On the first day of track practice, a ninth-grader named Ryan, shows up to join the team. Ryan wants to be a middle distance runner, maybe run the mile for his school. Ryan admits to having not run much in his life, but he wants to start today. The middle distance coach sends Ryan out for a 3-mile run around the lake by the school. The coach starts a stopwatch as Ryan leaves, and after a while he comes chugging back in a time of 24:00. Ryan has a very red face, he is breathing hard, and after stopping he immediately bends at the waist to recover. It takes him 10 or 15 minutes to rebound from the effort. He happily tells his coach that he did not stop once on the run. This is Ryan’s first day of track. Today we will focus on training aerobic capacity.
Exactly two months later Ryan shows up for practice, he has adjusted very well to the team, loves his coach, and has trained hard. Ryan’s workout this day is to run around the same lake as he did on his very first practice and is instructed to do the 3-mile run in precisely 24:00 as he did the first day.
Ryan starts his stopwatch and begins running. He does as he is told and returns in 24:00. Ryan is not red-faced, tired, or even breathing that hard from the effort like he was the first day. What has happened?
The answer lies in the biological processes that have occurred during two months of middle-distance practice. Ryan has dramatically increased his aerobic capacity.
A well-developed aerobic capacity system is an important trait for distance runners. Basically, it is how far you can run. On the first day, Ryan could barely complete three miles without stopping, but after two months of training, he could run at least 10 miles. It was not will-power that changed that, it was a biological adaptation to training stimuli.
* Coaching Resource: The Mile: Successful Coaching Strategies
Developing aerobic capacity is a systematic series of adaptations to the body’s cardiovascular, muscular, and metabolic infra-structure brought on by training stimuli. These adaptations include left ventricle volume of the heart increase, blood volume increase, red blood cell proliferation in the blood increase, capillary numbers in working muscle increase, myosin cross-sectional size increase, mitochondria numbers increase, mitochondria size increase, aerobic enzyme quantity increase, inter-muscular glycogen storage sites increase, and some myoglobin increase in volume.
All of these “increases” improve the ability to use oxygen more effectively at both sub-maximal race pace and race pace itself. The aerobic system can now carry a bigger load at faster paces which is crucial to racing success. The runner can now run further which also develops durability in the athlete and improves the strength of muscular contraction. The primary stimulus is the duration of the run, not the speed of the run.
As Ryan found during his first season on the team, all forms of distance running improve aerobic capacity. There were no junk miles for Ryan. But, eventually, Ryan will reach a point where three and four-mile runs do not produce a strong enough training stimulus to develop these aerobic capacity traits further. Ryan will either have to increase his weekly training volume for a stronger stimulus, or just increase volume on certain days of training such as the long run.
However, that may still not be enough stimulus to make Ryan faster in a shorter race like the mile run. A more likely training scenario at this time is to keep aerobic capacity work high, but also bring in work that concentrates on aerobic power. While aerobic capacity work is directed toward the ability to extend farther and farther the limits of one’s running distance, aerobic power is about getting faster at a selected sub-distance of running capacity.
Capacity has no time component, only volume. Power has a time component to go along with volume.
Think about filling a glass with water to as full as possible. The process is slow but can be done without spilling. This is analogous to aerobic capacity work. Now think about filling a glass ¾ full of water as quickly as possible without spilling. You can definitely do that faster than filling it to the brim. With exact practice you can get very good at filling to that sub-level as quickly as possible. This is analogous to aerobic power work.
In young runners, there have to be the beginnings of aerobic capacity development before aerobic power work can even be considered. But, in runners that are a little more experienced, aerobic capacity and aerobic power can be worked on concurrently. However, because of the nature of the stimulus, a training plan should have many more aerobic capacity days than aerobic power days.
Remember Ryan for a moment, all of his aerobic capacity training allowed him to run further and further more comfortably as the season progressed. But, that 3-mile run he struggled with to complete in 24:00 on his first day, he can run in 18:00 after three months of training. His aerobic power has improved as well as his aerobic capacity with specific workouts.
Is running capacity event-specific? The answer here is a definite yes. The marathon has a much greater need for extensive aerobic capacity development than the 800 meters does. Marathoners have to have the ability to run beyond race distance, while 800 meter runners probably need an aerobic capacity to carry them just 4-5 miles. Even on a high school team, a 3200 meter runner needs far more aerobic capacity than an 800 meter runner needs.
* Additional Teaching Resource: The Training Model for High School Middle Distance
Aerobic capacity is best developed through frequent stimuli of continuous runs. These runs should vary in length throughout a training week with the greatest emphasis on the long run which should equal 20% of their weekly mileage. A runner who completes 50 miles of training in a week should have 20% (10 miles) of it done as one continuous long run.
However, an 800 meter runner can unfollow some of this training advice. A 400 meter runner moving up to the 800 meters may not be able to do a 5-mile training run. A savvy coach will not put this athlete through that type of work, more likely doing 8 x 1000 meter repeats with a 45-second recovery interval between. It would add up to the same distance.
Aerobic capacity is a foundational piece of middle distance runners training. Always consider the preferred racing event, age of athlete, and experience of the athlete in designing aerobic capacity workouts.