The human body is always striving to maintain the status quo. This is quite normal and essential for healthy living.  The body strives to determine repetitive cycles of working, resting, and eating.  By establishing a basic pattern, the body can maintain a level of consistency.  Once accustomed to a particular living
pattern, the body regulates its “metabolic” requirements to suit.  The rate at which the body can produce these metabolic requirements varies.  They can be produced almost immediately, within several hours or over several days.

The body can and will adjust its available reserves of strength and muscle mass.  However, there must be a very strong present reason and, also sufficient time to build muscle fast.  The reserves within the body to produce these changes are strictly limited and easily exhausted.  Performing an intense, brief workout will cause the body to adjust its metabolic reserves (increase it’s size and strength).  This adjustment, however, can and will take up to two, and in many cases, more than two days.

As the body can’t produce these changes immediately, the increases  in strength and muscle mass must be based on possible future demands.  By using past physiological demands as a guide, the body determines how much strength and muscle it will need in the future.  The greater the intensity of previous demands the
greater the increase in strength and muscle mass.  This helps guarantee your body’s ability to cope with potential future challenges.

This phenomenon is obvious during and after illness.  When you catch the flu for example,  you are usually in a weakened state.  After recovery however, your body quickly returns to its pre-illness strength levels.  No form of intense exercise or a specialized diet was  required.

The process is similar to rapid increases in strength and to muscle mass.  If you gain muscle mass then cease training altogether, your body quickly returns to its previous state of strength and muscle size.  The body has a natural tendency to maintain levels of strength and muscular size which it previously considered ‘normal’.  These levels are determined by the your daily and weekly performance requirements.