In and Out Workout by Robert Saladino MS, CSCS

Muscles get bigger while you rest and sleep, not in the gym. Current studies regarding resistance training suggest sessions lasting as long 3-4 hours per day, 5 - 6 days each week, provide no greater benefit compared to training 1-1.5 hours per day, 3 -4 days each week. I'm realizing more and more the benefit of short and brief workouts. The human body can only take so much punishment before it actually starts to regress. While the more is better principal is true for money it doesn't apply when discussing overall fitness levels. When we're under physical (intense workouts lasting more than one hour) or emotional stress our bodies consume glucose at an extremely high rate. To keep our blood sugar levels in a homeostasis state the catabolic stress hormone cortisol is released. This hormone causes gluconeogenesis (making glucose from non carbohydrate sources) to be performed on your muscles. It does this by breaking down muscle tissue and releasing amino acids into the blood stream. Once in the blood stream the amino acids are shuttled into the liver to synthesize glucose. This ensures that our brain gets a sufficient amount of glucose to keep functioning properly. While it's a pretty efficient system to keep us alive and thinking properly, it wreaks havoc on those muscles all of us need to burn calories.  So, unless you want to run the risk of losing some of your hard earned muscles, shorter workouts is usually a better choice. 

Again, it's important to keep in mind; the workouts need to be short (max 45 min) and intense (reaching muscle failure). These 2 concepts must go hand and hand to achieve maximal results.  When you push your muscles to muscle failure (can't perform another rep) lactate acid builds up in the body. This raises human growth hormone and testosterone naturally in the body. Both of these hormones are catalysts for muscle growth. I have been performing the following routine for the past 2 yrs and the results have been nothing short of remarkable:

Legs are always done on Tuesday and back on Thursday. Studies show these muscles contain the most fast twitch muscle fibers and need the most rest between sessions. Chest, shoulders and arms are always rotating through a 5-day rest cycle, appearing on Monday, Wednesday or Saturday schedules. Friday is always cardio and Sunday is a full rest day.  From the example displayed above, Chest was performed on Monday, following a 5-day rest for Chest; the next chest session will fall on Saturday. If you keep repeating the cycle, you will always have enough rest for your muscles to get stronger and bigger. The variety factor is also present as Monday, Wednesday and Saturday are never the same workout.

• The workouts should never go past 45 minutes, with 30 minutes being the ideal time frame.
• The exercises should be free weight type movements, which produce the greatest amount of muscle mass and burn the most calories. Some examples are; Dumbbell chest press, dead lifts, military presses, squats and dumbbell curls.
• 2 sets per exercise, 3-4 different exercises per body part
• 30 seconds rest between sets: anything longer and you might be recruiting the same muscle fibers over and over again. The short rest periods forces new muscle fibers to take over the workload while allowing the exhausted fibers to rest. Once rested the working fibers will get recalled again and again without any of the reserves being called into the play. The more muscle fibers that get recruited the more muscular development you will achieve.
• Reps should fall into the range of 8-12, lower reps build strength and power and higher reps produce muscle endurance and hypertrophy.

Again In and Out is the game, if you really want to increase the intensity try these golden oldies 

• Force Reps: perform a set to failure (can't do anymore) and then have someone help you just enough to perform additional 2-3 reps.
• Giant Sets: perform 3 sets of 3 different exercises for the same body part in a row without taking a rest.
• Rest and Pause: Perform 1 set to failure, decrease the weight by about 10 pounds, wait 10 seconds and perform another set, repeat for 5 total sets.
• Super Set: Perform 1 set of 1 exercise for 1 body part and then immediately perform 1 set for another body part, similar to the giant set, except you are involving 2 different body parts: for example bench press followed by the front pull downs.

This is not a body building routine, but to be honest, body builders know something about gaining muscle, that's what they get paid to do! Some of these concepts are in-fact from famous body builder routines.  Muscle is an active tissue that burns calories, makes you stronger and keeps you looking physically fit. Try In and Out Workout and you'll be on your way to a fitter you.