HC is a series of workouts created by Sandra Koulourides. Here are the links:
Horizontal Conditioning : Purchase DVD's
http://www.totalfitnessdvds.com/Sear...l+conditioning
Here is a link to an older thread on VF that discussed the workouts when we all first sort of discovered Sandra:
http://forum.videofitness.com/showth...ght=horizontal
I totally think any Cathlete would be fine bypassing the "Getting" workouts and going straight to the volumes. Just a wee warning though...Bootcamp is super tough! Whatever you do, don't make that your first workout with HC! It'll scare you off! LOL I find Volume 4 very challenging balance wise with the stability ball work. I'm still working up to conquering that one, but I seem to have conquered Volumes 1, 2, and 3. I can do all of those now without pausing the dvd or making modifications. Depending on your starting core strength, that may take awhile or you may get it fairly quickly. You also have to build up the endurance in your wrists, shoulders and lower back with all the plank work. You hold plank much longer than in other dvds and she does really creative variations on it (stuff I've never seen)... so the brief plank work in Cathe's workouts won't totally prepare you. She does give breaks for the wrists by doing many moves in elbow plank and also going vertical throughout the workouts to work legs/glutes.
One thing to keep in mind, you really have to be okay with the fact that Sandra's production values aren't nearly as good as Cathe. She's just starting out...so the filming, sound, lighting, etc. is sort of amateurish. The club dvds (the Hardcore's and 101's) are even more so since they are really just dvd-r's of her filming her classes...she originally made these to sell the ideas to other fitness instructors througout the country. She didn't originally intend to sell them to the public.