Weight Training Routines

It must be short (between 45 to 75 minutes maximum; 60 minutes being best)
After 75 minutes, the levels of muscle building and fat burning hormones that your body produces (such as testosterone) begin to drop. What this means is that training more than 75 minutes will prevent you from gaining muscle and losing fat fast! It will also prevent you from fast recovery. As crazy as it sounds, that is the way it is.

The rest in between sets should be kept to a minimum (90 seconds or less)
Keeping your rest in between sets and exercises down not only helps you to perform a lot of work and still finish within the 75 minutes, but it also helps improve your cardiovascular system. In addition, it has also been shown that this kind of training stimulates growth hormones output the most.

Generally, the sets should be between 8 - 15 repetitions each
There are many reasons for this:- You get the best pump (blood flowing into your muscle cells) in this repetition range. This is important since along with the blood come nutrients that nourish the muscle cells and help them recover and rebuild bigger faster.- Since you are doing so many repetitions, there is less probability of injury since you'll be using a weight that you can control.- Again, studies show that muscle building and fat burning occur more efficiently at these repetition ranges.(Note: For bodybuilding, however, I also recommend periods of 5-8 repetitions as well. This is of crucial necessity for a bodybuilder as an increase of strength is required in order for continued muscle growth to occur.)

Training must be varied and cycled
Please, don't get stuck with the same routine day in and day out. If you are a bodybuilder, and you do this, this guarantees zero muscle growth. This is without even mentioning boredom and lack of enthusiasm. For bodybuilding cycle periods (3-4 weeks) of high volume (8-15 reps/set) with periods of higher intensity (5-8 reps/set).