Kidd, tell ya what Rick's uncle used to do when he had race horses... this used to crack me up... They actually had a deal in the pond where the horses swam across this pond... and I'm talking this was one heck of a pond. I've seen them do it twice, and once the horses get accustomed it, boy on those hot days, they just literally dive in.
On a side note with humans... we were lucky enough to have at our high school, our very own swimming pool. So as soon as school started, coach, to get us back in shape, would take us to the swimming pool, and we'd jog in place, hands out, knees touching our hands... depending on your leg length and heigth, would depend on how deep you'd be... I was always out in the deep... but we all absolutely loved it, had a big time with it, and sure wish the boys had that opportunity! Course half of us had already took swimming lessons or been at the pool every danged day, so it was like old news to us, but we still had fun... course started getting a little chilly later! HA!
I can tell ya this, if I had the opportunity, I'd have my horses one day out in the pond or the tread and the next day I'd be golf-carting their booties up and down hills...(in your case on the track) man-oh-man, those suckers would be in some tremendous shape! And I think that's good for all of 'em!