Polarized Endurance Training (PET) for Cardiovascular Endurance Optimization

Reviewing traditional endurance training models show that there are frequently three different types of models employed: 1) threshold/race pace (5K+), 2) high-volume/low-intensity, 3) high-intensity interval training. Threshold training is characterized by increasing intensity to a “hard” pace (rating of perceived exertion [RPE] of 15 – 16 on 6 – 20 Borg scale, or about 75 – 80% VO2max) and maintaining this pace for the duration of the workout while progressively increasing the pace each week in a linear periodization model (5). High-volume training is characterized by long workouts at a very light intensity (RPE of 9 – 10 on 6 – 20 Borg scale, or about 45 – 50% VO2max). High-intensity interval training is characterized by interval workouts at a “very hard” (RPE of 18 on 6 – 20 Borg scale, or at ≥ 90% VO2max) pace often on consecutive days with little to no long slow distance workouts and recovery (5).

An emerging cardiovascular endurance training model is Polarized Endurance Training (PET), a training regimen characterized by an undulating non-linear periodization model where the majority of training time is spent in long slow distance workouts. The PET model includes specific high-intensity workouts separated by one or more long slow distance workouts, with the exercise intensity tightly controlled. This dichotomous two-zone training model rewards maximal effort with optimal recovery. PET workouts are performed by exercising at a “light” (zone 1) intensity, interspersed with high-intensity interval workouts, with intervals at “very hard” pace (zone 3) with 2 – 4 min of rest. PET is most often characterized and optimized by little to no training at “hard” or race pace (zone 2) in any of the workouts (2,11,15). There is a growing body of scientific evidence supporting the use of PETs in performance enhancement and injury reduction compared to the three other mentioned traditional endurance training models (5).

This article originally appeared in TSAC Report, the NSCA’s quarterly, online-only publication geared toward the training of tactical athletes, operators, and facilitators. It provides research-based articles, performance drills, and conditioning techniques for operational, tactical athletes. The TSAC Report is only available for NSCA Members. Read more articles from TSAC Report