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Coaches Blog

Balancing the Components of Aerobic Capacity

One of the most essential aspects of training success is aerobic capacity or VO2 Max. It is well known that the two most influential factors in improving VO2 Max are Intensity and Duration.

All of the above is well-known knowledge. The part that is more art than science is finding the correct balance in the training plan.

Here are 5 factors that I consider when customizing a plan.

1. Race Distance: The race distance will determine whether training is favored more towards duration or intensity. In most cases, longer distances will lean on longer duration sessions and intervals.

2. Experience and Base: If the athlete is new and doesn't have a large base of training behind them, then I would always lean on the lower intensity, longer duration training to increase the aerobic base before increasing the intensity.

If the athlete has a large base, then more emphasis on increasing intensity is preferred. The more experienced and /or elite the athlete is, the more the intensity and duration will need to be micro-adjusted to maximize gains.

3. Training Time: The amount of time the athlete has available will determine duration and intensity. If an athlete has a relatively flexible schedule and few life commitments, then there is more freedom to adjust duration and intensity as you wish.

One thing to be careful of is thinking you need to give an athlete with limited time a bunch of higher-intensity training to make up for the lack of time they have available for training. This can lead to injury very quickly.

4. Period of Training: The location in the "training" year plays a role in structuring the training program. Years ago, all the talk was on periodization into 3-4 blocks throughout the year as the main way to structure a program. Now, multiple cycles of training blocks are viewed as optimal.

5. Response to Training: Some athletes respond better to a program that favors duration over intensity and vice versa. You often won't know the answer to this until you start training an athlete; even then, it may take a while to figure out the best combination to maximize gains.

Determining how an athlete responds to training is a higher-level skill, and the more experienced the athlete, the more difficult it can be to assess the athlete's response at a micro level.

The above factors are just a few of a multitude. Training is not cookie-cutter, nor is it always straightforward. It is an art that requires a combination of many components, customization based on the athlete, touch-ups, and sometimes even starting all over from scratch.


Aaron Scheidies is a USAT Level 1 Certified Coach and licensed Physical Therapist. A graduate of Michigan State University with a degree in Exercise Physiology, Aaron has coached World Champion Paratriathletes as well as Ironman World Championship qualifiers. Aaron is an 11-time World Paratriatlhon Champion and has set the World’s fastest time for anyone with a disability at both the Olympic (1:57:24) and Ironman 70.3 distances. (4:09:54).


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