For Ab Ripper X, I just pause the DVD when I need to. I made it my own goal that I was going to do all 25 of each exercise, + the 50 reps on the Mason Twist, no matter what. So I take an extra two minutes or so during the V-ups and wide leg situps to do that. Sometimes I'll take a few second break in between reps, but I always get to 25. Feels good knowing you hit the required reps

. During the Fifer Scissors, I can't get my leg up high without bending :lol , so I just go as high as I can go while still staying straight. I still feel a massive burn, so I'm getting something out of it.