I had legs a couple of days ago, and I am still feeling the effect of that Swiss ball. I first laughed at the thought of using the ball for legs, but what did I know. Not much I guess. I was to only do two leg exercises, and I was totally drained afterward.
Squat rack with one plate per side.
set one 20 reps rest 45 seconds
set two 21 reps rest 45 seconds,
continue till 30 reps.
Swiss ball one leg curls..
Same drill with starting with 15 reps and going to 25.