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.>>Apple Doesn't Suck -- but Its Stock Does 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. >>5 Stock Charts You Need to See ManTech International ( MANT) This company is a provider of innovative technologies and solutions for mission-critical national security programs. This stock is trading up 2.9% at $25.33 in recent trading. Today's Volume: 646,000 Average Volume: 145,982 Volume % Change: 546% From a technical perspective, MANT is trending higher here right off some near-term support at $24.50 with above-average volume. This move is quickly pushing MANT within range of triggering a near-term breakout trade. That trade will hit if MANT manages to take out its 50-day moving average at $25.72 with high volume. Traders should now look for long-biased trades in MANT as long as it's trending above $24.50 or $24.11, and then once it sustains a move or close above $25.72 with volume that hits near or above 145,982 shares. If that breakout triggers, then MANT will set up to re-test or possibly take out its next major overhead resistance levels at $26.50 to $27.54. Any high-volume move above $27.54 will then give MANT a chance to re-fill some of its previous gap down zone from last May that started near $31. Imperva ( IMPV) This company engages in development & sale of data security solutions that provide visibility and control over high value business data across critical systems within the data center. This stock is trading up 6.6% at $36.51 in recent trading.