I first heard about this innovative muscle building strategy when Arnold Schwarzenegger talked about doing in during his reign as Mr. Olympia. It is called "Running the Rack". It can be used for each exercise in your workout OR as a finisher to your normal workout.
This techniques refers to a high volume set where you pick a weight and perform as many reps as you can for a certain exercise. Then when you can't do any more reps, you pick a lighter weight and continue performing reps of the same exercise. As you fatigue, you lower the weight and repeat.
The reason it is called "Running the Rack" is, if the exercise you're doing involves dumbbells you will be moving down the rack picking lighter weights as you fatigue.
This form of density training improves work capacity, increases lactic acid which releases natural growth hormone. This in turn, builds muscle quickly.
Sample Exercise 1: Bicep Curls
Perform dumbbell bicep curls.
60 lb dbs – 3 rep, no rest, immediately go to
50 lb dbs – 4 reps, no rest, immediately go to
45 lb dbs – 5 reps, no rest, immediately go to
40 lb dbs – 6 reps, no rest, immediately go to
35 lb dbs – 7 reps, no rest, immediately go to
30 lb dbs – 8 reps, no rest
You could also reverse the order and start light, with higher reps and as you increase the weight, you decrease the reps. Again, little or no rest between weight changes.
Sample Exercise 2: Lat Pull Downs
Perform lat pull downs with a cable stack.
The stack – 1 rep
The stack minus 10 lbs – 2 reps
The stack minus 20 lbs – 3 reps
The stack minus 30 lbs – 4 reps
The stack minus 40 lbs – 5 reps
The stack minus 50 lbs – 6 reps
The stack minus 60 lbs – 7 reps
The stack minus 70 lbs – 8 reps