In my post yesterday I suggested that Jani Brajkovic of the Radio Shack cycling squad had improved his fitness as a result of his weeklong effort in winning the Criterium du Dauphine stage race a couple of weeks ago. This is a common benefit of an extended, high-workload period of training which I call a "crash" block. A seven-day stage race is, for all intents and purposes, a hard period of training.
So is there any proof that he has improved his fitness other than his reported sensation of feeling like he's "riding with a tail wind all the time"? It appears there is. I noticed in his tweet today that he has improved his CP5 (highest average max power output for 5 minutes) by 40 watts since the race. That's huge and probably on the order of a 7-10% increase (I don't know his power metrics). I would expect to see something in the range of 3-5% after a week of very intense crash training followed by several days of rest.
I consider CP5 to be one of the best predictors of performance in a bicycle road race. That's because the outcomes of road races are typically determined by two- to three-minute episodes in the which the key players work at or about their CP5 power. This is usually breakaways on hills or in crosswinds, or in the lead outs for sprinters.
Don't expect CP5 to improve just because you do a lot of miles on the bike during a crash block. It takes a great deal of high-intensity training at CP5 to see the sort of results Brajkovic is experiencing. He had many such opportunities with Alberto Contador trying get away, especially on the climb up Alpe d'Huez. It will be interesting to see how Jani does in the Tour de France which starts this weekend.