Running Indoors with the Garmin Forerunner 235 is very easy and the accuracy is of a level good enough to see your training effect and capture relevant data to use help improve your training
A built-in accelerometer captures distance and pace data when you’re running on an indoor track or treadmill
Running is one of the easiest sports there is. You put on some trainers and go out the front door for a run. However, sometimes it is not so easy when the weather is bad and there is a great temptation to just stay inside and run indoors on a treadmill or indoor track. Therefore, if you are into your data – as most runners nowadays are – then being able to track your workouts when indoors would be beneficial.
You can purchase the Forerunner 235 from Amazon here.
When indoors on a treadmill, you are not actually moving anywhere and there is no GPS connection. This would obviously mean that the basic GPS running watches would not be able to record anything other than the time which you have been running for. In the past, companies have got around this by allowing you t connect external accelerometer pods via Ant+, but they are at an extra cost and have to be attached to your shoes.
However, many of the new running watches being released have a built in accelerometer which allows you to measure your pace, distance and time of our indoor runs. This is no different on the Garmin Forerunner 235 which allows you to use this capability to record indoor workouts, whether it be on an indoor track or a treadmill.
How an accelerometer works
An accelerometer is a tiny internal device which monitors acceleration of movements and determines a range of data points as a result, from which way is up to your cadence. The movements you make whilst running cause an acceleration force which is constantly changing creating tiny voltages (or a change in capacitance) which can then be converted into numbers and understandable data points to tell you about your running. This therefore means that there is no need for any GPS tracking.
Running Indoors with the Garmin Forerunner 235
On the Forerunner 235, there are a few different activity types which you can choose from. These are specially time at running and cycling (although there is not an option to use it swimming, it is still possible shown here).
One of these Activity options is ‘Run Indoor.’ This is essentially exactly the same as the normal ’Run’ activity but it automatically is preset to use the internal accelerometer rather than the GPS functionality of the device.
As with the normal ‘Run’ activity, the settings are exactly the same: there are three available data screens for you to set up, along with the same heart rate data which is still recorded on the optical heart rate sensor in the same way. Therefore, there is no set up necessary, just go to ‘Run Indoor’ and press the top right select button on the watch to run.
Accuracy of Data
When looking to see the accuracy of the data gained, it is very hard to do so when the actual distance run is unknown, this is the case when using the watch on a treadmill. This is because treadmill running is renowned for being inaccurate in itself as the speed displayed on the treadmill is not always the same as reality. Despite saying this, it is assumed in most cases that there level of error in the treadmill speed and distance is of a minimal amount, allowing comparisons to be made between both the data given by the Forerunner 235 and the treadmill itself.
I have used my Forerunner 235 on a number of treadmill runs and have actually been pleasantly surprised with the quality and accuracy given by the watch. With this relatively new technology, it was expected to be not worth looking at, however it was almost spot on with both interval running and continuous running.
On one 20 minute run, the treadmill speed was set at 14km/h which is a pace of 4:17 min/km. The watch recorded this run at 4:19 min/km and a distance of 4.63km compared to the 4.67km recorded on the treadmill. This is only a 0.85% error in distance which is extremely accurate, and very encouraging.
There was also some very clear and good results from an interval workout I did on the treadmill. The session was a 5 minute warm up at 12km/h (5:00 min/km), followed by 3 x 1km at 16km/h (3:45 min/km). The warm up was recorded by the watch to be of a slightly faster pace of 4:46 but again this is only a 5.0% error which isn’t too significant. All three intervals were at the fastest speed the treadmill could go and potentially could be a factor in the different times for each kilometre as it struggled at the faster pace. However, it was only the first kilometre which was timed at 3:35 which was too fast, the other two were almost spot on giving very good and accurate times of 3:44 and 3:45.
It is also important to note that it s the built in accelerometer which measures cadence. This is also recorded in the same way whilst running indoors and gives accurate results seen on the interval session.
Connecting a Foot Pod
If you decide to run without the internal accelerometer, it is still possible to run indoors with a Garmin Foot Pod, connected via Ant+. This is easy to set up by going to Menu > Settings > Sensors and Accessories > Add New > Foot Pod.
From these results, it shows that Garmin have done a good job with the Forerunner 235 at gaining an effective device which can be used for indoor workouts. The internal accelerometer fairs well in both interval and long runs on the treadmill, however I have yet had the possibility of testing it on an indoor track. Despite this, many still say that the specifically designed Garmin Foot Pod is better for indoor running, but personally I believe there is no need for this extra purchase when results look to be reliable on the whole.
Thanks for reading!
Amazon link for UK readers is available here.