I am new to Cathe but guesstimate I am at intermediate fitness level. All the different names for her DVDs at times have been confusing to me. My approach to them is as follows.
One basic rule that different people seem to mention in fitness training is every other day. In some of Cathe's posts, for example, she mentions doing something 3-4 times a week (i.e. roughly every other day) or she'll say to do something, then skip the next day, then do it again, another way of saying every other day.
Another thing people distinguish between is aerobic work outs versus strength work outs. In Aerobic/cardio, the goal is to get your heart rate up and get your lungs working to pump oxygen through your body. Apparently in this type of exercise you mostly burn calories while doing the aerobic exercise, but not so much in between aerobic work outs.
As noted by other posters, there are two types of strength work outs - endurance (many reps, low weight) and muscle building (few reps, high weight, sometimes slow reps). During the strength work out, your activity actually is destroying the muscle tissue. In between work outs, assuming your diet provides the right raw materials, your body rebuilds the muscles, but bigger than before. A virtue of strength work outs is that you are burning calories even when you are not exercising in the process of repairing the muscles. I don't know to what extent this occurs with endurance work outs.
These are generalizations, there can be overlap. For example, if you do a kickboxing work out, that can be aerobic, but if you hold a 1 lb weight in each hand while you punch, you may be getting some endurance strength training also. And sometimes when you do high weight strength training, you start huffing and puffing and your heart rate zips up.
Anyway I try to do aerobic and strength work outs roughly on, alternate days. E.g. upper body weights monday, lower body weights Tues, kickboxing Wed (aerobic), upper body weights thurs, lower body weights Fri, kickboxing Sat, jogging on Sun. Some days though, I may do both, e.g. upper body weights and either kickboxing or jogging (not far), if I feel energetic. And some days, you're just in the mood to jump around and huff and puff so you do an aerobic something that day or run up a steep hill or two.
When you first encounter Cathe's DVDS, it is somewhat bewildering because there are so many with so many different names. To simplify, I try to categorize a Cathe work out as either aerobic or strength training and avoid ones that sound like a blend. So, for example, the Kick punch crunch work out I use for an aerobic work out, while the Legs/Glute work out on the same DVD I use for a strength work out.
No doubt other people have their own equally good approaches, but this works for me so far. Also, it depends what level of fitness you are. On the bodybuilding.com website, there are all these heavy duty body builders who seem to do one work out (ultra heavy weights) for each muscle group per week. When I was starting out, an endurance work out was amounted to a strength work out, because I had little muscle tone to start with.
Good luck.
