18. April 2021

Swiss Trail Tour, Darth Vader on a Treadmill

What does Darth Vader do on a treadmill? Breathe, breathe, breathe. This week, I treated myself to the futuristic world of performance diagnosis: I wanted to learn more about where I am as a hobby runner, how to improve from there, and how applied science in sports works nowadays.

For those not familiar with the Star Wars saga (spoiler warning), Darth Vader is a not-so-amiable character in a rather stiff metal suit which amplifies the noise every breath makes. That’s how I felt while being on a treadmill, strapped into a bleeding-edge mask that measures your oxygen consumption & what not. Though, for those familiar with Star Wars, don’t worry, I am a much less dangerous character should you bump into me on the streets. Anyways, it’s been a half-day in the sports laboratory, enjoying performance diagnostics with all the bells and whistles that come with it.

Previously, I wrote about the big goal that captures my interest this year (Swiss Trail Tour, Beginning or Comeback?), the beginnings of teaching myself the basics of the art and science behind running (Swiss Trail Tour, Training Differently), as well as how to use records from past activities to inform future training choices (Swiss Trail Tour, Incorporating Objective Feedback).

Thus, at least at a rudimentary level, I have some understanding of why and how training works, I have closed the feedback loop that helps me stay and adjust the course towards improvement, I know where at what level of performance want to be, but I don’t know where I am with my current running performance. This is the gap that prompted me to sign up for running performance diagnostics.

What is such a performance diagnostic like? Well, I can certainly not speak in general, since this was only the third test I participated in over the course of my life. The previous two tests from 2014 and 2015 were less in-depth, and more functioning as general health assessments rather than as running-specific performance assessments. This time, the diagnostics included also a whole new world of statistics relevant for endurance such as blood pressure, body composition, maximum fat combustion, maximum lactate production, and many more.

But wait, what do all those statistics mean? Why would you even care? Well, these are good─no!─these are absolutely essential questions. There’s no point in measurement and reporting statistics, if you don’t generate insight from these statistics and apply them to training. The one statistic about running performance, after all, might just be the race performance. From that perspective, all other statistics can be judged by their utility during training. We’ll get back to this point in a little bit.

When I arrived at the lab, I underwent a few tests that measured body composition, characteristics of my autonomic nervous system before moving on to the Darth Vader part of the diagnostics. It’s intriguing how some of these sensors work: I’ll have to place my hands and feet each on a metal plate connected with electrodes, and the system inferes various measurements based on resistance in the body. In addition, I’ll get one of my fingers attached to a pulse oximeter, and one of the readings I get is oxygen saturation. I’m the wrong person to teach you how all of this works at this point in time─I am looking forward to learn more about these things over time─but it’s intriguing from a technical standpoint alone. Unfortunately, the few hours in the lab are by no means sufficient to ask all the questions on how this works!

This series of tests left me with a sample of oxygen saturation, heart rate variability, blood pressure, characteristics of the nervous system, and even a picture of which vertebrae could be blocked, and body composition. What’s true in general for humans is also true for me: I’m mostly water. How can humans even just stand or walk, really?

Anyways, once we are done with these rather sedentary tests, it’s time for the treadmill. I dread the treadmill under normal circumstances because it’s the most boring way of going for a run. I don’t usually get bored running, but on a treadmill I do. The prospects of running at speeds below 1k pace on a treadmill while not being able to see my feet (the Darth Vader mask) are not exactly endearing: that treadmill might catapult me at > 15 km/h who knows how far back in the lab. But hey, I chose to do this on a day off work, and after getting instructions on how to safely stay on the treadmill, I get on with the job.

The treadmill test is a series of brief intervals at increasing pace, with periods of rest in between. Before and after each interval, lactate samples are taken from my blood. Whilst on the treadmill, I am breathing into a mask. This mask is a bit bulkier than your off-the-shelf Covid-19 mask, but probably lighter than the actual Darth Vader model. Unfortunately, the software was playing a bit funny that day so the data coming from the mask wasn’t that useful and requires a repeat some day in the future.

Overall this interval series provide a picture on how my energy systems work (compare A computer scientist’s diagram of the systems that turn macronutrients into energy for the muscles). This is a fascinating topic in itself. A topic that I started looking into after reading the initial chapters of Lactate Threshold Training [1], and taking the online course Science of Exercise.

In a simplified way, lactate─which is apparently easier to measure than many other products of the human metabolism─can be produced by the body, buffered in the body, and burnt by the body. The lactate threshold. I’ll have to run at a specific pace and over a specific duration on the treadmill. The sampling of the lactate measures the response of the body while subjected to the stress, with stress increasing from interval to interval. The general process reminded me a bit of the field of signal processing, in particular the impulse response. The good news from this test─for me as long distance runner─is that I have a very low VLAmax. In short, I’m not hindered in my aspirations in long distance running by a tendency of my body to produce a lot of lactate. But there are certainly sports where I would fare terribly─sprinting among them, but that’s something I had already figured.

Some of my future research is about understanding why e.g. the maximum is a meaningful statistic over several quantities, such e.g. the lactate production rate. For example, what if the maximum lactate production rate (VLAmax) had nothing to do with my performance at a pace well below the lactate threshold? Apparently, the VLAmax is indicative also for performance at paces where the lactate production rate is well below its maximum. Thus, I have now confirmed that I don’t need to necessarily invest more into building aerobic base alone, e.g. due to the “aerobic deficiency syndrome” as coined in Training for the Uphill Athlete [3]. I’m not super-surprised about that, but it’s nice to have a measurement in addition to my belief: it’s an example on how I can use the measurement to guide my training, supporting me to look for other things that hold me back.

Often, when it comes to measuring, I think of “The Principle of Useless Measurement: What gets measured may not get done” from The Principles of Product Development Flow [4]: consider how owning a thermometer in your house might not automatically reduce your gas & electricity bill. The same applies here when I take all those measured parameters from the running performance diagnostics home: I could put the test output into a “digital corner”, and let the test output gather dust, with zero net effect. There’s two reason I believe I won’t do this. First, these very personal measurements are a good starting point in learning more about how the human body generally works. Second, I walked away with a four-week training plan cut out based on these results, and with my race goal taken into consideration.

Oddly enough, the thing that apparently holds me back is poor running economy, as indicated by a video taken on the treadmill. I’m wasting a lot of energy while running, “sitting” too much, overstriding and thus cannot turn some of the energy from the impact into forward propulsion. I spotted my poor form immediately on the video (something you can do a bit cheaper with a phone’s camera and a buddy nowadays). It’s relatively easy to spot other people’s running form (I used to identify my football team mates by running style way before anything else), but you need a video to understand what is your own running form. At first was first a bit skeptical because I had not run on a treadmill for maybe two years, and I had not run in my indoor gym shoes for maybe about the same time. But ultimately, also after observing myself with my usual shoes on usual terrain, I started to move on from denial (think about the five stages of grief…) to acceptance. The training plan for the next four weeks now includes more training specific to improving running economy. Fun times ahead.

[1] Janssen, Peter Gjm. 2001. Lactate Threshold Training. Elsevier.

[2] Mazzeo, Robert. n.d. “Science of Exercise | Coursera.” Coursera. Accessed May 23, 2020. https://www.coursera.org/learn/science-exercise.

[3] House, Steve, Scott Johnston, and Kilian Jornet. 2019. Training for the Uphill Athlete: A Manual for Mountain Runners and Ski Mountaineers. Patagonia Works.

[4] Reinertsen, Donald G. 2009. The Principles of Product Development Flow: Second Generation Lean Product Development. Celeritas.

Other articles in this series: