thanks @steveneal for the clarification. Could you potentially use the field to determine maximum fat usage and try to stay around that wattage? The numbers below are from an XERT workout DFA Alpha 1 ramp I did this afternoon and shows wattage and Fat and carb usage. Could I say 179w is my peak fart usage and ride around that power level to increase FATMAx? It seems like the XERT app is saying something but maybe I’m over simplifying things or missing something
Makes sense and sort of what I was coming round to thinking. I know XERT are developing more endurance type metrics so maybe one of these might look at this. Thank you for your replies @steveneal for clarifying things. Inspired by the FB message from Armando below
Interesting to look at real time fat and carbs on EBC. The algo suggests my fatmax is well below LTP (224W) and fat rate rises to about 135W, levels off then declines with intensity.
Wattages in the screenshots are 174, 219, 224, 248 watts.
Not always, more the shape of the fat / carb utilization. There are people who burn carbs right from the beginning of a test, but that person would still have a spot on their graph where fat/carbs is closest to 50/50.
Don’t have many pictures of this but it does happen.
Most of what I see is LT1 and Crossover point close together. So when athletes with this type of profile do tempo-based off threshold they are using a lot of carbs when doing tempo.
You are famililar with the Balance Point Test I have been using for years, so LBP is the persons Crossover point. You can have an athlete with the LT1 at 200, crossover/LBP at 215 and Threshold of 300. Very different than an athlete with LT1 at 200, crossover/LBP at 250 and Threshold of 300. These two athletes would have to fuel differently and I would train them very differently.
For Fat Max I feel it will often come at or just before (depending on how you score fatmax and the individual).
Here are two examples, one from some I work with and one from someone else test but very similar lactate and fat ox points.
And again as you are aware (I think) of the LBP protocol, you will see below during the second part of the test, lactate stops being combusted and starts accumulating as the fat and carbs cross over again.
Steve, do you think that those who are maintaining a higher fat/carb ratio above LT1 as evidenced by the flatter lactate curve are incurring less metabolic stress? Put another way, is there a benefit to relying on fat longer beyond saving glycogen stores? These questions come back to the point that Seiler and others have raised about the relative cost of being above LT1 vs below it in terms of cumulative fatigue.
I’ll answer that from a different point of view than you are likely thinking.
I ride brevets, which are long distance events from 200km to 2000km (there are some longer up 3000km but not many). Most brevets I ride a little below LT1 on the flat and easy tempo up hills if they are not too steep.
A common reason for riders not finishing is stomach issues where the rider can’t keep anything down and / or digestion essentially shuts down. Brevets are unsupported and you can’t have the perfect nutrition at hand for the duration.
If you have good fat oxidation there are two main benefits. At the intensity you are riding a brevet you don’t need to eat as much to keep your glycogen topped up. This means you are less likely to have stomach issues. If you do get stomach problems then you can ride for a surprisingly long time (I’ve done in excess of 10 hours) at a slightly easier intensity without eating, to give your stomach a chance to recover, whilst staying within the event time limits. You are fast enough even when relying mostly on fatox as it’s shifted right in terms of HR. Mine shifts about 10 bpm to the right at my peak before my longest brevet of each year.
A high volume of low intensity in the months leading up to my brevets over 1000km makes a big difference to how much I need to eat during the event. That fatox moving right and upwards. I still add in the intensity but see that as icing on the endurance cake.
It is why I like to pinpoint my athletes aerobic and tempo zones as accurately as possible as there is a lot of quality training to be done here.
When done at the right level, it allows to build the training stress aerobically but also leave room for intensity when needed because the athlete isn’t as tired.
Funny you mention brevets because that is what I am training for. My goal is specifically to try and be as economical as possible with energy expenditures not only for training but for exactly the scenarios you’re bringing up.
I rode 73% below 75% max HR and 27% between 76% to 83%. I spent no time redlining any hills. From over 100 riders I arrived back in the first 10.
Was I fastest on the road? No, a number of riders passed and re passed me on the road
Did I find a short cut? No I rode the same route as everyone else.
What was different was that I kept my stopped time to 9 minutes across 6 controls. By managing my effort , I was able to eliminate the need for a proper sit down feed at intermediate controls.
The bulk of riders finished when I was sat chatting and finishing a meal at the finish.
This reflects that the clock never stops on a brevet, and minimising stopped time is as important as ride time. The extra expenditure of riding at a higher effort (a lot above LT1) is rarely returned, as it means you need to stop more often to get more food and water to fuel that effort. It’s a lesson that took a while to learn, and one you’ll see the wily old foxes teaching you time and again if you’re observant.
I’m kind of repeating the fable of the tortoise and hare. Both valid approaches to brevets if you accept that the hare needs to stop for longer than the tortoise.
By raising LT1 the tortoise not only gets to spare glycogen and can spend less time stopped and eating, but they get to go faster when they are moving. Which gives more time to stop and digest food when they need to. It’s win win
Hi @steveneal. Would like to learn more about how to analyze the HR Step Test. From a recent test (19FEB22), is it a fair assessment that where we see the steepest increase in efficiency is typically where we’ve been training? Looking at the results, they align pretty well with the power histogram showing where I trained in the 6-weeks prior to the test . And then moving forward, is it reasonable to try and increase efficiency in the 190-200 power range? Post step test, I’ve moved into doing more endurance in the 170-190 range, and I continue doing a bit harder work in the 220-240 range. Basically, I’ve been simplifying the training into those 3 ranges, occasionally dipping into some higher intensity work. Trying to maximize gains through the spring and summer before adding in CX-specific work before the fall.
In order to get more granularity (for you) we need the following, this will help you with the power surge the beginning, but use the heart rate govern each step.
3m 75w
3m 100w
4m 125w
4m 150w
4m 170w govern with 120 HR
4m 190w govern with 130 HR
4m 210 govern with 135 HR
4m 230 govern with 140 HR
4m 240 govern with 145 HR
4m 250 govern with 150 HR
4m 260 govern with 155 HR
Really … what I need is more data between 130 and 160 heart rate - going up 5 beats at a time - so if you want to just repeat the test that way totally fine.
