Nation,
I figured I would share that after decades of doing muscle split training programs, I decided to try full body push/pull circuits --- especially based on Scott's video on 3 reasons why you are not losing bodyfat. I trained like this 30 years ago the very first 6 months I began lifting and then never did it again.
I do 4 days (M/T/Th/F) a week with 2 days focusing on pushing and 2 days on pulling. I do 2 exercises per muscle group and 4 sets of 8-12 reps (not counting warm-up reps). I vary the exercises so not only are muscles getting trained twice a week but also I am doing different exercises each session. I group quads, chest, triceps, calves on Push days and back, shoulders (I prefer training them with back even though they are a "push" group), biceps, hams on Pull days. I work forearms and abs in every other workout and I keep rest between sets low so I am done in 60 minutes or less. I have to give props to all those people here who train like this. It is killer and with the full body workout combined with 30 minutes of brisk walking (15 minutes to/from home to gym) for my aerobics I can feel the burn and my metabolism churning. Granted this style of training is new for me and I am not taking anything away from or dissing everyone who does muscle splits and 5x5's but man this stuff really gives you a great workout :-) Incorporating full ROM, negatives, and varying the tempo I don't need to kill myself with heavy weights to maintain muscle growth and strength -- and believe me when many of you reach my age you will appreciate this fact :-)
John