This is a form of hedge fund trading, and can be utilized for long term investing, as a hedge (ex: hold a bear fund while investing to the upside), OR for a good swing trader can offer some tremendous opportunity for 5% to 10% returns, when traded like a swing trade.
Let's use two of my favorite trades. BGU and BGZ. Dirextion DailyLarge Cap Bear and Bull 3X funds, medium volume, priced well in the $30.00 range (leaving out the baby boy traders), and quite easy to play to 5 and 10% returns quickly.
These work very well as high risk, high profit options also