It is a bit hard to understand what you're saying. I understand you want a question to be displayed on top of the question list whenever a new answer is posted for that question.
That is already implemented but it is not in the Questions page but rather in the All Activity page. In order to enable that page you need to login as an administrator and goto the Admin page then to the Pages section and then check the All Activity checkbox.
This will add the All Activity menu item which will point to http://yoursite.com/activity which in your case seems to be http://www.fitness-online.org/activity
Hopefully, Googe will translate this properly to your native language :)