Conversations about fatigue usually come in the form of a complaint rather than its importance in the process of improvement. This is mostly due to the pussification of the training community, but it doesn’t have to be. Fatigue is a word usually expressed very generally and with negative connotation. When dealing with fatigue, it is important to understand its specific forms and how you can use it to your advantage. Any time that a person trains, there must be an overload of the body and its mechanics. Depending on the means of the training taking place, this overload changes the structure of the body as well as physically and chemically altering the brain. The body and brain will become structurally and chemically more efficient at the training in focus; if you are a long distance runner, your body and brain will reflect that — and so will your interest in Fox News and granola.
In order for this overload to be effective, it must disrupt homeostasis. Think of it as Newton’s first law: an object at rest will stay at rest unless acted upon. In this case, homeostasis is “at rest,” and the training overload is what must disrupt this rest. This overload is intended to produce fatigue in the body. Often during these periods of overloading the body, a trainee’s performance may drop off, or there may be a feeling of fatigue. However, coupled with proper rest, diet, and recovery protocols, these negatives response will result in supercompensation, and performance will return to homeostasis or increase beyond it. Often times, these negatives responses to overload are labeled as “overtraining.” In the majority of the cases, they are not. The human body is not a delicate system that will completely break down when you demand it to perform more work. It was built to adapt to levels of stress far greater than what can normally be produced in a gym. Therefore, it is important to be able to distinguish when fatigue is creating levels of overreaching before inappropriately chalking it up as overtraining.
During a period of overreaching, the trainee may exhibit all the signs and symptoms of an overtrained state. However, with proper recovery over a mater of days or several weeks, the period will result in a return or increase in strength, size, speed, etc.
Longer periods of overreaching become more common in advanced trainees. There is a point in an athlete’s training where it takes a much greater overloading process to disrupt homeostasis and produce the fatigue necessary to facilitate progress. Total volume and intensity needed for disruption becomes too great to be produced during an individual session or weekly training sessions, and therefore the trainee or coach will implement disruptions too difficult to recover from between training sessions. In these trainees, fatigue accumulates over time. The signs and symptoms that accompany over-reaching are necessary for progress, and should accompany bouts of difficult training.
This is not the case with overtraining. Instead of deloading or taking the necessary recovery methods needed for progress, fatigue continues to build and the trainee digs himself into a hole too deep to climb out of. The time taken for an overtrained person to recover far exceeds that of a trainee who is over-reaching. This state of overtraining has no benefits in the short or long term and is an extremely detrimental response to training that could takes months or years from which to fully recover.
For the coach and the trainee, it is of utmost importance to have the ability to distinguish between these two responses. More often than not, stages of over-reaching are mistaken for overtraining and the trainee is forced to take time off to recover rather than continue and reap the eventual progress. Just because you had a week or two of bad lifts does not mean you are overtrained. Unless you are a novice in training, understand that your body’s adaptation to training is a process. Just because you feel tired and haven’t hit a PR in two weeks does not mean you should chalk it up to overtraining.
The fatigue and performance decreases that accompany both overtraining (OT) and overreaching (OR) can vary. Fatigue manifests in a number of places, and different types of fatigue effect separate parts of training. Now that you are able to differentiate between OT and OR, let’s go a step further and define fatigue and its variants.
Fatigue determines the trainee’s ability to sustain effort. However, the word fatigue is redundant and when expressed without context is useless; specificity is key. The two types of fatigue in examination are Central Fatigue and Peripheral Fatigue. Their effects on training and the symptoms that accompany them are distinct.
Central fatigue is associated with the Central Nervous System (CNS) and is a decrease in performance due to the fatigue of its mechanisms. The simplest way to put it is to say that CNS helps link the brain to the muscle through synapses (nerve impulses). The synapses needed are fueled by chemicals called neurotransmitters — and the more neurotransmitters, the better. When stress on the CNS begins to accumulate, there is an impairment of nerve impulses and recruitment of motor neurons. Think of the CNS as one big network with information entering and leaving extremely fast. Generally, when something is fatigued, there is a temporary reduction of it; the CNS is no different. Everything begins to slow down and become less efficient.
Symptoms include a drop in maximal strength, joint and tendon soreness, trouble sleeping, decreased appetite, and decreased immunity. There has been evidence pointing to decreases in mood due to central fatigue and its effect on serotonin and dopamine levels. Serotonin is a chemical responsible for muscle contraction. However, it is also responsible for mood. This can be extremely difficult to assess, as the trainee may actually be suffering from low serotonin levels, or there could be a host of other issues influencing mood. Therefore, monitoring a trainee’s mood to determine central fatigue should not be the primary assessment.
Peripheral fatigue takes place at the muscle cell level. When an individual is resistance training, the CNS will attempt to fire or excite the muscle. However, if the muscle is too fatigued, it will negatively affect the excitation/contraction process and greatly lower the capability of a muscle to release its max contraction potential. Think of it as if the muscle is so fatigued that it just wants to lie on the couch rather than send and receive impulses from your CNS. Your CNS may want to send the impulses, but if peripheral fatigue is inhibiting them, you can forget about it. Peripheral fatigue can come from the accumulation or the depletion of products in the muscle. The accumulation of lactic acid, hydrogen ions, ammonia, and many other products can cause this. The accumulation of too much use of these products in the muscle fiber results in a blunting of contractions. There is also the role of depletion in peripheral fatigue where ATP, creatine, or glycogen results in contractile failure.
Lifters complaining about fatigue is nothing new, but it is important that we can recognize the forms of the fatigue an athlete is experiencing to determine if that fatigue is warranted. Both the CNS and the skeletal muscle system are linked. Without the knowledge of the symptoms of both in a fatigued state, the coach or athlete may just say “get more rest” or “eat more,” instead of diagnosing the symptoms. It is necessary for a coach or trainee to always observe and analyze performance, no matter what the task may be. The forms of fatigue and their path towards overreaching and overtraining are no exception. They must be monitored closely. If they are not, an athlete risks stagnation. However, if an intuitive approach to these forms of fatigue is taken, it will allow continual training progress.