Thank you for such a detailed answer.
So despite relatively low cardiac and respiratory strain,
amount of lactate produced is quite high and well above
proverbial “threshold”.
A few more follow up questions:
1. Would riding a bike in a heavy gear (low rpms) uphill
elicit the same stimuli as weighted uphill walking?
2. If one is to do muscle endurance session for legs and
then separately for upper body, would doing this on a same
day be too much stress? On one hand, one would think that
with low cardio/respiratory impact and lactate being produced
in legs, one could handle a similar session for upper body.
On the other hand, such session may be too taxing at a hormonal
level.
3. There’s plenty of literature on local muscle endurance for endurance
sports in Russian. Seluyanov suggested a session like 6-10 second uphill
sprint with 30-40 second rest (for 40-45 minutes). The idea is similar:
HR is well below threshold, low(er) respiratory strain and supposedly no
lactate accumulation (since 6-10 second sprint would be alactic anaerobic).
How does this differ from the sessions you mention? You are supposedly
taking lactate shuttle out of the equation.