According to this,
http://www.sauktri.org/reports/report30.php
Radcliffe has a V02 Max "In the region of" 80.
Other V02 max info shows,
Bjorn Daehlie Cross country skier 90.0
Miguel Indurain Cyclist (winner of Tour de France) 88.0
John Ngugi 5 times world cross country champ 85.0
Dave Bedford 10km World Record holder 85.0
Steve Prefontaine 1 mile in 3:54.6 84.4
Lance Armstrong Cyclist (winner of Tour de France) 84.0
Joan Benoit Marathon runner (2:24:52) 78.6
Bill Rodgers Marathon runner (2:09:27) 78.5
Sebastian Coe Middle distance (1 mile WR) 77.0
Grete Waitz Marathon runner (WR 1980) 73.0
Frank Shorter Marathon runner 71.0
Derek Clayton Marathon runner (WR 1969) 69.7
So, if V02 max is the only critera, why can Seb Coe run 800 in 1:41, and Radcliffe only 2:05?
Nikalas increased his V02 max from 49 to 66. From here on I'd suggest the law of dimminshing returns applies? I'd also speculate that he didn't push himself 100% in the first V02 max test.
Application is the key to knowledge
and intelligence.
All I can state with certainty is that Radcliffe has improved dramatically since I last took her on a training run...