I’ve been using the CycleOps Powertap wheels for about 2 weeks now – it’s shot by and I’ve been busily downloading the data from every ride and busily analysing it at every opportunity. Very sad, I know.

Arguably the most important number for training with power is your **‘Functional Threshold Power’ (FTP).** This is roughly the absolute maximum wattage that you can hold for 1 hour, for example, over a 25mile TT.

The FTP number is really important because you then use it to set training zones for yourself, for *‘recovery’* (walking the bike), *‘endurance’* (chilling or going for ages), ‘*tempo’* (riding at that awesome level we all quite enjoy),* ‘threshold’* (riding so it’s a bit hard to speak in sentences), ‘*Vo2 max’* (riding so hard you don’t know what you would say if you could speak), *‘anaerobic capacity’* (riding so hard you meaning the forget of words) and *‘neuromuscular’* (riding so hard you can’t see the power meter anymore) intervals. You can use these zones if you don’t have a power meter, either going my heart rate or perceived rate of exertion – using wattage just means you can be more accurate.

**There are loads of ways of establishing your functional threshold power.**

The simplest method is probably using your average wattage over a one hour TT. It’s still February and my first TT is in April, so I can’t do that yet.

An alternative is carrying out a **formal test** which takes 90mins on the turbo and is kind of boring. Basically you wear yourself out a bit with a long warm up and a 5 minute hard effort, then pedal all out for 20mins, using your average wattage over the 20mins -5% to find your threshold power (the minus 5% is because you’ll need to keep that up for an hour!).

Alternatively, you can use a number the software generates for you called ‘**Normalised Power’**. Ideally you use the Normalised Power number from a one hour mass start race. CycleOps software then figures out what your wattage would be if totally unaffected by changes in direction, sudden ramps in power or drops – basically it averages your power.

**The Results?**

I came to my first issue with power data when I did both of the above. Over a one hour (and 15min) race, my Normalised Power was 204.

I wanted a more formal test – so I did the turbo version too. The answer? Average wattage over 20mins was 183 (just 2 watts over my average over 20mins of an ‘easy’ endurance ride) – minus 5% of that and you get … 174. There is a possible technical explanation for this, in that I only discovered afterwards that I needed to reset, or ‘zero’ the power computer before riding on the turbo – so this could put me a few watts out. And in addition, such is life.. I did wake up with a cold the next day. So maybe I wasn’t at my best. But regardless, the two numbers are still very different.

**I was perplexed**. So I emailed British Cycling level 3 coach and Cycling Weekly journo Huw Williams (@huw_williams1) with my data files attached and asked : “Which number do I use?”

He came back to me with an answer: “*It’s very easy to overcomplicate this. Bear in mind that threshold is the maximum amount of watts you can sustain for 1 hour – then normalised power for a 1 hour race is pretty bang on the money. So your peak power for 1 hour at Cyclopark normalised at 204w and that will be very close to your FTP because that’s what you did.”*

He then gave me a simple test to check this – which is next on my ‘to do’ list. (just as soon as I get over the nasty cold!!) However, he reassured me too, that the difference in effort was pretty normal, explaining:* “This will be down to thermoregulation – you don’t have a nice cool breeze blowing in your face like you do on the road and motivation, the fact that you are far less motivated than you are on a track surrounded by other riders trying to beat you. So ideally you might want to do this re-test on the road on a suitable TT course.”*

Taking Huw’s advice, I’ve set my ranges using the race normalized power as a start. The next step is easy – zones are set as a percentage of my new FTP. The step after that – trying to train at a % of them – remains to be seen!

**How do I compare?**

Our social media man Balint keeps telling me he’d like to know exactly how the numbers compare with the pro’s (some sort of morbid cruelty? On my google searches I found this was actually a common question people asked – so maybe it’s just me who would rather not know!). I did try googling to find the FTP of Marianne Vos, but alas google will not yield. So instead, I pulled out ‘the chart’ (by Hunter Allen and Andrew Coggan) I used in the last blog.

Firstly – it all depends on weight. A cyclist putting out 300 watts who weighs 55kg will be faster than one putting out 330 watts and weighing 65kg. But if we use the chart I pulled out last time – then the FTP for a female world class cyclinst my weight would be 337watts, a domestic pro would be looking at 295watts and a cat 1 racer might be looking at around 253watts. Then bear in mind this is just the FTP – using the chart, that top end pro would be pulling out 1,145 watts over a 5 second max. That’s 630 watts more than I’m can sustain as my max (so far)…

**Did I learn anything else? **

The turbo wattage reading still puzzles me a bit and makes me wonder if the discrepancy might tell me something about how hard I’m working when I’m sweating it out in the garage. Clearly, I need to buy myself a better fan, and maybe I need some sort of massive posters of Marianne Vos and Beryl Burton. That’s another plus for the power meter – it doesn’t matter how hot and sweaty you might be, or how hard you think you worked- numbers don’t lie – and using the power meter you know exactly what your best is, and what you did in your last session.

**For the other blogs in the series – check out: **

1/3) A beginners journey: http://bit.ly/1eJuoYi

3/3) Using the data for the season and beyond: http://bit.ly/15vorpI

* (Michelle works in Marketing and also blogs* at www.trainbynumbers.blogspot.com )

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