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SUPERSETS are done by pairing two exercises together that train opposing muscle groups (i.e. chest and back). This is a great way to shorten your workouts without having a negative effect on your muscle growth, if done correctly.
With appropriate rest periods between sets, supersets can be done without sacrificing total training volume  and may also have aerobic conditioning benefits. 
Contrary to common belief, a longer rest period between sets has been associated to greater
strength and muscle growth. [3, 4]
Instead doing both exercises one immediately after the other, a short 45 to 60 second rest period between the paired sets can enhance your ability to perform your reps and effectively, ultimately accomplishing a greater total training volume.