Adventures with a Power Meter 7: Physiological Measures at Beds Uni Human Performance Centre

July 20, 2018


In my efforts to understand more about how to get faster and stronger on my bike, I have been using a power meter for targeted zone training. Now, I’m finding out more about how zones connect with my personal physiology through tests at the Human Performance Centre, University of Bedfordshire, Bedford.







I become a lab rat


 The door opens and I enter the testing lab. It’s a large room with a vinyl floor. Two walls are lined with floor and wall cabinets making it look like a fitted kitchen. But no cooker or microwave or kettle in sight. Instead the surfaces are covered in computer monitors and wires trail across to keyboards and printers and other machinery that is alien to me. It all looks very clean, almost clinical, with lots of wipe clean surfaces. In one corner is a treadmill. But my eyes are drawn to the middle of the room and the stationary bike. This is what I am here for.



Nervous anticipation


I’m not really sure what to expect. The guys in the shop who are members of the Flamme Rouge Cycle Team have had some testing done at the HPC. All I heard from them is how hard it was. And I have seen the picture of Jack collapsed in a heap on the testing room floor, face all red, hair dripping with sweat.


This is why I approach the centre with some trepidation. What is it going to be like?


Lactate profile measure


I have signed up to do two measurements, with sessions over two days.


Yes, blood is involved

The first is to measure my lactate profile. This involves taking regular blood samples from a pinprick in my finger while I cycle to exhaustion. I was a bit worried about the “cycle to exhaustion” bit. Surely this would take hours?


I meet the two guys conducting the tests, Shaun and Ryan. They are MSc students at the university and provide continual reassurance throughout the tests, reminding me that I can stop at any time.


Safety first


But first it’s a blood pressure measure. This is to make sure that it’s safe for me to go through with the testing today and critically for later in the week when I do the VO2 max measurement. This complements a health questionnaire I have already filled in.


My first measure is through the roof. Not surprising really, I’m nervous and anxious about what is to come. After five minutes it has gone down but not enough. Ryan gives me some advice: don’t cross my legs and take deep breaths. I chat to the guys about what the tests will show and I feel myself relax. My final blood pressure measurement is well down and I have the green light to go.


And so it begins


Ryan takes a resting blood sample, now all seriously attired in white coat and plastic gloves. He tells me I should only feel a small scratch in my finger. He’s right and I hardly feel it as he squeezes a dark red globe of blood out of my finger. He uses a small pipette to suck up the blood and rushes over to a magical machine in the corner which spits out results on a strip of paper within seconds.



The before picture

 It’s time to start the test proper. This involves cycling on the bike at a determined power setting. After a warm up, the power increases by 25 W, increasing again every 3 minutes. A blood sample is taken before the watts are ramped up each time. Once the test results show my lactate levels are increasing rapidly, the test stops. I wonder how long this will take and if I will manage to reach the end.


A quick check of the heart rate monitor I have strapped around my chest to ensure it’s connected properly and the test can start.


Shaun sets the bike up with the measurements of my own bike that I have brought. The pedals on the bike are single sided SPDs and I have not brought my own pedals. So I wear trainers and use the toe strap and cages fixed to the pedals. A few adjustments to ensure I’m comfortable. I grip the handlebars, the right one covered in clingfilm to catch escapee blood.


It’s easy! At first...


It starts off fine. The pedalling is easy and it feels great to be doing something I know how to do. What I find strange is that I can’t see any power readings. All I have in front of me is a readout of my cadence. I concentrate on keeping it at around 80 rpm. As the three minute countdown approaches, Ryan takes another blood sample, while Shaun shows me the chart for “rate of perceived exertion”. This starts at 6 with “very light” and goes to “very hard” at 20. It’s not something I’ve used before. I tell him it’s currently a 7.


The first few sets of three minutes are fine and I easily maintain my cadence of 80. Then it starts to get hard. In a workout, I’m used to pushing hard for a few minutes, then having a recovery period. But this test is relentless. There is no break and the watts I have to push out just keep going up. It starts to get hard. Really hard.



Not so easy now

The after picture, all red and sweaty


Sweat drips off me. My heart pounds. I’m breathing fast. My legs have lead weights attached.  Shaun encourages me to keep going. Every three minutes he asks if it’s okay for him to increase the power. He asks this very nicely. And I say “yes” very nicely. Though I’m not actually thinking nice thoughts.


After about 20 minutes, when I am starting to wonder when will it end, Ryan finally rushes over with the strip of paper from the machine that has been swallowing my blood. After confirmation from Shaun, he stops the test. “You’ve done it!” he says, “You’ve reached OBLA!” I have no idea what this means but I do hear that it’s now over. Rate of perceived exertion: 19.





VO2 max test


Only to do it all over again for the VO2 max test two days later.


At least this time I know a bit more about what to expect. No blood samples but I have a mask over my face. This feels strange and there is a slightly sweaty smell mixed with plastic as I breathe in. I thought the mask would restrict my breathing but a few practise breaths show me that I can still breathe quite normally through my nose and mouth.


The testing regime is slightly different this time. Instead of ramping up the power every three minutes, the power will increase by 25 W every minute. The good news is this means I will reach the end within 12-15 minutes.


I can do it, I know I can