Since adopting the 21 Day Training Cycle in late July, I’ve made some adjustments.
First of all, it makes more sense to not run or aerobically train on the strength training day. The swolework is already fairly challenging, and my body has lately responded better to an easy day of strength training with no running/cardio every three days than it has from running or cardio every day.
Secondly, continuing my research on training monotony, I’ve noticed that monotony scores are helped by not having any other training on the strength days. Monotony has gone up as I’ve gotten back to regular training, and it indicates that aerobically training everyday would probably be unsustainable. With every three days being only strength training, the monotony stays closer to normal.
This also indicates it may be sensible to make an otherwise do-able 2nd day run shorter, in order to vary that week’s training stress and reduce overall training monotony.
Conversely, it’s often a good idea to make the 3rd day workout longer, or add a 2nd cardio session elsewhere in that 3rd day, to increase the variance between days and reduce overall monotony.
Thirdly, it’s important to differentiate the training stress between the 2nd easy/moderate day, and the 3rd harder/longer day. While I could do a 45 minute run the 2nd day and a 60 minute run the 3rd day into perpetuity, this would also create high monotony long-term. The runs on their own, maybe not, but the stimulus of the strength training on the 1st day combines to create too even of a stimulus.
This also means I need to take it easy with walking or extra running during work breaks. Walks, however easy they are, do produce a non-zero amount of training stress. These can further even out the week’s training stress and increase training monotony.
However, if I decided on that 3rd day to incorporate extra walking or cross training to add to that day’s training stress, that helps bring the training monotony closer to normal. So there are some days where I need to avoid any other activity, but others where it can be overall beneficial (within reason) to do extra stuff on the side, a spin bike session, an extra walk during a work break, etc.
Fourth, within reason, the length of the long runs can effectively eliminate problems with the week’s training monotony on its own. Thus it’s important that either the long run in a given week be suitably long to get the overall monotony below the 1.50 threshold, or to shorten other workouts in a given week to get the monotony below it. If increasing overall training volume is important, then it becomes important to make the long run suitably long in kind.
I used to be a proponent of regular, frequent 90 minute workouts if you can’t run long. But now I see it’s better statistically, if not in practice, to build a varied schedule around regular long runs that total 35-40% of the week’s training volume. This long run length I have found is the sweet spot to minimize training monotony.
Finally, on a separate note, I’ve also been researching Workload Ratio, which is the daily training stress average over 7 days divided by the daily average over 42 days. This should not exceed 1.50 either, and in fact the recommendation typically is to keep it between 0.80 and 1.30.
I’ve recently began tracking Workload Ratio for my Estimated Mileage (EM) on my Performance Log, using conditional formatting to turn a day’s workload ratio orange when it goes over 1.30 and red when it goes over 1.50.
Bear in mind as well that while I’ve based on Monotony research on TRIMP scores from Runalyze, here I’m basing the Workload Ratio on EM. This for now makes it easier from a planning perspective on my Performance Log. Roughly, the end result should be close enough to the same as using TRIMP.
I won’t delve too far into past Workload Ratio results for now, though seeing past ratios proved somewhat telling where I was overtraining and matched up with training breaks I had to take.
However, I’ve used it with planning ahead as it’s helped with determining how to increase mileage as I work back into racing and marathon shape.

This is a snippet as of today (8/30/2022) of future training days, planned mileage, as well as estimated calorie burn from work break walking and swolework sessions.
The non-running numbers are very specific based on estimates from known prior sessions. The running numbers are not estimates: For these I plan to run the treadmill at a particular speed for a specific period of time and know exactly how far I should run.
Again, the Workload Ratio column is conditionally formatted on Google Docs. It turns orange after exceeding 1.30 and red after exceeding 1.50 (even by a thousandth, which is why 1.50 here is red even though it’s right at 1.50).
When planning mileage increases… if I see a lot of orange and red, that’s the bat signal to take it easy on the planned volume there.
Orange, while indicating some risk, is fine in the short term. If I see it over months, I need to dial back my training during that period.
Red, however, I’ve decided is unacceptably high risk for planning purposes, and I have to reduce the Ratio on those days.
Remember how I mentioned that increasing workout variance or long run lengths (within reason) can reduce excessively high training monotony. Similarly, recall that Workload Ratio’s denominator factors in your average training from the last 42 days (prior 6 weeks).
So, one way to reduce a high workload ratio in a given week… is to increase (within reason) the overall mileage in the prior five weeks.
In this instance, the top row of September 1 (2022) is only two days away from now as of this writing. I can’t go back and add volume for past days. The best I can do here is add extra volume to either the 1st or the 2nd of September. This will decrease the workload ratio on September 10, the offending day, by adding extra average 42 day volume to the denominator, but not adding to that day’s 7 day period and increasing the Workload Ratio. Anything added after 9/2/2022 will only make September 10’s Workload Ratio go up, because it’s within 7 days of 9/10/2022.
In this case, I could make that 9/1/2022 run longer (that’s 60 minutes of running at 5.4mph on the treadmill). Or I could add in an extra cardio workout like a spin bike session, which from experience will probably add about a mile to the Estimated Mileage (EM), and from experience isn’t terribly hard to add as a 2nd workout on top of an earlier/later run workout. (I could add more walking but, as you can tell from other rows, it doesn’t add much EM at all and probably won’t move the needle)
Believe it or not, today I have a rescheduled 60 minute run that should determine which option I take. I’ve done a spin bike ride this morning before work. If the run goes fine, I then know that doubling that longer run day with the spin bike is do-able going forward. If it’s a problem, then I know it’s probably a better idea to just make the run a bit longer.
So, at some point I will clean up this info with a revised piece on the 21 Day Training Cycle. This I have found is a sustainable approach, and in long term planning I’m seeing that it can work. It can get me ready for the marathon, allow me to run the needed mileage and long runs. And I think in the big picture this is an approach that can work for many, many others.
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