Everyone knows that riders must not be too heavy for the horse they are riding, and that as a rider must also be fit and supple. In this feature, we discuss how heavy is too heavy? As always, we will dive into the science behind this. We also look into specific horse breeds, including Norwegian Fjord , Paco Finos and the Tennessee Walking Horse. Can they really carry heavier people?
Horses show signs of backpain after being ridden by riders, who exceed 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 on rider weight available so far
In recent years, many guidelines have been drawn up for the welfare of horses. It is striking that not much is ever mentioned about the rider, and when it is included in welfare guidelines , recommendations are not really 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), published by the Dutch Equestrian Federation (KNHS) 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 specify.
The most concrete guideline dates from 1941, and was 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 many riders?
Cornwall University in the United Kingdom investigated how heavy riders actually are across a large group of riders. The average rider-horse bodyweight percentage varied between 14.2% and 16.6%. Based on these findings, it can be stated that a guideline of 10% rider/horse weight percentage is not realistic. Simply because most riders are heavier. The following table shows the percentages of riders found in the United Kingdom.
The horse’s back
When we refer to guidelines about the maximum weight of the rider, it is important to understand the biomechanics of the horse’s back. For a long time, people have thought of the horse’s back as a sort of ‘bridge’, but this is actually too static-a-concept. Nowadays, we often describe the working of the horse’s back as a kind of bow (as in 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 three ways. It a structured so that it can become more or less concave or convex, it bends to the left or to the right, and it can rotate on its own axis. The last two properties 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 counter-clockwise.
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 an additional 75 kilograms. The spine became clearly more concave at a weight of 75 kilograms. The mobility of the back, however, did not decrease. Alongside this the horses moved their forelegs further back with the 75 kg weight ,compared without the weight. Probably to help the back to flex again.
The mobility of the horse’s back in the concave/convex direction affects the stride length of the horse. The greater the mobility of the back in this direction, the bigger the steps it can make are. In older horses, the back is often a bit stiffer, which reduces movement in the concave/convex direction. Back pain also leads to reduced mobility of the back and, thus, results in a reduced step-length. In particular, the mobility in the concave/convex direction, and in the rotation around the longitudinal axis, are reduced in horses with back pain.
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, the experience pain in the muscles in the back. In a study of Dutch horses, 22.6% of the horses showed a slight form of back pain.
A study by Ohio State University, in the US, showed that horses with a rider weight of more than 20% had significantly more muscle pain in the back than horses that were ridden by a rider with less weight. Eight horses were ridden with an additional weight of 15% to 30% of their body weight. When carrying an additional 15% and 20% of their body weight, the horses showed little evidence of physical pain, or stress. While carrying an additional load with a weight of 25%, the horses studied had:
Longer lasting increased breathing and heart rate after training.
Increased Creatine Kinase (CK) immediately after training.
More painful and stiff muscles the day after the training.
All these symptoms were even more pronounced when carrying a load of 30% of the horse’s 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 stated 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 a Japanese study, with an equestrian weight of 30% of the body weight. Six mares of an average of 340 kilograms were slowly loaded increasingly. There was little or no change in the movement found up to a load of 95 kilograms (27.9% of the horse’s body weight). The horses moved significantly less symmetrically at loading of 100 kilograms (29.4% of the horse’s body weight) and more. In practice, this means that a horse burdened with 30% of its body weight will make mistakes earlier and have a higher risk of tripping.
Skill of the rider
Veterinarian, Krijn van Muiswinkel, has indicated that it is difficult to give a standard list for the maximum weight of a rider, but that riding skills and especially having an ‘independent 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 of the horse’s back 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 Norwegian Fjords, Paco Finos and the Tennessee Walking Horse are often ridden by heavier people. In one study, the researchers looked at the relationship between the construction of the horse and the rider’s weight. This showed that horses with wider hips and thicker legs experienced painful and stiff muscles less after carrying 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
(In Dutch) Sectorraad Paarden (SRP) 2011, Gids voor goede praktijken.
(In Dutch) Koninklijke Nederlandse Hippische Sportfederatie (KNHS) 2009, Paard en Welzijn: pag 146
(In Dutch) Daalen T. van, Muiswinkel K. van 2010, van Hoofd tot staart, Hals en Rugproblemen bij paarden, Eisma Businessmedia, Doetinchem: pag 102
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Matsuura A et.al. 2013. “Method for estimating maximum permissible load weight for Japanese native horses using accelerometer-based gait analysis.” Anim Sci J. 2013 Jan; 84(1):75-81.
Weeren, P.R. van 2010. “Science overview Development of a structural and functional understanding of the equine back.” Equine vet. J. (2010) 42 (Suppl. 38) 393-400
Visser E.K. 2013 “Risk factors associated with health disorders in sport and leisure horses in the Netherlands.” ANIM SCI 2014, 92:844-855