Dunlop et al (2005) demonstrated that lack of regular vigorous physical activity almost doubled the odds of worsening of limitations and that regular vigorous physical activity reduced this

worseing by as much as 32%. The results of our study show that the level of physical activity was higher in the experimental group than in the control group. We found a 5.3 fold in the short term and 2.9 fold in the long term greater odds of people receiving behavioural graded activity meeting the recommendation for physical activity compared with those receiving usual care, mainly due to an increase in the amount of time spent walking in the behavioural graded activity. The difference in physical activity between the groups may be due to the fact that more of the experimental group were advised to perform home activities than the control group. In the experimental group, the most problematic activities were increased selleck chemicals gradually and previous research has shown that walking is the most prevalent limitation in activities in people with osteoarthritis (Ewert et al 2004). There are a few limitations to this study that need to be mentioned. First of all, the design of our study does not allow any conclusions to be drawn about which aspect of behavioural graded activity (eg, booster sessions) is most important

for improving exercise adherence and physical activity. Second, a gold standard in measuring exercise adherence does not exist

(Sluijs et al 2006). In our study, exercise adherence was measured using a self-report questionnaire. Although used http://www.selleckchem.com/products/BIBF1120.html widely, the validity of using self-report questionnaires to measure exercise adherence is debatable. They are known to overestimate adherence and are susceptible to bias caused by memory, social desirability, and need for social approval (Sluijs et al 2006). However, a self-report questionnaire is a simple measurement to collect and is probably no more subject to bias than diaries and interviews. Although accelerometers/pedometers provide reasonably accurate measures of walking, they cannot evaluate other types of activities. Importantly, it is unlikely that potential sources of bias inherent in self-reports explain why the between-group differences, because both groups had similar baseline adherence. In conclusion, behavioural graded activity with booster sessions results in better exercise adherence and a greater amount of physical activity than usual physiotherapy intervention, both in the short- and long-term. Integration of behavioural graded activity principles and adding booster sessions to exercise programs seems to be useful in enhancing exercise adherence and physical activity after discharge from physiotherapy intervention. eAddenda: Appendix 1 and Appendix 2 available at JoP.physiotherapy.asn.au Ethics: The Medical Ethical Committee of the VU University Medical Center, Amsterdam, The Netherlands approved this study.