Eric is right about the low cadence drills: if they hurt your knees, don't do them. They assume at least a couple of years of prior training. However the smoothness that is the focus of these drills may actually help your knees by improving your form. By the time you get to them in April, your conditioning might be up to them. Then the high cadence road drills in May. I used to have bad knees, but cycling has fixed them. Not a torn ACL, though.