I guess I respectfully disagree with some of the above posters on which DVDs permit heavy lifting and strength gains.
To lift heavy, I need to be able to lower the reps and control my speed. This, for me, eliminates Muscle Max, Push/Pull, Supersets, and some of the Gym Styles routines, and most especially the Pyramids. The Pyramids feature 52 reps of every exercise and have a massive high rep feel to me. Cathe's speed on these is also turbo charged and to keep up, I have to lower the weight unless I choose to ignore her and do my own thing. But if I am going to do that, I may as well put on Pink or Lady Gaga in concert, as I frequently do, and do the same exercises with truly heavy weights at my tempo.
So, I would say, to lift heavy, you are only looking at 4DS, STS mesocycle 3 and Slow & Heavy. With S&H, you may have to lower the weight initially in order to complete the reps because the slow speed eliminates all momentum, but eventually, you will lift heavier weights because the ability to gain strength and muscle mass with this series is definitely there.
I am a hard gainer with very thin arms, weak pectorals and pathetic triceps, in short, an ectomorph upper body. I only gain real muscle mass and strength with these latter DVDs or when I do my own thing to Lady Gaga. The only time I ever gained strength with the Pyramids was after a rotation with S&H: when I came back to the Pyramids afterwards, I used heavier weights than before because of the S&H rotation.
Doing my own thing to Pink and Lady Gaga has the advantage that I can do drop sets and get to heavier weights than I normally use with Cathe DVDs. I can start with that heavier weight and keep dropping in poundage as I fatigue, but keep going. Even if you only manage 5 reps at the new high weight, this gradually enables you to master that new poundage eventually for a full 8 or 12, whatever your desire.
Lifting heavy requires a rep range per set of less than 8 reps. Hardly any Cathe workouts truly feature that rep range. Anything that includes band work is not heavy work, it's endurance.
Hope this helps,
Clare