Breeders' Cup Day

[BitPlayer]

TGJB -

I can\'t find a \"Changing Track Speeds\" link on the Archive page.  Are you referring the Las Vegas Expo presentation or the \"Are Racehorses Getting Faster?\" series?

BitPlayer

[TGJB]

It\'s the Expo presentation. I wonder how many others have had trouble finding it.

[beyerguy]

TGJB Wrote:
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> It\'s the Expo presentation. I wonder how many
> others have had trouble finding it.


Len?    (Sorry, couldn\'t resist!)

[BitPlayer]

TGJB -

So I watched the Changing Track Speeds presentation (again, I\'d gone through it before, but in deference to you and my unreliable memory, I watched it again).  To sum up (for those who don\'t want to spend the 22 minutes), there are three things that can change energy return/track speed:

1. Track composition (e.g., sand v. clay), which generally wouldn\'t change during the day.

2. Compaction, which can be affected by track maintenance (including sealing, flaking, water trucks rolling over the track, etc.) or by horses running over the track.

3. Moisture content, which can be increased by rain or track maintence (watering) and decreased by evaporation (which varies in rate depending on weather conditions, amount of sunlight, shadows, etc.).  Especially on the high-sand-content tracks that prevail today, loss of moisture tends to slow a track.

The presentation is convincing (at least to me) that a track can change speeds during the day in the absence of rain and that different portions of the track (e.g., one- v. two-turn races) may have different speeds.

I did not, however, see anything (and certainly not a zillion things) that would have caused a track to get faster and then slower within a span of 80 minutes, as your variants suggest happened in races 2-4 on BC Day, in the absence of track maintenance.  We\'ve talked a bit about wind.  Do you think you built a pace effect into the figures for Juvenile Fillies (as your exchange with SP suggests)?  Is there something I\'m missing?

BitPlayer

[TGJB]

Evaporation alone could do it (as the studies in that presentation showed, small changes through a typicl range of moisture content can mean a lot in terms of energy return). That could be caused by wind, or the effects of sun (differing with changes in cloud cover, shade leaving as the sun got higher over a period of time), or just plain cumulative effects of sunshine and wind over time. Porcelli also told me there\'s also the effect of high or low humidity, and changes in humidity, and I have no clue how that works in.

The important thing to keep in mind is that we don\'t always know what is causing the changes (like with the separate watering of the two Belmont grass courses). If you aren\'t gathering or looking at or correctly accounting for information that we now take for granted (like wind, weight, ground), and you ASSUME you have all the relevant data, you will get figures wrong. Same goes for a zillion other things-- but ONLY if you make false assumptions about certain conditions being identical.

[BitPlayer]

TGJB -

If I understood the presentation correctly, all of the things you mention (wind, cloud cover, etc.) only affect the rate of evaporation.  In the absence of water being added by the trucks (which you said it wasn\'t), the track only gets drier and, hence, slower.  Your variant adjustments have the track getting slower from Race 2 to 3, but then faster from Race 3 to 4.  If you tried to explain the change in direction by theorizing the odd case that the moisture level dropped through its optimum, the effect would be the opposite: faster, then slower.

BitPlayer

[TGJB]

Bit-- Drying out (or getting wetter) will have different effects on track speed depending on what the moisture content was to begin with. Since they didn\'t add water until before the Distaff, my guess would be they felt it had quite a bit in it. Not that I know for sure what that would mean-- that\'s my point about the interlocking variables. In this case it appears that the adding of water made it slower-- since (if I\'m right) the track they raced over in the Distaff was slower.

As for the second and third-- the way I did it, with that small a difference in corrections, means that I was treating the track as being the same speed for both. Even on a less windy day, and even without the races having the long straightaways, that difference would be insignificant-- check out the \"Wind Adjustments\" string from last week.