At first, I had meant to make this a part of my lesson post for last week. But then I thought it merited a post of its own, and of course that led to me forgetting about it entirely.
What happened was that towards the end of the lesson, our instructor told us about a seminar she had attended the previous weekend. One of the things discussed there was how much a good rider is able to affect the distribution of weight between the horse’s front end and back end. This had been studied by putting horses on treadmills, with and without riders, and the results that they came up with in this particular study were quite surprising.
The horses who trotted on the treadmills without a rider were in very good balance, with the weight distributed fairly evenly. Once a rider was added, the weight shifted—just as one would expect—to the front end of the horse. What was not expected, however, was how incredibly small the difference was between a rider just sitting on the horse, in good balance but without trying for any collection at all, and a rider actively riding the horse for as much collection and weight on the hindquarters as possible.
The best of the riders in the test, Olympic-level dressage riders riding their own horses (both apparently placed very well individually at the last Olympics, on these very horses), managed around or a bit over 1%. Others did not even get close to 1%. In short, if these results are accurate, any riding whatsoever, no matter how well-balanced and correct, will put a lot of additional weight on the horse’s front legs and will cause wear and tear. A rider seriously disrupts the horse’s natural balance and weight distribution and is unable to come even close to restoring it, no matter how skilled he or she is.
A bit depressing, all considered, though one thing that this also makes clear is that having horses with naturally very good balance and a tendency towards carrying more weight on their hind quarters is even more important. A tall, long-legged modern warmblood sounds even less like a horse likely to last a long time given these test results.