The OP asked a couple of questions that, with the help of Coach Chad, we’d like to address:
We checked in with Coach Chad to get his feedback for the OP on these main areas of concern, and here’s what he had to say:
Put simply, the takeaway here is that you don’t need to aggressively challenge your aerobic system to stimulate its adaptation.
You can (and you’re likely already scheduled to in Plan Builder as you progress), but you can also go a number of other ways too by mixing intensity & duration in a variety of combinations that still bring about greater aerobic capacity/VO2max.
The real evidence of that work comes 4-6 weeks later. If you’re consistent and your workouts are progressive in nature, almost any approach will bring about aerobic adaptation and performance improvement. We’ll discuss how and why.
Fist and foremost, taxing the VO2 system, or our aerobic capabilities, has to increase HR.
Aerobic uptake (aka VO2) and heart rate increase linearly, meaning, if one goes up, the other goes up. If aerobic update increases and HR follows as a result, because the heart is pumping more blood, delivering more O2, all in response to muscle that needs more O2.
To what degree and how much it increases our HR is where the flexibility in ‘VO2max’ interval structure reveals itself. When TrainerRoad assigns VO2max workouts at both high and low percentages of the zone and still stimulate adaptations, they just do it over different time courses. You can work at long & short durations at those different percentages to bring about aerobic adaptation, where for example, 125% and 105% at different durations both push us toward our VO2max.
All the while, the emphasis shifts between central & peripheral stimuli, also known as: heart and muscles. Longer intervals place more strain on the central/heart because it’s working hard for sustained durations. This is, in part, why longer intervals are considered ‘traditional’, because VO2max is often measured by a 5min all-out effort. This is why athletes may misinterpret that as the only way to stimulate improvements in VO2max, but in reality, there are numerous approaches and structures that result in improved aerobic uptake.
You can ride fairly intensely for short durations (30/30’s, for example) or long durations–hours–at breathe-through-your-nose effort levels, and in both cases, shift the strain more toward the muscles. During short-intense work, you pull on higher-force fibers (type IIa), repeatedly, and stimulate aerobic adaptation. During longer-lower work, you fatigue lower-force fibers (type I) through duration and bring about aerobic adaptation.
You can ride really intensely, actual 30s sprints, and repeat a few of them with long-ish recoveries (SIT) and derive aerobic adaptation by depleting fuels stores very rapidly–just a different type of stimulus that leads to similar, aerobic adaptations.
Then with moderate work, like 4x4, you impose longer-term, higher-intensity stress on the heart, the muscles too but to a lesser extent, and derive aerobic stimulus that way.
Alternatively, you can achieve aerobic adaptation by stressing the aerobic system (heart, muscles, blood vessels, lungs, blood itself, etc; any or all of these parts of the machine). At some point, specificity becomes very important, but earlier in training cycles, more flexibility is affordable and athletes typically prefer, and coaches prefer to prescribe, less punishing work that achieves the same ends.
This is why in your many instances, you’ll see Plan Builder include short-short VO2max workouts earlier on, while we build you towards the assigned longer structure VO2max workouts.
Finally, Heart Rate does come up with short-shorts, it just does it less obviously: interval to interval, set to set. Even in the cited Sleeping Beauty -2 example, you can see HR rises with each 30s effort and it rises with each subsequent set of 30s intervals.
The good news for the OP: they’re in a training plan that does have “traditional” VO2 workouts scheduled, the OP is just currently lower in their progression to get up towards those longer duration intervals. Adaptive Training is going to lock them in at the right VO2 workouts as they progress. Patience and trust in the process (and the science behind it) will yield the best results for you!
