Rachel vs Zenyatta, who wins in April?

Those of you who know me, know my feelings that the science behind exercise physiology can both optimize training and selection of racing thoroughbreds, as well as objectively quantify things such as surface differences.

In the development of Tapeta, Sir Michael Dickinson, with the help of noted researcher George Pratt from MIT, that dirt surfaces are 50% tougher on horses than are synthetics, namely Tapeta.

It took me a few hundred heart rate/gallop speed charts here in KY between Churchill and Keeneland to come to the EXACT same conclusion.

So, let's think about how that impacts training. Here are the recent breezes from both superstars prepping for the big race at Oaklawn:

Zenyatta Track Dist. Time Surface Condition

2/26/2010 HOL 6F 1:13.20 All Weather Fast B
2/18/2010 HOL 6F 1:14.00 All Weather Fast B
2/11/2010 HOL 6F 1:13.80 All Weather Fast B
2/3/2010 HOL 5F 1:01.60 All Weather Fast B
1/25/2010 HOL 5F 1:00.20 All Weather Fast B
1/17/2010 HOL 5F 1:01.40 All Weather Fast B
1/6/2010 HOL 4F :48.00 All Weather Fast H
12/21/2009 HOL 4F :49.40 All Weather Fast B
12/7/2009 HOL 4F :50.40 All Weather Fast B

Rachel Alexandra

3/2/2010 FG 6F 1:13.60 Dirt Fast B
2/24/2010 FG 6F 1:14.00 Dirt Fast B
2/18/2010 FG 5F 1:00.20 Dirt Fast B
2/12/2010 FG 5F 1:03.80 Dirt Sloppy B
2/6/2010 FG 4F :50.60 Dirt Fast B
1/31/2010 FG 4F :52.00 Dirt Fast B

Source: drf.com

Both fabulously bred animals, but the large edge here goes to Rachel.

Everytime Zenyatta breezes 6F on artificial surface, she only gets what Rachel would accomplish going 4F on dirt, in terms of fitness/conditioning.
Remember this come post time at the Apple Blossom.

I see Rachel near the front, Zenyatta in her customary last position. Zenyatta will certainly pass many of them in the stretch, but Rachel will hold her off by a few lengths due to superior physiological conditioning these past several weeks.

That being said, dirt is much more likely to cause injury to Rachel during this prep time. No such thing as a free lunch.