Polarized Training

This was a concept introduced to me from Joe Friel’s training blog over the last year, and substantiated with a number of other resources (see below). I decided to dig into the literature and attempt to follow the protocol myself. A teammate is currently following a similar plan and apparently seeing some great results

Yeah, doesn’t look pleasant

Polarized Training (POL) refers to specific training with 10-15% volume (by time) done at high intensity (above anaerobic threshold; ≥FTP, Z4 or Z5 if using Sweet Spot) and the remaining 75-80% volume done at low intensity (below aerobic threshold; ≤Z2). This training protocol has shown to produce great improvements to endurance performance metrics, including VO2max, 40km TT time, and time to exhaustion testing.

Polarized training protocol basically quantifies the ongoing trend in modern training methodology away from long slow distance (traditional base training) toward high intensity interval training (HIIT).

Another blog post from a few years ago delved into the topic and suggested some training protocol for imitating the studies that demonstrated the greatest fitness improvements. What Bicycling Magazine called The Ultimate Interval.

These involved self-testing of Peak Power Output (PPO) and Time To Exhaustion (T-max) to determine relative intensity at which the intervals should be performed. These guidelines are highly specific and effective, but require either a power meter, a power-based trainer (eg. Kickr) or using something like TrainerRoad’s Virtual Power (which I highly recommend as a first step to specific training).


Quick disclaimer. Don’t do this as your first training program. It’s not easy, it’s not fun and you can potentially do more damage to your body than any benefits. Read the Limitation section below. That said, It’s an impressive looking protocol that I’m looking forward to trying!

  • Set up your indoor trainer with TrainerRoad’s Virtual Power, or even better – an actual power meter.
    • Note: this doesn’t follow TrainerRoad’s typical training protocol – which is something for a future post – but I would recommend doing a 20-min or 8-min FTP test to set proper training zones and as a benchmark for comparing fitness before and after the training protocol
  • Test 20-min or 8-min FTP to determine training zones
  • Test Peak Power Output (PPO) after a rest day
    • 10 min warm-up at 100 W
    • Stage 1 begins at 100 W for 1 minute
    • Increase by 30 W every 1 minute
    • Test is complete at volitional exhaustion or failure to maintain >60 rpm
    • Record your last fully complete interval* as your PPO
      • *This is debated; some protocol use the highest final stage  power regardless of completion. It’s the first of many fudge-factors that will come down to subjective assessment)
  • Test Time To Exhaustion (T-max) after a rest day
    • 10 min warm-up at 100 W or as otherwise prescribed*
      • * I like TrainerRoad’s 10-minute ramped warm-up used for their 20-min FTP test.
    • Set power to PPO and hold on as long as you can!
    • Test is complete at volitional exhaustion or failure to maintain >60 rpm
    • T-max is usually between 4 to 6 minutes
  • Bicycling Magazine calls this the Ultimate Interval, based on established research methodology
    • 2 HIIT intervals per week
    • 8 intervals per session
    • Interval length = 0.6 * T-max
    • Power = PPO
    • Rest Interval (RI) = 1:2 Recovery-to-work
  • Other sessions (remaining ~75% volume) should be at Zone 2 or below.
    • Assuming 60 min Ultimate Interval workouts, this would be an additional 10-11 hrs @ ≤Z2
  • One of the more recent studies has the following weekly protocol:
    • 2x 60 min HIIT interval sessions
    • 2x 2.5-4 hr low (aerobic; ≤Z2) sessions
    • 2x 90 min low sessions
    • 1 day recovery
Stoggle & Sperlich, 2014

The first week of the protocol is basically testing, allowing sufficient recovery between tests, and the actual training methdology begins in the second week. It can be used as a 4- or 5-week mesocycle, with the final week being recovery. I will be using this methodology for my last Base cycle after following a modified version of TrainerRoad’s Sweet Spot Base plan.


    • Studies haven’t controlled for total workload between training conditions. Most studies have used HR and not Power to set training zones. Studying training response using specific power-based zones would be more reliable.
    • Specific training protocol requires power. Can be done based on RPE & HR, but I believe these metrics aren’t reliable enough to ensure desired training adaptations.
    • Study participants have been well trained cyclists with VO2max typically above 60 mL·min−1·kg−1 and accustomed to 10+ hrs training per week. Joe Friel suggests that less experienced cyclists may continue to reap benefits from more traditional high volume, low intensity base training:

[A] novice or intermediate athlete may find just the opposite – great improvement in physiology and performance by training with high volume and low intensity. In fact, training as the POL or, especially, the HIIT groups did may soon result in injury or overtraining. These methods are best used by advanced athletes (greater than 3 years in the sport).”

Joe Friel


I would agree that for cyclists with a shorter history of specific training there are still benefits to starting the periodized training cycle with lower intensities than the physiologically stressful Zone 4+ work found in POL training. This might not be 100% long slow distance, but could/should incorporate Sweet Spot Base training, as recommended by TrainerRoad. This keeps you well below threshold but will still give you the physiological adaptations of interval training.

I would suggest POL can be introduced as a transitional protocol as one approaches Build phase of the training cycle. The evidence is promising, but hardly conclusive that the methodology outlined above is the perfect (or ultimate) training protocol for every athlete. The most important n is n=1; that is to say, your own individual response to any training protocol will determine your ultimate training protocol.