WINDERMERE, Fla. ( Stockpickr) -- Professional traders running mutual funds and hedge funds don't just look at a stock's price moves; they also track big changes in volume activity. Often when above-average volume moves into an equity, it precedes a large spike in volatility. >>5 Dividends That Are About to Get Bigger Major moves in volume can signal unusual activity, such as insider buying or selling -- or buying or selling by "superinvestors." Unusual volume can also be a major signal that hedge funds and momentum traders are piling into a stock ahead of a catalyst. These types of traders like to get in well before a large spike, so it's always a smart move to monitor unusual volume. That said, remember to combine trend and price action with unusual volume. Put them all together to help you decipher the next big trend for any stock. With that in mind, let's take a look at several stocks rising on unusual volume today.Magellan Health Services Magellan ( MGLN) is engaged in the specialty managed healthcare business. The company provides services to health plans, insurance companies, employers, labor unions and various governmental agencies. This stock is trading up 1.4% at $49.76 in recent trading. Today's Volume: 247,000 Average Volume: 175,176 Volume % Change: 160% From a technical perspective, MGLN is spiking modestly higher here with above-average volume. This move has started to push MGLN within range of its 50-day moving average of $50.01, and within range of a near-term breakout trade. That trade will hit once MGLN manages to take out some near-term overhead resistance levels at $51.80 to $52.46 with high volume. Traders should now look for long-biased trades in MGLN once it manages to sustain a move or close above those breakout levels with volume that hits near or above 175,176 shares. If that breakout triggers soon, then look for MGLN to set up to re-test or possibly take out its next major overhead resistance levels at $56 to $56.58.