The Ultimate Guide to Double Threshold Training for Endurance Athletes

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About the author

Nathan Pennington

Dr. Nathan Pennington, DBA is a 2:19 marathoner, former member of the US Army World Class Athlete Program (WCAP) and founded the rundreamachieve.com blog in 2011.

Coach Pennington also has been helping beginner to advanced level runners weekly since 2019 at the RunDreamAchieve YouTube channel. He shares his over 30 years of running experiences to help runners meet and surpass their training and racing goals.