Originally Posted by
terrymorse
Yes, Zone 2 has been touted by many as this powerful mitochondria builder, but the science doesn't seem to confirm it. Training volume is reported to be the main influencer of mitochondria growth, with faster growth occurring up to about 90% of VO2max.
Increasing the amount of mitochondria is a good thing, but more important is how much oxygen the mitochondria can process. Studies suggest that higher intensity training develops mitochondria respiration (oxygen consumption) much more quickly than zone 2.
I agree with you regarding zone 2/mitochondria building. I've thought about this in regards to my own training...as a 68 year old amateur racer...and have wondered if there is a limit to the amount of mitochondria the body builds and uses.
I spent much of last year's off season training on zone 2 riding with some HIIT stuff like wtrl/ttt and the zrl. When I began my real world road season my high end abilities were at a lower level than the previous year and I had a hard time and a lot of effort getting back to that level...I'm talking about either chasing down an attack, staying with a break away attempt, launching an attack, etc. I didn't have the usual high end push I expected. I was able to ride at a higher level of steady pace with a bit less effort but it did not compare to those brief...hopefully lol...periods of near/full gas efforts without blowing up.
So this season's off season training is different than I've done before and I'm already seeing and feeling the results. I've started my training near two months ago and I'm now doing two sessions, one hour each, of yoga per week in addition to two near one hour sessions of weight/strength training per week following a program designed by my daughter specifically for me...she owns a fitness studio in Boston and has been a personal trainer, etc. for over a decade. I now do more zone 3 sessions per week and spend 45 minutes on average in zone 3 for maybe 3 days per week. I also still participate in zwift's zrl and wtrl ttt's on a weekly basis which also incorporates some of the zone 3 time.
So far I've noticed it is far easier to ride at a higher w/kg level without noticeable impact and I've increased my ability to ride at higher w/kg's during hiit's efforts with a bit more power and ease. I've also increased my thigh circumference by 2cm's which I have noticed when pushing hard for brief periods.
I keep a journal and track my data so it will be interesting to see how it all works out during the winter training season and next year's IRL racing.