The Proper Use of a Garmin GPS Watch in Training.

This post was inspired by a reader who commented on my last blog post.  I mentioned in the Dallas White Rock Marathon Recap that I used a Garmin GPS watch in the marathon and that I never wear it in a race.  The comment asked if I basically could elaborate on wearing a GPS watch in training vs in racing. Several of the people I coach have had issues with Garmin GPS watches messing with their heads in training.  It’s time to write a more detailed post on the proper use of a Garmin GPS watch in training and in racing.

First, let me admit I love my Garmin watches.  In fact, I have three of them.  They are the Garmin Forerunner 405CX, the Forerunner 210, and the Forerunner 50.  You can purchase these on Amazon for between $100-$220.  (Note: if you purchase them through my Amazon Affiliates store I receive a portion of the sale, which is nice…  The first two are GPS watches and the third can be used to measure distance and pace through a “foot pod” that attaches to the laces of your shoe.  As of December 4th, I’ve run 4680 miles this year.  That’s an average of 97.5 miles per week.  I would estimate that 4000 of those miles I’ve used a Garmin GPS watch.  The other miles were likely treadmill or races.  I can guarantee that my log on is the most accurate log in terms of mileage and pace than anyone else’s log.  Right now you are probably thinking, “Oh man he is neurotic! Always wearing the GPS watching! Doesn’t he ever run by feel???”

…And you wouldn’t be more wrong!  Running by your perceived level of exertion is key in this sport.  Following McMillan’s or Daniel’s pace charts on easy days is a big mistake in my opinion.  I’m in no way, shape, or form criticizing their coaching or that their pace charts are inaccurate, in fact I believe they are very accurate.  You need to run by feel though – and that is the key.  If one of the charts tells me my easy run pace is should be 6:45-7:00, there is a good chance that 50-75% of my easy runs are in that range.  But what about the other 25-50%?  This morning I did a Fartlek workout and after this blog post I intend to go run six miles. Tomorrow I have one easy ten mile run on the schedule. Both this afternoon’s run and tomorrow’s run are labelled as “easy” so shouldn’t they be the same pace?  No.  Tonight I really need to recover.  There are many benefits to running 8 minute miles and that’s what I intend to do (note: I ended up running 6 miles in 46:40 – about 7:45 per mile).  If I feel good and start running 6:45 that is great, but I’m not going to force my body to be at that pace.  That pace might be too hard for a second run after a morning workout!  Tuesday after the marathon on Sunday I ran ten miles in 90 minutes.  Wednesday morning I did ten miles in 71 minutes.  Both were easy and the appropriate pace to recover.  I definitely used the Garmin to let me know when to turn around on the out-and-backs or how much to add on, but I didn’t worry about what the pace said!  That is the most essential point in using a Garmin for training.  You need to be able to run by feel.  Quit worrying about a chart telling you what your easy pace should be and go by feel.  I bet some of you are reading this and saying, “but I’m not getting the same workout at 7min pace vs 9min pace.”  This is true!  You could actually be getting MORE out of running SLOWER!  I’m training for a marathon and a huge component of the marathon is getting time on your feet.  My ten miler in 90 minutes is another almost twenty minutes of running than my ten miler in 71 minutes! The most important thing to remember is that your easy runs are NOT within 10% of your marathon race pace, correct? Thus, you’re not doing anything to support your race pace specificity.  Instead the goal of these easy runs is to facilitate recovery and build your aerobic capabilities. There’s no point on trying to run harder on easy days just to run a “specific pace” that someone says should be “easy” for your ability level.

The Garmin is a great training tool, however, because it let’s you know what pace you did run and how you are recovering.  If you have too many ultra-slow easy runs you might know you are over-training.  Too many runs where you feel good and are running faster on your easy runs may show that you need to make the workouts a little faster.  More importantly, by wearing a Garmin you know that your weekly mileage is accurate.  It’s easy when you are training harder and harder to run easy runs slower and slower.  If you base your mileage on estimating by time (like estimating each run at 7:00/mile and running for time) then there is a good chance you are over-estimating your mileage when you are training hard.  The first time I ran a 100 mile week was actually not a 100 mile week.  I thought it was until I ran the loop I called 10 miles several times that week and my Garmin showed 8.5.  I was so tired and over-training I didn’t even realize I was running that slow.  Oops!

Another important benefit is that I can look back at my log from Jan 1, 2008 until now and know that it is as accurate as can be.  Are Garmin’s 100% accurate?  No, but the minimal amount that they different is not the issue.  Over ‘the long run’ I’m sure that it averages out.  This is NOT the case for a race, which brings me to the point of not wearing a GPS watch in a race and the reason I wear the Garmin Forerunner 50 without the foot pod.  If a GPS watch doesn’t match up with the marked miles on the course, which I highly doubt any courses would measure the same as the Garmin shows, it can throw you off.  Most marathon courses show significantly further on the GPS than for a marked course.  In fact, during the Dallas White Rock Marathon when I passed the half-marathon my GPS showed 13.35 miles (.25 too long) yet when I passed 14 miles it showed 14.1 (only 0.1 too long).  All courses are USATF certified but that doesn’t mean the mile markers are placed in the correct spots.  Instead of trying to compare the course with a GPS, I just wear the forerunner 50 without the foot pod and hit split each mile mark.  In fact, I wouldn’t even wear a watch and just compete the competition if it wasn’t a marathon or a half-marathon I was specifically shooting for a time.  Anything less than half-marathon you need to learn to compete and run by feel, so ditch the watch!

In summary, the GPS is an essential tool for training.  When you are trying to keep an accurate running log to learn about your training and recovery it is important.  When you are trying to hit goal paces on a marathon or half-marathon specific workout the GPS is very important.  The GPS can mess with your head on easy days, don’t let that happen and run easy by feel!



6 thoughts on “The Proper Use of a Garmin GPS Watch in Training.

  1. This is great. Where I find the GPS helpful is at the start of a race… with adrenaline, what I think is race pace is sometimes >1:00 faster than my goal pace (for the first quarter mile or so)… it’s tough not to relay on it throughout a race though if I’ve got it on.

    Your opinion on this is super helpful though.

    ps. do you know if you’re running Grandma’s in Duluth in ’12?

  2. I always wear my Garmin during races, I just turn off the auto-lap and hit the splits myself. That way I still have race stats to upload.

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