Dumbbell and barbell complexes have proven very popular in recent years amongst the S&C community. They are probably most widely used within Martial Arts circles as they are great at developing large work capacities. The man credited with developing them is Istvan Javorek, Head Fitness Coach at Johnson County Community College.
Despite their name complexes are an easy way to get fitter and stronger in a hurry. Increasing strength, work capacity and reducing body fat are often thought to be time consuming or difficult to manage. Complexes allow all three to be done at the same time.