Conditioning for Performance: Humans vs Horses


If he was a thoroughbred, the guy on your right, Kirani James, would be excoriated for his poor conformation and/or fail any stride analysis at a 2yo in training sale. His lower legs ‘paddle’ out at strange angles compared to the other two runners: Jeremy Wariner on the far left, and Lashawn Merritt in the middle. Of course, Kirani James is the defending gold medalist in the 400m (the only gold medalist ever from the island nation of Grenada), and those other two fellows are world class as well. Go figure.

While watching James race Merritt last weekend in Oregon, I began to put together some ideas on the differences between conditioning equine and human athletes. First off, we can use many of the same tools and exercise physiology principles for both, but the magnitude of these can vary greatly. All differences can be boiled down to a single concept: that of ‘predator vs prey’.

Humans are predators, we hunt animals and eat the meat they provide. Horses are prey, they are hunted by animals such as wolves, their primary natural enemies in the wild, and are vegetarians. Yet, both humans and horses undertake physical conditioning in order to compete amongst each other running over a distance of ground. Humans primarily race from 60 meters on up to 26 miles – while quarter horses may run 220 yards and endurance horses often race 100 miles. For the sake of simplicity, we’ll focus on human middle distance runners at 400m, and compare them to thoroughbreds racing at 1600m/1mile/8 furlongs.

A world-class human 400m runner may post a time of 44 seconds, and a champion thoroughbred miler approaches 1:34, or 94 seconds. I choose these 2 distances because each matches up with an approximate energy expenditure of:

-14% ATP-CP (phosphagen)
-38% aerobic (with oxygen)
-48% anaerobic (without oxygen)

That’s my basis for comparison; neither total time of the event nor total distance covered, but the relative metabolic requirements. Likewise, it’s not accurate to compare a horserace to other human sports such as basketball, because horses just run – they don’t shoot, pass, or execute strategy. These track-based events are often referred to as ‘middle-distance’ for both humans and horses alike.


Horses are literally bred to run, humans are not. For the sake of this post; we’ll call the ideal race pace of a human the 4 minute mile, and that of the horse the 12 second furlong. All selectively bred horses can achieve that 12sec/f pace for limited distances even in the absence of training, whereas no human can accomplish the same. Think of it in terms of a progression:

*Horse: 12 sec/furlong achieved nearly from birth
*Human: must first achieve speeds of, say, 8 min/mile, then 7:30, 7 flat, etc.

The horse, as an animal of prey, is ‘hard-wired’ from birth to achieve top speeds at a very early age, and without the benefit of physical conditioning, otherwise he/she would be eaten by wolves. Conversely, the human must progressively GROW physiologically in order to step-by-step reach the 4 min/mile benchmark, over a period of several years (4 min/mile equates to 15 sec per 100m).

How is this reflected physiologically? A newborn horse can ‘rev-up’ his engine to achieve maximal HR (heart rate) within 6 seconds, while a world class human must train extensively for several years to accomplish the same feat in 40 seconds. That is a massive difference. Humans must condition themselves progressively to reach ideal race paces, allowing their internal systems to grow and support such a progression. Horses don’t. A talented horse can make the worst trainer look like a genius, for a brief moment in time.


Both horses and humans have built in safety mechanisms within their muscles, ligaments, and tendons – these are called proprioceptors. The Muscle Spindle Apparatus is found within the muscle itself, while the Golgi Tendon Organ is found within the softer tissues. Both act to protect damage to these structures resulting from excessive loads and/or extreme stretching. However, the threshold for each to become active and lesson muscular contraction is vastly different between predators and prey. Today you may be capable of rising from your desk and running 100m in 20 seconds and coming out of that experience in one piece. But, if a criminal was to point a gun at your head and demand you go faster, your proprioceptors would change their thresholds for activation – and you would find a way to cover the same distance in perhaps 17.5 seconds – but tomorrow you would be sore as hell, and likely injured to some degree. Horses run as if a metaphorical gun is pointed to their heads every morning, until they become psychologically trained to relax and obey rider cues. This ability is what allows them to survive in nature when confronted by a predator, it also allows them to win races that they shouldn’t win.

*A quick aside: just out of college I lived in a house with a football player and a baseball player. I played basketball in school, and one night all of us were arguing which sport had the best athletes. We were all the same age and had about the same level of success, or lack thereof, in our respective sports. After some discussion, we headed outside to race – I think roughly 100m. I was the only one who had been drinking quite a bit that evening, so I was certainly being quite annoyingly sure of myself. I remember it being pretty cold out, and none of us idiots warmed up at all. We raced 3 times and I won every single race, but it was close. I was sore for WEEKS afterwards, in places I didn’t even know I had. The alcohol had dumbed down my proprioceptors, and I was allowed to run much faster than I was capable of on that night. Lesson learned – don’t do this to your horses.

There are probably other differences I could cite, but you get the idea – it all boils down to who is a predator and who is prey. A human is fit if he wins a race, but not necessarily a horse. If a horse wins a race and emerges injured – it is not always a ‘bad step’, it is just as often unpreparedness and or a willingness to run past his/her physiological infrastructure that is the true culprit – something humans cannot do unless under an imminent threat, or a case of beer fueling a too large ego!


Everyday around the world, horseracing is the only sport where females and geldings routinely beat males. How can that be? Simple, if nature allowed female horses to be less athletic than males – all of them would soon be eaten by wolves and the species would become extinct. So, in addition to being wired differently in order to escape predators, nature has neutralized the effects of male hormones such as testosterone on equine athletic ability. Unless every filly/racemare/gelding in the world is being given regular injections to compete on equal footing with the boys, that is. Some will make that argument, believe it or not, but that doesn’t explain the equal athletic performance found in nature that ensures survivability of the species.

Now drugs meant to mask pain are a different story entirely. Not only do these substances cover up an unpleasant sensation within the body, but they also dumb down the proprioceptors much like several beers does to a human subject. They simply allow horses to run faster and further despite the presence of physiological warning signs. It could be argued that Lasix does the same, but that is another subject for another time.

Similarly, it’s commonly postulated within the veterinary community that a horse’s respiratory system is untrainable. I tend to agree – no amount of conditioning can change the size of a horse’s airways. But drugs can. Any bronchodilator serves to expand the diameter of an airway, allowing for more oxygen to reach the lungs and working muscles. Don’t confuse the true reason for use of clenbuterol – it’s not merely to alleviate allergy symptoms.


(Quick disclaimer: I market and sell an equine supplement named STORM worldwide.) Often it takes me 20 minutes to explain what an equine exercise physiologist does, so a few years back I went out to find another product/service to sell that I could explain to anyone in 20 seconds. Enter STORM.

During this process, I first looked at creatine – a common human supplement for bodybuilders and other power athletes. I used the substance myself 15+ years ago, and immediately noticed significant strength gains in the weight room alongside an approximate 3% gain in bodyweight within 10 days. This was not muscle, but it was retained water within the muscle – which allows for greater leverage and more powerful muscular contractions. Many equine shops sell creatine, despite the fact that 3 separate research studies done in the lab could not definitively prove absorption through the equine gut. So, no go. Horses and humans are different, remember.

Next up, I looked at EPO Equine – a natural substance purported to legally increase red blood cell production, and therefore, improve oxygen delivery to working muscles. The equine spleen stores as much as 30% of the RBCs found in a thoroughbred’s bloodstream; contracting and releasing these cells into the blood when deemed necessary during exercise. That makes it quite difficult to assess the changes in RBC concentration when dosing EPO Equine, as you never know precisely how much of that splenic blood is in circulation. So, I passed on this one as well – but the experience highlights the uniqueness of the equine spleen, no human spleen serves as a RBC storage device: predator vs prey, remember?

Lastly, we come to the amino acid known as beta-alanine. Humans have been experimenting with it for years, albeit with not a lot of proven data backing up its efficacy. Of course the equine nutrition PHDs behind the product handed me much laboratory data, and one fact JUMPED off the page. Beta-alanine combines with another amino acid in the body to form a dipeptide known as carnosine. Carnosine is gold to a racehorse, as it is released into the muscle during intense exercise, blunting the buildup of lactic acid. However, the typical human muscle possesses but 8% carnosine concentration, while the typical equine muscle holds over 30%. Bingo! Carnosine as an intramuscular buffer during exercise is 400% more important to horses than humans. Yet another significant difference between the two species. Realizing these physiological differences can save you time and money when attempting to improve your thoroughbred’s performance on the track.

Lastly, we can discuss actual physical conditioning. It would be rather boring to dissect the traditional, at least in the US, program of 1.5 mile daily gallops and 4-5F weekly works/breezes. Let’s talk about something controversial instead: Interval Training.

For our 400m human athlete, interval training forms the basis of his regimen. If he is a 44sec runner like the elite, that averages out to 22sec per 200m and/or 11sec per 100m. Many of his exercise sessions will be based up on these shorter distances: completing multiple repetitions at race pace or faster, with varying periods of rest in between – hence the name ‘intervals’. Common among human athletes are rest intervals between periods of work that allow only incomplete recovery – perhaps along the line of a 120bpm heart rate, roughly 60% of a 200bpm maximum.

The legendary Tom Ivers, rest in peace, was perhaps 3 decades ahead of his time with the publication of his work entitled The Fit Racehorse (volumes 1 and 2). He understood the benefits of interval training and its massive effect on human performance.

For example, in 1972 the legendary Mark Spitz won a gold medal and set a world record in the 200m freestyle with a time of 1:52.78. Just 26 years later a 15 year old named Ian Crocker posted a time of 1:49.48, more than 3 seconds faster! The kid was 15 for crying out loud. Michael Phelps? In Beijing he won the gold medal in 1:42.96. Water hasn’t changed in the last 40 years; the primary drivers behind these faster times are interval training and improved nutritional supplementation.

However, Mr. Ivers prescribed human style interval training, with short rest periods eliciting incomplete recovery, for racehorses. Some thrived, namely an Irish horse named Stanerra who famously won 2 group one stakes races in 3 days at Royal Ascot – while galloping as many as 12 miles a day and firing off numerous half mile breezes in a row in a typical training session. Sadly, for every Stanerra there were perhaps another several hundred horses who broke down under such a demand.

Owner/trainer Frank Dunne called me on the phone a few years back to talk about his brilliant racemare. She was quite literally plucked out of a pasture and put on Ivers’ program. Oh yeah, she also won the Japan Cup.

Pretty much everyone who has ever tried interval training on horses has done it incorrectly. You must be galloping a solid 2 miles or more daily for weeks to develop a sound foundation of mitochondria and capillary beds, and you must have a HR monitor to assure complete HR recovery to 80bpm or so between intervals of fast work – and 3 such intervals would be the maximum, 2 more the norm.

Think of Interval Training as the icing on the proverbial cake; if you don’t yet have the cake baked, the icing does you no good. And you will likely get sick just eating icing by itself-

In conclusion; we can use the same tools behind improved human performance, but we must use them at different magnitudes on these animals of prey. Tools such as heart rate monitors with GPS, blood lactate analyzers, high speed treadmills, etc. are becoming more commonplace around the world, although the US seems to lag behind in this regard.


About bpressey

Equine Exercise Physiologist

Posted on June 18, 2013, in Uncategorized. Bookmark the permalink. 1 Comment.

  1. Nice job Bill. I’ve wondered–given Stanera’s success whether Frank Dunne ever tried a long Ivers type interval program with any other horses.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: