From different websites, training books and articles I found out that the concept has many definitions and it can represent something different to many coaches. Some people refer to it as a period to develop and improve one’s body ability to oxidize stored fat for fuel and they recommend limiting our training intensity to a specific training zone. They also advice using specific methods to determine that limit (like the Mafettone or MAF formula) (1). Others refer to it as a training period to mainly focus on developing our aerobic energy system via low intensity training.
Others refer to it as a training period ideal to enhance our endurance through the Aerobic Threshold aka as AeT. And yet others refer to it as the first training cycle with a simple training load to better prepare the athlete to handle greater training loads down the road. Although high intensity sessions are not avoided, they are limited to a certain extent. This approach seek to address most aspects of endurance performance most of the time, the only variation is to what extent (volume vs. intensity).
Before attempting to define this mysterious base concept, I think it is important to start by explaining the periodization concept and how it is typical applied for triathlon training. Periodization as it is presented by some books and used by coaches based on Tudor Bompa's Periodization Training book (2) is not necessarily accurate.
You can refer to my "What's Periodization" article to learn in detail about this concept often misunderstood, but in short periodization refers to the combination of general and specific preparation or training and for optimal performance on any sport the progression in training load should be planned from general need to specific needs. This mean, when we follow periodization, we will structure our season training plan starting with general training, that is all the training that will enhance the general fitness needs for an athlete and as the plan progresses over time the training will become more and more specific to the particular demands of our goal race and our specific fitness needs to maximize performance.
The main objective to follow periodization is, for the coach or athlete to make better choices about the type of training that needs to be accomplished to achieve peak performance for the main event. The structure of periodization can be as simple or complex as needed. Beyond setting the plan from general to specific training, there are no set norms for its distribution. In the end, a coach/athlete has to consider the individual's current fitness level, specific needs, weaknesses/strengths, specialization level need to accomplish his/her goals, time available for training, time until main event, etc.
Based on the above concept it seems that base training could relate to the general preparation phase of an athlete; although the specific focus remains unclear. Considering some of the popular definitions, let’s look at each of them to find out if one makes more sense or if we can standardize one from all.
First we have: “base training is the period to develop and improve one’s body ability to burn stored fat for fuel and they recommend limiting our training intensity to a specific training zone. They also advice using the MAF formula as the method to determine that limit” – This sound like a plausible definition however there is a problem; Fft oxidation occurs at different intensities hence it is not limited to a specific pace/power. It is true that we will burn more carbohydrates (CHO) for fuel as the intensity increases but the point in which we are basically burning around the same percentage of CHO and fats will vary from athlete to athlete.
Though roughly, there is a correlation that it occurs around our lactate threshold defined as the increase of 1 mmol/liter over the athlete’s exercise baseline. Also fat oxidation is dependent on many variables such as intensity/pace, duration/distance, fitness level, diet after training, long term and short term diet, genetics, and environment (3) and will vary depending on the method applied to gauge intensity (% of MHR, % of VO2, % of LT) which indicates that the optimal fat oxidation pace/intensity will vary from individual to individual and a general formula to set up training intensity might not be optimal.
Furthermore on the scientific training for triathletes, Dr. P. Skiba cites that one of the benefits of training at different intensities specifically at your lactate threshold is that it will reduce your body’s production of lactate at a given workload (4) and this will result in your body's ability to increase production of certain enzymes in your muscles, which allows a shift in your fuel balance to use more fat and less glycogen (5). Knowing this I can’t help to question: a) how can we trust a general formula to determine training intensity in order to optimize fat oxidation when this is affected by many variables and b) why are we limiting training at different intensities since we can optimize fat oxidation through different training zones depending on the athlete fitness?
Let's look at the second definition: “base training is the period to mainly focus on developing our aerobic energy system via low intensity training” this sounds like good definition, right? Not really. All triathlon distances almost exclusively relies on our aerobic energy system to fuel our training and races. Even when performing sessions at lactate threshold or VO2Max power/pace, the muscle fibers doing most of the work are type I (slow twitch) which rely on the aerobic system, although type IIa (fat oxidative) and IIx (fast twitch) get recruited as the intensity increases or the Type I get fatigued. In other words you’ll be training your aerobic system whether going easy or hard as long as the efforts are two minutes or longer.
For the third we have: “base training is the period ideal to work on endurance by training the Aerobic Threshold aka AeT” as I mentioned on the paragraph above there are good benefits of training our endurance pace/power, hence this definition sounds good right? Not really; the term AeT utilized by some coaches is nothing more than a coined term. This term is not a physiological term and it just doesn’t exit! Knowing that then, what are we exactly training at AeT?!
It seems Dr. John Hellemans a sports medicine practitioner and coach from New Zealand started using it in order to estimate your lactate threshold via a field test using a heart rate monitor and relate it to 6 training zones he suggests. The problem is that there is already physiological term (Lactate Threshold), hence there is no need to add a non-existent one and create confusion among coaches/athletes.
This brings up an important point; we should strive to use of proper terminology because it would help us understand what we are talking about and allows us to compare one concept or approach vs another. I can see why we all get confused when talking training concepts. But it is not terrible surprising that we face these challenges when coaches, books, magazines and even governing bodies spread around this misinformation and made up terms portraying them as scientific terms.
Let's review the last definition is: “base training refers to the training preparation during the general phase at varying training loads to better prepare athletes to handle greater training loads as the plan progresses. Although high intensity sessions are not avoided, they are limited to certain extent” This definition sounds simple and to the point. It is common for coaches to suggest beginning the general preparation phase with a simple training load to prepare the athlete for future phases with higher training loads.
Jack Daniels follows this approach on his Running Formula (6) through this phase the bulk of the load is performed at lower intensities but some sessions include intervals of higher intensity training although the length and intensity type will depend on the athlete’s fitness level. After this period is completed, the athlete can then focus on other training adaptations and progress from general to specific needs training. Personally I believe this definition makes the most sense because it considers the athlete's needs and defines the focus.
So now what do we use? It is obvious the term base training have a different meanings depending on who you ask; while some coaches advocate the emphasis on developing our endurance by limiting our training load at lower intensities, others suggest performing simple training load but training intensity is not necessarily limited. I personally believe it is not a good idea to generalize base training as a phase devoted to only x or y training.
I think the base phase will and should be different for every athlete depending on their goals, needs and fitness level. The emphasis made that we should not train above certain baseline during this phase has no real physiological reason and it is not applicable for all athletes. While that approach might benefit untrained individuals it very well could limit training gains for trained ones. It is also true that low intensity/high volume can produce great results but the caveat is that athletes need to have the time available and resistance to train a lot of hours. Hence this approach won't work for those with limited time or injury prone.
Those athletes limited in time or injury prone need to manage the training load in a different way and address their needs (i.e. muscle imbalances). Of course this doesn't give athletes with limited training time a free pass to go crazy with high intensity, what it means is that with proper planning and added intensity in a controlled manner, athletes can enhance their fitness gains by training at different loads (short, easy, long, hard sessions) through different phases, and considering periodization how much and when will depend on the athlete's main event.
After all, training at different intensities (pace/power) will produce important training adaptations: from inducing recovery without actually resting, promoting the improvement of Type I fiber fatigue resistance, developing our capacity to store glycogen and the more storage we have the more we could race at or near this intensity, promote interconversion of fast twitch muscle fibers (type IIb -> type IIa), maximizing metabolic fitness of muscles and our cardiac fitness. (7)
In summary, I think it is safe to conclude that base training is nothing more than a coined concept used by different coaches, books and websites without a standard definition. I believe athletes and coaches will be better served by forgetting about this base training “concept” and instead use common sense defining their individual needs and goals, set up a simple general to specific plan address specific needs based on weaknesses, goals (race distance) and current fitness level.
1. Dr. Philip Mafettone. The Maffetone Method. McGrawHill. 1999
2. Tudor Bompa, Human Kineticz, 2005. Periodization Training
3. Alfred F. Morris. Burning Fat During Long-term Running. AMAA Journal. http://findarticles.com/p/articles/mi_m0NHG/is_1_20/ai_n19187412/pg_1
4 . Wilmore JH and David L. Costill. Physiology of Sport and Exercise. Human Kinetics, IL, 1999.
5. Philip F. Skiba. Scientific Training for Triathletes.
6. Daniels Running Formula by Jack Daniels, 2005, 2nd Edition.
7. Andrew Coggan. Power Training Levels. Cycling Peaks. http://www.cyclingpeakssoftware.com/power411/levels.asp