About 20 years ago, strength and conditioning coaches began to search for better ways to warm-up their athletes while minimizing the time in order to keep an efficient workout pace. They came up with the complex routine where a single barbell or set of dumbbells would be used to perform several different exercises strung together to form a routine.
The word complex carries the direct dictionary meanings of "an interconnected whole that has many parts" and/or "difficult to perform, analyze or solve." When loosely translated into gym speak, it means "Get ready for one intense workout."
Either way you cut it - and as strength coaches began to realize - if you load up on the weight, you can get into a whole new level of burn and build plenty of muscle in the process.
A complex routine consists of several exercises strung together that form either segments of a bigger lift or completely autonomous exercises to get the entire body worked in a single period. In either case, you set one weight - either on the barbell or with dumbbells - and then set your rep scheme.
An example of the first complex scenario involves moving toward the clean and jerk. Beginning with the deadlift, you would then move to upright rows, push presses or jerks and finally to full reps of the clean and jerk. In other words, the clean and jerk lift is broken down and each segment of the lift is trained before the whole entire lift is executed.
In the second scenario, you may go with a more isolated approach like deadlifts, squats, bent over rows, shoulder presses, triceps extensions, biceps curls and then finish with push-ups to complete the package.
So what makes this so difficult? Exercises are circuited with no rest. That means as you are finishing off the last rep of an exercise you are already starting the next exercise in your list.
In general, a complex will have anywhere from 4-6 exercises (you can use more) for 8-20 reps each. In a complex, since there is no rest between transitions making the average complex set last for two excruciating minutes! Each complex routine is then completed for 2-4 more times.
The keys are to maintain form and technique and, of course, to complete the routine. This type of training requires serious discipline and while you will see some benefits to your overall muscle mass, it is your endurance, athleticism and general strength are pushed to the limits with this type of training.