Conditioning in sand is valuable for 2 reasons. Done correctly it can (1)
build up the cardiovascular system and (2) build up the CV system without
stressing the legs. Caution - build up speed and distance carefully and
slowly. Horses can handle sand ( Holland in 1992 had ?18?miles of it),
but it takes time. Almost as good (?better?) than hills. Comments?
The 1996 ROC video is interesting. I don't know if it's $40 worth of interesting.
I got it free with my Trailblazer subscription. It's about 60 mins. long.