Friday, 19 September 2014

Using a GPS watch for running

GPS watches are fantastic tools that provide accuracy and valuable feedback for running. The most obvious feature that a GPS provides that you cannot get from other heart rate monitors or watches is real time distance and pace feedback from the GPS location data. In addition to this, most new GPS watches provide data fields including chronograph, heart rate, elevation gained and lost, calories used, ground contact time, vertical oscillation and many others. Post training or racing, most GPS watches provide a means to transfer the run's data to a computer or online tracking site thereby reducing the need to write down and capture data manually. Digital records are much more searchable, provide better input for long-term analysis and are quite secure (especially if stored in a few places).

I'm a huge fan of using a GPS watch and have logged almost every training session that I've done in the last three years using a GPS watch. The data has been extremely useful for me. I've been able to analyze trends in my training, share the data with my coach immediately after uploading it, review race profiles and routes that I've run repeatedly, and collect an objective set of data about my performance. I know that training and racing cannot be analyzed and measured purely by the objective data, confidence and enjoyment and feeling are vital too, but there is definitely no cost in recording this data and adding it to create a robust training environment.

GPS watches

There are lots of options for GPS watches! The two largest manufacturers are Garmin and Suunto, but there are lots of options beyond this like Polar, Oregon Scientific, TomTom, Adidas, Nike and others. It's easy to be overwhelmed by different features, specifications and watch brands. I think that the three key aspects of a watch that need to be considered are the data recorded and displayed, the battery life, and device size. There is a compromise between these features, for example a longer battery life necessitates a large watch size, more data options often require additional sensors therefore requiring a larger watch body.

I would suggest the way to choose a watch is to start with the features needed. To track simple data like distance, time and pace the simplest and cheapest GPS watch can provide that data. These are the introductory watches in most brands' range of watches. From there the options become more diverse as specific features are added. A trail runner who spends lots of time in the mountains would want a watch that includes the basic features along an altimeter to measure vertical gain and loss. A runner following a heart rate training program would want a watch that can provide that information. After deciding on the features the next step is think about the battery life. Most watches provide about ten hours of GPS recording which should be sufficient for almost all training and racing, however, an ultra-marathon runner might need to look for a watch with greater battery life. After picking the features and battery life, the options have probably been narrowed significantly and there's only one or two choices in terms of size and brand. Choose the watch that fits best and is the smallest and lightest for the features desired.

My Garmin Fenix 2.

I use the Garmin Fenix 2. It provides the data that I want: time, distance, heart rate, vertical gain, and has the ability to program in workouts (more detail later). The battery life is about 20 hours in the most accurate recording mode and can be extended to 50 hours for ultra-marathons. The size and fit are good for me. My first GPS watch was a Garmin 310XT and it worked perfectly. Based on that experience, familiarity with the functions and the fact that I have thousands of kilometers recorded in Garmin's training logs it made sense for me to stay with Garmin. I couldn't be happier with the Fenix 2 and would recommend it if you're looking for the same features that I am.

While I make it sound quite simple, there is a lot of choice and it can be confusing and difficult to decide what to get. The best resource that I've found for reviewing and seeing the various GPS watches is DC Rainmaker. He has very, very detailed reviews on almost all the GPS watches and provides tables of data to compare various options.

Data Pages

Setting up the GPS watch and deciding what information will be displayed during a run is the next step. There are many different options for various data fields that can be shown and most watches have options of how they can be set them up. Each "page" is a set of fields on the watch screen. Generally watches show three or four data fields on each data page and can have a number of different data pages that can be scrolled through during a run. My straight-forward guidance for choosing data fields is to select the fields most important to the runner often based on the reason for selecting a specific watch.

I have a a main data page that I always use when racing and training. It contains the three most important fields for me: time, current heart rate and distance. The time tells me how long I've been out and allows me to follow a schedule for nutrition. The current heart rate field I use to guide my effort and to help me follow the expectations of my coach while I'm out running. The distance lets me know how far I've gone and in a race it also can be used to calculate the distance to the next checkpoint or finish. If I'm doing a trail run I also add a page of vertical ascent that shows the total vertical ascent for the run and a rate of ascent. The total ascent is a useful measure as it can be used as a verifying factor of what point I am at in a race (to coroborate the distance reading) and lets me aim for specific vertical gain goals in training. The rate of ascent helps me to judge the steepness of an ascent and my progress which I find most useful when running on gradients that are not steep, but don't feel flat either.

My main data page: heart rate, time, and distance.

A key training session that I do is a performance check that I run every few weeks. The goal of the training session is to test how long it takes me to run a specific distance (12km) at a heart rate level (140-145bpm). Hopefully over time as my fitness improves the time for the route will improve at the same effort. I have a data page set up for this run. I need to know my heart rate to control the effort, and I need to know the distance to make sure I run the 12km. However, I don't want to know my time or pace as this might influence me to try and run faster or beat previous times by running harder and going outside the heart rate range. This is a great example of where using a GPS watch can guide training, but also limit certain information so the session meets a specific purpose.

My performance test data page - heart rate and distance only.

These are two useful pages for me and the key data fields that I like to look at. I often have other pages set up in case I need the data or if I want to achieve a specific goal for a run. Fields like pace, which are not that important for me as a trail runner, and running metrics like cadence are useful to have on background pages if I do want to check on them.

Alerts and workouts

Along with displaying data fields and pages while running, a GPS watch can also display alerts. An alert notifies the runner when a specific event has occurred. There are plenty of different options for alerts based on: distance, time, heart rate, vertical gain, proximity and others. The alert displays a notification on the device screen and can also vibrate and/or play a tone. Alerts are useful as they can be reminders of progress, warnings to change an effort level and they can also provide intermittent information that is different to the data fields on the current data page.

I like to use a 30 minute time alert during all my runs. This lets me know every 30 minutes that I need to take on some nutrition or drink. I also like to use an ascent alert that lets me know every 100m of vertical climbing that I've done as a progress alert. When racing I also set up an auto lap every 30 minutes. This records a lap on the same basis as my nutrition plan and lets me analyze each 30 minute segment after my race. I like to think about making it to the next nutrition point and use that as a motivational tool when racing so it's useful to analyze each segment and lap on that basis. I haven't tried it yet, but I'd like to put in proximity alerts for the aid stations during a race. The idea is that the aid station GPS coordinates would be logged on my watch and then when I reach a point that is 1km away from the aid station I get a warning so I can prepare for it.

There are also alerts that can be set up based on a range of paces or heart rate values. Whenever the pace or heart rate falls outside of the range the watch provides an alert. These can be extremely useful alerts when training, but I find them less useful when racing as my pace and effort can often be based on the race conditions and competitors.

Workouts are another extremely useful feature of GPS watches. I use a workout on my watch for every hard or focused training session. The workout is set up on the watch or online and it provides alerts for each step of the training session. For example an interval workout might be set up as follows:

  1. warm-up until lap key is pressed - no goal effort
  2. run for 1km - pace alerts when outside the range 3:50min/km : 4:10min/km
  3. rest for one minute - no goal effort
  4. repeat steps 2-3 six times
  5. cool-down until lap key is pressed

My watch will then guide me through the training effort. I'll warm-up until I press the lap key which is when the first interval starts. During the first interval the watch will alert me if I run too slow or too fast and I'll get a notification when the 1km distance is complete which automatically starts the rest period. I rest and after a minute the watch automatically starts the next interval. After all the intervals and rest periods are complete, the cool-down is started and that ends when I press the lap key.

It's possible to create many different (and much more complex) workouts. The watch can also display the normal data pages or a specific workout data page. During my interval sessions the watch will change the data page automatically depending on where I am in the training session. For example, during an interval the distance and pace will be displayed. During the rest period the time and my heart rate will be displayed. Without a doubt these workouts are extremely useful tools for training as they easily guide the runner through each step without a need for measuring the distance or time or route and with alerts to regulate the level of effort.

Racing

Racing always brings its own set of challenges that test the runner and equipment to the absolute maximum. Usually I find that my GPS watch functions exactly as it should and provides me the same data and alerts that I've used repeatedly in training. However, a watch shouldn't be relied on extensively during a race for multiple reasons. The first is that the distance of the race may be measured slightly differently due to discrepancies between different GPS devices. This can have a huge effect when trying to pace a marathon for a certain time. In a trail race there can be differences between the route listed in the race information and the distances and vertical gain that you see on your watch. While these differences may be small and generally are insignificant, they can affect motivation during the race which is important to keep at a high level.

I used my Garmin 310XT in the Kalahari last year and it worked well. However, I used a combination of a footpod for measuring the distance and the GPS for measuring the distance depending on the importance of the stage. The footpod measures the same information as GPS although it is slightly less accurate. The benefit is that the footpod uses a lot less battery power meaning that the watch would last for the full length of the race at over 20 hours. [With my Garmin Fenix 2 I will no longer have to make this adjustment.] In the Amazon this year I was working on the same footpod and GPS arrangement and it turned out that I used the footpod much more because it was more accurate. The foliage and trees were so dense in the jungle that the watch would lose satellite connections and measure the distances as being much less than they actually were.

Some conditions are super challenging even for the best equipment!

The key to remember is that you must rely on your feelings and the feedback that you get from you body to help set a race effort. A GPS watch can help tremendously (I use the heart rate function for managing my effort and the time for planning my nutrition when racing), but it can also fail or face unexpected issues like a jungle too dense to get reception. Like every tool, no matter how useful, the runner must be prepared for the occasions when the tool doesn't work as planned.


A GPS watch is a valuable tool that can provide very specific information and take training to a new level in terms of consistency and feedback. It is not necessary to use a GPS watch during every session or it could be used to record the session for later feedback without showing data fields that might influence the run. When using a GPS the quality and detail with which the training session can be managed far exceeds any other means of measurement. I would seriously recommend embracing this form of technology as a means to provide an useful advantage in training and racing.

3 comments:

  1. Daniel, what software are you using to analyze your running data? I typically use Garmin Connect or Strava for a quick and dirty view but I'm not happy with them for detailed analysis. Eventually, I wrote my own website www.GraphMyRun.com to do some deep dives on my run data. Take a look and let me know what you think! Thanks! Best, Phil

    ReplyDelete

I'd love to hear from you and get your perspective on my stories, thoughts and training. Please feel free to comment.