Hi all, new to using Xert, but with several years using Golden cheetah as my main training tracking/analysis tool. I have come across a rather curious problem regarding my estimates and wonder if this has happened to someone else. Xert estimates my fitness signature quite accurately in terms of threshold power and lower threshold power. When I set out to do 10-20 min intervals the numbers are quite accurate and getting a breakthrough hurts, and if I get one is by a second or two. So those numbers correlate quite well with reality. The issue comes with the estimates for HIE, specially for shorter intervals. No matter how hard I try I cannot get the numbers to do a workout in the less than 5 min range. If I use the power curve calculator with the numbers that I know I can produce at 15 and 3 min, then the estimate of HIE is almost half of what Xert usually calculates for me. I can change it by hand, but after a breakthrough the values get recalculated and I go back to the over inflated HIE. I have always been more of a diesel TT person, rather than a sprinter.
Some background numbers, HIE estimated usually at 30kJ by Xert, when I use my numbers it goes down to 18kJ. 317W 10 min power, 360 3 min power. Any thoughts would be appreciated.
Have a look here:
There’s a chart showing the relationship with peak power.
Thanks for the reply. I had looked at that post before, and am sure my issue has to do with my Peak Power. Ironically enough, as a heavy rider (86kg) getting 1200watt is not an issue, problem is those pesky 1-5min sets that overestimate HIE.
Using that chart for reference, a PP of 1200 would range from 20-28 on the bell curve with a median of 24.5. Perhaps you are an outlier. 
You can file a support request with support@xertonline.com and they’ll take a look at your numbers.
Here’s a related thread –
HIE understanding - Support - Xert Community Forum (xertonline.com)
Do you mean you can’t do the workouts at all (so not one rep), or you can’t hit the power from your power curve for the duration (which would be a breakthrough)?
If the former, there is definitely an issue and you’re best to contact support directly actually…
Thanks for the reply Wesley. I can’t do even one rep at the duration estimated from the power duration curve, I can hit 50% of the time estimate and then collapse by the side of the path, the next interval I’ll be lucky to hit 30% of the time estimated at that power. I did contact support, and I seem to be in an outlier where my max power is messing things up, as max power is linked to HIE they both raise. Once max power is lowered the estimated HIE makes more sense and I can now see numbers that are realistic.
What is your current status stars count?
Post an example of your XATA guidance for the day including the text below the Training Pacer.
Are you attempting to perform a workout from the recommended list outdoors or free ride to a Focus Type?
Stars at 3. I’m doing simple 3min intervals outside, rather than focus type. The main thing with the power curve estimates is that they are really good at ~10-20 min duration, I get the power numbers and duration predicted. But with shorter duration, 3-5 min, the power curve suggests both power and time to exhaustion that are way beyond what I can do. I come from years of using GoldenCheetah with monthly tests, using a 3 and 20 min performance test, so the power predictions have been more or less accurate. I’m not focusing on numbers with Xert, it’s more the curiosity of these differences, see attached the analysis of a 3min series of efforts, the MAP barely drops, and that session was painful. I re-analyzed that session using a value of HIE that was about half, and the drop in MAP did reflect how I felt. As far as I can tell, what messes the model is my max power estimate, using the power curve calculator with my 3 and 20 min power numbers it predicts a lower HIE, and a PP way lower that what I can do, but it’s way more accurate at tracking MAP during those 3min intervals. Guess I’m still in GoldenCheetah mode trying to get used to Xert.
I don’t think this will offer any help, but just thought I could share my woes. 
I’m in a similar situation. I like data but I have never been that serious about my riding, especially not for the past 5 years or so, so this hasn’t bothered me too much. It could also at least partially be down to that I have always struggled on the trainer. Anyhow I had a look now and the power curve produced by Xert is from 1 second up to 20 minutes higher than my highest ever recorded number going back almost 20 years (using Golden Cheetah) To me that was a bit unexpected. Maybe I just never show my real potential? My PP is 1160 and my HIE is 27.6 and I’ve always considered myself a diesel.
When doing workouts on the trainer I tend to stay between 2 and 3.5 stars. Of all the different workouts I’ve tried I would rate the ones where there are hard efforts from 1 minute up to perhaps 5 as incredibly much harder (sometimes impossible) than the ones that either lack effort way above TP or that keep them down to 30 secs or less.
I’m not saying that the problem is necessarily with Xert (the workouts prescribed are generally much more spot on than other platforms I’ve tried) but I do really struggle with HIE sometimes. As said, in part it may have to do with me struggling on the trainer and maybe it’s a bit of “garbage in …”. I do tend to make most of my breaktroughs on quite short stretches of road going home from work (10-30 min) where I’m either quite a bit above FT or coasting. Sprint training I do one set every 5 years, and my longer efforts are usually a bit too long for breaktroughs. So I guess I’m perhaps not making it easy for the algorithm.
Sounds a lot like me Johan. I am more of a data nerd than an athlete, fisheries background. I haven’t used the prescribed workouts as in central Spain I ride outside year round. Main difference I’ve found between GC and Xert is the estimate of W’ and HIE. With GC my W’ is way lower so at those 3
5 min durations I can achieve, graphically speaking, good workouts. With Xert, since HIE is estimated higher, mostly I think due to a high PP, the workouts for me at 3-5 min look like I’m warming up and not taking things seriously, like the image above. That being said, 20-20 min estimates from the power curve are right on for me.