Everyone knows that you cannot be too heavy for your horse and that you as a rider must also be fit and flexible. Without talking everyone into an anorexia, we would like to talk about how heavy is too heavy? As always we will dive into the science instead of just shouting out opinions. We also look into Icelanders, Paco Fino’s and the Tennessee Walking Horses. Can they really carry heavier people?
Horses show signs of backpain after being ridden by riders exceeding 20% of the horse’s body weight.
The coordination of the horses movements is influenced if the rider equals 30% of the horses weight.
For a narrowly built, poorly muscled horse, or a less experienced rider, with a less independent seat, the maximum permissible equestrian weight should be less, for example 15% of the horse’s body weight.
Signals for too heavy a load include longer breathing and heart rate recovery time, increased CK (creatine kinase) values and stiffness in the back muscles the day after a workout.
Guidelines known so far
In recent years, many guidelines have been drawn up for the welfare of horses. It is striking that not often something is said about the rider and when it is said that the recommendations are made little concrete. For example, in the Dutch Council’s Guide to Good Practices (2011), in which the minimum guidelines for keeping horses are described, equestrian weight is not mentioned at all. The book Horse and Welfare (2009) by the KNHS (Dutch federation) indicates that physique and the weight of a rider influence the choice of a suitable horse. But no concrete weights are mentioned. Apparently it is a difficult point to make specific.
The most concrete guideline dates from 1941 issued by the American Army in the book ‘The cavalry manual of horse management’ in which it was indicated that the total weight of the rider and the pack should not exceed 20% of the horse’s weight. Apparently, during the war, experience was gained with overloaded horses who could not keep up with the work.
How to calculate your weight percentage
In the equine weight study, the percentage (%) of the rider’s weight is compared with the horse. This is how you can calculate your percentage yourself.
Weight% = Your own weight / the weight of your horse x 100%
If you do not know the weight of your horse you can estimate it using the height of your horse at the withers according to the following table.
For example, if you weigh 75 kilograms and you have a horse of 165 cm high, then your weight percentage is:
75/600 x 100 = 12.5%
How heavy are riders actually?
The Cornwall University in the United Kingdom has looked at how heavy riders actually are in a large group of riders. The average rider-horse bodyweight percentage varied between 14.2 and 16.6 percent. Based on these findings, you can state that a guideline of 10 percent is not realistic. Simply because most riders do not make it. The following table shows the percentages of riders found in the United Kingdom.
When we talk about the maximum weight of the rider, it is important to understand the biomechanics of the horse’s back. For a long time there has been written about the back of the horse as a kind of bridge, but this is actually too static a concept. Nowadays we often describe the working of the back as a kind of bow (of a bow and arrow). Where the inflexible part with the handle represents the spine in the back and the string represents the more flexible belly muscles at the bottom.
Movement of the back
When the horse moves the back moves in 3 ways. It is more or less hollow and convex, it bends to the left or to the right and it can rotate on its own axis. The last two are linked together. If a horse bends to the left, the back turns slightly to the right around its own axis. Seen from behind, the spine rotates a little clockwise. If the horse bends to the right, the spine turns a little counterclockwise.
The back of the horse can move in three directions. When bending to the right it also rotates counter clockwise. The weight of the rider has the most effect on the bulging movement in the back. In a comparison between the back movement with only a girth, only a saddle and a saddle with 75 kilograms. The spine became clearly more hollow at a weight of 75 kilograms. The mobility of the back however did not decrease. Besides that the horses moved their forelegs further back with the 75 kg weight compared without the weight. Probably in order to help the back to flex again.
The mobibity of the back in the convex / hollow direction effects the stride length of a horse. The greater the mobility of the back in this direction, the bigger the steps it can make. In older horses, the back is often a bit stiffer, which reduces movement in the hollow and convex direction. Back pain also leads to reduced mobility of the back and thus a reduced step length. In particular, the mobility in the hollow / convex direction and in the rotation around the longitudinal axis are reduced in horses with a painful back
Back muscle pain
When horses hollow their backs under the influence of the weight of the rider and they are unable to sufficiently flex their backs again afterwards, it will lead to painful muscles in the back. In a study among Dutch horses 22.6% of the horses showed a slight form of back pain.
A study by Ohio State University showed that horses with a rider weight of more than 20% had significantly more muscle pain in the back than horses that were ridden with less weight. Eight horses were ridden with a weight of 15 to 30% of their body weight. When wearing 15 and 20% of their body weight, the horses showed little evidence of physical pain or stress. At a load with a weight of 25% the horses had:
Longer lasting increased breathing and heart rate after training.
Increased Creatine Kinase (CK) immediately after training.
The day after the training more painful and stiff muscles.
All these symptoms were even more pronounced with a load of 30% of the body weight. For example, the CK was also raised at 24% and 30 hours after the training at 30%.
Based on these results, the researchers state that horses should preferably not carry more than 20% of their body weight.
Symmetry and coordination
In addition to an effect on the muscles of the horse, an effect on the symmetry of the movement was found in Japan with an equestrian weight of 30% of the body weight. 6 mares of an average of 340 kilograms were slowly being loaded more and more. Up to a load of 95 kilograms (27.9%) little or no change in the movement was found. At loading at 100 kilograms (29.4%) and more the horses moved significantly less symmetrically. In practice, this means that a horse burdened with 30% of his body weight will sooner make mistakes and have a higher risk of tripping.
Skill of the rider
Veterinarian Krijn van Muiswinkel indicates that it is difficult to give a standard list for the maximum weight of a rider, but that riding skills and especially having an iundependant seat is of great importance on the strain on the back of a horse . “An obese person who can ride well and is always moving with the movement can in that respect be less stressful for a horse than a bouncing lean type.” It is not clear how much extra load a poorly seated rider produces. In addition, the riding skills of the rider also has a great effect on the ability to flex the back under the rider. To be sure, an extra safety margin of, for example, 5% can be used for novice riders.
Developing an independent seat that follows the movement of your horse is very important in relation to the maximum weight your horse can carry.
Different breed differences
Finally, it is known that many gaited horses such as Icelanders, Paco Finos and the Tennessee Walking Horses are ridden by heavier people. In one study the researchers looked at the relationship between the construction of the horse and the equestrian weight. This showed that horses with a wider hip and thicker legs had significantly less painful and stiff muscles after wearing heavier loads compared to the less roughly built horses. No relationship with height at the withers was found in this study, other than the weight of the horse.
The club for ‘Gaited Horse Enthusiasts’ gives the following calculation as advice:
(Total weight rider + horse / circumference of the leg)/2 = Weight index
Weight Index <75 = Good
Weight Index 75 – 80 = Acceptable
Weight Index 80 <= Caution is advised
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