Jajaja, I need time to think a little bit....

Thanks Facundo, we've discussed in private this question already. Tlim at VT2 its supposed to be similar to Tlim at MLSS, and I thought IAT too, but you know for example Billat show some reports about differences in Tlim at MLSS and IAT. Its logic to think that there will be differences between Tlim at  VT2 and at MLSS or IAT too, and I can't find any research about that specific matter.  

Generally, above anaerobic ventilatory threshold, the subjects could remains about 6 min, not more. Probably some studies could help you

http://www.ncbi.nlm.nih.gov/pubmed/?term=work+time+above+ventilatory+threshold

Thanks Moacir. But, it would depend on the relative intensity, true? Taking into account that Tlim at wVO2max its been reported to be near to 2-6 min (depends of fitness), as intensity is reduced Tlim has to be higher. Tlim at VT2 (70-80% of wVO2max in most people) must be at least near or above 30 min... or that is what I though, but I can't find any concrete data about this. 

Yes, I agree.If the intensity is reduced to a value slightly below the threshold, individuals can run for example a marathon. It could be found some paper about this.

Carlos

My Ph.D related to this area. 

I used Critical Power rather that VT2 (my data showed that in practical terms: VT2 power = 0.78 x CP + 66.0, r = 0.83, P= 0.002)

Time to exhaustion at CP was 1244 sec +/- 364 sec. 

I've attached my thesis. Data is in Study 1. Please feel free to email me at [email protected] if you would like more detail.  

kind regards

Hi Andrew, 

Thanks! I really appreciate it. I will read it right now. 

Wouldnt tLIM at RCP depend more on the protocol that you used to determine it in the first place. Various papers have found the power output corresponding to gas exchange thresholds are higher with larger ramp values whereas the O2 uptake is unaffected. I dont have the paper in electronic format but this is the title - effect of ramp slope on determination of aerobic parameters from a ramp exercise test - davis & Whipp et al 1982.

Thanks Alan, 

Of course I agree, VT2 determination (ramp protocol and even method used to determine it) will influence Tlim. But is hard to find any scientific report about Tlim at VT2. The best I've found is Andrew's thesis, which relates Critical Power with VT2 and has data of Tlim at Critical Power. His results are similar to previous research about CP Tlim (https://www.researchgate.net/publication/235762602_Time_to_exhaustion_at_and_above_critical_power_in_trained_cyclists_The_relationship_between_heavy_and_severe_intensity_domains). 

Article Time to exhaustion at and above critical power in trained cy...

Carlos, 

According to some previous tests that we did in our laboratory, we guess that "Tlim" at VT2 should be around 20-25 minuts. It's true that the relative load is linked with the protocol used to establish the intensity, in the same way that "Tlim" at MLSS intensity depends on the protocol actually used. Considering that, there are several studies showing that MLSS and VT2 intensities are in fact diferent physiological facts, "Tlim" at both intensities vary greatly.

There are lot of research works testing tlim at diferent intensities in percentage terms (between 85 and 95% of VO2max), that can help you to guess the answer you are searching.

We did a work where analised "Tlim" at MLSS and just tested the tlim at VT2 in two different subjets (not published as I told you previously), so feel free to read it if you consider interesting to do it.

You can find it here: https://digitum.um.es/xmlui/bitstream/10201/46914/1/TFM-JRLB.pdf

Best regards,

Andrew,

Great work!. Did you work with untrained subjects?. Critical power should be related to FTP (functional threshold power), and in the field (I do not have just now scientific data from TLIM at FTP) I measure continuously that highly trained cyclist can sustain FTP much more than 1200 seconds. I will study your work!.

Thank you!.

Thanks Jose Ramón, I see you've worked with Pallarés at UM. Great work. 

I agree, I've read about MLSS and VT2 differences, but never thought that Tlim would be so different. Your results shows 77 min (mean) Tlim at MLSS! That's miles away from 20-25 min of Tlim at VT2 that you've proposed and also Andrew's results. It's choking, but it will explain why in my current study an 80% of VT2 is hard to maintain during 35 minutes.

Regards!

Hi Carlos,

We have two papers that can help you.

At MLSS we found a mean Tlim of 60-65 min I healthy untrained subjects. After six weeks of aerobic training Tlim did not change in the new MLSS (in attachment).

In another paper, we determine MLSS and VT in a hot and temperate environment and found a difference in exercise intensity between these methods (in attachment)...

Maybe, the differences found in Tlim may be due to small “errors” in relation of one method (VT for example) and MLSS evaluation (gold standard).

Some methods are protocol dependent!

 (I have the data for analyze VT before and after the training protocol, but I have not performed this analysis yet.)

 Regards

 Thiago

Article Maximal Lactate Steady State is Altered in the Heat

Article Six weeks of aerobic training improves VO2max and MLSS but d...

 Thanks Thiago, I'll read your carefully your papers. Interesting, your data shows less power at VT than MLSS... 

Best regards!

I believe you are embarking on a question in no-man's land.  Should you set the intensity at 10% > that value, determining time limit to exhaustion is easy.  When you at exercise at the precise intensity, the sources of exhaustion become more complex (e.g., "I quit because I am sick of sitting on this saddle"), and often the subjects do not evoke VO2 values attaining true VO2max.