Just in case someone doesn’t know what a superset is, I thought I might throw out a definition.
A superset is when one performs two exercises that stress two opposing muscles or muscle areas (agonist/antagonist) or it can be for the same muscle group. Even though it is comprised of two sets it is considered one set. Hence the name superset.
Example: I do a set of squats and I immediately follow it with stiff leg deadlifts; I perform a set of barbell curls and immediately follow it with triceps extensions.
I can perform lying leg curls and then follow it up with standing leg curls.
Benefits: It saves a lot of time because you are cutting out much of the rest period between sets in the case of opposing muscle group. In the case of the same muscle group you give that muscle group a fierce stimulus. In this way you overload the muscle and it produces the positive training adaptation of hypertrophy also known as muscle growth.
By the way, this method of training is not for everyone. It is generally utilized by bodybuilder, athletes and folks who have a good strength foundation.
Thanks for your question!