You can do this protocol using dumbbells, a barbell, or on a seated row machine. The isometric is held at the full contraction because it forces you to focus at the top of the row – the part of the exercise where most people cheat.
Also, if you're using free weights you can vary your torso lean from a 45-degree angle to parallel to the floor, thereby hitting your muscles a bit differently.
Admit it. A lot of times you plan your workouts around your major muscle groups and just "throw in" a few sets at the end for your ancillary muscles – calves, abs, and forearms.
This six-week program breaks some of the currently accepted rules for workout volume and duration. That's why you'll do more than 20 sets per workout and you'll train for 60 to 75 minutes.