Ergonomics for Rehabilitation Professionals [ Active ]

Preface

Ergonomics for Rehabilitation Professionals is an attempt to integrate ergonomics in rehabilitation paradigms toward societal gains. It has been argued before that ergonomics and rehabilitation are complementary disciplines (Kumar 1989, 1992). Despite their apparent distinctly different appearances their constituent components are the same and they deal with the same issues, albeit at different ends of the spectrum. One of the manifested goals of rehabilitation is prevention of the affl iction the clinician treats. The latter brings the efforts of rehabilitation beyond the patient group and into the normal population. However, leaving aside severe disability, the defi nition of disability has blurred signifi cantly. According to the American Disability Act (1990) disability is defi ned as health condition(s) that signifi cantly impair a major life activity. Interpreting this defi nition of disability, Fulbright and Jaworski (1990) stated that 20% of the U.S. population has some form of disability.

Aging is a major contributor to disability. Demographic shifts around the world indicate a trend of rapid growth in the senior population. One of the inevitable consequences of the aging process is a progressive decline in functional capacity in most bodily functions, which may vary in rate for different people based on many factors. Some argue that a full tilt progression of technology has shifted the job demands from physical to cognitive and skill realms possibly undermining overall health, and hence promoting impairment and disability. Others counter this with an argument of their own, that technology tends to compensate for functional impairment and disability enabling people to get out of the "disability" umbrella. Regardless of the validity of either argument, the fact remains that functional subnormality, with reference to the standards set some years ago, is on the rise. Regardless of the genesis of functional subnormality of the general population and the disabilities of patient groups, ergonomics can make signifi cant contributions to both the prevention of affl ictions and their treatment. It has been argued elsewhere (Kumar 1997) that the ergonomic approach signifi cantly enhances both the accuracy and effectiveness of the rehabilitation regimes in some of the established methodologies and treatment methods. Clearly, as has been stated before (Kumar 1997), both disciplines (ergonomics and rehabilitation) are broad in their scope and have a vast body of knowledge. In this modest effort, I have tried to choose topics that, by example, will serve to blend the two disciplines topic by topic, albeit with differential emphasis. It has been the goal of this volume to reveal the commensalism of the two disciplines for mutual enhancement and not to force one on the other.

In the general section (Section A), to exemplify the philosophical perspective of the book, Kumar presents the conceptual basis of rehabilitation ergonomics. In this chapter, he traces the origin of both fi elds; explores their philosophy and goals; their parallelism, divergence, and complementarity; the role of ergonomics in rehabilitation; and also defi nes rehabilitation ergonomics. All human physical activities require motion of the human body involving muscle activities and joint loads. Mechanical activities can be achieved by expenditure of physiological energies. However, the mechanical components and their confi guration determine not only the mechanical effi ciency but also the physiological effi ciency. In Chapter 2, Lin has initially provided the scientifi c basis of physiological cost consideration and subsequently described the impact of pathologies like orthopedic, neurological, and cardiorespiratory disorders, assistive devices, wheelchair propulsion, aging, and obesity on energy consumption. This interesting chapter has a good citation of relevant literature. In Chapter 3, Moseley and Jones tackle the all-important topic of pain. They provide a broad overview of the fi eld with their perspective of its biology, assessment, and management. The authors have provided a signifi cant list of references, which will help the reader to fi nd more information. In the last chapter (Chapter 4) of the general section, Liu and Lederer have dealt with aging. As aging impacts performance, the role of ergonomics becomes more central. They initially describe the age-related physical, sensory, and cognitive changes and design changes necessary to address these problems. The authors advocate universal design, which will be good for everyone including older adults. They provide a few examples to indicate the manner in which these concepts can be integrated for a practical solution.

The second section, Section B, deals with disorders, disabilities, ways to deal with them, and ergonomic measures to prevent some and reduce others as the case may be. One of the primary needs of every organism in the animal kingdom is that of motion. Given the upright bipedalism of Homo sapiens, the kinematics, kinetics, and effi ciency of ambulation with any pathology or disorder become a signifi cant challenge to the individual, and their analysis (and understanding) poses additional diffi culty. In Chapter 5, Striker describes normal gait and those associated with pathologies. In all these conditions, he considers loading, progression, and stability. However, when one is unable to ambulate on his/her own legs, wheelchair ambulation becomes inevitable. This changes the premise of ambulation profoundly. The biomechanics of the phenomenon becomes totally different as the ambulation is powered by either upper extremities or by a motor. By virtue of incorporation of a device to enable ambulation, ergonomic implications are relevant for both the device and the occupant. In Chapter 6, van der Woude et al. deal with these issues. In manually propelled wheelchairs, there is a transfer from leg to arm work for ambulation. This leads to a host of issues unique to this situation. One aspect deals with the discomfort, overuse, and ultimately injury, while the other deals with the effi ciency of the design. The authors of this chapter have discussed vehicle mechanics, human movement system, and the wheelchair interface. One of the consequences of being wheelchair bound is that one is sitting for a much longer period resulting in problems of pressure sores and ulcers. In Chapter 7, Solis and Mushahwar deal with the serious side effect of prolonged seating. The authors give an overview of the etiology of pressure ulcers, their classifi cation, treatment, method of detection, and prevention. They also describe appropriate support surfaces and devices that can dynamically distribute load over seating surfaces. Such approaches have a role in the reduction of pressure localization, which in turn is a causative factor in ulcer formation. In Chapter 8, Haennel and Tomczak describe common cardiac disorder problems and disabilities. The authors look into the problems associated with both myocardial infarction and coronary artery bypass graft surgery.

They examine the typical progression of the patient from an acute event through rehabilitation and various factors that play a critical role in determining the success of the strategy employed in return to work.

Chapters 9 through 12 deal with musculoskeletal disorders. In Chapter 9, Freivalds describes musculoskeletal disorders of the upper extremities and ergonomic interventions for them. He describes the etiology of the common musculoskeletal disorders including tendon, muscle, nerve, vessels, bursa, bone, and cartilage. Subsequently, the author goes on to describe both static and dynamic upper extremity models. Finally, the chapter turns its attention to the intervention strategies of hand tools. Jones and Kumar in Chapter 10 present an entirely original contribution where they examine the methodologies of ergonomic risk assessment for primarily upper extremity disorders. One of the primary diffi culties in ergonomic methodologies is that authors of various techniques rely on partial or qualitative validation of their methods. When a person in the fi eld is faced with different methodologies, it becomes a daunting task to determine which to pick. By using clear and objective defi nitions, the authors have compared fi ve commonly used and cited risk assessment methodologies and demonstrated that each one of them is defi cient in predicting risk and injury. They acknowledge that a direct comparison of these methodologies is not possible. This opens up the fi eld for rigorous and objective studies for developing and validating techniques that could be reliably used. In Chapter 11, Maitland considers factors related to musculoskeletal disorders of the neck and shoulders with possible ergonomic interventions. The author concludes that the causative mechanisms for these disorders and effective interventions for these are not yet conclusive. In the last chapter of this section (Chapter 12), van Dieën and van der Beek describe workrelated low back pain, focusing on biomechanical factors and primary prevention. It is evident that the subject of low back pain is both vast and complex. The authors describe low back pain and the risk factors associated with it. Finally, they elaborate on a few ergonomic interventions.

The fourth section, Section D, is entirely devoted to selected ergonomic interventions that rehabilitation professionals can use. In Chapter 13, Feney and Harman take a clinical approach to intervention and rehabilitation. The authors provide a critical analysis of therapeutic exercise for subacute low back pain and carpal tunnel syndrome. The authors argue that therapeutic exercise is the foundation for a successful rehabilitation of musculoskeletal dysfunction. However, unfortunately, therapeutic exercise has not been effective on these affl ictions. The authors discuss the reasons for this lack of success and suggest approaches to remedy this. Chapter 14 deals with the effective utilization of assistive devices in the workplace. In this chapter, de Jonge has identifi ed the role that assistive devices play in workplace accommodation and has highlighted the value of using a consumer-centered process when selecting and using the technology. Such a selection must also be followed with training where appropriate. Chapter 15 by Bloswick and Howard describes some of the current innovations in assistive technology. Chapter 16 on enabling design by Anderberg et al. discusses universal design at length that will allow an effi cient design for all, regardless of their age and disabilities. In Chapter 17 on functional capacity evaluation, Davidson discusses the intricacies of the approach and the challenges faced by rehabilitation professionals. She points out the shortcomings of this approach especially with respect to reliability and validity. However, imperfect as it may be, this tool is in wide use among professionals. Also, it is absolutely essential to determine defi cits before they can be compensated. Chapter 18 by Wiker deals with the latter topic. Wiker delves into the concepts, strategies, and techniques of reasonable accommodation to render an individual functional and integrated in the society, who without such accommodation will not be a functional and integrated citizen.

Hopefully, the selection of topics from two vast and seemingly diverse disciplines will initiate the knowledge of some ideas and concepts not only to bridge the gap between the two disciplines but also to spur some activities in the direction that will benefi t individual citizens as well as the society at large. This is a lofty dream, but even some activity in this direction will justify the goal of this book.