1. Ergonomics is the science of fitting the job to a group of workers.

b. Webster's New World Dictionary (College Edition) defines ergonomics as "The Study of the problems of people in adjusting to their environment; especially the science that seeks to adapt work or working conditions to suit the worker.

b. When there is a mismatch between the physical requirements of the job and the physical capacity of the worker

d. Workers who must repeat the same motion throughout their workday, who must do their work in an awkward position, who must use a great deal of force to perform their jobs, who must repeatedly lift heavy objects or who face a combination of these risk factors

b. Ergonomics studies the various risk factors brought to a job. There are three areas within which ergonomics risk factors exist: risk factors inherent in the worker, risk factors inherent in the task, risk factors inherent in the environment.

b. Musculoskeletal disorders are among the most prevalent medical problems in the U.S., affecting 7% of the population.

a. Often MSDs can be prevented by simple and inexpensive changes in the workplace. Adjusting the height of working surfaces, varying tasks for workers and encouraging short rest breaks can reduce risks. Reducing the size of items workers must lift or providing lifting equipment also may aid workers. Specially designed equipment, such as curved knives for poultry processors, may help.

a. Work-Related Musculoskeletal Disorders are musculoskeletal disorders caused or made worse by the work environment.

d. Musculoskeletal disorders include a group of conditions that involve the nerves, tendons, muscles, and supporting structures such as intervertebral discs.

b. The contributing factors you and your employees should be aware of include: awkward postures, repetitive motions, forceful exertions, pressure points e.g., local contact stress, and vibration.

a. Recently however, the share of MSDs due to overexertion has been shrinking as the proportion of disorders resulting from repetitive motion and bodily reaction is on the rise.

c. The level, duration, and frequency of the loads imposed on tissues, as well as adequacy of recovery time, are critical components in whether increased tolerance (a training or conditioning effect) occurs, or whether reduced capacity occurs which can lead to cumulative trauma disorders CTDs as well as other MSDs.

b. The musculoskeletal system is made up of the soft tissue and bones in the body. These are the parts of the musculoskeletal system: Bones, muscles, tendons, ligaments, cartilage, nerves, and blood vessels.

b. By the age of 35, most people have had their first episode of back pain. Once in their working years of ages 25 to 65, however, the prevalence is relatively consistent.

d. The age groups with the highest rates of compensable back pain and strains are the 20–24 age group for men, and 30–34 age group for women.

b. Whether the gender difference seen with some MSDs in some studies is due to physiological differences or differences in exposure is unclear. One 1991 study found no gender difference in workers compensation claims for CTS. Another study found no gender difference in reporting of neck or upper extremity MSD symptoms among newspaper employees using monitors. In contrast, other studies have reported that neck and shoulder muscular pain is more common among females than males, both in the general population and among industrial workers.

a. An important study noted that significant gender differences in work posture were related to stature and concluded that the lack of workplace accommodation to the range of workers' height and reach may, in part, account for the apparent gender differences.

a. When physical fitness is examined as a risk factor for MSDs, results are mixed. One study reported that only 7% of absenteeism could be explained by age, sex, and physical fitness. On the other hand, another study found that physical capacity was related to musculoskeletal fitness.

b. False. Although physical fitness and activity is generally accepted as a way of reducing work-related MSDs, the present epidemiologic literature does not give such a clear indication.

a. True. The probability of injury increases as muscles weaken. Consequently, demanding repetitive or static muscular work requires energy, not necessarily strength. You may be strong, but not have sufficient energy to do the task.

b. Anthropometric data are conflicting, but in general indicate that there is no strong correlation between stature, body weight, body build and low back pain. Obesity seems to play a small but significant role in the occurrence of CTS.

d. The effort depends on the type of grip, object weight, object dimensions, body posture, type of activity, slipperiness of object, temperature, pinching, vibration, duration of the task and number of repetitions.

b. From the Joyce Institute, Principles and Applications of Ergonomics: Compressive forces on L5 / S1 disc exceeding 550 lbs. (250 kg.) causes four times the injuries than forces of less than 550 lbs.

c. Common locations of injury due to exerting excessive force are the neck/should, low back, foot/ankle and wrist/hand.

d. Contact trauma describes a condition when any part of your body presses against an external object and the resulting sustained force may cause too much mechanical stress on tissues.

a. The Pinch Grip which depends on the fingers to exert the force and manipulate the object. This grip strategy requires much greater muscle strength so it is more likely going to cause an injury. The Power Grip uses the muscles of the entire hand to apply force and manipulate objects. Consequently, it's the most effective, and safest, grip to use.

c. Static exertion combines force, posture, and duration to create a condition that quickly fatigues our muscles which increases the chances of acquiring a CTD.

a. When handling vibrating tools for a prolonged duration, vascular insufficiency in the hand and fingers which can also result in interference with sensory receptor feedback. If a worker can't "feel" the grip properly, he or she may compensate by applying more force than is necessary to hold and handle an object.

b. Recovery time is a measure of the rest (or low stress activity) period available to the muscle group between similar exertions.

d. Awkward postures typically include reaching behind, twisting, working overhead, kneeling, forward or backward bending, and squatting.

a. Angular velocity is nothing more than the speed at which the body part moves. Acceleration is the rate of change of the speed at which the body part moves.

d. Heat exhaustion, heat cramps, dehydration, electrolyte imbalance, and loss of physical/mental work capacity can also result from heat stress.

b. Heat stress is made even more dangerous in the presence of high humidity due to the reduced ability of the body to cool itself.

b. If the worker is exposed to an environment so cold that the body cannot maintain adequate deep core temperature, hypothermia, which can also be life-threatening, may result.

a. Symptoms brought on by cold stress include shivering, clouded consciousness, pain in the extremities, dilated pupils, reduced grip strength and coordination, and possibly ventricular fibrillation.

b. The most common whole-body vibration forces are not sudden, but rather occur over a period of time. For example, this type of vibration is usually created by large vehicles as they travel over highways and especially terrain.

b. The body's response to vertical vibration will be greatest between 4 and 8 Hz, while vibrations between 2.5 and 5 Hz generate strong resonance in the vertebra of the neck and lumbar region.

a. Factors influencing the adequacy and effectiveness of illumination include the following: the quality of light in terms of freedom from glare, and correct direction, diffusion and distribution; freedom from shadows and extreme contrasts; all skylights, side windows, lamps and other accessories which are necessary for illumination are kept clean, and in working order.

b. Noise is any sound that is unwanted. It can be so powerful as to cause pain in the ears, or it may represent only a nuisance. Its pitch may be quite high or very low; its duration, continuous or intermittent; and its onset, sudden or gradual.

c. To create a healthy work environment, all parties should understand their roles in the overall work process; end users should participate in the selection of equipment, software, tools and accessories; and employers should provide adequate operator training on the setup, adjustments, and risks associated with performing the job.

d. Though the findings of the studies reviewed are not entirely consistent, they suggest that perceptions of intensified workload, monotonous work, limited job control, low job clarity, and low social support are associated with various work-related MSDs.

a. The following control measures are widely accepted as intervention strategies for controlling workplace ergonomic hazards: Engineering Controls; Management Controls; and Interim Measures. Intermim measures are only temporary.

b. Engineering Controls reduce or eliminate potentially hazardous conditions through design, redesign, substitution, and replacement.

Engineering Controls reduce or eliminate exposure to hazardous conditions by changing work procedurs and schedules.

a. There are five components of proper computer workstation design that you must address to maintain proper posture: the work surface, the keyboard, the pointing device or trackball, the monitor and the chair.

d. Work Surfaces need to be deep enough to allow proper keyboard positioning and to accommodate a monitor viewing distance of 18-24 inches; wide enough to accommodate keyboard, mouse and reference material; Surface height should be adjusted for the user or adjustable for multiple users; free of hard or sharp surfaces upon which the wrist rests; and leg room to allow your legs to move freely.

b. Changing work procedures and schedules describe management controls.

a. Safe procedures maintain workers in neutral postures, and reduce frequency, duration, and severity of exposure to risk factors.

b. One of the most controversial questions in the prevention of MSDs is whether the use of personal protective equipment (such as wrist supports, back belts, or vibration attenuation gloves) by the employee are effective.

d. When hazardous conditions and unsafe behaviors exist, it's usually because the safety management system is failing somehow. These system failures represent the root causes for accidents.

d. Design root causes. Inadequate design of the safety management system. The development of written safety plans, policies, processes, procedures and practices is very important to make sure appropriate conditions, activities, behaviors, and practices occur. Implementation root causes describe the failure to carry out the plan as designed. Failure to effectively implement the safety management system is critical to the success of the system. You can develop a wonderfully designed system, yet if it's not implemented correctly, it won't work.