I'm not a huge fan of lifting heavy for my upper body but I want to use the upper body workouts in xtrain. Do you think that one could easily modify xtrain's upper body workouts and use lighter weighst and do 15 reps?
Just FYI, The Xtrains use 16 rep sets, so you do use a somewhat lighter weight (but it feels heavy!). Only the Burn Sets workouts use less than that (10 reps). I think you could easily modify Burn Sets to go lighter with heavier weights....since you'll be lighter, your reps can be faster than Cathe's, so the timing might work out. What may be more challenging with lighter weights will be going to failure on the third set.