It has now become common practice, mainstream in its entirety to periodize programs in order to maximize results. Clients are used to it and every new trainer is either encouraged or forced to periodize programs as a common practice.

A new research proves something which many professionals in the field have been claiming for years, that periodization is just one method and there is no proof that it is more effective than other methods. While variations is key to maximize adaptation to exercise, different athletes respond differently to identical programs and it is not possible to predict the exact results of a training program.

Resource: http://www.ncbi.nlm.nih.gov/pubmed/22356774