Jem Arnold
@jemarnold.bsky.social
PhD candidate & physiotherapist | 🩸Iliac artery endofibrosis / FLIA | Endurance testing & NIRS.
Treat declarative statements as questions?
Treat declarative statements as questions?
Pinned
Jem Arnold
@jemarnold.bsky.social
· Nov 14
Conservative Management and Postoperative Return to Sport in Endurance Athletes with Flow Limitations in the Iliac Arteries: A Scoping Review - Sports Medicine
Background Flow limitations in the iliac arteries (FLIA) is a sport-related vascular condition increasingly recognised as an occupational risk for professional cyclists and other endurance athletes. S...
link.springer.com
Recently published from my (eventual) PhD thesis 📚📑
Review of conservative treatment (CTx) for Flow Limitations in the Iliac Arteries (FLIA, endofibrosis) and proposal of Return to Sport (RTS) guidelines after surgery
Here is what we learned🧵👇/14
(full PDF link at end of thread)
Review of conservative treatment (CTx) for Flow Limitations in the Iliac Arteries (FLIA, endofibrosis) and proposal of Return to Sport (RTS) guidelines after surgery
Here is what we learned🧵👇/14
(full PDF link at end of thread)
Thanks, if I was brighter I probably could have listened to this and shortcutted a much longer troubleshooting process 😅
The issue ended up being a simple missing dependency 🤦♂️
Config/Needs/website: quarto, tidyverse
But it works now!
jemarnold.github.io/mnirs/articles/oxcap-analysis.html
The issue ended up being a simple missing dependency 🤦♂️
Config/Needs/website: quarto, tidyverse
But it works now!
jemarnold.github.io/mnirs/articles/oxcap-analysis.html
February 8, 2026 at 8:01 PM
Thanks, if I was brighter I probably could have listened to this and shortcutted a much longer troubleshooting process 😅
The issue ended up being a simple missing dependency 🤦♂️
Config/Needs/website: quarto, tidyverse
But it works now!
jemarnold.github.io/mnirs/articles/oxcap-analysis.html
The issue ended up being a simple missing dependency 🤦♂️
Config/Needs/website: quarto, tidyverse
But it works now!
jemarnold.github.io/mnirs/articles/oxcap-analysis.html
You're right. The most interesting question is under what conditions could those metabolic values be true? Challenge our assumptions. Treadmill incline is an interesting one. Could certainly appear to reduce economy. Could it also explain lower RER alongside protocol duration?
February 8, 2026 at 7:29 PM
You're right. The most interesting question is under what conditions could those metabolic values be true? Challenge our assumptions. Treadmill incline is an interesting one. Could certainly appear to reduce economy. Could it also explain lower RER alongside protocol duration?
So I don't think the answer is "don't post until we know everything" (I don't think that's what you're saying), but a bit more acknowledgement and curiosity about what we don't know would go a long way to improving the conversation, I think
February 8, 2026 at 5:32 PM
So I don't think the answer is "don't post until we know everything" (I don't think that's what you're saying), but a bit more acknowledgement and curiosity about what we don't know would go a long way to improving the conversation, I think
Appreciate this Philip. Yeah we either saw uncritical acceptance or rejection without knowing enough the detail. For my part, big initial error thinking it was a bike VO2peak! But I learned so much from the responses across platforms. Posting and seeking conversation is how we learn. So...
February 8, 2026 at 5:32 PM
Appreciate this Philip. Yeah we either saw uncritical acceptance or rejection without knowing enough the detail. For my part, big initial error thinking it was a bike VO2peak! But I learned so much from the responses across platforms. Posting and seeking conversation is how we learn. So...
Wonderful timing, thanks! I think I have need for this
February 8, 2026 at 3:23 AM
Wonderful timing, thanks! I think I have need for this
Also realised the 300 hr project didn't include data collection at all. It was a secondary manuscript with an existing dataset. And the 400 hrs project was a systematic review. So no wonder my current data collection is already exceeding that 😬
Thanks. Research has always something I’ve squeezed in on the side so I’ve never tracked hours but know it’s a lot. I think your hours are consistent with some other estimates I’ve gotten back.
February 5, 2026 at 3:11 PM
Also realised the 300 hr project didn't include data collection at all. It was a secondary manuscript with an existing dataset. And the 400 hrs project was a systematic review. So no wonder my current data collection is already exceeding that 😬
Good article I was able to contribute to, covering the good, the bad, and the unknown of endofibrosis in professional cyclists
But don't worry, despite the hyperbolic title, endofibrosis is not "coming for you and your little dog too" 😂
But don't worry, despite the hyperbolic title, endofibrosis is not "coming for you and your little dog too" 😂
All you need to know about Iliac artery flow limitation and endofibrosis, the mysterious and misdiagnosed scourge of elite cycling. bit.ly/4af6JiL
February 5, 2026 at 2:55 PM
Good article I was able to contribute to, covering the good, the bad, and the unknown of endofibrosis in professional cyclists
But don't worry, despite the hyperbolic title, endofibrosis is not "coming for you and your little dog too" 😂
But don't worry, despite the hyperbolic title, endofibrosis is not "coming for you and your little dog too" 😂
Of course, that doesn't include my co-authors' time
February 4, 2026 at 3:56 PM
Of course, that doesn't include my co-authors' time
I feel like I will want to delete this post when submitting my CV anywhere in the near future 😅
February 4, 2026 at 3:55 PM
I feel like I will want to delete this post when submitting my CV anywhere in the near future 😅
I'm seeing on the order of 300+ and 400+ hrs for a couple of my completed first authors projects over 1-2 yrs. Let's say that's >75% accurate recording. My final PhD project is over 500 hrs already with data collection not quite complete, and poor recording over the past ~4 mo, so... 😬
February 4, 2026 at 3:55 PM
I'm seeing on the order of 300+ and 400+ hrs for a couple of my completed first authors projects over 1-2 yrs. Let's say that's >75% accurate recording. My final PhD project is over 500 hrs already with data collection not quite complete, and poor recording over the past ~4 mo, so... 😬
I don't want to know but I really would like to know 🫣
#academia #academicchatter #AcademicSky #datascience
#academia #academicchatter #AcademicSky #datascience
How many hours of work typically go into publishing a sports med/phys research paper start to finish? @drphilipskiba.bsky.social @peter-leo.bsky.social @jemarnold.bsky.social @james-spragg.bsky.social (please share with whoever you else is on here)
February 4, 2026 at 3:42 PM
I don't want to know but I really would like to know 🫣
#academia #academicchatter #AcademicSky #datascience
#academia #academicchatter #AcademicSky #datascience
Pushing my sport science social media sleuthing to the limits here 😂
February 1, 2026 at 6:38 PM
Pushing my sport science social media sleuthing to the limits here 😂
Ah, good point. I've been told it may be a mixing chamber. Appears to be this system, but he has a (quite long) hose on his face, not sampling lines?
www.ntnu.edu/documents/22...
Hard to tell from the video edit, but it seems to not be updating on-screen values at BxB frequency, so maybe binned?
www.ntnu.edu/documents/22...
Hard to tell from the video edit, but it seems to not be updating on-screen values at BxB frequency, so maybe binned?
February 1, 2026 at 6:38 PM
Ah, good point. I've been told it may be a mixing chamber. Appears to be this system, but he has a (quite long) hose on his face, not sampling lines?
www.ntnu.edu/documents/22...
Hard to tell from the video edit, but it seems to not be updating on-screen values at BxB frequency, so maybe binned?
www.ntnu.edu/documents/22...
Hard to tell from the video edit, but it seems to not be updating on-screen values at BxB frequency, so maybe binned?
Incredible, thanks Jamie. How do we even validate numbers in his range then? Break out the sled dog equipment?
February 1, 2026 at 4:28 PM
Incredible, thanks Jamie. How do we even validate numbers in his range then? Break out the sled dog equipment?
Pointed at from elsewhere, this is the calibration device they are using
Valid to 6 L/min gas exchange and 240 L/min VE. So Kristian is reporting ~25% higher than that. It's too bad, he's clearly pushing limits of human physiology, we just don't have tools to accurately capture it?
Valid to 6 L/min gas exchange and 240 L/min VE. So Kristian is reporting ~25% higher than that. It's too bad, he's clearly pushing limits of human physiology, we just don't have tools to accurately capture it?
Metabolic Calibrator/Simulator to 6L Volume with Mass Flow Controller, Super-Athletic Range (#17057) - VacuMed
Metabolic Calibrator, Super-Athletic Range (#17057) *The Ultimate Laboratory Standard This 6L metabolic simulator can be used for: Producing an exact, simulated VO2 and VCO2 to verify the overall ac...
vacumed.com
February 1, 2026 at 3:36 PM
Pointed at from elsewhere, this is the calibration device they are using
Valid to 6 L/min gas exchange and 240 L/min VE. So Kristian is reporting ~25% higher than that. It's too bad, he's clearly pushing limits of human physiology, we just don't have tools to accurately capture it?
Valid to 6 L/min gas exchange and 240 L/min VE. So Kristian is reporting ~25% higher than that. It's too bad, he's clearly pushing limits of human physiology, we just don't have tools to accurately capture it?
Around 16:00 they talk about some fancy metabolic sim calibration. Again I don't know anything about it. What are the chances that accuracy systematically falls off at 70 brpm and 250 L/min? 😅
youtu.be/AQm254ktjPY?...
youtu.be/AQm254ktjPY?...
The Norwegian Method Episode 3: A year on since Kristian and Gustav’s pivot to short course
YouTube video by Santara Tech
youtu.be
February 1, 2026 at 12:23 AM
Around 16:00 they talk about some fancy metabolic sim calibration. Again I don't know anything about it. What are the chances that accuracy systematically falls off at 70 brpm and 250 L/min? 😅
youtu.be/AQm254ktjPY?...
youtu.be/AQm254ktjPY?...
Turns out he was on a treadmill and we all missed it!
Ignore all the obsolete cycling economy estimates! 🥲
Does that change our interpretation of RERpeak?
Ignore all the obsolete cycling economy estimates! 🥲
Does that change our interpretation of RERpeak?
February 1, 2026 at 12:20 AM
Turns out he was on a treadmill and we all missed it!
Ignore all the obsolete cycling economy estimates! 🥲
Does that change our interpretation of RERpeak?
Ignore all the obsolete cycling economy estimates! 🥲
Does that change our interpretation of RERpeak?
I think you're right Alex. In the last video a couple years ago he was at 70 brpm. I wish we knew more about the system to say more about validity
February 1, 2026 at 12:19 AM
I think you're right Alex. In the last video a couple years ago he was at 70 brpm. I wish we knew more about the system to say more about validity
Thanks Jamie. Wow, yeah that's good perspective. So. Where are the other 2 L VO2 going? 🤷♂️
January 31, 2026 at 7:35 PM
Thanks Jamie. Wow, yeah that's good perspective. So. Where are the other 2 L VO2 going? 🤷♂️
I've started to upload my #sportscience #rstats #datavis plots to github to improve reproducibility. Double check my work!
github.com/jemarnold/da...
We don't have to go on vibes when we have data! And we can make quantitative predictions from historical literature
github.com/jemarnold/da...
We don't have to go on vibes when we have data! And we can make quantitative predictions from historical literature
data-vis-threads/2026-01-30 at main · jemarnold/data-vis-threads
A repo for sharing data visualisation projects. Contribute to jemarnold/data-vis-threads development by creating an account on GitHub.
github.com
January 31, 2026 at 4:09 PM
I've started to upload my #sportscience #rstats #datavis plots to github to improve reproducibility. Double check my work!
github.com/jemarnold/da...
We don't have to go on vibes when we have data! And we can make quantitative predictions from historical literature
github.com/jemarnold/da...
We don't have to go on vibes when we have data! And we can make quantitative predictions from historical literature
In conclusion, we shouldn't naively take the 101 ml/kg/min value as valid, like many uncritical media headlines I've seen already
Instead, we should ask *how* could one achieve that value? Either through measurement error, protocol manipulations, or social media trolling 😄
Instead, we should ask *how* could one achieve that value? Either through measurement error, protocol manipulations, or social media trolling 😄
January 31, 2026 at 4:09 PM
In conclusion, we shouldn't naively take the 101 ml/kg/min value as valid, like many uncritical media headlines I've seen already
Instead, we should ask *how* could one achieve that value? Either through measurement error, protocol manipulations, or social media trolling 😄
Instead, we should ask *how* could one achieve that value? Either through measurement error, protocol manipulations, or social media trolling 😄
From these rough estimates, we can draw his potential cycling economy (W/L/min O2; blue line)
And compare this range to other published data points in World Tour cyclists and a XC-skier turned Junior TT World Champ
Interesting, it's quite low, but not entirely implausible? 😮
And compare this range to other published data points in World Tour cyclists and a XC-skier turned Junior TT World Champ
Interesting, it's quite low, but not entirely implausible? 😮
January 31, 2026 at 4:09 PM
From these rough estimates, we can draw his potential cycling economy (W/L/min O2; blue line)
And compare this range to other published data points in World Tour cyclists and a XC-skier turned Junior TT World Champ
Interesting, it's quite low, but not entirely implausible? 😮
And compare this range to other published data points in World Tour cyclists and a XC-skier turned Junior TT World Champ
Interesting, it's quite low, but not entirely implausible? 😮
More interesting to me is what what Kristian's peak power at VO2peak?
We can sleuth through the video frames to see the vertical progress bar mid-way through the ramp
Digitising the last image, we can estimate Wpeak was around 440 W
We can sleuth through the video frames to see the vertical progress bar mid-way through the ramp
Digitising the last image, we can estimate Wpeak was around 440 W
January 31, 2026 at 4:09 PM
More interesting to me is what what Kristian's peak power at VO2peak?
We can sleuth through the video frames to see the vertical progress bar mid-way through the ramp
Digitising the last image, we can estimate Wpeak was around 440 W
We can sleuth through the video frames to see the vertical progress bar mid-way through the ramp
Digitising the last image, we can estimate Wpeak was around 440 W
Others have said 0.93 RER at VO2peak is not plausible
But after what appears to be 2-hrs threshold intervals, we would expect RER to be depressed to some extent
Although still maybe not that low? 🤔 There might be other interventions going on. Dietary? Environmental? 🤷
But after what appears to be 2-hrs threshold intervals, we would expect RER to be depressed to some extent
Although still maybe not that low? 🤔 There might be other interventions going on. Dietary? Environmental? 🤷
January 31, 2026 at 4:09 PM
Others have said 0.93 RER at VO2peak is not plausible
But after what appears to be 2-hrs threshold intervals, we would expect RER to be depressed to some extent
Although still maybe not that low? 🤔 There might be other interventions going on. Dietary? Environmental? 🤷
But after what appears to be 2-hrs threshold intervals, we would expect RER to be depressed to some extent
Although still maybe not that low? 🤔 There might be other interventions going on. Dietary? Environmental? 🤷
VO2peak is usually measured over 30 sec. My assumption is that 101 might be the highest single sample
Given pseudo-breath-by-breath recording from a mixing chamber, the variance below this value might be 2-5%
If true, this would estimate his actual VO2peak to be ~92-97 ml/kg/min, still very high
Given pseudo-breath-by-breath recording from a mixing chamber, the variance below this value might be 2-5%
If true, this would estimate his actual VO2peak to be ~92-97 ml/kg/min, still very high
January 31, 2026 at 4:09 PM
VO2peak is usually measured over 30 sec. My assumption is that 101 might be the highest single sample
Given pseudo-breath-by-breath recording from a mixing chamber, the variance below this value might be 2-5%
If true, this would estimate his actual VO2peak to be ~92-97 ml/kg/min, still very high
Given pseudo-breath-by-breath recording from a mixing chamber, the variance below this value might be 2-5%
If true, this would estimate his actual VO2peak to be ~92-97 ml/kg/min, still very high