The noise caused by the movement of users on their chairs in the work environment may indicate structural weaknesses and risk, and still significantly reduce productivity by increasing employees stress level. By understanding the activities to be developed in a work place one may understand what should be necessary to a good development, thereafter a search for improvement of labor activity with the aim of better use of resources in the operation of product use may be done. The analysis of the incremental variation of noise in professional chairs aims to identify its origin and the time the emission of noise starts during the period of use, its development and the major causative agents. Determining the characteristics of the sound of different materials and adjustments mechanisms of the chair can determine how different materials interact with each other. The measurement of these noises in an acoustic isolated room using directional microphones, if recorded and analyzed properly makes it possible to investigate and orientate to suspect elements in order to propose solutions and identify the quality of other similar chairs. Based on the results recommendations can be established for the orientation of users, managers and people responsible for the acquisition of the products, inducing them to review the employment of materials and the choice of the processes of production. These aspects are not covered in the Brazilian ergonomics norms and standards in the use of chairs.

The systematic of device development for support in the period after surgery and for consolidation of fractures of lower limb, manufactured in aluminium alloy and PVC, integrated with quick fixes, cleanliness simplified, retractable, and adaptable to wide range of biotope. Has as value-added a possibility of transforming an axillary crutch in Canadian and, where necessary, the transformation of the Canadian crutch in cane to aid the balance and safety on return to walk independently. The proposed instrument enhances the limited movement capabilities and mobility by ensuring greater security and versatility of the beginning of the user's recovery until the end of his convalescence.