This is my muscle-building routine from a few years back, when I was in my late 20s. I made a pact with myself that I would give up when I was 30, which I did. Most of the world's top bodybuilders continue to improve throughout their 30s and into their 40s but I wasn't convinced of the wisdom of doing so - little aerobic exercise, vast amounts of food, and that much physical strain is a young person's thing. To put it into a lifestyle context, at the time I was eating 6 small meals per day, a meal consisting of an egg-white omelette, a couple of turkey breasts and some rice, or a protein shake. And I never took any performance-enhancing drugs.
The main principle behind this workout is maximum recovery - 2 days of total rest before legs, which is the biggest bodypart; a day before back, the next biggest. I also went by the pre-exhaustion principle, which fits quite well with maximum recovery - in other words, you work your biceps as a bodypart on the same day as you do back, because they'll get a workout with the back exercises anyway - same with chest and triceps. The final principle is to start with the exercise that works the largest muscle groups (not the most intense - they should always be intense), and 1 light warm-up set per exercise - warm-up is to stop injury, not to exhaust your muscles.
Day one - legs
Squats: 4 sets of 12, 10, 8, 6 to total failure (like every set)
Leg presses: 3 sets of 10
Stiff-legged deadlifts: 4 sets of 12, 10, 8, 6
Calf raises: 3 sets of 15
Day two - lower back, shoulders, and traps
Deadlifts: 3 sets of 10
Shoulder presses: 4 sets of 12, 10, 8, 6
Shoulder flyes: 3 sets of 10
Shrugs: 3 sets of 10
Day three - rest
Day four - back and biceps
Pull-ups: 3 sets to exhaustion
Bent over rows: 4 sets of 12, 10, 8, 6
Dumbbell rows: 3 sets of 10
EZ bar curls: 4 sets of 12, 10, 8, 6
Day five - chest and triceps
Bench press: 4 sets of 12, 10, 8, 6
Incline bench press: 3 sets of 10
French press: 3 sets of 10
Days six and seven - rest
Every day - abs: 200 crunches.