This "Polarized Endurance Distance Triathlon Training" plan is based on the healthy training concepts that Ben Greenfield teaches in his book "Beyond Training" and also in the article at http://www.bengreenfieldfitness.com/2013/03/best-ways-to-build-endurance/

It relies on the 80/20 principle, Maffetone style training, and an emphasis on high quality aerobic efficiency and economy to allow for optimum endurance building and Iron distance triathlon preparation without doing lasting damage to the body.

This 24 week (6 month) plan is perfect if you are a beginner to advanced triathlete who has ample amounts of time to train (15-30 hours per week), would rather focus on long distance training rather than high intensity intervals, and also want to ensure you stay completely healthy in the process of pursuing your endurance goals.