When futures prices are moving, the amount of pressure being applied to the move is certainly worthwhile information for the trader to know. In futures trading, that pressure is volume, the number of contracts traded during a specific period, and is directly related to the psychology of the marketplace.
The key question is this: How many contracts are traders willing to push in the direction of the price? In other words, how much confidence – or how much fear – do they have in what prices are doing? If they have strong convictions, a logical move would be for them to back up their belief by trading more heavily.