The Flow
So, why was an obstacle course the training routine of the flow?
Well, it was simple.
The flow entailed the power gained from movement and momentum. That was why Reve's [Morai] was a 'moving skill'.
As long as he moved, he would be capable of dishing destructive capabilities.
There were other technicalities involved with this skill, though. One simply couldn't convert speed into power. They would need techniques, specific movements that can guarantee an instant win.
For instance, Reve mirrored The Shadow's heel kick and double kick.
His friend, Nikan, had made him understand that was not the only skill viable, so he wondered what the first generation might develop.
Hence, he didn't teach them what he knew… not yet, at least. Through their obstacle course, they would come to adapt to their intrinsic skills.