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Are you consistently getting faster, stronger and hitting your performance goals? There has been some excellent research conducted on various types of athletes which indicates that “polarized” training plans can have an enormous impact. Marathoners and swimmers who train exclusively using high volume (low effort long runs / swims) have not shown significant improvements in sprinting velocity or endurance. Training over 2 hours a day has been found to not only reduce performance, but to put the athlete at risk for overtraining syndrome leading to illness due to strain, monotony and load. The concept behind a polarized training program is to mix high intensity interval training (HIIT) for short durations and low intensity high volume workouts throughout the week with recovery days.

The above chart from a 2014 polarized training study compared four different training programs.

  1. (A) high volume low intensity (HVT)
  2. (B) lactate threshold (THR)
  3. (C) polarized (POL)
  4. (D) primarily (HIIT)

The results were clear that over the three week period group the polarized group showed massive gains while the other groups were not as significant. This is a difficult concept to except that leisurely back to back runs for up to two hours paired with high intensity on the third day can cause significant performance gains. These athletes were never training at “normal” levels rather they had very slow low effort days and super brief high intensity minutes. Here is what the gains looked like:

  • VO2Peak : +11.7%
  • Time to Exhaustion : +17.4%
  • Peak Velocity / Power : +5.1%
  • HIIT : +5.6%

Getting more specific when we talk about low intensity in this case we are talking about < 80% of peak heart rate. When we talk about high intensity days these are intense workloads > 90% peak heart rate. This leaves a gap or what is known as “the black hole” between 80% – 90% of peak heart rate. The polarization study is suggesting from its results that we should avoid drifting into the black hole. Slow training days need to stay at low effort and be longer while high intensity training needs to be extremely focused and brief. Never the two shall mix.


Competitive endurance athletes should schedule their training sessions at a ratio of 80% low intensity to 20% high intensity. Training at a moderate intensity in the black hole zone of 80% – 90% of peak heart rate has been strongly correlated with worse performance.