MacMillan et al. BMC Public Health 2011, 11:120 http://www.biomedcentral.com/1471-2458/11/120 statistician). Steering group meetings were held monthly to drive the development of the study. Challenges Several challenges should be considered when designing an intervention to be delivered via a general practice setting for older adults. Delivering a walking intervention via a general practice The study was based entirely in primary care (including recruitment, intervention delivery and follow-up). It was recognised that time scheduling in general practices is tight and thus we attempted to make the intervention not too time intensive. The duration of each study visit is between 5 and 60 minutes (see Figure 1 for visit time length). In this study there were 6 study visits in total. However three study visits (visits 1, 3 and 5) were for the measurement of physical activity. These visits would not be required if the walking intervention was to be implemented in general practices without the research components included in the WEW65+ study. Targeting older adults The trial recruited both men and women aged ≥65 years. Population data for Scotland highlight the alarmingly high proportion of older men and women that are inactive. Also, population data show that walk- ing declines steadily with age in both men and women and that this decline is more marked and occurs earlier in men [3]. Thus efforts are required to encourage both older men and women to increase their walking levels by developing interventions that target and are accepta- ble for both genders. Screening for participation in physical activity Little is known about how best to screen for physical activity participation and who is able to do this. In this study the general practitioner was the only team mem- ber granted full ethical access to medical records and who could therefore complete screening for eligibility into the study. An outcome of this study will be the development of a list of physical activity contraindica- tions that are specific to an older adult population which can be used to aid physical activity screening in the future and could be used by other primary care staff, removing the requirement of a general practitioner for eligibility screening. Screening out those who are already active Defining who is ‘already active’ and ‘insufficiently active’ and the cut-off points for these using both objective and subjective measures of physical activity is a major chal- lenge in physical activity intervention research. In an attempt to ensure that insufficiently active individuals were included in this study and already active indivi- duals were excluded from participation the protocol had two physical activity level screening phases (verbal/writ- ten screening with a researcher and objective screening Page 10 of 12 based on pedometer step counts). It is possible that dur- ing the initial screening phase individuals will over or under report physical activity. Objective physical activity readings can be affected by ‘reactivity’ [64] (when an individual changes their normal physical activity pattern because they are aware that their activity levels are being assessed) or wear compliance (e.g. forgetting to wear the activity monitor or not wearing it in the cor- rect position). The use of self-report measures of physi- cal activity, reactivity and wear compliance could adversely affect recruitment into the study. Individuals who are already regularly active may be incorrectly recruited (if for example they under-report the amount of activity they do or forget to wear the pedometer for all waking hours). Conversely, reactivity can lead to rela- tively inactive individuals incorrectly being excluded from study participation (if they walk more than usual during the monitoring period). Limitations Generalisability Participants were recruited via a single general practice thus the feasibility findings may have limited generalisability. Physiological health and cost-effectiveness outcomes Another limitation of this study is the lack of physiolo- gical health outcomes due to funding constraints. However, the health benefits of walking are already well-documented, whereas research is lacking in the area of determining how best to support people to walk regularly. A cost-effectiveness analysis will not be con- ducted in this study but the gathering of well-being data will aid such analysis in the future. Comparison group As mentioned earlier the CONSORT guidelines were used to guide the design of this study [63]. This study did not have a control group over the full study period as it was viewed as unethical to withhold the walking inter- vention and consequently the possible health benefits that could occur from increasing physical activity partici- pation. Thus we opted for a ‘delayed’ group rather than a true control group for the entire length of the study. Conclusions The feasibility elements of WEW65+ will inform research in the area of physical activity intervention delivery through a primary care setting via a general practice. The pilot component of this study examines efficacy of a walking intervention (already shown to be effective in younger adults [17]) in an older adult popu- lation in Glasgow, by measuring pedometer step counts as well as secondary measures including well-being. Use- ful information as to why individuals did not wish to participate in this study and the reasons for exclusion