Fitness can be a fickle b*#tch.  I have listened to athletes lament their lackluster results despite brutal workouts, increased volume, and careful preparation.  Others have been amazed at a new PR despite going into a race under-trained due to an illness or other circumstance.  A coach once confided that her best Ironman was her first very first race as an under-trained newbie; a result she could not duplicate or exceed years later.  There is often a gap between an athletes perception of how fit they are, and that of their actual physical performance and capability.  The most successful professional athletes that I have worked with have a true and intimate understanding of their capacity on race day, and are rarely surprised by their results one way or the other.  

"Fitness" is a large umbrella under which resides a stronger, more powerful, faster, longer lasting you.  But there are a great many complex systems within your body that must adapt to the stress (workouts) that you put on them.  These systems all have their own timelines for development both physiologically and individually.  Some of them repair and adapt quickly, most quite slowly.  Muscle fibers hypertrophy and get bigger, osteoblasts make bones stronger and more dense, connective tissue such as tendons and ligaments thicken and become more resilient, capillary density increases moving more blood, mitochondria that produce fuel in the cells become more dense, the heart wall thickens and stroke volume increases, hormonal responses change and even neuromuscular firing of the muscles improve.  And this is to name just a few!

It would be impossible to chart all these changes slowly occurring in the human body but a good rule of thumb is that fitness (compensation) follows a workout by several weeks or more for most of these systems.  Yet if you were to ask the average person they would likely say a few days or a week.  In many cases an athletes destiny is already written several weeks before an event.  They must train to maintain their edge and fitness, but the psychological tendency is to attempt to put more in the fitness bank.  This most commonly produces "flat" or lackluster performance on race day.  You see we humans, especially athletes, are hardwired to push harder often to our detriment at least athletically.  What we really need to be learning is how to rest hard; we already know how to train hard.

There are a great number of devices, profiles, tests, etc.. that attempt to identify over-training (or under-resting), but a good coach can usually take one look at an athlete, ask a few questions, and know to reduce volume.  For the self-coached athlete this objectivity is more difficult but the signs are usually pretty apparent...

• Sudden drop in performance
• Feeling, tired, drained, lack of energy
• Mild leg soreness, general aches, and pains
• Pain in muscles and joints
• Moodiness
• Insomnia
• Headaches
• Decrease motivation
• Depression
• Decreased appetite
• Nagging injuries

The longer these systems persist or get worse the longer it will take to get your performance back; sometimes month or more.  I have seen over-training syndrome become career ending in some cases.  

That little voice that tells you to push harder, faster, MORE can be pushing you towards a fitness cliff.  How do you bridge the gap between that voice and what your body can physically absorb?  By careful tracking of your fitness data and performance, and listening to your body.  It is important to remember that any improvement in fitness is hard to come by for most seasoned athletes.  But if you are seeing great gains in performance do not reach for more.  Just on the other side of that is over-reaching.  How you are recovering should be constantly evaluated on a daily basis.  A successful athlete knows that a day or rest or active recovery, interjected at the right time, is their secret weapon.  Compulsively training athletes are not in sync with their bodies, they are feeding their compulsion.  Being able to control the need to train is as important as training itself.   

Training plans should be flexible, not written in stone.  It is important to have a plan then adapt it as needed as often as needed.  Checking workout boxes does not necessarily lead to improvement.  Fitness does not improve linearly, and every body has it's own timeline and capacity to absorb fitness.  Even the plan that lead you to success in the past may not be successful in the future.  In short the ground is constantly shifting under your feet.  Developing keen instincts, listening to your body and not your mind, and becoming in sync with your stress/recovery cycles is what will lead you to that next PR.  Treat your body with kindness and respect, and not as if you are at war with it, and it will pay you back on race day.