Guides and tricks

Things I used on the IM70.3 Portugal and how it was configured


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A few days ago a reader asked in the Ironman 70.3 Portugal about which clock I used during the race. As is often the case when I am near a keyboard what can be answered with three or four words at the end becomes thousands of words. This is how I work.

Not only because there were really several devices used, but also because I can go into more detail about the reasons for the different choices. And besides telling you which devices I took, I will take the opportunity to comment on how they were configured.

I think it may end up being quite an interesting article, especially considering that I am not a "standard user" and that, to give a simple example, I can choose from many multisport watches when it comes to racing.

I'll tell you what I used DURING the race, but this doesn't include what I used during training (which is quite a few other things and I don't leave them here, including very different watches) and BEFORE the race, when I made a lot of use of the Compex both to regain legs after the long car ride and to oxygenate the left twin, which was arriving quite heavily at the appointment.

Devices and sensors I used during the race

Before going into more detail about each sport and its specific sensors I will start with the watch used. On this occasion I chose the Garmin Forerunner 935Most people will probably think this is the most logical choice, as it is Garmin's top model for triathlon.

Well, I'm sorry to disappoint you. Choosing the FR935 was not because of having the quick mount kit (which I didn't use), or because of its higher performance compared to other models; but mainly because of its size and weight. And of course for supporting all the sensors I wanted to use during the race which in the end is what matters most to me. I could have used any other one like the Fenix 3. But the advantage of the new 935 is that its size is quite contained, something very important when you have to wear it under your neoprene and you don't want to have many problems when you take it off.

It was in this watch that I recorded all the data from the competition for later analysis, but not the only thing I used. But we go through every sport.


During swimming the only sensor I can use is the pulse sensor. The idea was to bring the sensor HRM-Tri during swimming and cycling, and when the race arrives assess whether to remove it and switch to the optical sensor to avoid possible discomfort from rubbing.

Garmin HRM-Tri

The choice of the HRM-Tri is simply because of its memory, which allows the data to be stored while transmission to the watch is not possible. When the race is over the watch synchronizes with the sensor and downloads all the data, adding it to the activity file. When worn under the wetsuit and neoprene there is not a single movement - as there is in the pool - so the record is not perfect at all times.



Swimming is quite simple as there are not many things you can use, but when you get on the bike things get a little more complicated.

Although I continued to wear the 935 on my wrist, in the cycling segment I didn't look at it once. For the bike I chose to use the Garmin Edge 520The watch on my wrist can be more difficult to see, while the computer is always in front of my eyes, in the front hydration system (I use the Profile Design FC35).


Why Edge 520 and not another one? Well, it's also very simple. It's the only cycling computer I own, everything else that's gone through the test page has been returned. Edge 520 perfectly meets all my needs for both training and racing, so I don't need to move to a different unit.

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Garmin Edge 520 - K-Edge Support

As far as sensors are concerned, in addition to continuing to use the HRM-Tri, he was wearing the new Favero Assioma pedals. They have recently replaced the bePRO pedals from the same manufacturer, and are just as reliable as the previous ones. The change is due to their Bluetooth compatibility (for the various tests and analyses), because although they are much easier to change from one bike to another, this was not the determining reason.

Favero Assioma

The pedals themselves give me cadence information (as this is necessary for calculating power), so I can dispense with this sensor, which in this case would be the Wahoo Blue SCAnd as for the speed sensor... honestly, I don't care about speed or distance, plus in the conditions of this race with the Edge 520's own GPS it's more than enough.

Although the Edge 520 was recording the activity, I discarded its file, because I already have my watch to record the data. The only thing that interests me about the Edge is to see the data on screen.


I get off the bike and the Edge 520 stays behind, back to the Garmin 935.

Garmin Forerunner 935 - GPS and GLONASS

As I told you before, the initial idea was to leave the HRM-Tri sensor in T2 and run with the optical sensor of the watch. Finally I decided to take it with me, if it bothered me during the half marathon I could take it off at any time. In the end the sensor was going to be the last of my problems...

For running there was another device that accompanied me and much more important to regulate the pace, the race power meter StrydThis little device will give me power data during the whole race, which especially on the constant Cascais slopes would be very useful. But it does not only give me power data. Being paired to the clock also as a pedometer it gives absolutely reliable information of pace and distance without any delay. Much more precise than GPS.


Display settings

Now that you know what devices I had, let's go with the configuration I chose for the different devices, both for data screens and for alerts or automatic rounds.


To be honest I have no idea what data screens I have set up for open water swimming, simply because I don't look at the watch while I'm swimming. Obviously I'm not going to stop my strokes to see any data, I'm just guided by feelings.

I'm not exactly a fast swimmer, on the contrary, but I'm not the last one in the group either. What I do have is a pretty good regulation capacity. In fact, for the 1,900m swim I estimated that it would take about 35 minutes... and that's exactly how long it took.

Going back to the settings, I haven't changed what comes standard with the clock, in fact with the time and distance display I have more than enough for the workouts, as I leave the series to the pool.

What I do have active is the autolap, configured every 500m. In this way the watch vibrates every time I reach that distance, and as each buoy is at a certain distance it serves as a reference to know how my navigation is going and if I do more meters than necessary. Likewise, I also know the remaining distance and it helps me to be able to regulate the effort as I go along.


Again, I have no idea what screen settings I have on the clock for the bike segment. As I said before, the clock simply goes there to record the activity, but not to be consulted.

Edge 520 is different. Here I have it perfectly configured for the occasion. In fact, I have a different sport profile for training than for competition, where I only use one screen with the only data that interests me, which are the following:

  • WeatherIn this case it is the total time on the bike. On the watch I could take the total time of multisport (i.e. including swimming and T1), but I prefer to calculate the duration of the bike independently.
  • Power at 3 secondsI choose the 3-second option because it avoids excessive variability of the instantaneous power and for my taste 10 seconds on average is too long to see changes quickly.

Those are my two main fields, located at the top of the screen and to which I pay more attention. Additionally I have also configured these others to smaller size:

  • Intensity factorI was also interested in the conditions of the route, starting below that figure and going up from the middle of the race (that is, when the climbs arrived).
  • Rated powerVery similar to the above, but looking at it in a different way. The information it gives me is exactly the same: real intensity up to that moment, but in this case in watts. Remember that nominal power is not the same as average power as I explain in the Garmin Connect guide.
  • Rated power in turnsIt's ideal to compare the intensity I'm doing on the current lap with the total intensity. One data is next to the other, so I can check it at a very quick glance and see if my performance is dropping even though by feeling the effort is the same.
  • PendingIt's not very important, but I want it there to know if the reason I'm having trouble moving forward is because my legs are dead or because the slope is too steep. It's also very useful on the false plains, where it suddenly seems that you're having trouble moving forward and you feel like you're being slowed down, but the reality is that the road has a slight slope of 0.8%. It's a field of psychological reassurance that I don't really use in the development of the race for any kind of calculation.
  • CadenceI use it simply as a reminder to change gears up or down, and to check for feelings of pedaling too fast or too slow. It also serves as a fatigue warning, because when I start to get tired I tend to slow down.
  • Heart rateI am guided by the power alone, but I can compare with the heart rate and see if there is a problem. If I am putting 250W on the pedals and my heart rate is 165, something is obviously wrong.

Things I used on the IM70.3 Portugal and how it was configured 1

And that's all. No speed, because I have no interest in knowing whether I'm going faster or slower; nor distance -I'll get there.

As for other settings, I programmed an alarm to alert me if I reached POWER zone 6. That is, the alarm would sound if I exceeded 314W. It does not mean that I stop pedaling immediately, it is simply a "beware" warning. That is to say, if I am overtaking until I leave the 10 meters of rigor I do not mind too much pedaling at 350W for example, but not to make a climb for 5 minutes.

The automatic lap setting was set to the default distance of 5 kilometres, but simply to be able to contrast the nominal power data seen previously. If I didn't have a fish memory I would choose to mark the laps manually between the points I am interested in (flat part, uphill, downhill, etc.) and carry the power in a much more reliable way with respect to the terrain, but I know I will forget it.

So here I do look very carefully at what data I want to control and how to control it. Not for nothing is the longest segment of any triathlon, and here the excesses will take their toll later, as I saw on a T-shirt the day before: Swim, Overbike, Walk.


After the bike, back to the clock. Here too, I am very clear about which data I want to see on the screen and which I will pay attention to. In order of importance, these are the data:

  • Stryd PowerIt's the main value that I contemplate while I'm running, especially on winding terrain like the Cascais course. It allows me to perfectly regulate the intensity between the ups and downs. It's what I look at most... until fatigue sets in and I lose my concentration and simply go for sensations, forgetting about the power. It's a field that is downloaded from Connect IQ and that depends, logically, on the external sensor.
  • Rhythm in returnDifferent from the instantaneous one, since it is much less variable. Every kilometer (which is the autolap I have configured) is updated. I use it to confirm sensations. It is usual that as fatigue arrives my running economy worsens, with a reduction in the average pace in spite of maintaining the same power levels.
  • Heart rate which, like cycling, I use as a mere reference to compare data; but I do not look for particular frequency ranges.
  • WeatherFinally, the time I've been running. As in the cycling segment, only the time of the race segment since it is a question of having a reference to the target times set before the competition for each of the segments.

Garmin Forerunner 935 Display Settings

Additionally I have a second screen with the same data but replacing the race time by the total multisport time. I change to this screen when I have a few kilometers left to run so I can estimate my final time at the finish line.

Here I don't carry any alerts of any kind and, as during cycling, I use the autolap function to automatically have values to compare, in this case the lap time. Again I could use the manual laps in a much more intelligent way, but I know that I will forget about marking them.


Here it is, my tactic totally exposed. This is just one of the thousands of options that exist both of devices to use and the way to configure them. I hope you can extract some ideas, although the most important thing is that you find a combination and configuration that best suits you and your goals.

In terms of devices used you will see that there is a lot of Garmin. You might be thinking, "if he uses it, then that's as good as it gets".

Well no, as I said at the beginning it is simply what was best suited to the competition I was going to do, in what was most important was the combination of sensors to be used beyond the clock or cycling unit, which are simply there to display or record information from them.

Where a watch or cycling unit is most important is not in the day of the competition, but mainly in the day-to-day of your training, and that's where you have to make sure that what you buy is what suits your particular use.

Nothing else, thanks for reading!

Eduardo Mateos

I've been surrounded by electronic devices of all kinds for more than 25 years. Using them, testing them, taking them apart and dissecting them. Long distance triathlete: I swim, run and cycle for a long time. Maybe too much.

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  1. Thank you Eduardo, as always very interesting and constructive.
    On this occasion I have a question/suggestion. Could you provide more information on the usefulness and conditions in which Compex-type electrostimulators should be used?
    As an amateur runner, I suffer sporadic physical problems that I don't know to what extent they could be solved or at least prevented with this type of apparatus.
    Thanks in advance.

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