Saturday, December 5, 2009

SportTracks "Training Load" Plug-In Primer

My new Garmin 310XT has taken over my life!!! Actually, I've been obsessing over the thing over the past few days and thought it may be of some value to pass on the results of my research...

My friend Justin suggested I look at Sporttracks. This program is an incredibly powerful way of unlocking many of the things Garmin watches can do, without the limitations of Garmin Connect, Garmin's online program.

Sporttracks is reasonably priced payware that enables you to download your activities from the Garmin into a logbook where you can monitor where you went and see all the data at all the points that you were at (things like heart rate, speed, etc.).

Unlike Garmin Connect, you can easily edit workouts, data points, and check total data for laps, sections of laps, or any part of any workout you'd like.

Given SportTracks licensing model, a community of users and developers has formed. As a result, there are a plethora of very useful add-ons, called plug-ins. These enable you to, among other things:

- download from the nearest weather station the weather for your ride or run;
- calculate headwind and tailwind for any point on your ride/run;
- analyze power for your ride/run;
- correct the elevation, using known elevation of points on the earth (GPS in general is only accurate +/- 10m, apparently I was surfing 12m waves whilst paddling in an outrigger canoe last week!);
- transfer all this data to workout websites, like, where you can analyze it further, and share it with others;
- upload data from other devices, like Polar's high-end heart rate monitor models; and
- import and export historical data from spreadsheets, so you can transfer all of that historical data from months and years ago.

The most fascinating plug-in for me is one called Training Load. It's very similar to a program called Training Peaks WKO+ Training Manager. This thing can act as a virtual coach, and with a little research can tell you how your fitness is improving, if you are training too much or too little, when to start tapering for a big event, and how to manage your fitness and rest to ensure you get there on a peak. It does this by applying known rates of change of fatigue, fitness, and performance based on one's training load - i.e. the stress that you subject your body to that improves your fitness - and the rest you take during which your fitness may decay whilst your fatigue decreases.

Training Peaks Training Manager is designed for cyclists, and it uses power data to determine a daily training stress score (TSS), which is just basically a way of quantifying how much a particular workout can contribute to your overall fitness. Some disadvantages of using Traning Peaks Training Manager include the fact that it is expensive, and it is for cycling only, so of limited use if you are a multi-sport athlete. You also need a power meter to use it. Power meters these days are very expensive ($1000 USD and up), and somewhat heavy, though a number of companies are promising lighter and better power-monitoring units for 2010).

The training stress score in the Training Load plug-in of Sporttracks uses only heart rate data, not power, so you don't need a power-meter, and it's results are valid for just about all endurance sports (though it takes a bit of effort to make it work for swimming, since nobody has figured out how to collect heart rate data under water). From the time you spend in different heart rate zones (all configurable in Sporttracks), it calculates a Training Impulse, or TRIMP. TRIMP basically determines a value for workout stress based on the time you spend in each zone, and gives you more credit for time spent in the harder, higher zones. Apparently, there is much research that shows that the use of TRIMP to determine training stress is quite valid, but very little to show that power does, so the results that you'd get from the Training Loads plug-in are perhaps even better than those you'd get from Training Peaks Training Manager.

There are a few good blogs out there that show the power of this plug-in in action, like this, this, and this.

However, it's not the easiest thing to use, as there is no manual, and all the information from the developer is posted in the form of a user forum, which takes a while to get through. Also, the flexibility of Sporttracks gives it somewhat of a lack of user-friendliness, though you quickly get used to its quirkiness after a few uses (meaning, after a few intimate late night sessions with the computer!).

In posts to come I plan on explaining some of the basic features of Training Manager in the form of a primer. I'll also explain how you can use Sporttracks to pump some of that data out to sharing web sites, like, and show how it can simplify the analysis of all that data.

In the meantime, here's my latest Training Load Chart (click image for larger):

The gold bars show my Training Stress Score for each day, with the column breaks giving me an idea of how much time I spent in each of heart rate zones 1-5. The jagged red line gives me an idea of my acute, or short term training stress. The blue area chart show my improving fitness level up to today (December 5th), and predicts how my fitness will decay if I do no exercise thereafter. The greyish-green area chart shows how my Training Stress Balance (sometimes referred to as "form") is getting really low because I've been training so much, but also tells me that if I do nothing after today, it may hit zero in mid-December.

The red curved line is the influence line. It tells me that the training I do around Feb 01 to Mar 08 (where the bulge is) will have the most influence on my performance on a half-Ironman I hope to do on March 21st. The curve goes negative on March 11th, meaning that if I do a lot of training after that, it will only have a negative effect on my performance, so that is when I will start to taper.


  1. Your fitness is not necessarily increasing becasue the blue line is going up, it's just a product of you accumulating data in the first 45 days. If after 45 days it continues to rise then you know you're getting fitter. Ignore the first 2 month's data- it's just you establishing an initial set of data to then work with.

  2. True. I guess it's only correct to say that fitness is increasing if you've been completely sendentary prior. I'm in the process of entering all my Polar data back to August. Not a simple task since there is no way to get data from the Polar Personal Trainer to Sporttracks. Plus, I have to build heart rate tracks (time in zone) to get accurate TRIMP results. Curious to see what the curves will look like.

  3. great write up! geez, i wish i could ride more these days, but the 2x20min commute in -25C is plenty for the time being.

    But some friends and I have been thinking that a gps-google mashup would be a good way to map some of the trails in k-country. no doubt someone's already on the case.

    a small detail; technically speaking, the iphone is not open source. Apple allows 3rd parties to develop apps for the iphone using their software development kit, but the iphone OS itself is not open source, and apple reserves the right to ban/delete apps as it sees fit. The apps themselves may or may not be open source, depending on how they are developped.

  4. SportTracks isn't open source, either.

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