Every Zoned workout rests on decades of sports science research.
All workouts in Zoned are based on established sports science. The intensity zones are not arbitrary: they correspond to real physiological thresholds that can be measured in a lab or estimated from field tests.
Our 6-zone model is derived from key physiological markers: the first ventilatory threshold (VT1), the second ventilatory threshold (VT2, also called the lactate turn point), and maximal oxygen uptake (VO2max). These thresholds define distinct metabolic states that require specific training stimuli.
"Quantifying training intensity distribution in elite endurance athletes" (2006, Scand J Med Sci Sports)
View publication"Intermittent runs at vVO2max" (1999)
View publicationBook: "Daniels' Running Formula"
Pioneer of the base-building approach
Book: "Lore of Running"
Foundational work on lactate metabolism
"Lactate Threshold Concepts" (Sports Med, 2009)
View publicationResearch on metabolic health and mitochondria
Quantifying training intensity distribution in elite endurance athletes
Seiler & Kjerland · Scand J Med Sci Sports 16(1):49-56
View studyInterval training at VO2max: effects on aerobic performance
Billat et al. · Med Sci Sports Exerc
View studyIntermittent runs at vVO2max enables longer time at VO2max
Billat et al. · Eur J Appl Physiol
View studyThe significance of the aerobic-anaerobic transition for training
Kindermann et al. · Dtsch Z Sportmed
Detecting the threshold of anaerobic metabolism
Wasserman & McIlroy · Am J Cardiol