*** many thanks to Finn "Dataman" Zwager for this blog post.  Dataman explains what data to collect and how to do it. He also scratches the surface on watches and tells you where to get more in-depth information ***

In the last blog post I said we’d be looking at collecting training and non-training metrics. Let’s start by reviewing the non-training metrics I (attempt to) collect myself.  [Click on the chart for a larger version]

SIDE BAR: Withings Scale.

There are many good scales out there.  This one is cool as it uses your Wifi network to send your data directly to your app or to your Trainingpeaks account (for instance). It also measures your fat percentage by measuring electrical resistance between your two legs and then making a calculation based on a body model stored in the scale. This is not very accurate, but because you are always using the same method the result should still give you a reasonable idea of the changes in fat percentage. Ideally you would calibrate this measurement by using another method, such as the ones that use electrical resistance throughout your body by measuring it from your foot to your hand. Using this method, I discovered that my fat percentage hovers around 12, not 6 as my scale was telling me. (Needless to say I was depressed for a week and only ate fried, cooked or baked air). Changing the body composition profile in the scale settings from athlete (“Those who practice sports more than eight hours a week and who have a resting heart rate below 60 bpm”, according to Withings, although I train way over 8 hours per week and my resting heart rate is 37), to normal fixed the problem.

[click on the chart below for a larger version of the training metrics]


I’m not going to go into much detail on watches as there are already many great reviews out there. By far the most comprehensive reviews can be read on the website of DCRainmaker. His reviews and measuring tips are very detailed and yet easy to read and understand. If you are serious about data collection and considering any new equipment purchase you should really visit his website

For Dubai based triathletes the Garmin range seems to be the most popular. Garmin has two triathlon specific models, the 310XT and the new model that came out a bit over a year ago, the 910XT. Besides being a bit less bulky than the 310XT it gives much enhanced swim data. But, unless you really plan to focus on swimming efficiency, for instance because it is your weakest sport, the 310XT is currently a good choice as it is quite a bit cheaper than the 910XT (and you may be able to get them second hand from those who upgraded to the 910XT).

The second most popular choice may be the watches from Polar. The main difference with Garmin is that Polar comes from a heart rate measuring background and Garmin from a GPS/mapping background. Polar watches tend to have slightly cumbersome GPS measurement (most models use a separate GPS pod, which makes for very slim watches) and more accurate heart rate (straps). Other well-known makes are Suunto, Timex and the Decathlon home brand, most of which can be bought in Dubai. Lastly, there are also specialised swim watches such as Finis Swimsense and Garmin has one now as well. DC Rainmaker's web pages will give you all the details.

SIDE BAR: Heart rate straps problems.

After using them for some time, in my case a few months, I often find that I start getting in-accurate heart rate readings with the values jumping all over the place. Of course, being ‘Data man’, when this happens it totally throws me into next week. My wife reminding me that I can also “just train” usually doesn’t help! The culprit is the heart rate strap. Your watch manual will tell you to remove the heart rate sensor immediately after training, give the strap a rinse and hang it out to dry. But, if I train outside Dubai more often than not I end up stuffing the sweaty strap in a bag and I suspect many of you are not too consistent with the rinsing and drying either. But, even when taking care of the strap I find that they go haywire after a while. Team members and the internet offer steps to a possible solution:

  1. Wash the strap (not the sensor!!!) in the washing machine. This sometimes helps fix the problem for a while.
  2. Thoroughly clean the sensor-strap connectors as they can get corroded (sweat is basically salt water).
  3. Replace the strap with another one. Garmin sensors are compatible with Polar Decathlon straps.
  4. Replace the sensor/strap combination. If you watch is ANT+ compatible you can connect any ANT+ sensor.

Until next month.

Yours in training, Dataman.