Best of luck! We have friends that regularly ride 25 and 50 milers (every other weekend, at least) and are top ranked in the region/nation. I rode one of their best arabs that has never been beaten in a flat-out gallop, and BOY is he fast! He's 17 and still coming in top 5 in 50 milers. I am excited to get into endurance more in the next year or so. Currently 7 months pregnant, so I've decided going *that* fast is an unnecessary risk at this point.
Note that we also rode with an older woman whose OTTB (I believe) was middle-aged or a bit older, and kept up pretty well with the two arabs. It's all about conditioning, and as you become more in tune with your horse, you will be able to condition him even better. :)
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