The design of work Chair between ergonomics and human performance quality.

Office work has special characteristics that differ from other business. It depends on the stillness and stability in certain postures to perform definite activities and tasks in a specific work space for long periods of time.. As the modern life impose this kind of work on us, there are many health issues emerged that were not existed before. So that, The design of office chair is a challenge for the designer as it is one of the most detailed designs that the designer of the office furniture could face during his work, as the office chair has special characteristics that makes it different from the other chairs or furniture designs and these differences include:

-Close connection between the office chair and the human body as the office chair is the mold that contains human body and supports it.

-The period of sitting on the office chair in certain postures with a limited range of motion is long because the employee has to sit on the chair most of the day at work to perform his work.

This study determines the design Considerations of the work chair elements which is based on the human aspects associated with the human body and aspects related to the requirements of the tasks and the work environment And give the ability to design work chair can reduce harm of  long sitting and provide comfort to user, which in turn increase the production rates and improve the quality of performance .

The first part : Historical introduction for work chair

chapter I : The first beginnings of work chair idea to the end of World War II

This chapter opens the discussion about the beginning of the emergence of the idea of the history of the work chair development, where it discusses the beginnings of the idea and presents different forms of this type of chairs, from manual models, and even those that were produced in the mid-twentieth century. And it will focus on the roots of the first mechanism and the first wheelchair and how it contributed to the main feature - mechanism - in the development of design work chair over time. And it will analyze the evolution of the production of this type of chairs, the contribution of modern materials and those producing factories, in the design of a chair.

Chapter II : The factors and the appearances of the evolution of work chair elements across the most prominent models in the second half of the twentieth century

This chapter discusses the factors that contributed to the evolution of the elements design of the work chair and the manifestations of the evolution of these elements through the analysis of the most prominent models that were designed during the second half of the twentieth century, according to the time line to be included in terms of shape and materials used and the movement mechanism . And it emphasizes role of modern materials and production technology in the enrichment work chair . as this type of chairs was developed in this pariod rapidly.

The second part :- the relationship between human and work chair

Chapter I : The importance of ergonomics and study of human body features to design a healthy sitting posture for work chair

The first chapter reviews the health aspects that might be exposed to man during sitting for long periods of time and illustrates the importance of ergonomics in the design of work chair and to make  correct sit position through the study of the physical human characteristics and identify the anatomical variables when moving from a standing position to a sitting position and to avoid severe conditions of sitting postures that results in discomfort and pain, which gradually lead to chronic health injuries.

Chapter II : Functional Considerations of work chair design

This chapter is based on the study of the work environment and study the sitting postures during practice the work assignments and studying the balance of human body while sitting, and to know the behaviors and activities carried out by individuals to determine the functional requirements of the work chair. It also studied the anthropometric aspects and constructional dimensions of the human body and rules for the design elements of the chair.

The third part : applied part

Chapter I : Reactivity and work chair design

This chapter reviews the concept of reactivity and interactive design and their effect on the design of chairs in general and the work chair specially , and in particular the role of artificial intelligence and smart materials in reactivity support between the human and the work chair.

Chapter II : The design of interactive office chair

This is the applied part of research that presents the steps of the design of interactive model of work chair designed to fits most of people with different bodies and meet the requirements of various work tasks and be comfortable and be more effective and luxury.