Your nervous system has a nasty of habit of adapting.
Adaptation is the ultimate goal of training. Physical training is intended to create the stimulus needed for adaptation. Adaptation takes on a number looks, be it increased muscle mass, increased strength, improved speed and power outputs, or increased cardiovascular efficiency. The desired adaptations will always depend upon the needs of the athlete and how periodization influences each training phase or block.
Training phase? Training block? Periodization?
If these terms are unfamiliar to you, let us emphasize why they need to be important to you: Your nervous system gets bored of everything. Our bodies are wired in such a way that unless we change some variable (volume, intensity, frequency, etc.) of the training stimulus, we will ultimately fail to continually adapt.
Periodization and the pursuit of adaptation is the foundation of scientific progression in physical training and athletic development. Great coaches will put you on a program long enough for you to adapting to it, then they introduce change.
Periodization is simply organization of training. One must have an expertise of how organization of training and exercise selection expertise impacts development. This is a prerequisite to training anyone, but unfortunately there are many under-qualified trainers and coaches out there that do not understand these concepts. Entire teams or groups of individuals should not all be performing the same training. This would assume the entire team or everyone in your group training class has the same deficiencies. Approaching training in this fashion is just ridiculous and deserves to be criticized. Periodization and training is an individualized process. The fitness industry and fad-based training has convinced the public that periodization and planning is not needed. Well, at least until training fails to produce meaningful results.
Understand there is no perfect program or system, just phases of training. Training is an ongoing process. Periodization and the planning of training is an ongoing process. This is why your trainer or coach must be putting some thought into your training, otherwise your success is always in jeopardy.