How does one train "against limits of endurance"?

Question

I understand that limits of endurance are:

• limited amount of lactate one can reabsorb
• limited amount of carbs one can "refill"

Assuming I cycle slow enough that I will never create more lactate than I reabsorb and burn less carbs than I refill, those would not be limiting factors.

If one looks at athletes in ultra endurance races, like race across America, the main limit seems to be sleep.

When I read training plans, they often seem to be optimized to increase vo2max, Lactate Resorption or fat burning.

Question:

Which training unit / signal cascade optimally improves how long I can ride before getting to fatigue?

What I tried / assume?

I would assume that I can improve the endurance by taking long rides. But I don't really understand what I actually improve (muscle fatigue but how?). Also, which length and frequency of training units would be most effective? (E.g. Taking one ride of 100% of my maximal capacity or five rides with e.g. 80% of my maximal capacity).

Answer 1

The two types of workouts you want to be looking at are threshold and interval training, both will help. Threshold (lactate threshold, not aerobic threshold, some coaches mix the terms) training is a little below race pace for a sustained amount of time, repeated a few times depending on the structure of the workout with shorter rest intervals. Interval training is faster than race pace, with enough rest to ensure you can make the next interval. Threshold training will enable you to go longer near or at race pace, and interval training will increase your top end speed.

As an example, say your race pace for a 40k time trial is 20 miles per hour, or 3 minute miles which is around a 1:14 for a 40k. (Yes, I know I'm mixing my measurements.)

A typical threshold workout should be 70-85% of your race pace. Using 80%, you get 3:36 per mile, or about 16.7 miles per hour. So a threshold workout would be 5-10 miles warmup, 20 minutes at 16.7 mph, 1-3 minutes rest, repeat x 4 or 5, cooldown.

For interval training, same concept except the pace would be 20+ mph, distance/time would be shorter, and rest interval between longer.

Each of those taken together will increase both your race pace and the length of time that you can sustain that pace.

Answer 2

the limiting factors for endurance are in order:

-Breath

-Soreness

-Pain

First one improves with the heart becoming more efficient and the muscles building more nucleus which in turn make them both stronger, more enduring and with a higher capacity of growth. a single muscle cell can have around 120 nucleus, but it's not certain and the number might be actually way higher.

Second one improves by increasing frequency, when you exert yourself way too often, your body will not make you feel sore anymore, it's like getting used to a certain smell after years and not feeling it anymore.

The third one improves by growing stronger bones and bigger calluses, tendons can also be a cause of pain and they can develop calluses and scar tissue to, making them less precise in rare cases but most importantly less prone to injury.

Technique, diet and genes or drugs can improve all factors.

Also quality of oxygen is important, there's a reason giant dinosaurs evolved multiple and complex lung systems to compensate for their poor diet or why divers breathe pure oxygen before competitions.