Ageing is associated with a number of physiological and psychological changes. These include declines in muscle mass, strength, functional ability, and balance, which are associated with increased risk of falling and reduced quality of life. In addition, many older adults have osteoarthritis and the associated symptoms of joint pain and stiffness may exacerbate the age-related changes in physical function. Regular exercise can help offset the age-related declines in muscle strength, functional ability and balance, however many older adults do not regularly exercise. In particular older adults with osteoarthritis tend to have lower levels of physical activity than older adults without osteoarthritis. Aqua-based exercise is recommended for older adults with osteoarthritis due to the properties of water, however relatively few studies have investigated this type of exercise among this population.

The first aim of this thesis was to investigate perceived benefits and barriers to participation in aqua-based exercise among older adults with and without osteoarthritis, who regularly engage in this form of exercise. The key perceived benefit for those with osteoarthritis was pain reduction, whilst those without osteoarthritis identified general health and fitness as the primary benefit. Both groups identified social interaction as an important benefit. Cold changing facilities, particularly during winter, was a key potential barrier for both groups. The second study examined perceived barriers and benefits of aqua-based exercise among older adults with osteoarthritis who had tried, but no longer participated in aqua-based exercise. Key barriers were a lack of suitable classes and insufficient instructor knowledge, as well as cold changing facilities and pool temperature. Benefits included the cushioning effect of the water and the ability to move around more freely.

The third study was undertaken to gain greater insight into the effect of different types of aqua-based exercise on pain and heart rate response of older adults with osteoarthritis. In addition, participants’ opinions and attitudes towards each exercise mode were explored. Participants tried different types of aqua-based exercise including: hydrotherapy, which is a therapist-supervised programme which takes place in warm water; aqua-jogging, which simulates running in deep water whilst wearing a flotation device; resisted-aqua jogging, which is similar to aqua jogging but utilises resistance equipment to increase drag; aqua-fitness, which involves strength and cardiovascular exercises to music in the shallow end of the pool and resisted aqua-fitness, which is similar to aqua-fitness but resistance equipment is used to increase drag. Pain scores immediately post-exercise decreased for all modes of aqua-exercises. Heart-rate response and rating of perceived exertion was also similar for all aqua-exercise modes. Overall, participants enjoyed the hydrotherapy session most, however the aqua-fitness session (un-resisted) was also enjoyed and identified as an acceptable alternative to hydrotherapy.

The final study explored the potential health benefits of a 12-week aqua-fitness intervention for older adults with osteoarthritis. An active control group, who undertook a seated aqua-based exercise session once a week, was used help minimise any effects of social interaction on the outcome measures. Positive physiological outcomes were associated with the aqua-fitness group who improved scores in several functional measures, as well as significantly reducing their fear of falling compared to the control group.

The findings of this thesis are relevant for future design of aqua-based exercise interventions aimed at older adults with osteoarthritis. The research undertaken may help to identify and therefore address barriers to this mode of exercise for this population. Furthermore, the findings of this thesis offers some insight into the acute responses to different modes of aqua-based exercise, as well as long longer-term chronic adaptations to an aqua-based exercise programme similar to those which are readily available in the community.