I think those behind the "big moves" don't want to be very predictable, since they want to avoid front-running purchases by others. If you can predict the moves of the market you can front-run it with leverage and gain big. But that would elevate the big buyers average cost per btc and it's obviously something they do not want. I wouldn't be surprised if the large players cause spikes down/up to liquidate shorts and longs that try to get ahead of the trends.

I wouldn't be surprised either at transferring altcoin money to bitcoin through trend-creations which act as a hook for potential altcoin buyers/traders, which makes people buy altcoins during some rising trends and then dumping on them to get their bitcoins. This mechanism would be something like a secondary source for bitcoins that allows more bitcoins to be acquired without making the btc/usd go through the roof - since bitcoins are taken from btc/altcoin pairs. The side effect is obviously the ascent of bitcoin dominance.