I purposefully tried to keep the article simple as to not confuse too many people lol…You are right this is a fairly hot topic.

I like to take a balanced approach with most runners. It’s important to have the lower intensity (below threshold) training to promote aerobic metabolism improvements. Many athletes don’t spend enough time in the lower zone and can suffer during long events (let’s say ironman) because of that. At the same time if you always train slow, you’ll likely remain slow.

If you are an elite marathon runner your focus will be different as your event is only 2 to 2.5 hours in duration.

Truly the best approach is a periodized and individualized one coupled with an understanding of the physiology invovled.

That being said, would it not be most beneficial for an endurance athlete to train equally at 80-90% as well as at 70-80% intensity? Because training at a higher intensity will produce more lactic acids, this would inevitable promote a lactic acid removal adaptation. Although at such high intensity’s, the main energy system in gear is anaerobic, the goal is to increase the intensity at which you can sustain work.

In addition, consider the rate of removal of lactic acids being dependent on the vascular system, which shuttles the acids to the liver for gluconeogenesis. Because of this, heart adaptations are necessary to ensure rapid removal of lactic acid, and replacement of carbohydrate.

Training zones are always such a hot topic for debate, and I’d like to know what you think about my ideas!