To do that you would need to include a research proposal covering about a page and a half of text.
The question you should aim to answer is why that might be the case by looking at what factors influence
activity levels.
There is a lot of evidence that physical activity is a driver of good health. Yet on average many people do not meet
the recommended levels.
whatever other factors you think might be important including weather factors and individual factors.
I am thinking of a project something like the attached, combined with a wider survey of individuals measured just once.
my proposal should detail these two approaches and what exactly I would do.