Check Howie Green’s work, or Pette’s studies of chronic electrical stimulation. Or just look at the graph in the study I posted, which shows things starting to plateau after just 90 minutes.
There may be benefits to training more than 2 hours per day on average, but if so they are unlikely to be related to further increases in mitochondrial respiratory capacity (except perhaps in some normally hard-to-recruit motor units). In fact, contrary to the OP’s suggestion the law of diminishing returns clearly kicks in before this, versus adaptation only induced by going at least that long.
As you can tell, you have (accidentally?) stepped on one of the forum landmines - which is the best approach to building fitness???
I’d suggest you read the TR blogs, listen to as many podcasts as you can, read other endurance coach/company/product blogs and podcasts and get a feel for what suits YOU in your specific situation. The TR philosophy is that shorter and higher intensity work will do just as well (or better) but not everyone is in agreement as you can see
There are probably a million answers to your question depending on a million different factors specific to you, your history, your genetics, your situation etc etc and the answer for you is never going to be the same as the one for me I’d suggest.
Please circle back and post when you find the Holy Grail though. Lots of people waiting to hear the answer
These topics have this chronic issue where people completely ignore the fact how much your current state matters.
Just think about it. If you improved only after doing something for 2 hours, you would forever stay at 0 because you wouldn’t be able to progress so far to even be able to do something for 2 hours.
So yea, if you’re TDF rider you might need 6 hours to notice improvement, but if you ride 1h rides, you will improve even with 1.5h rides.
Of course, not talking about “optimal training split” but we have to be aware that volume/progressive overload is key for human body strengthening.
Oddly enough, I had pencilled in a 30 min HIIT session from our own TR this morning because the weather is raining on my planned long slow parade outdoors. Hope my mitochondria didn’t read NYT this morning.
You’re showing the details of the study that I can’t see? If so, thanks!
As barely even a wannabe nerd, I’m not certain I’m seeing what I ought to see. Would you say that Ms. Reynolds’ synopsis is on the whole accurate? – leaving aside any flaws in the study itself, such as nutrition.
The only thing I would change is the phrase ‘supplement it with long Z2 rides’. It, perhaps unintentionally, suggests that the long rides are the icing on the cake, whereas I believe they are a key ingredient for sustained performance and progress.
Even our own aacc podcast crew doesnt answer the question that way. As they keep repeating that one needs to train a lot in order to benefit from lower intensity, when the answer is much more nuanced. Considering it can take years to build up to 20 hour weeks from doing 10-15, there seems to be quite a lot of adaptation along the way.
That minimum effective dose works until it doesn’t, then you do more as your capacity increases.