Justine:
it occurs to me that there may be different ways to achieve what you are seeking. Not having a better answer for you than the one I previously gave has been bugging me!
I currently have excellent definition in the back, shoulders and obliques. I'll tell you how I got it. Maybe there's something there for you?
I got achilles tendonitis and elbow tendonitis at exactly the same time in May of this year. Double drat: I was incensed, how dare my body betray me?!! So, I had to make changes to the way I was working out. My dual plans to focus on both running and STS for the summer had to be ditched. We must remain flexible, right? I had to avoid heavy weights for the arms, and strictly no jumping. So, how to work on cardiovascular endurance and muscular definition and maintain that healthy metabolism?
I couldn't even do my customary power walks until 3 weeks ago, so I decided to go the metabolic workout route: i.e., use weights to provide my cardio and muscular conditioning. Hence, I have been doing my KCM mash-ups that I have spoken about before, basically taking 4 premixes from 4 different KCM DVDs and blending them together into 1 long session that does it all. I use the weights only premixes from Kelly's 30 MTF Step Boxing, 30 MTF Boot Camp, (the whole of) Powersculpt and finally from 30 MTF Circuit Burn.
I now have better definition in shoulders, back and obliques, and I have been doing this mash up once per week since May. It's a 2 hour bend of compound exercises with little breaks in between because Kelly packs a lot into 30 mins. But, her moves for back are usually explosive in nature and while she uses only dumbbells, I have always used either 15s, 17.5s or 20s on all these exercises. This is equal to or more than Kelly herself uses on the same exercises, and the results are in. So, this seems to produce better results for me than traditional splits, partly because the moves are explosive for back, but also because when doing compound moves, you tend to sneak work in for muscle groups you didn't know you were using! So, extra work gets done for most muscle groups than you might get done in a traditional splits workout. And, maybe, it's also the "change it up" factor at work here and the body responding to something new?
As for the butt portion of the posterior chain... Well, I currently have a bigger, more muscled, more rounded, steelier (can I just make that a word?) butt than I previously had. I am still getting used to this new development. I am a 5' 8" ectomorph and have had a flat butt most of my life, thanks to a previous attachment to heavy, steady state cardio and running. However, two things have effected this change: an emphasis on powerwalking rather than running, and these compound weights workouts. I don't do much in the way of either HiiT or plyo, so it's not that at work. The powerwalking produces the kind of muscle development in all three glutes muscles that women turn to barre work to achieve (fast walking at a 4.7-5 mph clip hitting as many hills as possible in 2 hours). I don't do barre much at all, no need really! When I flex my leg behind me in a ballet attitude, the muscle is taut and the definition is obvious from the hamstring through the gluteus minimus , through the entire hip area, and up through the back and obliques.
So, this is not me boasting, I must hasten to add, because, heavens above (!), I am not the proud possessor of the perfect physique and I know you can lift way more than me! After all, I am a ruler shape with little waist definition and no boobage to speak of..... But this is just testimony of what seems to work for me, right now. Maybe there is something you can take from it?
I don't think the answer lies in any one DVD in particular (short answer). Rather, it lies in experimentation and a combination of different techniques, both cardio and weight oriented.
Does this help at all?
Clare
So, these are the changes I have experienced in the posterior chain, for this my body type, during this year of my (peri-menopausal) life.