Garmin Forerunner 910XT – First Impressions

I got my new training gadget on Friday, a Garmin Forerunner 910XT that I’ve been wanting to get hold of for a while. Stocks are limited and they’ve been a little difficult to get hold of but I managed to get a good deal and excellent service from Tristan at There was no messing around with slipped shipping dates or false promises, as soon as he could get some in he let me know. That was on Thursday, I paid for it online and it arrived recorded delivery the very next day.

What can it do?

I won’t go into details about everything the watch can do yet, but it is pretty amazing. Essentially its a training watch with four main sensors. It has a GPS chip in it for accurately tracing your exact position on the planet. This also allows it to tell you where you’ve been, how fast you are going and much more. It has a barometric altimeter so it can tell how high you are. It has a triple axis accelerometer that can detect the movements of the wrist that you wear it on. This allows it to count the number of strokes and lengths you do whilst swimming. It also has a ANT+ transmitter and receiver that allows it to receive data wirelessly from ANT+ sensors such as Heart Rate Monitors, Speed and cadence sensors, foot pods and many other devices. The ANT+ technology also allows it to communicate wirless with a computer.

In essence it is similar to my old Garmin Forerunner 305. I’ve had two of these, both of which I’ve managed to kill due to water ingress. The Forerunner 910XT should be a step up in this regard as is it fully water resistant to 50m, much more so that the 305. The barometric altimeter in the 910XT should also be more accurate than the GPS map based altimeter that was present in the 305. It should therefore provide more accurate data as far as climbs and descents whilst running and biking are concerned. The accelerometer is a completely new addition and the main reason I wanted to upgrade. This will allow me to use the watch in the water whilst swimming and it should provide me with a wealth of swim metrics. Not only the distance and time that I’ve swum, but the speed, number of lengths I’ve done, what stroke I was using and even the number of strokes I take per length. From these swim metrics, the software can also work out various other figures for things such as swimming efficiency and SWOLF scores.

It’s quite a bit slimmer than the 305 and looks much more classy with its sleek black finish.

First Turbo Trainer Session

I was only due to do an hour long turbo session on Friday so I quickly put it on charge for a bit and then decided to try it out (without reading any instructions) whilst on the turbo trainer. The menus and set up is similar to the 305 so I soon had it up and running and had entered a few quick details about myself. As I brought it into proximity of my heart rate strap (I was using the one from my old watch rather than the new one) it automatically paired with it and started displaying my heart rate. As I got on the bike it also paired successfully with the speed and cadence sensor I have on it. So far so good.

I pressed start, did my workout and then pressed stop and it seemed to have been functioning perfectly throughout. After a quick shower, it was time to sit in front of the computer and see how we had done.

ANT+ Data Transfer

I had to quickly install the ANT+ Agent so that the watch could communicate with my computer and plug in the ANT+ USB stick, but as soon as I did, the watch was detected and my workout data was transferred to my computer.

This data transfer works a little differently to the way things used to work with my Forerunner 305. With the 305 I used to connect it via a USB cable and then would download the files from the watch to each application individually. If I wanted the data in Garmin Connect I would download it to that, if I wanted it in Ascent I would do a separate download from the watch to Ascent, the same was true for any other application that I wanted to view the data in.

The ANT+ system is wireless, so no plugging the watch in, I just bring it within a certain distance of my computer and the data is transferred automatically. The data is then stored within a directory on my computer. On my Mac the location is:

Macintosh HD/Users/username/Library/Application Support/Garmin/Devices/[device id]/History/

This Devices directory is also used for storing many other files but I’ll get onto those later. Apparently these history files are stored in here for a month before they start getting overwritten. It seems to work quite well though because all of the applications / services that I use to view my training data can access these files from my Hard Drive meaning that they don’t have to individually (and slowly) download the files from the device each time.

I’ve got things set up so that the files are automatically sent to Garmin Connect, but I also import them in Ascent and into Strava. That may sound like overkill but I use each service / application for different things and having the details of my training in more than one place provides me with a back-up as well. Using the ANT+ transfer protocol seems to work well so far and now that I know what it is doing with my files and how the data is being moved about I feel quite comfortable with it. It is certainly a lot quicker than doing several individual downloads from the device.

Here’s my first Turbo Trainer workout on Garmin Connect using the Forerunner 910XT

As you can see the watch accurately measured my speed, distance, cadence and heart rate throughout.

ANT+ Reception

I didn’t have much time to play with the watch after that on Friday as my parents arrived for Morgan’s birthday weekend, but I did read the manual and had a play with it on Saturday morning. I wanted to try sending some workouts and a geocache from my computer to the watch. It was here that I hit my first stumbling block. Whatever I did, I couldn’t get the device to receive the data from my computer. When I tried sending a workout from Garmin Connect, the computer would say that the workout had been successfully sent to the watch, but it was nowhere to be seen on the watch.

Further investigation showed that the Workout file had indeed been sent from Garmin Connect to the “Macintosh HD/Users/username/Library/Application Support/Garmin/Devices/[device id]/Workouts/” directory on my computer (told you I’d tell you about the other files that are stored in this directory), but the files hadn’t made their way from here to the watch.

Similarly if I tried sending a geocache from I would get a message saying that it had been successfully written to the device, but it was nowhere to be seen on the 910XT. If I tried sending it again though it would tell me that it already existed on the watch. I’m assuming something similar is happening here and the file is being sent to my computer but not to the watch. I’ve yet to work out where this geocache file goes though.

I couldn’t get it working so read the manual and lots of forums online that evening and then started to worry. Lots of other people were having trouble with sending workouts to the 910XT and even worse were lots of reports of poor performance whilst swimming with it. Many people seemed to be having trouble getting the watch to accurately record their strokes and lengths with the watch both over-counting and under-counting and seemingly adding extra lengths whenever there was a slight change in pace. It seemed to work well for others though so I was keen to try it out in the water to see how well it worked for me.

A Reboot Cures All!

I tried installing the latest firmware update for the 910XT which was released on the day bought the watch and I made sure that my ANT+ agent and Garmin Communicator plugins were up to date, but still no joy with transferring data to the watch. Then I had a realisation that I hadn’t rebooted my Mac since installing all of this so gave that a go. And, as is often the case, the reboot worked. As soon as my Mac started up, the ANT+ agent opened and the workout and courses that I had been trying to send to my 910XT were sent to it. Success at last. I tried a few more and all was working well. If only I’d rebooted a few hours before!

Although, I’ve yet to get it working for geocaches, but I shall investigate that further some other time as it isn’t essential and not really what I bought the watch for. It would be nice to get the uploading to the watch though.

Out in the real world.

Sunday morning was a gorgeous morning and my first chance to use the Forerunner 910XT in the real world. I strapped it on for a lovely run with the triathlon club in the hills behind Machynlleth and then got to use it in the pool. It worked well out on the run as I would have expected it to. Speed, distance, time, elevation and heart rate were all recorded accurately and the watch was easy to use and comfortable.

Swim Metrics

The swim metrics features of the Forerunner 910XT were my main reasons for wanting to upgrade from the 305. These features are completely new and I couldn’t wait to try them out. I was however worried that they wouldn’t live up to expectations, especially after reading all of the problems some people had been having with it.

I shouldn’t have worried though as the watch worked flawlessly. It counted every single length of the swim that I did, getting the number of lengths and therefore distance that I swam spot on for every single interval. I only did a simple set in a 20m pool that consisted of:

  • 200m warm up
  • 5x400m steady
  • 1x 80m IM
  • 120m cool down
The 910XT picked up everything I did without any issues. The only thing it got ‘wrong’ was my one length of butterfly at the beginning of the Individual Medly which it incorrectly identified as freestyle. Every other length was perfect. I can forgive it the error with the butterfly as the arm movements between butterfly and freestyle are pretty similar and I don’t do much butterfly anyway!

The best way to use the watch whilst swimming is to start it when you start your session and then press the lap button at the end of an interval and then press the lap button again when you start another interval, finally pressing the stop button at the end of the session. Doing this allows the watch to record your rests between each interval as well as the intervals themselves.

I didn’t do this between my warm up and my first 400m interval, instead I pressed stop at the end of the warm up and then start as I started the first 400m interval. This isn’t as good because it didn’t record the rest interval and joined the warm up and 1st interval into one longer 600m interval – I’ll know next time.

Overall I was very impressed with its performance in the pool and can only surmise that the people having issues either have a faulty watch or have fairly poor swim technique with inconsistent arm movements. There were plenty of people in my lane and plenty of times that I had to slow down or speed up to overtake and that didn’t seem to cause any problems. I do have a fairly good technique though and more importantly a long push and glide off the wall at each end of the pool. It is this glide phase when the watch isn’t moving that allows the accelerometer to detect a turn and therefore count your lengths. A short, erratic glide may cause it to miss turns.

You can see my full swim workout on Garmin Connect here. But here is a screen shot of some of it.

Swim Metrics

Swim Metrics

Garmin have done a good job here – It’s all well and good having a watch that records all of these things but you then need a way to visualise them afterwards and the swim session graphs that Garmin Connect provides look good. In the left hand pane you have a summary of the session with data such as the distance you swam, the pool length, your time spent swimming and your average pace per 100m. It also displays your average efficiency rating and SWOLF score (lower numbers are better). Below this are more details and some information on the number of strokes you take and then finally a summary of the various intervals swam. You can click on the ‘View Lengths’ link here to see every length individually and the metrics such as time, distance, speed, stroke, number of strokes, efficiency and SWOLF Score for each length if you wish.

The right hand columns show various graphs for the workout. The purple graph at the top shows every length that you swim and you can scroll horizontally though them. All in all it looks nice and has plenty of data to analyse should you so wish.

Overall, I’m thoroughly impressed with my Forerunner 910XT so far… let’s hope the motivation it provides to get out there and train will make me faster as well!

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Alan Cole

Alan is a Freelance Website Designer, Sports & Exercise Science Lab Technician and full time Dad & husband with far too many hobbies: Triathlete, Swimming, Cycling, Running, MTBing, Surfing, Windsurfing, SUPing, Gardening, Photography.... The list goes on.

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