In other words, low trading volume in the short term may imply the continuation of the current trend, while high trading volume in the short term may indicate a reversal of the trend. This actually makes a lot of sense. Low trading volume suggests that there is a consensus in the market regarding the direction of the stock's movement (if everyone expects the price to rise, holders will naturally not sell; if everyone expects the price to fall, then, of course, there will be no buyers). On the other hand, high trading volume represents significant disagreement in the market (during an uptrend, some might believe the peak has been reached and begin selling, while others believe the peak is yet to come and continue buying). The shift from low to high trading volume signifies the market moving from consensus to divergence, and as a result, a change in the stock price trend is likely to occur.
AwNil : Very informative article