Horse speed has not improve over the past 50 years but humans did drastically. Why?

I was one of those girls who was horse-crazy growing up including following racing as much as possible. And then started losing interest in the sport maybe 20 years back because it seemed like there were more and more catastrophic breakdowns on the track and I was just sick of seeing the horses dying way too often.

There's billions of humans but only half a million thoroughbreds. It's just math.

Just to restate the problem, it means that humans have been able to increase their watts/kg and horses haven't. Hmm...

I saw Henry Rono back in the day, and while I've only seen pictures of Cheptegei I do have a theory. :)

I've been aware that horses aren't faster for some time now.

Basically I've heard two theories.

1) If we remember that modern day horse racing is much more like sprinting than distance running , then their lack of improvement isn't that shocking as humans arne't really much faster either. Just the tracks / shoes have gotten better.

2) I've heard horsemen complain that horses aren't really bred properly. too much inbreeding for speed as a 2-year old to make a buck. But then again, the theory that we've already reached perfection is interesting to me. You can breed a horse ever 2-3 years. You can't do that in humans.

But in the year 2500, do we really expect humans to be running a marathon in 45 minutes? There is a maximal level at some point, right?

This may be true to some degree, but the women's mile record is still under threat. All three of these women have run 1500m times under the equivalent of the mile record at 4:12

3:50.37 Faith KIPYEGON
3:51.95 Sifan HASSAN
3:53.09 Gudaf TSEGAY

I suspect we will eventually see a woman drop close to or even below 4:10 in the mile, as its equivalent to the times they are already running in the 1500. I also wouldn't be surprised if Kipyegon broke the 1500 record.

Horse racing is tactical and not related to world records

Really? I've always wondered why horses are so lightly trained.

People I know who watch horse races say it’s all about the stud fees. You can’t have the ‘Kipchoge’ or ‘Bolt’ of racehorses because they run the equivalent of middle/high school racing and then the fastest are just bred for the rest of their lives. If they were treated like iconic horses from the olden times it might be different but nobody is going to risk stud fees to win relatively minor stakes at races once a horse has proven themselves.

Several parts to this.

The thoroughbred has been bred for competition for more than 350 years. Horses were raced in England from Roman times, and doubtless somewhat selectively bred since then, but the 1600s marks the period of importation of Eastern bloodstock (general called 'Arabs' but in reality more of them being Turkoman/Ahkal-Teke). The Eastern horses weren't as fast the domestic product, but positively altered the biomechanics when crossed with the).

With more than 350 years of selective breeding there has to become a point where incremental improvement is so small (if at all) that it's virtually imperceptable.

That point was probably reached in the 60s and 70s.

What has happened since is that while the top end isn't moving forward or is doing so impercetibly, the average is still progressing. So fairly ordinary horses are recording times which would have been noteworthy 60 years ago.

With running the trend has been for tracks and shoes to become faster, and training to increase in volume and intensity.

With horses tracks (if we are talking about North American dirt tracks, mainstream US racing) the trend overall has been to them being deeper and slower. A faster shoe isn't going to happen any time soon (aluminum plates were already commonplace in the 1930s).

Training is one area where improvement is possible. Very few trainers have much knowledge of exercise physiology. Increasing volume and intensity isn't likely to be effective (we're not going to see an equine Cam Levins).

What could happen is monitoring of horses and recovery rates could lead to more efficient training with regard to the windows in which a horses is working, and also a better management of when a horse peaks.

I'll finish by saying 'too much inbreeding' is something of a myth. To begin with there are multiple measures of inbreeding (at least four, some dealing with close inbreeding close up in the pedigree another, the Ancestral History Coefficient with deep inbreeding) and paper inbreeding (what the pedigree shows) and genetic inbreeding are not identical. There have been great horses with a wide range of inbreeding, from the European horse Coronation V, who was by a son of a stallion out of a daughter of the same stallion, to Secretariat, who was a complete outcross at five generations.

There are, however, optimal ranges for all of these coefficients, generally edging towards lower coefficents for inbreeding in the first five generations, and higher coefficients for deep ancestry (the pattern of Secretariat).

What most people are think of here is what's know as "Inbreeding Depression" - caused by increased homozygosity from partially recessive detrimental variants. There is some danger of the thoroughbred suffering from this across the board (as opposed to individual examples), but this point has what to occur. There are some negative alleles (for cartilage formation for example) that do occur more frequently in inbred horses, although that is tending to impact soundness (likelihood of being injured) rather than speed.

This is all correct.

I'll add to it, that the horse racing industry is basically fixed in maintaining it's status quo. The belief is that champions are bred, not trained, and there's too much money at stake to risk injuring a horse (and albeit ending it's career) through new training methods.

I have many relatives involved in the racing industry, and I've often been surprised at just how little training thoroughbreds do.

Track has only recently been able to draw top athletes away from sports like soccer. It took a generation of coaches working hard to get them there. The top horses are still choosing sports like chariot racing and polo over the thoroughbred race circuit. Perhaps trainers could incentivize the sport more with things like summer camps and trips to mcdonalds. Another thing is to get a sponsor to help putting together prize purses for the races, some big company like Tyson.

I think the claiming system in racing, where for most races, you enter with the understanding that a horse can be bought out from under you for s set price (ie. a $30,000 Claiming Race means any registered owner at the track can file a claim slip before the race and is obliged to buy the horse for $30K after the race) rather discourages that kind of long term attempt at development. Horses are expensive to keep at the track, and the bottom 80-90% are inherently running for a tag if they’ve gone through the allowance races but may not be stakes horse quality. So you’re looking at trying to retrain and if you get a reputation of moving up claimers, unless you can move them all the way up to the stakes level, they’re going to be sold at a slight profit when you move them up to a $40K or $50K tag race before you get a really good training cycle into the horse.

Super shoes for horses, now! And super spikes too

I don't think todays horses have access to those tasty burritos capable of making them next level Mr. Ed's

You've reinforced my previous point, that horses have been bred to run. Humans haven't.

I'm not sure what you mean by saying that "too much inbreeding is something of a myth". Plenty of studies have found that heavily inbred horses are statistically less likely to win races than those which aren't. Those which succeed, like the Arc winner Enable, are very much in a minority.

We all know what is meant by inbreeding. We all know it means lack of genetic diversity. Obviously now in the racehorse, the male line lacks genetic diversity (Secretariat's male line has long since died out) but this has not been due to natural or even true performance selection, its also been heavily influenced by operations such as Coolmore who are such large players on the market that they can actually influence market and breeding trends. I think we can state that we are talking about inbreeding to the speed gene and to the very limited number of stallion in the past 50 years that provide that with reliability.

Are you confusing the criticism of inbreeding with the study by EW Hill, which linked it to higher levels of musculo-skeletal failure? We know how to measure inbreeding coefficient, whether its by blood test or on paper. We know that heavily inbred horses can still do well, but they are the exception to the rule and lead to a lot of "wastage".

What Professor Hill has also done is to isolate the gene which encodes for the protein regulating muscle development and muscle fibre type, basically the C/C gene variant which leads to early maturing racehorses which develop muscle more quickly than their counterparts. Those racehorses are also sprinters running a mile or less. The so-called "speed gene". However, inbreeding in the racehorse is not done particularly well, because genes which influence soundness and stamina are not being preserved and "bad" genes, such as bleeding, are not being bred out.

The horses which you mention - Coronation V and Secretariat - are still far less inbred than the typical racehorse today. Coronation is a particularly interesting example because of course his close up inbreeding to Tourbillion means he is descended heavily from the Byerley Turk, the male line of which has almost been lost now, and is therefore far more outcrossed than the typical modern racehorse of today.

Obviously, the modern racehorse with its closed stud book was already developed from a heavily inbred population - there were only so many of those Arab/Turkomen/Barb imported stallions around. Nevertheless, some commentators maintain that a type if still discernible today from the 3 surviving founder lines, e.g. the Godolphin Arabian type is typically later maturing. We have long since known that the Northern Dancer male line descending from the Darley Arabian is now quicker maturing and more likely to produce sprinters/speed horses.

What is being lost is hybrid vigour. Its not possible to introduce outcrosses and the little remaining foundation line diversity is being lost as we speak. The female line is more diverse but still remarkably small.

Many racing devotees are genuinely worried about the future of the TB racehorse because those breeding lines which produced the champions of the past are long gone, in favour of many stallions who either didn't race due to unsoundness or who had a limited race programme over short distances only. Are we going to end up with another type of Quarter Horse in effect? Maybe one that runs 5 or 6 furlongs instead of quarter of a mile?

The other factor which hasn't been mentioned so far is riding style. Around the 1920s, jockeys began to stand up in their stirrups while keeping their heads low in a crouching position, thus reducing drag and the weight carried on horses' backs during the race. This reduced load and enabled the horse to run more efficiently. This cannot really be improved upon now - we cannot have lighter jockeys and equipment has just about peaked and is restricted by rules to ensure uniformity and safety.

You mean get it "straight from the horse's mouth?"

Breeding is going to take some quantum leaps forward in the near future with crispr gene editing. That will allow them to select out better traits.