For the last couple of years, I’ve been a Strava user. I’ve enjoyed the social aspects of the service, it’s been a useful tool for tracking mileage and other training metrics, and I’ve been inspired and encouraged by the activities of the Strava community. So much so that I’ve paid the money and been a Premium user.
But I’ve discovered something – and I’m not alone. Strava has an accuracy issue.
My operating platform
Last year, I purchased an Apple Watch Nike+. I’d held off on the original Apple Watch as the lack of integrated GPS and waterproofing were showstopper features for me.
But once the new Apple Watch hit the shelves I picked one up from a Nike Store in Las Vegas.
It took Strava a few months to release their Apple Watch 2 application so I was left with the option of carrying my iPhone on runs and rides for a while. I don’t like carrying my iPhone when I run but I was prepared to live with that pain for a while.
Even with the iPhone, I noticed that the distance I was tracking didn’t match my partner’s Garmin watch, or the offical distance of some official runs on measured courses. The differences weren’t great – just a few percent here and there. And Strava always over-measured distances in my experience.
However, I was patient. I waited for Strava to release the offical Apple Watch app. That came a few weeks ago and that’s when I realised what was going on.
I ran in the Roller Coaster run. This is a measured 21.5km course down and up some monster hills.
At the end of the first kilometre, Strava had me at 1.1km. OK – so it was different to the marker but I had no evidence to suggest that the Parker was 100% right. And besides, 0.1km is a relatively minor difference.
As the run went further, the gap between the offical markers and Strava became greater and greater.
By the end of the 21.5km race, Strava had measured my running distance at more than 30km.
This gave me pause to go back and check some previous runs.
Using MapMyRun, I checked a couple of my regular running courses. Strava was adding distance to all of them. While the Roller Coaster measurement was woeful, most of the others were “only” out by around 10%.
That might not sound like much but when a 13.5km run is measured as 15km, I’m being shortchanged on a scheduled training run and fooled into thinking I’m running faster than I really am.
The other thing I found was that if I used a different running app on the Apple Watch and then imported the running data to Strava – it was being altered. The amount of time I was running was going shortened – again by around 10%.
Before abandoning Strava, I put a call in via their online support portal. For Premium (paying) members, there’s a 48-hour response time.
Dealing with Support
Strava’ support was delivered within the promised 48 hours. Given I had several rounds of back and forth with the support tech assigned to my case, the process from when I started with my initial questions to the end was a couple of weeks. The same person handled my matter all the way through which was handy.
My inital query to Strava stared with specific issues I’d discovered.
On measured courses that I have validated using other tools Strava routinely over measured distances. For example, it always measures a 13.6km course I run at 15km. And it messed up a 21.5km race, measuring it at over 30km.
Also, at a Parkrun – which is a measured 5km course, Strava added 140m to the distance and took 40 seconds off my time.
Strava’s response was
“…these variances is due to some bad GPS points that was recorded. We tend to looks at these GPS points a lot closer compared to other platforms”.
Bad GPS points? Really. That doesn’t explain why the elepsed time as changed. So I asked about this and received the following.
Strava is more strict about resting time so we remove less of it than other platforms. In other words, we’re a bit more likely to consider you moving in places where other platforms considers you stopped. This means that even though the elapsed time is the same, the moving time can be a bit different, which can cause differences in average speed. Strava typically reports a bit more moving time and so a bit slower average speed.
I pointed out another 5km run to the support tech that highlighted this issue – in that one, Strava took three minutes off my time.
Ultimately, it was clear after this and several other messages, that Strava’s algorithms were making some serious changes to my data.
I might not be a professional athlete but I like to track my activity and expect my gear to be accurate.
What am I doing?
I’ve cancelled my Strava Premium subscription. It’s still active until the end of the period I’ve paid for which is next February so, if Strava picks up their game I’ll reconsider a new subscription.
I’ve migrated all my data from Strava to Runkeeper using an online service called tapiriik
. It lets you sync data between a bunch of different platforms.
I’ve removed the Strava app from my Apple Watch and now use Runkeeper with their Go subscription so I have access to a bunch of extra features.
Why do I pay? Because software development isn’t free – it’s hard work and if you want a service to survive you should support it financially.