You should never make a trade based only on a trend indicator. The Volume Oscillator (VO) is another indicator that will help you determine whether a trend is breaking support or resistance. In essence, the old saying is true: without volume there is no price movement and without price movement there is no volume. Use that old saying to your advantage.
Several oscillators like the Percentage Volume Oscillator (PVO) and the Market Volume Oscillator (MVO) and are based on the VO.
The VO calculation is based on two Volume Moving Averages (VMAs). The base of calculation is simple:
VO = [Fast VMA] / [Slow VMA]
The Fast VMA is short term moving average, and the Slow VMA is a long term moving average.
If we use set a VO (5, 20) as an example, the setting would be the Fast VMA to 5 bars and the Slow VMA ito 20 bars. At 5 bars, the Fast VMA is the shorter period and, at 20 bars, the Slow VMA is the longer period.
In essence, the VO calculates the difference between 2 VMAs. This calculation reveals surges in volume and possible abnormal volume activity. The VO tell us where the current volume is in relationship to the average volume over a longer period of time.
If we take a look at the VO setting above, that means that when the VO is over 1 then the Fast VMA is over the Slow MVA and we can conclude that the volume activity in the market is higher than usual. In other words, we can conclude that there is an unusual volume surge based on the parameters we set (5,20).
By knowing how the basis of calculation works in the VO, the indicator becomes a very effective tool in your trading. You should never solely rely on trend based technical indicators. By doing so, you will only see one half of the total picture and it will lead to more losses than wins. When you combine your trend indicators with an oscillator like the VO, you will be able to distinguish whether the changes in the trend are based on abnormal volume activity and make a better decision as to whether to enter a trade.
A final thought is that you should consider a break in support combined with unusual volume activity as panic selling and the opposite is true with a break of resistance with an unusual volume surge which should be considered as greedy buying.