There are three primary forms of complex training:
1. Complex I Training
2. Complex II Training
3. Ascending-Descending training
There are minor difference between the three types of complex training but are all based on principle of alternating exercises
Complex I Training
A Russian complex involves a continuous alternation between exercises of heavy and light loads in the same session; or more specifically, alternating between a slow-speed strength exercise and a high-speed strength exercise. In most cases a complex is made up of two exercises. For example:
1. Intra-set pauses of 7-12 seconds
2. Training loads above the optimal tension threshold
3. Perform more reps than you normally could with a certain weight