Post 78 - Maths and formulae

This week I had to go to Italy with work. Next week I also have to go to Italy with work. Not ideal, with the North Norfolk 100 mile time trial following immediately afterwards… lots of stale aeroplane air, carrying heavy luggage, hot meeting rooms, squeezed taxis, standing around, eating strange hotel food, sleeping badly in stuffy hotel rooms, unable to train as I want… none of which is great, all of which causes stress. Buuuuuut what can I do other than drink lots of water and cross my fingers?

Italy was hot and sunny. I managed a short and easy 30 minutes on the exercise bike in the hotel gym on Tuesday evening. I didn’t want to push hard because it’s impossible to set an exercise bike up properly and to get a good fit. I don’t want to push hard on an ill-fitting bike and end up wrecking my knees or back. Plus, pushing hard in a hot and airless hotel gym is pretty much asking to get sick. After the 30 minutes, I jumped in a hot bath, right up to my neck, to try to heat all my muscles and allow them to de-tension a bit. On Wednesday evening I went out for a short and easy 20-minute jog, and jumped into another hot bath. It was scorching (on the run and in the bath) and I was sweating so much that I poured an entire litre of cold water over my head (in the bath). As well as treating myself to a scorching hot bath, I also treated myself to some steak...

Who photographs their food anyway?!

It was uncomfortably hot at night, but I didn’t want to put the air conditioning on. It’s an old hotel, with an ancient ventilation system. Turning it on would have been asking to get sick. So instead I slept with no covers and tried to make the best of it, but I didn’t sleep great. It’s not that long since I was in Italy and it was freezing, icy and snowy, when I filled the bin in the hotel room with hot steaming water, and I put it beside my bed to try to humidify the room at night. The things I do. Crazy.

I had brought with me three big tupperware boxes full of oranges, bananas, apples, flapjacks and vitamin tablets. Fruit is delicate as I discovered to my detriment on a previous trip, when I opened my bag to discover squashed banana mulch all over my stuff. Put the fruit in a tupperware box and at least it is protected.

My Garmin bike computer was also protected by one of these boxes, and I spent some time this week fiddling about with it in Italy. Having invested in a power meter this season (I say invested rather than bought, it makes me feel better…), I now need to work out what data I want to have displayed when I am on the road. I still haven’t worked this out. A single screen can have 8 data fields displayed, and ideally I don’t want to have to programme the Garmin to scroll through different screens, I want it all on one screen. But there is too much data for a single screen – I want to be able to see current speed, average speed, distance, time, cadence, heart rate, average heart rate, 3-second power, average power, intensity factor/%FTP, and normalised power. So I’ll have to get my thinking cap on and sort my power meter data fields. I've also been buying a few bits and pieces because I'll have to get my bike serviced before the time trial next week.

Possibly the best tyres you can buy:
Continental GP 4000 S II with black chili compound.
At £60, they better be good and not puncture...!

Bike servicing orders...
To this was added "properly lube chain and transmission",
"replace any bearings if necessary", and "check greasing of
all bearings including wheel bearings and regrease if necessary".
Need to have 100% confidence in the bike!

I survived Italy and used the weekend to catch up on sleep. I’ve found it’s much more effective to go to bed at the same time each night, rather than staying up a bit later at the weekend and then sleeping very late. Last season, I used to really binge on sleep at the weekend, and stay in bed until as late as 11am. Now I try to get up between 9 and 10am at the weekend, which keeps my natural body clock slightly more aligned. During my weekend swims this week, I felt that my right shoulder and down through my upper right arm was a bit sore. So much so that on Sunday in the pool, I mostly did kicking drills without much arm action at all. I hope that tapering down for the 100 miler next week and not doing much swimming or weights will allow it to settle. I also noticed that my right calf is a bit sore, and again all I can do is hope that the easy tapering week ahead will allow this to settle down too. Cross my fingers and hope for the best…

My Ironman bike strategy this year will be to “spike” as little as possible. I’ll really try to minimise spikes in heart rate and power output – this will mean taking it a bit easier up the hills, using lower gears, and not accelerating too quickly out of the corners. I’ll keep everything nice and steady and controlled on the bike. This will hopefully set me up for a better marathon. I’d rather lose 5 minutes on the bike and gain 20 minutes on the run.

With the power meter, I can now do a lot of number analysis. I like this, as I enjoy working with numbers, graphs, data and science. With the power meter, I can know the intensity factor (IF) and variability index (VI) of my training (and racing). These are interesting figures, but to understand these, some other values must be discussed. The power meter tells me my instantaneous power (based on a 3-second average). That’s easy to understand. It also tells me my average power – again simple to understand – the numerical average of my power for an entire session, including any times at zero power (for example when freewheeling).

It also tells me the normalised power. This is a bit more difficult to understand. When riding, power output is rarely constant, especially on the road – hills, weather conditions, road surfaces and all sorts of factors combine to make a power output graph look “jumpy”. Normalised power is simply an estimate of the power output that could have been maintained for a ride if the power output had been completely constant. Normalised power will always be higher than average power. Makes sense…?!

Variability Index is another important measure. If a ride is not “consistent” and involves lots of surging, climbing and accelerating, it stands to reason that normalised power described above will be much higher than average power, and the ride will feel tiring. If a rider maintains a consistent power output, then the normalised power and average power will be more similar. VI is a measure of how steady a rider’s power output was. Normalised power divided by average power equals variability index. Let’s say I did a smooth turbo session at an average of 250 watts for 2 hours. Let’s say that my output for this turbo session was fairly consistent, with no surges or high-intensity efforts. My normalised power might therefore be 255 watts. My VI would be 255/250 = 1.02.

Now, let’s say I cycled the Ironman UK bike course – a tough, hilly, twisty 112 miles. Let’s say I averaged 210 watts for 5-and-a-half hours. Let’s say I didn’t hold back, pushed hard up the hills, and accelerated hard out of the corners, and generally rode the course as if I didn’t have to run a marathon afterwards. My normalised power might be 240 watts. My VI would be 240/210 = 1.14. The closer the VI is to 1.0, the smoother the output over the whole ride. VI is very important for Ironman triathlon pacing, and should be less than 1.06.

Next, we have Intensity Factor (IF), which requires knowledge of threshold power. My threshold power is the maximum power output I can sustain for one hour. A one-hour threshold power test is a very tough session, so it can also be calculated by multiplying the 20-minute value by 0.95. A couple of months ago, my 20-minute test value was 324 watts, giving a threshold power of 307 watts (I’d like to think this value has improved since I did the test, and I will re-test myself in the next few weeks).

Anyway, the IF is the ratio of normalised power to threshold power. If I did the Ironman bike and my normalised power was 240 watts, given that my threshold power is 307 watts, then my IF for the Ironman bike would be 240/307 = 0.78. Generally, the intensity factor for “recovery rides” should be less than 0.75. An IF of around 1.0 could be sustained for a 40km time trial (roughly equivalent to a 60-minute threshold power test).

All this data can also be used to work out my Training Stress Score (TSS), which helps to determine how much rest is needed after training and how hard the training was. TSS = IF squared x time in hours x 100. A “very high” TSS would be 450+, requiring several days of recovery. But back to IF…

Generally on tough, twisty, hilly Ironman courses (such as Ironman Wales and Ironman UK), it’s easy to “spike” repeatedly. I know this from experience, as my heart rate got to over 170bpm on quite a few occasions in the bike section of these races. This would have led to a high intensity factor and a high variability index, setting me up for a poor marathon. My standalone run times indicate that my Ironman running should be much better than it is. So, maybe the problem is with the bike, and I need to calm things down, keep the bike nice and smooth, and preserve myself as much as possible. Then I might run a better Ironman marathon.

Tables exist to tell you how hard you should ride the Ironman bike. For me, I’m looking for something around 5:30 for the bike at Ironman UK. In a flat Ironman, I’d be well under 5 hours, but for Ironman UK, I’m looking at 5:20 to 5:30. According to the table below, if I assume that I am a “proven, strong Ironman runner” then I should ride at an intensity factor of somewhere between 0.73 to 0.75 to give me an optimal Ironman bike time which will also allow me to run a good marathon. This optimal Ironman bike time will be slower than if it was a standalone bike time, but Ironman is a sum of three parts… This level of holding back on the bike requires a huge amount of discipline and trust in the numbers.

On Saturday I did 2:20 on the turbo, with 2 hours at around Ironman intensity. I made the second hour a bit tougher than the first. For the first hour my IF was 0.73 (bang on for an Ironman), and for the second hour it was 0.81. The power difference between the first and second hour was 27 watts, and my heart rate only averaged 12bpm more for the second hour. So there’s a fine line between “too hard” and “not hard enough”. I’ll do a few more longer sessions at Ironman IF to learn how it feels and to see how my heart rate responds over a longer time, and to see how running feels afterwards.

A purist might say that all this data detracts from the age-old business of racing without technology, of judging by feel, of going at it without being “guided” by timers, beeps, power meters or heart rate monitors. I did the 2013 Ironman season without a power meter or a heart rate monitor. In 2014 I had a heart rate monitor, and it helped a lot. In 2015, I’ve got the heart rate monitor and a power meter, and they both help a lot. There’s a justifiable argument that says without these tools, you are disadvantaging yourself, and with the data available and the assistance with judging how hard to push, they are definitely useful. Unlike doping, heart rate monitors and power meters are completely legal, and are used by pros and amateurs alike, almost as standard. I’m looking forward to getting all this data on the 100 mile time trial next week.

But equally, you still have to have the fitness, the discipline and the strength. No amount of gadgetry or equipment or anything else can help you in the Ironman “death zone” beyond mile 16 of the marathon… then it comes down to pure guts and determination, when you find out how much you really want it…

Training done this week was as follows:

Mon 4 May: Rest
Tue 5 May: 30 minute ex bike
Wed 6 May: 20 minute run
Thu 7 May: Rest
Fri 8 May: Swim 3k (5 x 400m: 5:55-6:20, 40 second recovery)
Sat 9 May: 2:20 turbo (1 hour at 221W/141bpm/IF 0.73, 1 hour at 248W/153bpm/IF 0.81), 25 min run
Sun 10 May: Swim 3.1k (250s, normal/legs), 30 minute turbo, 30 minute fartlek run

Totals: Swim 6.1km, Bike 66 miles, Run 11 miles.