By Nenad Rodic,
posted 04/05



     The term adaptation refers to changes the body goes through in response to training. This happens when organs and tissues operate on a higher level than usual. Some changes take only few days to occur while some like increase in enzyme activity or number of mitochondria can take up to 6-8 weeks. Improvements in physiological functions may continue to occur for up to four years. Every adaptation process needs to include these steps:

-Create the need for adaptation with proper training.
-Provide enough nutrients for growth and repair of tissues.
-Provide enough rest for growth and repair to occur.
Each mezzo-cycle in season planning deals with a specific adaptation, and as we mentioned earlier some adaptations take longer time to occur than others, hence the difference in length of cycles. In a sport like triathlon all cycles have certain adaptations in common (increase of aerobic capacities).


     Adaptations will not occur if the demands of training are not higher than normal demands on a certain physiological mechanism.


     Systems will go through overload only until they adapt to the training volume. In order to increase performance and have new adaptations take place, volume and/or intensity need to increase at that time. The systematic process of increase of overload is called progression principle.

     This can be done in three ways:
-By increasing intensity overload can be achieved especially when training anaerobic systems.
-By increasing the training volume. This is definitely the most interesting way of applying the overload principle to our training. This is the least stressful method and also the best way to increase aerobic abilities. This method of producing the overload is preferable as long as you have time to spend training. If you are training for an ultra distance race (Ironman) this is the only way to do it.
-By increasing the training density. This method entails the gradual reduction of rest between repeats which causes athletes to train closer to their race speed and tends to favor aerobic development and limit the anaerobic systems engagement during practice. This is the most effective way to become a faster swimmer.


Physiological adaptations will occur only in the specific tissues and organs stressed during specific training.

     Four aspects of specificity need to be noted:
-The activity the athlete is training for: For example, cycling has very limited effects on your swimming performance and vice-versa. Training specific sport is the best way to improve in it.
-Specific movements. The most obvious example is time-trialing in cycling. By training in specific time-trial position the athlete benefits more than when training in a position that is not the race position. Though, there is a carryover from one position to the other, some fibers are not properly stressed when not in the race position.
-Competition speed. Speed specific training will not only train all muscles and energy systems needed for a race performance but will also train your mind. It is necessary to experience in training what race speed feels like and learn to deal with mental issues this type of effort poses.
-Training a specific energy system. Specific energy systems need to be targeted and developed properly at certain times in the season (refer to our season planning page). This needs to be done in specific order since some energy system training are antagonistic with others.


     How an athlete responds to training will depend on athlete’s state of conditioning and his/her genetic makeup. It is a known fact that athletes who are poorly conditioned progress rapidly while those who are well conditioned need much more training to make any progress. It is important not to do more than necessary to insure progress. Genetic makeup plays crucial role in determining how much training can increase the physiological functions of the athlete. This means that some people will have to work much on certain aspects of their athletic development while others will have to train much more. It is up to you and your coach to spot your weaknesses and devise appropriate training regimen to minimize them. Be realistic about your potential. Some people are just better at certain things and wishing to be as good will not help. Just by looking at the Olympic final in 10000 m it is obvious that people from eastern African plains (Kenya, Ethiopia …) have a huge advantage in this event. Their light built, amazing aerobic capacities (high elevation region), and centuries of genetic selection favoring faster runners made them into an unbeatable running force. We all have genetic limitations and our goal as athletes should be to reach them or get as close to them as possible.


     Lack of training leads to reversal of adaptations and the decline in performance. Studies show that only three weeks of no training resulted 25-30% decline in endurance performance. In only one week of no training and endurance athlete can loose up to 50% of additional mitochondria produced during five weeks of training.
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     What is the optimal training duration and frequency? This is not a simple question to answer. How long you need to train depends on many factors. The goal is always to improve in some physiological aspect. Having that in mind the duration of practice and intensity will vary. If you are training for a long race for example and you are in the peak phase, it is natural to train many hours 6-10 a day, which will allow you to train only once a day. If, on the other hand you’re in taper for a short race it is likely that you’ll train three times a day with sessions no longer than 90 minutes. It is up to your coach to determine the proper duration and frequency of training for each mezzo-cycle (refer to season planning page).


     Similar to duration/frequency dilemma, intensity/distance question depends on the specific needs of the athlete as well as the training phase (mezzo-cycle) the athlete is in. While higher intensity training (above anaerobic threshold) can bring results quicker, it is possible that this type of training can have opposite effects of those desired, and in fact lower the aerobic abilities. Generally, long distance racing will require more distance and shorter races more intensity. Duration and intensity are complex issues that you definitely need to consult about with your coach.
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By Nenad Rodic, founder of