I hear some fitness organizations boast that they “never have their clients do the same workout twice,” while other reputable organizations promote using periodization training to create adaptation in the body, followed by the shock of change in the next phase. I get confused over which method is better, or if it’s a combination of the two ideas that works best.
According to current research, undulating periodization i.e. changing your training/workouts in some shape form or fashion on a daily basis has been shown to be superior for optimal gains over traditional linear periodization i.e. weekly or monthly changes.
J Strength Cond Res. 2009 Dec;23(9):2437-42.