LA has used altitude tents (query whether he is still using them now). Kloden trains with altitude, according to the T-Mobile website:
"In the springtime [Kloden] was in Berlin for altitude training under the supervision of altitude specialist Dr. Fuchs at a specially equipped centre. Using the most modern methods the oxygen in the air is reduced until the oxygen levels are down to 14 per cent. That is about equivalent to an altitude of 2,400 metres."
