Development and validation of a complex intervention: A physical exercise programme aimed at delaying the functional decline in frail older adults.

The Criteria for Reporting the Development and Evaluation of Complex Interventions in health care process has the potential to help practitioners in developing and planning complex interventions, such as an exercise programme. Its components can be adjusted to the context and to the characteristics of the target population. A study protocol and a pilot study will be developed to test the effectiveness of the physical exercise programme on delaying the functional decline of frail older adults.