It’s interesting that Joel is training some of the best triathletes on the planet and he keeps things simpler than most of us age-groupers. There’s definitely a lesson in there 
From memory of one of your older podcasts isn’t this a similar approach used by Arild Tveiten with the Norweigan triathletes?
Absolutely. Matt Dixon talks about this in “The Well-Built Triathlete”:
The classic way of setting up training progression is to do three weeks in a row of hard training, or progressively harder training week over week, followed by one week of recovery. This program of training hard, then recovering for an entire week makes it easy for coaches to build training plans and allows athletes to easily identify each week of training as a “build week” or a “recovery week.” When it is put into practice, the athlete completes too much training with accumulated fatigue, and other training opportunity is wasted by overrecovery. Not only does this formula absolutely fail to achieve my magic word of training success, “consistency,” but also I believe it contributes to a higher risk of injury. In addition, it does not take into account an athlete’s resiliency or speed of recovery, let alone how that athlete absorbs workload.
Table 10.1 considers a typical scenario by breaking down a cycle of three weeks on, one week off…
In Week 1, following a prior week of recovery, the athlete is fresh and demolishes training sessions with gusto. An effective training week.
In Week 2, the athlete is still able to absorb and manage the workload; the progressive sessions are challenging, but the training week remains effective. Fatigue accumulates, as by the end of the week the athlete is likely 14 days into an overall build (not all days are high load).
In Week 3, the biggest training-load week is under way, but many of the training sessions are completed with massive fatigue, not with optimal performance. The athlete is hanging on, desperate for the upcoming rest but determined to finish the block. There is little emotional capacity to focus on form, and aches and pains creep in from the accumulation of fatigue. Training becomes ineffective.
In Week 4, the athlete is so physically and emotionally spent that they fall into the recovery week with delight, often wanting to escape the torture of that last daunting week. The athlete bounces back and feels fresh after three to four days but keeps recovering for the full week to ensure readiness for the next three-week cycle. An entire week of desperate recovery results in ineffective training.
And so the cycle continues, with about half of the total training opportunity providing effective training. The other half is marked by the great peaks and valleys of fatigue that limit triathlon performance. Our mission is to find rhythm and consistency. While you should accumulate fatigue, and you will endure days (or even blocks of days) of feeling tired, the highs and lows created by this approach are what we want to avoid.
There are multiple routes to performance, but I suggest that you abandon this outdated approach and get in front of the fatigue with regular short breaks for recuperation and recovery. These minibreaks can be one to four days of recuperation—just enough to prevent the accumulation of too much fatigue, which leaves the athlete desperate for recovery and devalues training for several days in a row. Because our mind-set is all about achieving long-term consistency and accumulating as much effective training as possible over an extended period, properly integrated minirecovery is critical.