One of the easiest ways to increase the intensity of your strength training workout is to add weights to your normal exercise. So if you're acclimated to doing the pilates 100, then add a set of three pound weights, holding them in your hands as you shift them up and down. The addition of weights makes the motion much harder, which means greater muscle intensity for a better workout.
Similarly, the leg curls in this workout add a weight to make it difficult for you to lift your legs up and down. This bench curl exercises works the hamstrings, glutes, and butt.