Wet Grass Races

[tonto1944]

I don't know if antone else goes by the same rule I do. If I am betting a grass race and the grass is wet,soft or yielding I always go to the European horse if they are in the race. They seem to handle that type of footing better. And I think that is because they race on the grass no matter if it rains or not. So they should handle it better than American horses. I have made some nice money betting this way.

[kgonzales]

Another tool I find useful in these situations is the NFT (non-firm turf) rating that is part of the reports at www.breedingwinners.com

It's similar to a mud rating for the sire, but obviously based on success of offspring when trying non-firm turf. The reports are free.

BTW PLease forgive me if that comes off as shilling. I have no connection to the site whatsoever. Just use the reports on occassion and think they are useful.

Kristian

[Valuist]

Speaking of soft turf, on TVG recently they mentioned that at Calder, they almost never use the designations "soft" or "yielding". They just throw up "good", even after one of the many deluges they have.

It never hurts to keep a stockpile of old DRFs, in case a horse has no soft turf races showing in its pps. Sometimes you may have to go back over a year but its often worth the extra effort.

As for breeding, it does seem that the more "dirt oriented" the pedigree, the less likely they are to handle softer grass.

[speculus]

I am really sorry if, on this board, I might be looked upon as a "mathematical bore", but if you are talking about wet grass, there is no way I can "stay on the river bank" and "not jump into mid-stream."

So here I go headlong into the discussion.

I have some little research on the topic, and, without "boring" you with its mathematical details, I want to put forward this view:

Whenever weather conditions render the grass wet (due to rains or dew), EVERY HORSE, from very fit to fit to unfit to very unfit, will face a stronger "normal reaction" (the vertical force that opposes the gravity) from the wet turf. This force causes the angle theta, which the horse's "operative" hind leg makes with the turf while "taking off", to go up, so to say, and therefore, the "reach" of a horse's stride is "reduced" due to such conditions, resulting in less speed. The most interesting fact is that a turf track, dry or wet, can be accurately characterized by this increase in angle, as ALL HORSES register EXACTLY the SAME INCREASE in theta, IRRESPECTIVE OF THEIR BREEDING, CLASS, CONDITION OR RUNNING STYLE.

~Speculus

P.S. I don't know if the same is true for dirt tracks, though, technically, it MUST BE.

[kenwoodallpromos]

This is new to me.
What about in regard to a horse's weight or body type?

[speculus]

This is new to me.
What about in regard to a horse's weight or body type?

Theta is the greek letter which, in trigonometry, is generally used in symbol to denote an angle. I don't know how to depict theta pictorially.

So let me show theta as [theta], as I have done on another thread, to show that I am talking about an angle.

[Theta] designates the angle that the "operative" hind leg of the horse (the one that hits the track "harder" than the other hind leg) makes with the surface "while taking off".

For fit horses racing on turf, the measure of theta is close to 7 degrees. It is also noticed that [theta] can accurately predict the current fitness of a horse. If a horse gains in condition the [theta] becomes smaller, on the other hand, if a horse loses condition, the [theta] gets larger.

I don't know what you mean by "body type", but if change in body weight (putting on or shedding weight) is linked with better or worse condition, [theta] would surely swing accordingly.

[speculus]

In case someone finds this [theta] business a bit confusing, here is my formula for angle theta (in degrees, not radians):

[theta] = tan^-1 {(g*R)/(2*S^2)} degrees

where g is earth's gravitational constant,
R is the reach of a horse's stride,
and S is the speed of the horse.
(tan^-1 signifies the tan inverse function)

For example, if R = 6.86 meters, S = 16.62 meters/sec, then

[theta] = tan^-1 {(9.86*6.86)/(2*16.62^2)}
= 6.98 degrees
(the gravitational constant g = 9.86 meters/sec^2)

[kenwoodallpromos]

OK, I understand. Thanks!

[yak merchant]

I agree with some of what you say speculus, but I don't agree that the affect of soft or yielding going is the exact same on every horse in the field. In mathmatical terms from the information you have to measure you are correct, but all horses do not have the same hoof size or shape, which will affect your "normal" force. I do think you are correct in that the main affect of the soft going on a horse is the reduced stride length, which pretty much translates into an advantage for horses with more stamina (see breeding). So here is the million dollar question. How do you get the stride length? I attempted to count strides in a few videos for test purposes, but talk about a beating. It would be almost impossible to track stride length race by race for all competitors; which is what you would need to take advantage of your theta calcs.

YM

[thoroughbred]

Since you did the research, your conclusions are probably correct.

I do, however, have a problem understanding the effect of wet turf on the resulting angle theta.

I, until reading your note, had thought that wet turf had more "give" than dry turf, or, equivalently there was a greater tendency for the hooves slipping. If this is true, and I admit that I really don't know, it seems that the hind hoof of the horse, on contacting the ground, would "slip" further back, thus making the angle theta smaller not larger.

Of course, if wet turf is, somehow, firmer than dry turf, and it is difficult for me to visualize that, then I can see that the angle would increase as you state.

Where am I going astray in my thinking?

[speculus]

I agree with some of what you say speculus, but I don't agree that the affect of soft or yielding going is the exact same on every horse in the field. In mathmatical terms from the information you have to measure you are correct, but all horses do not have the same hoof size or shape, which will affect your "normal" force.YM
I know you will find it VERY DIFFICULT to digest that claim--I also did! But personally I can now vouch it is true. In fact when I found some "contrary" results, I felt perhaps it was not so, but more experiments confirmed beyond doubt that the minutest variation was ONLY CAUSED BY THE FACT THAT NOT ALL POINTS OF CONTACT would obviously be IDENTICAL in their level of firmness, flatness (or otherwise), texture and so on.
You need to re-check your second statement (about hooves), however, as it can be mathematically proved that "normal reaction" is INDEPENDENT of "AREA OF CONTACT" between a moving body and the surface.

I do think you are correct in that the main affect of the soft going on a horse is the reduced stride length, which pretty much translates into an advantage for horses with more stamina (see breeding). YM
Please read my statement again. I am only saying that "ALL HORSES register EXACTLY the SAME INCREASE in theta, IRRESPECTIVE OF THEIR BREEDING, CLASS, CONDITION OR RUNNING STYLE."
Now look at the equation, and you know why "stamina" horses would benefit on a wet track. Because of their normal longish stride, they anyway have a bigger [theta] than speed horses, therefore if the "increase is the SAME", percentagewise it affects the speed horse considerably more than the stamina horse.
To take an example, say a particular stamina horse has a theta of 7.2 degrees as compared a speed horse with a theta of 6.7 degrees. Now consider the track today is such that it's going to add 0.4 degrees to ALL HORSES. This means (0.4/6.7) = 5.97% increase for the speed horse but only (0.4/7.2) = 5.56% increase for the stamina horse. If you slolve the given equation with empirical data, you see how even half a percentage change in [theta] causes appreciable change in the "speed-generating ability of a galloping horse"

So here is the million dollar question. How do you get the stride length? I attempted to count strides in a few videos for test purposes, but talk about a beating. It would be almost impossible to track stride length race by race for all competitors; which is what you would need to take advantage of your theta calcs.
YM
For my research work, I would use the old "Xingplayer" software (of Chinese origin) which allowed me to control the rate of film anyway I desired. But I agree it is VERY DIFFICULT to accurately count the number of strides (and a fraction of it at the wire) in normal motion. And it is surely impossible to do it for all competitors. But the point is, if you have developed the math, then by observing even one feature (say T, time taken by a horse for one stride soon after jumping out from the gate) can give you amazing insights.

It is a moot point how much value such research would add to your being a more successful bettor, but I believe it may play a role in putting handicapping as a theory (and horse racing as a sport) on a more respectable pedestal.

[speculus]

Since you did the research, your conclusions are probably correct.

I do, however, have a problem understanding the effect of wet turf on the resulting angle theta.

I, until reading your note, had thought that wet turf had more "give" than dry turf, or, equivalently there was a greater tendency for the hooves slipping. If this is true, and I admit that I really don't know, it seems that the hind hoof of the horse, on contacting the ground, would "slip" further back, thus making the angle theta smaller not larger.

Of course, if wet turf is, somehow, firmer than dry turf, and it is difficult for me to visualize that, then I can see that the angle would increase as you state.

Where am I going astray in my thinking?

I don't know if this example will help you in visualising. Of course, it is different, but then maybe a parallel can be drawn.

When you throw a rubber ball on a surface, it will start going ahead with "shorter" strides successively, and finally will stop. What happens is the force of friction (leave air resistance aside for a moment) goes on increasing its theta with every bump (and therefore reducing the "length" of its stride), until finally it becomes 90 degrees and the ball "stops bouncing", and will slide until it loses even the kinetic energy due to friction.

[thoroughbred]

[QUOTE=speculus]I don't know if this example will help you in visualising. Of course, it is different, but then maybe a parallel can be drawn.

When you throw a rubber ball on a surface, it will start going ahead with "shorter" strides successively, and finally will stop. What happens is the force of friction (leave air resistance aside for a moment) goes on increasing its theta with every bump (and therefore reducing the "length" of its stride), until finally it becomes 90 degrees and the ball "stops bouncing", and will slide until it loses even the kinetic energy due to friction.[/QUOTE

OK, I can visualize the bouncing ball. Now lets change the surface from say dirt to wet grass. Wouldn't the friction be less thus keeping the theta of the bouncing ball smaller longer? Wet grass is more slippery than dirt. Or, even going from dry grass to wet grass, the friction would be lower and the angle would be less.

[Valuist]

The only problem with bringing math into it is that horse's hooves are definitely NOT all the same. Some horses have normal hooves, some have a turf foot and some have a mud foot. Check out Joe Takach's video "Beat the Beam".

[tonto1944]

No matter what the sciences say,look back at your grass races and you will see that when it is soft or yielding the European horses have the edge. In Europe they race on grass no matter how much it rains. Here in the Us if it rains very hard they will cancel the turf races. And if you look at the times they are all faster on firm turf.

[speculus]

Now lets change the surface from say dirt to wet grass. Wouldn't the friction be less thus keeping the theta of the bouncing ball smaller longer? Wet grass is more slippery than dirt. Or, even going from dry grass to wet grass, the friction would be lower and the angle would be less.
I am not sure I am competent to comment about dirt. The only form of non-turf tracks that I can say something about are the All Weather Tracks (AWT) like in the U.K.

If you want to arrange tracks in the ascending order of friction, this order would be right. AWT, Turf, wet turf.

Frictional forces would be the least for AWT, a little more for Turf, and even more for wet turf.