Some people seem to believe that horses are only more left sided than right sided because we primarily handle them from the left side. I don't believe that to be the case. I've seen horses that are more right sided than left though the left does seem to often be their more preferred side, just as the right is in humans.
What is interesting to me, and helpful as I train, is that the side the horse prefers is his stronger side - whichever that is. The opposite side - often the right but sometimes the left - is typically more supple or the "softer" side. Now, this is important. Horses are not as one sided as most people are and some show little preference for the right or the left. It seems the more athletic a horse is, the more "ambidexterous" he will tend to be.
So, how all this works out is: horses have what is called a stiff side and a hollow side. Often the horse that is naturally left leaded will turn better and easier to the right, and, for example, will do a flying lead change easier to the right. That horse changes easier into his softer, more supple side.
As trainers and riders, our job is to make our horses more evenly sided. As I mentioned, very talented horese don't show strong prefrences and are often much easier to train but the majority of horses do have a clear supple versus stiff side.
By understanding which side your horse is supple on and which side he's stiff on, you can focus your work accordingly. Perhaps starting excersises on the stiff side, then going to the supple side, then ending on that harder side until the day you find that you can't really tell the difference! I hope these thoughts help during your next ride! Talk to you next week, JD.