Equine Athlete - Ambrose
Conditioning is what you do after your horse is legged up and you have a few miles on them. But the same principle follows almost every thing you do with your endurance candidate. A "slice of work at a time", never increase speed or distance at he same time. That goes for conditioning or legging up. You just follow the process all the way to the "fit horse". You will ALWAYS race slower then you train..... I think lots of people make that mistake, racing faster then they train, hence injuries and metabolic issues. The horse that wins the ride, and looks they just jumped out of the trailer is how you want your horse to look.
You are not going to go out and train for 50 miles, so you need to have shorter harder works that will help the horse get in condition for that first 50 miles. After you start doing some 50 mile rides then you can throw that into your training mix.
In order to get a "fit horse" , at least what my view of what a fit horse it, you have to stress that horse. So, what that means is that if you ride every day for 10 miles, just the same everyday, you have not accomplished much in the way of increased fitness. Now you can do 10 miles and you can do 10 miles.... You can break it up into mini sprints, pick up the trot, canter some etc etc.., so there are too many ways to count that you can do that 10 miles. So, what you have to determine is when you are stressing your horse a little. I don't believe in riding to failure, like in the human conditioning, but you do need to find the happy medium.