The minimal effective dose. What is it, and why is it important to understand?
Minimal effective dose. Ever heard of it? No? If you have a job, have a family, study, or heck even if you’re a world tour rider, a clear understanding of the minimal effective dose is crucial to maximizing your training with zero time wasted. Did you say “Yay, no junk kms”? Well maybe. To clarify, I firmly disagree with the junk kms concept. If you are riding your bike, you are getting fitter. End of story! Yes, some methods of training are more time effective than others, but if you’re riding, you’re getting fitter. Now we’ve addressed that, what is the minimal effective dose? It is the minimal dosage that is needed to elicit the desired physiological response. Simply put: The bare minimum training you need to do to get fitter. This concept is regularly ignored for a more is more approach, but is a core tenant of effective coaching.
A classic example of this is the training “zone”. Most of us with a lactate threshold of above 200W know that our prescribed training zones can vary by up to 50W between our upper and lower limit. For example, at a lactate threshold of 250W, Z2 (depending on the method you use) can be between 150W and 187W. That means that broadly speaking, you will elicit the same physiological response at 150W as you will at 187W. That’s huge. Think about that for a minute. You can get the same fitness benefits at 9% less work! Obviously nothing in sport science is concrete and the above is a rudimentary example, but you get the idea (before I get any comments about specific event power, the above is an example of a general fitness principle. Of course when it comes to event specific training, things become a bit more targeted).
The minimal effective dose is crucial for riders who have to juggle their high performance aspirations with school, work and family commitments. You don’t have 20 hours per week to train, so every minute you spend on a bike must be controlled, measured and purposeful. This is where we add some alternative methods to programming. Using HIIT training is a great way to elicit a V02max response. I won’t be going into those concepts here. Instead I refer you to the book HIIT Science by Dr Paul Laursen and Dr Martin Buchheit. Nutrition is a key piece of the puzzle in all sports. When it comes to the minimal effective dose and nutrition, carbohydrate manipulation and “train low” periods can elicit a superior oxidative adaptation while enhancing glycogen sparing when compared to aerobic zone riding only.
Another tool we have at our disposal is hypoxic training which is essentially training in a reduced O2 density environment (think altitude training). By restricting oxygen availability, we essentially provide a higher level of stress on the cardiac system than what we can achieve at sea level. While short term performance decrements are expected, the benefits once the individual returns to sea level are an enhanced power output relative to oxygen availability due to what was essentially a period of resistance training for your lungs. A less expensive and more readily available manner with which we can elicit a similar (although not identical) training adaptation to altitude training is heat training. Sometimes you’re lucky enough to live in a hot climate for several months per year. Others may need to find ways to elicit this heat stress via mechanical means (heat chamber, household heater, intentionally overdressing on rides).
Whether it’s carbohydrate timing / restriction, HIIT types, hypoxic or heat training, all have impacts on the body’s adaptation to external stress due to an increased demand for mitochondrial adaptation via the PGC1ɑ - AMPK cell signalling pathways. They provide examples of ways in which a minimal dosage of a stimulus can be an effective tool to enhance performance. The timing of these stressors relative to your season goals is crucial, and you should only ever attempt them under supervision of a well trained and knowledgeable coach.
As a coach I too often hear from athletes “You want to get faster, ride more kms!” While it is true that riding more kms will likely increase your fitness, we all have a natural ceiling to what we can handle, as well as a ceiling to what our life commitments allow us to commit to and therefore, I believe this approach to be flawed. Perhaps it should be changed to “You want to get faster, make the most of your kms!” The minimal effective dose is a key to this as using this principle via training zones, HIIT, nutrient timing and environmental stressors can all enhance your aerobic capacity on the bike. Creating a champion isn’t a one piece puzzle but is more like a 1,000 piece puzzle. Every piece counts. Thinking outside the box, having the discipline to train consistently every day and having the mental focus to avoid going “off script” all play a key role in this minimal effective dose puzzle.