Thassos 2016 DNF report

Another beautiful race, and yet another defeat. The MTB race on Thassos island is one of my favourites – the weather is already actually nice at the end of April, the views of the island and Aegean from above are dazzling, start and finish is on the beach (what’s better than jumping in the sea after 3+ hours of sizzling effort?), great organization etc. It was also my first race in another country back in 2013, so that might play role as well.

This year was my 4th attempt at it, but apparently Thassos mountains are not yet ready to let me through. Although I get faster and better each year, I’m still to execute my “perfect” race there. I’m far from elite level, and there are no categories (racing levels or “cats”) – that’s why I compete against the clock and myself. In this regard the perfect race is not the one where I step on the podium, but one where I ride with good flow, use all of my available power and finish strong without major technical failures or crashes.

In 2013 I completed the course without technical issues or crashes, but I wasn’t too fit and ended up past mid-pack.

In 2014 I trained quite a bit harder, acquired better bike and was doing well overall, but then crashed badly in a stream bed above Theologos. Thankfully no lasting damage, but lost more than half an hour due to tyre repairs, pain and loss of motivation.

In 2015 I became even faster, but got sick (common cold) the day before race and also torn tyre sidewall just 3 km from finish, so the perfect race remained elusive.

This year I’m in best shape of my life (so far 🙂 ). I trained hard and prepared for a strong ride with well tuned nutrition, hydration and light bike with tubeless tires. Went a little bit conservative from the start, but then picked up pace 10 minutes into the race. Felt strong and fast all the way up to Trikorfo peak, which is ~21 km into this 58 km race, but time-wise it is about the half-way through.

Just bellow Trikorfo check-point I noticed my front tyre (Rocket Ron) is hissing and spilling sealant from near the centre. This is not something unusual – it happened to me several times before, so I kept going feeling confident it’ll seal quickly. 2-3 minutes later it was still bubbling, so I had to stop and check what’s going on. There was an odd, very thin stone piece stuck just at the base of one of my central knobs. Like a piece of glass, but actually very small piece of rock. I removed it and left with ~1 mm hole, which sealed almost instantly. So, I jumped on the bike and resumed climbing only to find that my tyre started hissing again. Got off the bike, and hole sealed up quickly. This time I decided to push instead of ride for several minutes to give it chance to seal better. Unfortunately, when I tried riding it remained sealed only for few short minutes and then the hole re-opened.

More and more riders began to catch-up and pass me. My motivation was declining. I think the hole kept reopening because of its location at the base of a knob. The knob provided too much leverage and was forcing the rubber around hole to flex and re-open. I think that one possible solution would have been removing (cutting) the knob. Anyway, it was apparent that the sealant is not going to fix the problem and it’s time to put an inner tube. That’s when I found that I have inner tube with Schrader valve while my front rim is Presta valve 🙁 Motivation nose dived to zero. I descended slowly to Theologos (by topping up air every 5 minutes) and quit the race. Bonus insult to injury points: I’ve ordered tubeless repair kit (the one where you use rubber thread plugs) before going to Thassos, but due to national holiday it didn’t arrive on time.

Well, at least the weather was nice, the views spectacular, the food and the company awesome. I improved my Potos – Trikorfo climb time by another 15% compared to 2015 (1h54 -> 1h39m); 37% faster than my first ride from 2013 (2h16m back then):

 

trikorfo-segment-2016

So, I guess we are not done yet! Ну, Τρίκορφο, ну, погоди!

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Abbott FreeStyle Libre initial impressions

Human body is an amazing machine (consisting of many different, interconnected machines) and I’m really curious about processes that happen in it. I also love measuring, quantifying and modeling things (as my wife can attest). So, I’ve been very excited to get my hands on the Libre.

Abbott FreeStyle Libre is a CGR (continous glucose recording) device, which measures glucose in interstitial fluid (a solution that bathes and surrounds the cells), or to say it another way the glucose in the subcutaneous fatty tissue. More info about Libre can be found in this diaTribe article.

I bought only the sensor without the reader, but thanks to CTAPP Software there’s a free Android app called Glimp, which can be used to read current values from Libre with a NFC equipped phone. I use Samsung Note 3. The sensor has to be activated first using another app called Glimp S.

Maybe now’s the time to mention that I’m not diabetic. However my father is, and apparently I don’t tolerate carbohydrates very well. So far my pancreas appears to work just fine. I have to keep it low carb (<130 g/day) if I want to maintain lean body composition.

Accuracy:

I used Abbott Optium Xceed (with blood glucose strips) for comparison. I’m well aware that it’s not super precise either, but since it’s the standard used for insulin dosing it’s good enough for me.

I did 20 fingerprick tests in 8 days, and here are the corresponding pairs:

Glimp mmol/l Optium Xceed Diff
6.2 6.6 −0.4
6.4 6.0 0.4
6.9 6.9 0.0
6.1 5.4 0.7
5.4 5.4 0.0
6.3 5.7 0.6
6.5 5.2 1.3
6.5 6.0 0.5
6.5 5.3 1.2
8.1 7.1 1.0
6.3 6.4 −0.1
6.5 5.6 0.9
5.9 5.5 0.4
7.4 5.6 1.8
5.7 5.6 0.1
6.8 6.7 0.1
6.8 5.5 1.3
7.0 6.1 0.9
6.8 5.7 1.1
7.3 6.1 1.2

Some variations are to be expected, because the two devices measure different things and Libre only tries to convert its results to blood glucose equivalent. Also there’s an inherent lag (delay) of about 5-10 minutes for glucose change in the interstitial fluid compared to blood glucose. Still, the variation I see is too big to be used directly. I read that other users have better accuracy and even use Libre data for insulin dosing. Maybe it’s interpersonal variation or maybe my sensor is not up to par. Another possibility is that I didn’t insert the sensor at the best possible place – I used the back of the upper arm as advised but maybe I’ve hit some internal anatomy (blood capillary?). I also don’t know if Libre’s original reader is smarter than Glimp and compensates in some way.

So, here we go with some more analysis of the variation I see.

First, a diagram of the raw BG (blood glucose) pairs:

glimp-vs-xceed

Libre often (but not always) reads about 0.5 mmol/l higher. Here’s the polynomial regression of the pairs:

glimp-vs-xceed-regression

Seems like the higher the reading, the bigger the error.  Here’s the % deviation for all Glimp values I have:

glimp-vs-xceed-deviation

If I use the coefficient calculated in the polynomial regression above to adjust raw Glimp values and then calculate deviation, it looks like this:

glimp-vs-xceed-deviation-mmol

And finally this is how my adjusted blood sugar trend looked yesterday (probably :-)):

glimp-bg-trend-adj

I have another unopened sensor and I plan to try it in a few weeks and compare data with this one.

That’s all folks.

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2015 cycling in re(ar)view

Moving with my bicycle through 2015 I’ve produced more than 126000 kJ of mechanical energy, which translates to approximately 35 kW/h. I didn’t have my power meter with me on several occasions and few rides data got corrupted or missing for various reasons, so 126 MJ is a conservative figure. “Обиколката на Витоша” 2015 cost me 2468 kJ, so overall it’s like doing 51 rounds of it or in other words doing it every week.

Due to many other commitments (it was crazy year for sure!) I didn’t have the opportunity to ride outside as much as I liked, so many of the rides were on the indoors trainer. Also my primary discipline is MTB, and that’s another reason for my unimpressive accumulated distance of 4853 km (compared to road cycling). Still, I climbed 44570 meters. That’s roughly the elevation gain equivalent of doing “Велорали Черни Връх” 28 times.

Ultimately, despite all obstacles this is my fastest year ever! 🙂 Using “Обиколката на Витоша” as benchmark, because it’s both the first bike race I’ve participated back in 2007 as well the most popular mountain bike race in Bulgaria (xcm), here’s how I did through the years:

Year Time
2007 10:30
2010 7:57
2012 6:22
2013 6:10
2014 7:16
2015 5:23

To be fair I didn’t think of 5h23m as a possibility. I just hoped I can go slightly bellow 6 hours. This was also the year where I participated in the biggest number of races – I think I stood at the start line of at least 13 races.

I’ve also learned that if you smile more you’ll enjoy things more.

So, cycling-wise 2015 was a good year 🙂

Looking forward to 2016 with high hopes!

And now some pictures, each worth more than thousand words of course:

velo-viewer-2015

2015 Ride locations

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