I'm just curious as to why these groups even bother with altitude training. At home they have the ideal condition: "live high, train low." They have altitude sealed apartments, homes, tents, and then access to world-class facilities at sea level (not to mention perfect temps/climate for training), why do these groups bother going to Park City, Mammoth, Flagstaff, etc.? It is a pretty clear consensus that being able to work out in sea level conditions while "living" at altitude (a la living in Flagstaff and training in Phoenix for ex.) is the best possible scenario, I wonder why these groups bother. Opinions?