This marathon plan is designed to focus on intensity and training is based on a five zone training system to prepare an athlete for a marathon. The preferred method of training is by power, followed by pace, then by heart rate, then, if no other training tools exist, RPE. The zones are as follows:

Zambrano Run Power Training Zones (based on % of threshold):
Z1 (recovery) < 82%
Z2 (endurance) 82% - 88%
Z3 (tempo) 89 - 95%
Z4 (threshold) 96% - 104%
Z5 (anaerobic) >104%

For athletes using pace, this plan uses Joe Friel's running pace zones, however zones 5a, 5b, and 5c will not be used separately in this plan.

For athletes using heart rate zones, this plan uses Andy Coggan's heart rate zones.

The RPE scale used in this plan has only five zones and is roughly equivalent to the zones listed above.

Zambrano Run RPE Training Zones:
Z1 (recovery) This is easy. You should be able to hold a conversation at this pace without breathing hard.
Z2 (endurance) This is your all day pace. Conversation becomes difficult, but not impossible.
Z3 (tempo) This is your marathon pace. Holding a conversation isn't impossible, but it is challenging to run and converse at the same time at this point.
Z4 (threshold) This is almost the top of your ability. You aren't sprinting, but conversation is impossible
Z5 (anaerobic) This is everything you have - all the gas in the tank that you can give. Intervals here don't last more than a few minutes because your muscles simply can't go much longer than that.