I don't know how big of a stone you mean? Like how much does a stone weigh? Don't they vary in size? 
I don't do gyms but I definitely have to get exercise to stay in shape already lol. And with my fm if I don't stay active my body hurts a lot more too.

I don't do gyms but I definitely have to get exercise to stay in shape already lol. And with my fm if I don't stay active my body hurts a lot more too.