These routines call for one set per exercise. They represent an excellent bodybuilding workout for the beginner to get going in weight training. Studies have shown that, at least initially, single-set workout routines are just as effective as multiple-set routines for gaining mass.
Just because they are great for beginners, doesn’t mean a more experienced lifter can’t benefit from training with single sets from time to time. They are great to use without splits (working all muscle groups in each workout) because they allow you to hit more muscles with a greater variety of weight training exercises while keeping the workout quick and effective.
As I hope you can guess, multiple-set routines call for multiple sets of each exercise with each set having approximately the same number of reps in it (straight sets).
Generally, for the purposes of gaining muscle, it is best to lift medium or light with multiple-set routines. These workout routines with lighter weights may not be where you see the most gains in strength but they work to keep the body guessing and add definition to the muscles.
The general number of sets per exercise is three, with reps of 8-15 in each set. Three is a good number, but don’t be scared to design and follow a workout that has a higher number of sets on occasion.
Studies have shown that as much as 85% of the benefit derived from the exercise will be accomplished with the first set, but it has been my experience that the other 15% is very important.