Due to kids and schedule, I do doubles on M,T,W if I ride. Usually SST or Tabatas for 60' in the am then 60-90' SST or a MTB/Cross workout in the PM. Thursday/Friday is my long ride of 3+ hours leaving around 700am. Anyway, my comprehensive study is that I have at least 5% more power in the pm. Comprehensive in that I look at my powermeter data in WKO+ Older racers have told me that my legs are blocked because I don't wake up early enough. I go to bed earlier the night before then get up at 0600, drink some OJ eat about 250 calories, get dressed and go. So from waking to on the bike is ~25 minutes. I get what they're saying, because I feel like I'm not even awake yet.

But I did find this artice which I thought was interesting. There may be something to the pm boost in power.

http://www.bikeradar.com/road/fitnes...cking-on-20339