffer & less elastic If arms are flexed with elbows at angle less than 90 , muscles will be shortened & their ability to contract decrease

Wrist position

Wrist Position Applying a very light force very often with the wrist in dangerous positions will put more stress on the tendons that go through the carpal tunnel Wrists should be as close to the neutral position as possible

Wrist Dangerous Positions Extended Flexed Radial deviation Ulnar deviation

Wrist Position Tools should be designed and located to allow the wrist to be in the neutral position without any flexion , extension , radial or ulnar deviation

Wrist dangerous positions

Proper hand & wrist position

Force Required to perform the task

Force Force is the amount of physical effort required by a person to do a task or maintain control of tools or equipment For a job requiring very much force , It is important to reduce the frequency & to use the best position A small amount of force can be damaging if it is repeated often enough & applied in an awkward position When tools are easier to grip , the employee does not have to apply as much force

How to make the tool easier to grip Tool handle sized right for the employee’s hand , not too large or too small Textured or cushioned handles Flange at the base of the handle to keep the hand from slipping

How to grip the load Pinch grip ( Squeezing an object between the thumb & the fingers) should not be used to lift heavy objects A pinch grip produces 3-5 times more force on the tendons in the wrist than a grip with the whole hand Power grip is preferred , The whole hand used to grip the load Use both hands - not just one Weight of the load to be balanced by both sides of the body

Power Tools Using power tools can significantly reduce the amount of force required to be applied . Power tools has vibration risk Vibration from power tools can place stress on the tissues of the fingers , hand and arms

Frequency of the task

Frequency When a job requires frequent repetitions , it is important for employees to work in the best position & with as little force as possible

How to reduce frequency Task interruption by breaks Job enlargement , increase the number of tasks each person performs Job rotation , employees work at one job part of the day & then go to a different job for the rest of the day

Office Ergonomics

Office Ergonomics By applying ergonomic principles to the office setting , risk factors are minimized , productivity is increased and overall workplace quality is improved The workstation must be adjusted to promote a neutral position while a person works When adjusting a workstation , keep in mind that all of the equipment interacts Making one adjustment may alter another

Office Ergonomics guidelines Adjust the Chair Adjust reach requirements Adjust focal requirements

Office Ergonomics guidelines Check lighting , noise and temperature Check work pace and stress levels Check work processes

Office Ergonomics guidelines Modify wrist / hand motions Improve neck and back postures Consider personal preferences

Office ergonomics basic criteria Adequate lighting Adequate contrast , no glare , or distracting reflections Distracting noise minimized Leg room and clearance to allow postural changes

Office ergonomics basic criteria Window covering if needed to minimize glare Software : Appropriate to task , adapted to user , providing feedback on system status Screen : stable image , adjustable , readable , glare and reflection free Keyboard : usable , adjustable , legible

Office ergonomics basic criteria Seat back adjustable Good lumbar support Seat height adjustable No excess pressure on underside of thighs and backs of knees

Office ergonomics basic criteria Foot support if needed Space for postural change , no obstacles under desk Forearms approximately horizontal Wrists not excessively bent ( up , down or side ways )

An important Office Ergonomic Principle

Workstation operator postural issues

The End Thanks