Development of a human-powered watercraft for people with lower-body disabilities

Spinal cord injuries (SCI) or other lower-body disabilities can change the life of a person significantly both physically and psychologically. Chapter 1 describes how physical activity is associated with improved physical fitness, health and psychological well-being for people with lower-body disabilities but also that a number of limitations exist to potentially discourage this population from exercising. One of these limitations is a lack of exercise water activities as traditional aquatic sports such as rowing, kayak and canoe requires a level of trunk muscle activation that is often missing for people with SCI. The main aim of this dissertation has been to develop a human-powered watercraft that could be maneuvered by people with lower-body disabilities. This process is described in chapter 2 including the results of a study, which showed the metabolic expenditure when using the watercraft to be similar to other physical activities performed by people with lower-body disabilities. Moreover, the mechanical efficiency was found to be comparable to other human-powered watercrafts and could, as a result, be an alternative fitness tool especially for people with lower-body disabilities, who seek water activities. Chapter 3 describes the development of an improved version of the watercraft, and the results of testing that shows improved hydrodynamic resistance and relationship between mechanical power output and speed. Chapter 4 investigates how velocity fluctuations may affect the speed of the watercraft and if different propulsion modes have an influence. No significant differences are found but several ideas for further research are given. Finally, the interface pressure is evaluated in a setting that mimics the one on the watercraft. It is known that high interface pressure for long periods of time increases the risk of pressure ulcer development for people with SCI. Chapter 5 describes a case-study of an Italian handcycling champion arm cranking on an arm ergometer at two difference backrest inclinations while interface pressure and oxygen uptake was measured. The results showed a difference in pressure between backrest inclinations and from arm cranking and resting. This could help people with SCI to still be able to exercise even if suffering from pressure ulcers.