The effects of pinch grip exertions on the intrinsic muscles of the hand were considered in a study of employees in a garment shop. They found a positive correlation between pinch grip duration and hand pain in this population.
Emanoil (2000), discusses research that found that subjects using the vertical split keyboard kept their wrist angles and forearm movements in the lowest risk zone for carpal tunnel syndrome 71% and 78% of the time, respectively. When typing on traditional keyboards, subjects were in the lowest risk zone only 44 and 25% of the time. Wrists were in the highest risk zone only 2% of the time when using the vertical split keyboard compared with 12% with the traditional keyboard. (p. 13) Increased extensor activity, combined with wrist extension, may also increase carpal tunnel pressures. This may be intensified given the flexor tendon loading to depress the keys and increasing the carpal tunnel pressure as well. (Keir & Wells, 2002) research suggest that the specific interaction between a worker's body and tool use may be important, since pressure on the carpal tunnel from work tools is affected by this interaction " (Messing, Lippel, Demers & Mergler, 2000, p. 31)
Another study that Emanoil discussed compared an oversized, flat, and adjustable computer mouse with a built-in palm support with a smaller, contoured mouse device. Researchers measured the wrist extensions and hand movements of 24 men and women while they used the different mouse devices to move the cursor position and to scroll on the computer. Subjects also rated the smaller and larger mouse devices for comfort. The researchers found that the larger mouse reduced wrist extension by an average of more than eight degrees. At high levels, wrist extension can lead to carpal tunnel syndrome. The adjustability of the larger mouse also kept subjects from making small hand movements, such as flicking their wrists, which could increase their risk of injury. (Emanoil, 2000, p. 13)
The aim of this study was to perform a comprehensive investigation to document wrist and forearm postures of users of conventional computer keyboards. Researchers instrumented 90 healthy, experienced clerical workers with electromechanical goniometers to measure wrist and forearm position and range of motion for both upper extremities while typing. For an alphabetic typing task, the left wrist showed significantly greater (p [less than].01) mean ulnar deviation (15.0[degrees] [plus or minus] 7.7[degrees]) and extension (21.2[degrees] [plus or minus] 8.8[degrees]) than the right wrist (10.1[degrees] [plus or minus] 7.2[degrees] and 17.0[degrees] [plus or minus] 7.4[degrees] for ulnar deviation and extension, respectively). On the other hand, the right forearm had greater mean pronation (65.6[degrees] [plus or minus] 8.3[degrees]) than the left forearm (62.2[degrees] [plus or minus] 10.6[degrees]). Researchers further noted minimal functional differences in the postures of the wrists and forearms between alphabetic and alphanumeric typing tasks. Ergonomists should consider the statistically significant and probable practical difference in wrist and forearm posture between the left and right hand in ergonomic interventions in the office and in the design of computer keyboards. Actual or potential applications of this research include guiding the design of new computer keyboards. (Simoneau, Marklin & Monroe, 1999, p. 413)
Considering previous research conducted, it appears that deviated wrist posture in the flexion/extension plane is implicated in the etiology of work-related musculoskeletal disorders (WMSDs) of the wrist. Studies measuring carpal tunnel pressure have shown that carpal tunnel pressure decreases as the wrist moves toward a neutral posture in the flexion/extension plane. Less pressure in the carpal tunnel is beneficial because the median nerve, which passes through the carpal tunnel, is under less compression and is less likely to show the symptoms of carpal tunnel syndrome. In theory if a typist were to type on a negatively sloped keyboard...
Professional Journal Field Ergonomics Arti The article critiqued in this document is entitled "Workplace economics." It was authored by representatives from the American Chiropractic Association -- although a specific author is not identified. This article serves as an overview to the field of ergonomics as it affects the workplace. The author approaches the topic from a decidedly broad perspective. There are a number of generalizations that are made in this
Nurse-Care Analysis of Sheepshead Bay The area is 4,074 square miles. Its population is 123,178. The people density of people who live in Sheepshead Bay compared to general inhabitants of Brooklyn of people per square mile is 30,233 to 34,917 (City-data.com; web). On my visits there, I was astounded by the mass of people rubbing shoulders one with the other. The streets seemed dense and crowded with a great number of
There are a variety of approaches to diagnosis and treatment in American acupuncture that incorporates medical traditions from China, Japan, Korea, Tibet, Vietnam, and France. " (2002) The American Medical Association additionally reports: "Acupuncture has been used by millions of American patients and performed by over 5,000 U.S. physicians, dentists, acupuncturists, and other practitioners for relief or prevention of pain and for a variety of health conditions. After reviewing the
Ergonomic Risk Assessment The human body encourages a specific posture and has muscles and joints which can become overstressed through repetition or overextension. Unfortunately, every job has actions which cause these types of problems. Injuries in the workplace are expected to a degree because it is impossible to determine every area that could cause an incident, but the science of ergonomics is used to act as a mitigating factor for some
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