Exploration of wheelchair propulsion biomechanics in straightforward propulsion, turning manoeuvres and obstacle crossing: The impacts of sex, age and training

A high incidence of injury in wheelchair dependent populations relates to a low mechanical efficiency and a high mechanical load of wheelchair propulsion. The user-related elements such as sex and age as well as training consequences were believed to be main determinants of wheelchair propulsion efficiency and performance. The aim of the present work sought to determine the impact of user-related components on straightforward and more complex wheelchair propulsion tasks, e.g. turning and obstacle crossing, in novice able-bodied users. The thesis consists of 4 parts 9 chapters. The first part introduces the topic in the form of an introduction (chapter 1) and a literature review (chapter 2), followed by six experimental studies and general discussion in the final chapter. A hundred able-bodied participants partook in different studies of the thesis. The first three experimental studies (chapter 3 – 6) were focused on the straightforward wheelchair propulsion. More complex wheelchair propulsions were explored from chapter 6 to 8. The analysis of asynchronous turns in three phases: approach, turning and depart phase, and compared to straightforward wheelchair propulsion was a novel approach and included in chapter 6 – 8. These chapters offer theoretical insight in human movements and provide detailed biomechanical information during turning manoeuvres. The sex differences in propulsion efficiency and characteristics (push speed, frequency, angle and force application) exist in the younger and older group regardless of the complexity of propulsion tasks, ranging from straightforward wheelchair propulsion (chapter 3) to turning manoeuvres and obstacle crossing (chapter 7). The differences between men and women, aged 20 – 85 years, were more pronounced with age. Timing parameter changes and propulsion efficiency decline with age were present in straightforward wheelchair propulsion and more clearly expressed in more complex wheelchair propulsion, in particular obstacle crossing. The individualised handcycle upper body training, consisting of 2 sessions/week for 4 weeks of resistance training at 70% of 1RM and 2 sessions/week for 4 weeks of 7x2 min handcycle high intensity interval training at 80% – 90% of maximal heart rate, does not seem to be helpful for improving propulsion efficiency during straightforward wheelchair propulsion, but it was for improving maximal physiological capacity in young able-bodied men (chapter 4). Chapter 8 emphasised that the 4x30 min wheelchair practice was beneficial to improved propulsion efficiency and characteristics during straightforward wheelchair propulsion. The wheelchair practice also improved propulsion characteristics and force application during turning manoeuvres and obstacle crossing. Finally, the present thesis provides insight into user related elements that affect propulsion efficiency and performance. Furthermore, it is the start of knowledge development on the biomechanics of more complex wheelchair propulsion i.e. turning and obstacle crossing.