Ergonomics- "An applied science concerned with designing and arranging things people use so that the people and things interact most efficiently and safely - called also human engineering" - Merriam-Webster's Collegiate Dictionary.

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PREVENTION OF REPETITIVE STRESS INJURIES OF THE FOREARM, WRIST AND HAND BY USE OF AN ERGONOMIC PAINT BRUSH

Scott Stanley, D.C.

Introduction

On the 2nd day January 1999 Messrs. Herron and Cox ("Inventors") presented a new, patent pending paintbrush handle design alleging certain physiological and production enhancing benefits. Inventors claimed that the ergonomic paint brush design would reduce the incidence of repetitive stress syndrome(s). Further, Inventors requested that I research and, if possible, provide an independent analysis of their claims either crediting or discrediting it.

Inventors provided me with a working sample of the Brush (the name of the new paint brush design), a videotape demonstrating the advantages of painting with the Brush. They also supplied me with verbal descriptions of the Inventor's painting experience and the genesis of the new brush design and limited feedback from professional painters on the design.

Inventors allege numerous user benefits: 1) that the new paint brush is an ergonomic solution to problems inherent in traditional brush designs; 2) the Brush reduces forearm fatigue as it guides the user's fingers into grooves formed on the brush head thereby providing a natural extension of the hand at the proper hand to forearm angle; 3) that the new design is precisely weighted to provide optimal user control via an elongated brush handle which acts as a counter balance to the paint filled brush head; 4) the Brush design improves the efficiency of the user by providing molded control points at the top and bottom of the lateral brush head control surface and 5) the Brush design allows ambidextrous use. (See attached illustrations)

Inventors cite national statistics from the U. S. Government Bureau of Labor Statistics ("BLS") which summarize research conducted annually of over 250,000 private sector establishments who reported in 1994 that there were approximately 705,800 cases (32%) which involved days away from work due to overexertion or repetitive motion. Of these cases, 92.576 were due to repetitive motion and 55% affected the wrist.

Research

Humans are plagued by numerous conditions, which can as a group can be called repetitive stress injuries or cumulative micro trauma disorders. Included is this category are "MSD's" or musculoskeletal disorders which refer to conditions that involve the nerves, tendons, muscles and supporting structures of the body.

There are several conditions to consider within the hand and wrist region. Combined work factors of forceful and repetitive use of the hands and wrists are associated with carpal tunnel syndrome. Workers in industries which spend their workdays performing forceful exertions and repetitive movements of the hand and wrist have been found to have a strong association with tendonitis of the wrist and have also been found with disorders of the elbow such as epicondylitis. Carpal tunnel syndrome is usually associated with a) ill-designed tools, poor job techniques and repetitive work processes involving the hands.

My initial analysis began with a review of available research on the subject of musculoskeletal disorders, carpal tunnel syndrome and other reviews of epidemiological evidence for work-related disorders of the hand, wrist and forearm. Here we are interested in those conditions specifically related to repetitive flexion/extension and side bending of the wrist as well as forceful and or prolonged gripping of the fingers. We have chosen these particular activities because they are the movements involved the use of the standard paintbrush. Contained in Table 1 below are some of the most frequent disorders associated with these movements.

Table 1 disorders and causative motions
Disorder Motion

Sources: Tichauer (1978); Kurppa et al. (1979); Armstrong and Chaffin (1979); Waris (1980); Armstrong et al. (1982,1986); Viikari-Juntura (1984); Wallace and Buckle (1987); Putz-Andercon (1988)

Further, research supports the fact that "repeated or continuous contact with hard or sharp objects such as non-rounded desk edges or unpadded, narrow tool handles may create pressure over one area of the body (e.g., the forearm or sides of the fingers) that can inhibit nerve function and blood flow".

NIOSH's publication, Elements of Ergonomics Programs succinctly summarizes as follows: "The affect of repetition on intramuscular tissue, nerves and joints is also an important consideration. A series of motions performed every few seconds with little variation may produce fatigue and muscle-tendon strain. If adequate recovery time is not allowed for these effects to diminish, or if the motions also involve awkward postures or forceful exertions, the risk of actual tissue damage and other musculoskeletal problems will probably increase. A task cycle time of less than 30 seconds has been considered repetitive."

From Kilbom A, Repetitive Work of the Upper Extremity

After a careful review of these papers, the research question posed becomes somewhat axiomatic...does the new paint brush handle design reduce or eliminate stressful finger/hand/wrist positions in comparison to standard paint brush handles? Certainly, the new brush design will not reduce the number of brush strokes required to adequately paint a surface but it may reduce the fatigue associated with such application due to its alleged ergonomic design. This became the focus of my research.

Observations

Utilizing a standard goneiometer, wrist flexion, extension, as well as ulnar and radial deviation were measured while using a standard paintbrush and again using the Brush. It was evident that the motions and postures outlined in table 1 above were significantly reduced or eliminated when using the Brush verses a standard paintbrush.

In addition, this author studied videotaped footage of painters using a standard brush and the new invention. It was determined that painters utilizing the standard brush move their hands and wrists in numerous combinations of the positions mentioned above. However, painters using the inventor's design were found to use no fewer, but better finger and hand placements on the brush handle. Their hands and wrists tended to remain in more anatomically neutral positions.

Conclusions

It is the opinion of this author that the physiological benefits claimed by the inventors are legitimate and are supported by the existing literature on the subject. Further, my independent analysis of the newly invented paint brush handle indicates that the brush handle design can be considered "ergonomic" in design in as much that it reduces stressful positions and motions of the hand, wrist and forearm.

The Brush, with its attention to ergonomics and user comfort appears to significantly reduce mechanical stress and adds control, which should decrease the incident of repetitive stress injuries for paint applicators. Further, the Brush's handle design should provide such benefits as a reduction of hand/wrist fatigue and, thus, increased productivity.

REFERENCES

1) Pheasant, Stephen Ergonomics, Work and Health 1991

2) NIOSH (National Institute for Occupational Safety and Health), Elements of Ergonomics Programs, March, 1997, U. S. Department of Health and Human Services.

3) NIOSH, Cumulative Trauma Disorders in the Workplace, September, 1995, U. S. Department of Health and Human Services.

4) NIOSH, Musculoskeletal Disorders and Workplace Factors, July, 1997, U. S. Department of Health and Human Services.

Illustration A:

Recent recognition of the causal relationship between motions, postures and repetitive stress injuries has led to ergonomic design in everything from toothbrushes to paring knives. Compare the modern automobiles interior to those of 20 years ago for a perfect example of how ergonomics has influenced design. The keyboard is an excellent example of the necessity for better, low stress ergonomic design.

The "Brush" with its patented ergonomic design addresses the concerns outlined in this paper (see illustration B). First the ferrule has been replaced by a molded design which both secures the bristles and presents comfortable control surfaces which permit the use of more natural and more forceful finger positions (1). The control surfaces are textured to decrease the tendency for the fingers to slip (2). The curved handle allows the bristles to be presented to the target without overly extending or flexing the wrist (3). Also, the curved handle when used to extend the reach, eliminates ulnar deviation and flexion of the wrist. (4).

Illustration B:

Conclusion:

Stresses, created by motions and postures which are associated with repetitive stress injuries, particularly those related to the forearm, wrist and hand are an inherent part of the use of the standard "stick" handled brush. The "brush" with its attention to ergonomics and user comfort, significantly reduces stress, adds control, decreases incidents of repetitive stress injuries. The incorporation of these innovative design features allow the user to work longer with less stress and fatigue. The bottom line is that the brush allows you to be a better painter and not have to worry about injury.

OSHA

Date: Apr. 5, 2002
Contact: Sue Hensley (202) 693-4676
Bonnie Friedman (202) 693-1999

OSHA Announces Comprehensive Plan To Reduce Ergonomic Injuries
Targeted Guidelines and Tough Enforcement Two Key Elements

WASHINGTON - The Occupational Safety and Health Administration today unveiled a comprehensive plan designed to dramatically reduce ergonomic injuries through a combination of industry-targeted guidelines, tough enforcement measures, workplace outreach, advanced research, and dedicated efforts to protect Hispanic and other immigrant workers. "Our goal is to help workers by reducing ergonomic injuries in the shortest possible time frame," said Labor Secretary Elaine L. Chao. "This plan is a major improvement over the rejected old rule because it will prevent ergonomics injuries before they occur and reach a much larger number of at-risk workers."

Guidelines
Occupational Safety and Health Administrator John Henshaw said his agency will immediately begin work on developing industry and task-specific guidelines to reduce and prevent ergonomic injuries, often called musculoskeletal disorders (MSDs), that occur in the workplace. OSHA expects to begin releasing guidelines ready for application in selected industries this year. OSHA will also encourage other businesses and industries to immediately develop additional guidelines of their own.

Enforcement
The Department's ergonomics enforcement plan will crack down on bad actors by coordinating inspections with a legal strategy designed for successful prosecution. The Department will place special emphasis on industries with the sorts of serious ergonomics problems that OSHA and DOL attorneys have successfully addressed in prior 5(a)(1) or General Duty clause cases, including the Beverly Enterprises and Pepperidge Farm cases. For the first time, OSHA will have an enforcement plan designed from the start to target prosecutable ergonomic violations. Also for the first time, inspections will be coordinated with a legal strategy developed by DOL attorneys that is based on prior successful ergonomics cases and is designed to maximize successful prosecutions. And, OSHA will have special ergonomics inspection teams that will, from the earliest stages, work closely with DOL attorneys and experts to successfully bring prosecutions under the General Duty clause.

Compliance Assistance
The new ergonomics plan also calls for compliance assistance tools to help workplaces reduce and prevent ergonomic injuries. OSHA will provide specialized training and information on guidelines and the implementation of successful ergonomics programs. It will also administer targeted training grants, develop compliance assistance tools, forge partnerships and create a recognition program to highlight successful ergonomics injury reduction efforts.

Hispanic Outreach
As part of the Department of Labor's cross-agency commitment to protecting immigrant workers, especially those with limited English proficiency, the new ergonomics plan includes a specialized focus to help Hispanic and other immigrant workers, many of whom work in industries with high ergonomic hazard rates.

Ergonomics Research
The plan also includes the announcement of a national advisory committee; part of their task will be to advise OSHA on research gaps. In concert with the National Institute for Occupational Safety and Health, OSHA will stimulate and encourage needed research in this area. "Bureau of Labor Statistics' data show that musculoskeletal disorders are already on the decline. This plan is designed to accelerate that decline as quickly as possible," said OSHA Administrator John Henshaw. "Thousands of employers are already working to reduce ergonomic risks without government mandates. We want to work with them to continuously improve workplace safety and health. We will go after the bad actors who refuse to take care of their workers." The new plan was announced barely a year after Republicans and Democrats in Congress rejected the previous Administration's rule, which was developed over a period of eight years and was broadly denounced as being excessively burdensome and complicated. Over the course of the last year, the Department of Labor conducted three major public forums around the country and met with scores of stakeholders, collecting hundreds of sets of written comments and taking testimony from 100 speakers, including organized labor, workers, medical experts, and businesses.

U.S. Labor Department news releases are accessible on the Internet at www.dol.gov. The information in this release will be made available in alternative format upon request (large print, Braille, audio tape or disc) from the COAST office. Please specify which news release when placing your request. Call 202-693-7773 or TTY 202-693-7755.