Our research group is working on experiment involving physical activity in intervention. This is at two levels, pre-school and primary school level. In our study, by physical activity, wee mean activities of children close to nature. In India, there is a place called Dayalbagh in Agra. Many people who are believers in the Oriental Philosophy of Saints, start their morning activity with meditation followed by group prayers followed by 3-4 hours of agricultural work. In this activity, the toddlers of age-range 3 months to 3 years participate regularly with their parents. They are enrolled in superman scheme. The concept of superman is not the one who can fly and is also different from the description of Aristotle. The details can be checked at

http://sigmasixq.blogspot.com/2017/08/supermen-of-dayalbagh-glimpse-into.html

They get opportunity to move around, play and explore the nature while their parents work in fields. The parents are not farmers by occupation but still agricultural activity is part of their routine. There occupation range from school teacher to university professors to employee in multi national companies, etc.

Laura if I understand correctly your research involve which strategies will you use to get your desired out come regarding physical activity. At first I was going to say the population but then I thought about it and you can start with the physical activity of a smaller going into a larger group then bring in the population. For example: How does physical activity effect senior ages 65 to 75 who attend aerobic classes to those who attend the YMCA regularly for circuit training? Then compare it to the population of seniors who do have physical activity at all. What is the out come of their physical health. Hope this helps.