To answer this dangerous question generally, I would say no. Well first, get your mind out of the gutter. Second, considering the mix of a hill and some gravity, I would still say no, its more fun to go down. Going down a hill was a treat as a kid, whether it be by sled or by rolling, but running up a hill as an adult is a whole different concept. Most fitness ideals can be achieved by simple changes in things everyone did as a kid but simply updated to an adult level of activity. Hill running is an advanced level of core and leg development but the benefits are unmeasurable. This video below is a great example on how to do this challenging exercise with his own personal twist on it. Watch the video and give this a try. This 10-15 minute workout will benefit the entire body. Enjoy.