The great weight debate: How heavy is too heavy?

How heavy is too heavy? Many factors are at play in assessing a horse's load-bearing capability.
How heavy is too heavy? Many factors are at play in assessing a horse’s load-bearing capability.

How much weight can a horse comfortably carry?

It is a difficult question. Science provides some guidance, but there are several important caveats.

Anyone hoping for a simple formula will surely be disappointed, as there are too many variables in the equation, and many of them are subjective.

The most recent research to garner publicity was carried out in Cornwall, England.

Researchers from Duchy College produced findings, published in the latest issue of the Journal of Veterinary Behaviour, that suggested only one in 20 riders may be within what they described as the optimum weight range for their horse.

rider-weightThe study found that a third of recreational riders were potentially too big for their horse, leaving the animals at risk of back troubles and lameness. However, 63 per cent of riders in the survey fell within the satisfactory range for body weight, falling within 10-15 per cent of the weight of their mount.

The researchers from Duchy College, in Cornwall, assessed 50 horse-rider combinations from stables across Devon and Cornwall.

It has to be said that the researchers never set out in this particular study to come up with weight guidelines for riders. Their aim was to explore horse and rider body-weight relationships.

To that end, an industry practitioner proposed a 10 per cent rider-to-horse ratio for optimum performance, up to 15 per cent as satisfactory and a level of 20 per cent to be a potential welfare issue. Just 5 per cent of the riders involved in the study met the optimum threshold. Thirty-two per cent of the riders weighed more than 15 per cent of the weight of their animal, which is considered to pose a potential welfare risk.

The online reaction to the findings were swift, with some dismissing them out of hand. Many seemed not to grasp what optimum meant, believing that if they weighed more than 10 per cent of their horse’s body weight then they were unsuited to ride it.

The optimum riding weight is surely a rider weight at which the animal can perform to the best of its ability, such as jockeys in control of thoroughbreds.

Equitation scientists Dr Hayley Randle, who conducted the study with Emma Halliday, suggested guidelines be put into place to protect horses from overweight riders. She noted that guidelines for riding weights were not widely known by those in the horse industry.

“Since observed rider-to-horse body-weight ratios varied between 14.2 and 16.6 per cent, the suggested 10 per cent guideline appears unrealistic within the general riding population,” the authors noted.

There were currently no industry-wide guidelines for the suitability of rider weight to horse size, they added.

They said they hoped their findings would go some way toward allowing the development of a scientifically based guideline allowing informed decisions to be made on horse-rider suitability.

Some publicity in the mainstream media around the research played upon the sensitivity some riders have over their weight.

Suddenly, the issue was one of rider obesity, which was surely not the point at all.

Headlines emerged such as “The horses saddled with our obesity epidemic”, “British beasts of burden: Obese UK riders put horses’ health at risk”, and “Study: Horses injured by rider obesity”.

Some riders got it into their heads that, if they weighed more than 10 per cent of their horse’s body weight, they were potentially risking its welfare, when in fact the study declared that, on top of the 5 per cent that fell in the optimal weight range, 63 per cent were 10 to 15 per cent of the weight, which was rated as satisfactory.

It is understandable that some riders will be sensitive about their weight and, equally so, any suggestion they may be too heavy for their mount.

Researchers may one day deliver a rider-weight-to-horse ratio that meet welfare criteria, but it will surely only ever be a broad-bush measure. There are simply too many other factors at play.

What is the age of the horse? What kind of riding will be undertaken and for how long? Is the rider balanced and capable? What kind of conformation does the horse possess? Is the animal well-conditioned and adequately fed and watered? What breed is it? In what condition are its feet? What kind of saddle is being used and does its fit properly?

Science has not yet delivered a formula to calculate the rider-bearing capabilities of horses, but it has certainly provided some insights into the upper limits of load-bearing abilities.

American researchers found that horses forced to carry between 25 and 30 per cent of their body weight have more physical problems related to exercise than those who carry 20 per cent or less.

rider-weight_8968Horses carrying 30 per cent body weight showed a significant increase in muscle soreness and muscle tightness scores.

Such changes were less marked when they carried 25 per cent of their body weight.

Dr Debra Powell and her colleagues at the Ohio State University Agricultural Technical Institute, in Wooster, conducted a study in which eight horses, carrying up to 30 per cent of their body weight, were monitored during a standardized ridden exercise test in an indoor school arena.

The study used one mare and seven geldings, all of light-horse breeding and weighing between 391 and 625 kilograms. The horses ranged in age from 6 to 18 years.

After a five-minute warm-up, the horses were ridden at a trot (three metres per second) for 4.8km, followed by 1.6km at a canter (five metres per second).

The exercise schedule aimed to simulate a 45-minute workout typical of an intermediate-level riding school horse.

The animals’ heart rate, plasma lactate concentration and creatine kinase were monitored. Lactate is produced in the muscles during exercise. At low levels of work the body can metabolise it and so levels in the plasma remain low. However, as the work level increases the rate of lactate production exceeds the body’s ability to remove it and so concentrations rise. Creatine kinase (CK), an enzyme present in the muscles, is released into the blood as a result of some types of muscle damage.

An animal massage therapist assessed muscle soreness and muscle tightness before and after exercise.

The findings supported the view that horses can carry up to 20 per cent of their body weight without difficulty.

There was little difference between all the measures when horses carried either 15 per cent or 20 per cent of their body weight. However, the scientists started to detect differences when weight levels  increased further.

The heart rate when horses carried 25 per cent or 30 per cent of their body weight remained elevated for longer after exercise. The serum CK level was also higher immediately after exercise, and also 24 and 48 hours later, in horses carrying 30 per cent body weight compared with those carrying 25% or less.

Powell and her fellow researchers, Karen Bennett-Wimbush, Amy Peeples and Maria Duthie, also investigated whether conformation affected weight-carrying ability.

The scientists looked at the horses’ height, the circumference of the cannon midway between the knee and fetlock, and the width of the back (loin) behind the saddle, between the last rib and pelvis.

They found that horses with wider loins and a thicker cannon bone circumference showed less muscle soreness and tightness when carrying the heavier loads.

The researchers stressed that it was a small study involving only a small number of horses, and suggested further investigations into the value of loin width, muscle depth and hoof size as an indication of weight-carrying ability would be worthwhile.

rider-weight_8962They concluded in the study, entitled Evaluation of Indicators of Weight-Carrying Ability of Light Riding Horses, that, for lighter riding horses, a total weight (rider, saddle, other equipment) not in excess of 20 per cent of the horse’s body weight was quite acceptable and did not appear to stress the horse.

Interestingly, that correlates with a military rule of thumb. In its 1920 Manual of Horse Management, the US Cavalry suggested a horse should not be asked to carry more than 20 per cent of its body weight. This assumed a combined weight of rider, saddle, bridle, and other equipment.

It goes without saying that cavalry units around the globe lived and breathed horses, but even that figure needs to be viewed in context.

First, cavalry horses were generally picked with quite specific requirements in terms height, body size, back length, hoof shape and bone to give them the best chance at standing up to the demands of service.

In Europe, there were major differences in the weight-bearing requirements of light cavalry and heavy cavalry.

At times, the attrition rate among horses in various conflicts around the globe from lameness soared, and horse shortages frequently saw the quality of the mounts decline.

The standard load on an American cavalry horse ran to 230-250 lbs, meaning most were required to carry more than 20 per cent of their body weight.

It goes without saying that the whole question is fraught, and an arbitrary percentage will only ever be the crudest of tool.

The research would seem to suggest that once a rider and their tack presses into the 15-20 per cent range of their horse’s body weight, they need to staying paying close attention to all the other factors that have a bearing on their animals’ ability, from fitness to conformation.

That unfortunately, leaves riders assessing their own performance in the saddle. How many riders would consider themselves unbalanced in the saddle? Almost certainly, practically none. Some may have an inflated view of their own riding abilities.

There is no simple answer, it would seem, except to err on the conservative side.


14 thoughts on “The great weight debate: How heavy is too heavy?

  • April 1, 2013 at 1:51 pm

    This article has been done to death over the past 2 weeks on other sites and most people believe their figures are wrong….20% being acceptable and 10% being ridiculous…..

  • April 1, 2013 at 2:02 pm

    Thanks for a more informed view on this subject and a look into in depth studies done.

  • April 11, 2013 at 4:46 pm

    While I have read the 20% weight limit before, it does not apply to all horses. For your interest, I rode an Arabian endurance horse over 2000 miles from Mexico to Canada. I went solo and virtually unsupported. Primo is 14.3 hands and weighs about 900 pounds. He carried up to about 275 pounds (around 36%) after a resupply – less as we used up the food and as I drank water – down to about 225 pounds. Arabians are stronger than other breeds – they have stronger, shorter, backs and strong hind quarters. They have one less vertebrae and two fewer ribs. Primo had no problems with that much weight.

    • April 14, 2016 at 12:25 pm

      My halflinger is 14.3 hands and weighs about 950-1000 lbs and I am 5’5.5″ and weigh 260, I am scared that I weigh too much for her, what do you think? We have a synthetic saddle that is pretty light weight

    • July 27, 2017 at 11:42 am

      Arabians are NOT “stronger than other breeds”. Your bias is evident.

  • May 29, 2014 at 6:13 pm

    When I was 16 my father got me a spotted saddle horse for my birthday. I weighted 115LBS and 5 feet tall and he’s 14HH. Now I’m 31yrs old and weight 155lbs. Is it OK for me to still ride him?

  • August 21, 2014 at 3:01 pm

    I guess we have to go back in time to the middle ages when horses had to carry a knight in armor. A man in the US today is easily 240 to 280 pounds and many exceed 300 pounds. Despite what people think draft horses are not suited to carry much weight on their back. Draft horses cannot gallop for any significant distance because they cannot carry their own weight well. There are 3 italian breeds that can gallop and carry weight well. These are the Murgese Horse (a direct descendant of the Neapolitan horse), the Tolfetano Horse brought to Italy by the Bulgarians and the Huns and the Sanfratellano horse,who was the mount of the Lombard knights (the greatest cavalry of the dark ages). The Murgese horse is so docile that stallion are routinely ridden. If a contest were held between a Murgese horse and a Thoroughbred over a distance of 19 miles, with each horse carrying a load of 250 Lbs upon their back, I am confident the Murgese will finish first in an easy canter, while the thoroughbred will be dead of an heart attack or lying in agony after its cannon bones fractured and exploded only a mile into the race. The ancestors of the Murgese fought at the Battle of Cerignola, the Battle of Pavia, The Battle of Ravenna and The Battle of Marignano, the Thoroughbred and even the Andalusian did not exist at that time. Claudio Corte wrote a book about war horses (il Cavallarizzo)in 1562, shortly after those great battles and he did not mention the Andalusian or the Arabian (they did not exist).I dare you to find any primary reference to the Arabian as a warhorse before the time of Napoleon. Napoleon is the first warrion in history who rode an Arabian.He “invented”the Arabian. In our modern world, where people are getting heavier, the horses who can carry these heavier people are the horse who carried medieval knights in armor. These horses were not arabian, thoroughbred, andalusian or quarter horses (a breed started in the 1940s). You now know what those horses were.

    • September 28, 2014 at 11:15 am

      The Murgese horse was developed by crossing Arab horses and Barbs with native breeds, so the Arab predates the Murgese.
      And a horse cannot gallop flat out for 30km, they are able to “race” over much longer distances (endurance horses for example do 80km a day for 5 days in the longest race in the world) they do not gallop throughout, most of the race is in trot and canter.

    • December 5, 2014 at 10:19 am

      On the contrary, Napoleon Bonaparte was not the first warrior to ride an Arabian, the Bedouins rode them into war. The Arabian existed long before we have any proof of medieval destriers. The first known written pedigree was written in approximately 1330 CE, and was the pedigree of an Arabian horse. In the 7th century, the prophet Muhammad, during the rise of Islam (dated roughly 601-700 AD) sought to spread the love of the Arabian horse all around the world. The Tolfetano is the only horse that you mentioned that makes sense as an ancient breed, as they were theorized to have existed when the Etruscans existed, which was around 700-something BCE to 200-something BCE. Note that Ghengis Khan was also theorized to have ridden Arabians, or at least horses crossed with Arabians.

  • August 21, 2014 at 3:06 pm

    you may ask….why a contest over 19 miles? Since the time of Genghis Khan it has been known that 19 miles (30 km) is the longest distance that an excellent horse can cover at a full gallop before needing to stop, or drop dead. 30 Km at a full gallop is the ultimate test of an horse’s endurance. I call it the “trial of Genghis Khan” or the “trial of Testori”

  • September 26, 2015 at 4:08 am

    As an obese person I would not ride a horse because I felt it would be abusive to do so I am 6’2 and weigh 308 lbs a horse would have to weigh 1540 lbs for me to be 20% of his weight. Do you know how sore my legs would be if I had to ride an animal that big. I think for obese people it would be better to have a buggy and let a horse pull you instead of riding them.

  • October 16, 2016 at 3:26 am

    “Horses who carried 25% of their body weight had increased breathing and heart rate” Good golly, you don’t say? Carrying a heavy rider means a horse has to work harder when doing strenuous exercise. In other news, the sky is blue. I’m sure every horse would prefer to have a rider who’s 110 lbs soaking wet (or better, no rider at all), but that just isn’t reality. Adults like to ride. Men like to ride. People who aren’t 5’3″ like to ride. And, yes, chubby people like to ride, too.

    There are SO many other things equestrians do to their mounts which cause immediate damage amd danger to their horses (racing two year old babies, for example, or doing enormous jumps at 4) but the issue we choose to beat to death is people who aren’t the ideal equestrian image (around 5’9″, slim, and female) riding their horses.

    I’m not saying that anyone should be free to jump on any horse and take them for a gallop. Obviously we need to use common sense when choosing a mount and need to do our best to stay in shape for our horses, especially if we expect them to be in shape for us. There’s a reason I chose a 16h thoroughbred over a little 14h quarter horse; I’m 23% of my horse’s body weight (with tack) and he carries me without so much as a flick of his ear at all speeds, and has never demonstrated a sore back or any reluctance to go forward with me on his back. (In before someone lectures me on the merits of a quarter horse as a weight carrying breed over a thoroughbred: I tried a 15hh quarter horse and a 16hh thoroughbred. Guess which one happily carried me?)

    A horse doesn’t do math, and he doesn’t care about percentages. He’ll let you know if you’re too heavy for him to carry comfortably (they’re honest like that.) And to be honest, he’ll probably let you know the hard way.

    Listen to your horse, and not the people around you. You know him better than they do. Watch for signs of discomfort, be compassionate, and stop obsessing over what a calculator tells you is too heavy for your horse. Ride and enjoy.

  • September 24, 2017 at 6:41 am

    Too many people don’t have common sense on an issue like this and need to have some kind of scientific standard for their ‘education’. I personally dig this issue out for the world of small
    ponies and miniature horses where too many owners think nothing of plunking a ‘kid’ that weighs a good third or more than the poor mini, saddle skirts over flank and shoulder, toes nearly dragging the ground, bouncing around on the animal’s back.

  • March 4, 2018 at 10:06 am

    Do you believe Ed Anderson. Arabians are the strongest horse! Strength does not exist in physics. We as humans generally accept 1 repetition max as functional maximum strength. That’s how much we can lift or a horse can pull a dead weight! Ed, i said generally… put your horse against a Clydie for strength! Speed well we know that most quarter horses and thoroughbreds will beat an Arab over their distances, and speed is understood as maximum top speed, 1 repetition max. Endurance, real endurance is measured in time over a life time! Now Ed, I know your not going to agree with me there but even what we accept as horse endurance, is still officially a speed endurance race, that’s why it is called a race! The first horse that, abiding by the rules, wins, wins. As such, their is an element of speed even in an endurance race! However, to complete is to win, as is the motto, what a fine motto! Now having trained barrel horses, quarter horses, gallopers, standardbreds and endurance horses, arabs included let me say to you that I do not know of any breed of horse that would train as far and as fast in a life time than the standardbred race horse. When was the last time your Arab ran at 50km per hour over at least a mile. The best Standardbreds approach that time over a continuous 2,800 meters in the “Prix de Amerique” in France! Ed, they are only trotting and have roughly the same slow twitch to fast twitch muscle fibres as Arabs.

    Ed, might i ask you to give Garcia a message! Google, A Message to Garcia!

    All that said, well done, especially to the horse. Please respect all horses for all their abilities.

    Oh and Ed, physics has a lot to do with horse training unless you think that the letters p h y s i c in physical and physics are just coincidental!


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