**3.1 Design and standards**

*Public Health in Developing Countries - Challenges and Opportunities*

unable to walk to work for themselves and earn a living [6]. It is in this regard that some effort has been made to improve the mobility of wheelchair users so that they are able to move from one point to the other despite how rough the terrain maybe.

Users of wheelchairs continue to encounter some difficulties as they seek to navigate from one point to the other on rough terrain due to lack of stability when using rural off-road environment pathways [4]. Most existing wheelchairs are not suitable for use on extremely rough terrain thereby compromising the safety of the occupant [7]. Hence the objective of this chapter to design a wheelchair frame that

Effort to navigate extreme rugged pathways in a rural setting could be a challenge, such that even a great modern wheelchair may be found to be of limited usefulness [8]. What could be needed is an off-road design that is easy to manufacture and repair compared to designs done for a city environment where there are sidewalks. All terrain wheelchairs can increase the mobility range and access by taking occupant where one always wanted to go but were not able [9]. All terrain wheelchairs could be in various shapes and sizes, powered, manual and sometimes with a lever drive. Some have specific advantages such as the ability to maneuver on loose terrain covered by sand or gravel, in snow, over hilly terrain or on hills [10]. It is the unstable nature of existing wheelchair frames that demands for a wheelchair design modification to ensure increased increase stability on "non-ideal" terrain surfaces. Such rugged terrain may entail (but are not limited to): gravel, grass, dirt, and cracked asphalt or concrete. A wheelchair design modification is required for successful traversing of the adverse terrain while keeping four points of contact between the wheels and ground as well as maintaining the required stability

offers optimum stability on rough terrain and does not readily overturn.

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**2. Background**

**Figure 1.** *Rough terrain [5].*

The intended mandate is come with a design with improved performance that provides requisite seating and postural support without compromising strength, durability and safety [12]. The International Organization for Standardization (ISO) formulated international standards for wheelchair frames, the ISO 7176 series (1). The series specify the relevant terminology and testing processes to evaluate wheelchair parameters such as performance, size, strength, durability and safety. In some cases, the required conditions in the ISO 7176 series may not capture all typical requirements in less-resourced environment, as some of the requirements were meant to simulate the conditions in city environs with smooth tarred roads. It is therefore necessary to consider varied environments when formulating national standards, by looking at key parameters such as the weights and sizes of users, typical uses, and the available wheelchair designs and associated technologies within the country [13].
