XTERRA TR150 Treadmill vs Garmin Instinct
I'm providing a backstory first, read on or skip to the end if you want to know how to determine the accuracy of your treadmill...
3 months ago I purchased my treadmill. Like many others, my decision was based on the effects of covid-19 and having no safe access to my normal gym during 2020. I knew I needed another option as the cold, rain and snow moves into my region and I would still need to run. I must say that I have been very happy with this purchase, I did research and looked at an economically priced, highly rated treadmill that would support my 6’ stride and 215lb weight. There weren’t many options, but this one definitely hasn’t disappointed.
The TR150 is a basic model that is easily folded and weighs around 110lbs assembled. It has a top speed rating of 10mph (a lot faster than I will ever be able to run personally), and it is rated for heavier runners up to 250lbs and boasts a 50” running deck. For taller folks, or those with a longer gate, this is a great choice for a lower class treadmill in my opinion. Other models like Nautilus, Sole, Nordic, etc can easily accommodate my needs, but also cost 3x-4x more. I only intend to run on a treadmill if I cannot run outside (weather or time management), so I didn’t want to shell out a lot of cash for something that will likely not be used year round. My setup is at a 2 degree incline, just enough to give me a pretty good cardio workout when running at a 10m/pace. I tend to push myself a little harder on the treadmill because it is a lot easier with a fan, bottle of electrolytes and a towel within constant reach. My normal route is pretty hilly, but my intention is to simulate, “as closely as possible”, what my pace would be running outdoors on a relatively flat route.
The first few runs on the treadmill I took were horrific, I thought I was going to die keeping up with a 10m/m pace. This was very uncharacteristic for how my outdoor runs were trending at the time, so I suspected that something was very wrong with the speed of the motor vs. what was registering on the digital display. I contacted support about a separate issue with the display and discovered that the rpm sensor was not even installed at the factory (seriously)! Support was very helpful and they quickly sent a brand new console with the missing sensor, I had both new parts installed within an hour and proceeded to run a quick 5k as a check. My Garmin Instinct recorded a 5k run of 8:18/m avg, I had been running 5k’s in October around 9:30/m avg and chalked it up to the treadmill "doesn’t have hills" and it’s far easier to run with the help of a motor.
The problem, I quickly realized, was that the display on my treadmill showed I only ran 2.4 miles! At the cadence and time for the run, I knew the treadmill display was still inaccurate. But by how much?
So now the conundrum of what machinery do I trust? Obviously the Garmin Instinct is deadly accurate on outdoor runs. I’ve ran it through several separate tests over measured 1 mile tracks and it is within what I would call extremely accurate GPS data collection, but that does not necessarily mean that it is really reflecting what is happening on the treadmill. My Garmin watch has a nifty “treadmill calibration” feature that you can use after you run 1 mile and match the watch data to the treadmill display. After several attempts, I realized this was an exercise in futility and decided to see just how accurate my treadmill really is.
I’m sorry for the above 4-5 paragraphs, but feel the backstory is necessary to establish “why” it is good to benchmark a treadmill you plan to use (if accuracy is important to your training).
How I determined the accuracy of my treadmill display (or inaccuracy):
I created a benchmark on the frame of the treadmill and another corresponding double line on the belt. Then I marked 12” spaced evenly along the belt back to the benchmark point. My treadmill belt is exactly 102” long (or 8.5 feet).
Now the math (I hate this part too…)
1 mile = 5,280 feet
How many rotations will my treadmill belt make in 1 mile?
5,280/8.5 = 621 full rotations per mile
To scale down to 1/10th mile: 621/10=62.1
Now to put the treadmill on a very low setting and start counting (the boring part). When the belt reached 60, I set it to the lowest possible speed and hit stop right at rotation mark number 62. My display still didn’t read 0.10 like it should (no shocker). So next I "un paused" and continued counting the rotations until it reached the correct distance. It took another 10 full turns!
So I know what you are thinking at this point… “10 more turns, what’s the big deal Ike?”.
Let’s put this into perspective: In 1 mile, it rotates 100 additional times.
100x8.5=850 additional feet per mile. Or 0.16 (nearly 2 tenths of a mile). This is a HUGE discrepancy vs. the display distance! If I run a 5k using only the treadmill display, instead of running 3.1 miles I would in fact be running 3.6 and not getting the street cred I’ve worked hard to acquire. I would run an additional FULL MILE on a 10k, but the time it took would only reflect 6.2 miles (reality would be 7.2 miles).
So now to tune my Garmin Instinct running watch:
I (1) ran a mile, (2) saved the run, then (3) selected “treadmill calibration” and (4) entered “1.16” as the actual distance covered, and (5) saved the new data to my profile. The Garmin stored the data and all future runs on this treadmill will give me back the 0.16 tenths of a mile the treadmill steals.
Will this calibration and knowledge mean that my treadmill is an exact replica of my performance on an actual outdoor run? Not hardly, too many real-life variables like crosswalks, weather, hills, cars, phone calls, etc. that make outdoor runs "real". But at least it's a good indication of current level of fitness during the treadmill run.
If you don’t have a running GPS smartwatch that can perform this calibration, I would still advise that you take the steps I’ve outlined should you suspect something is “off” on your treadmill runs vs. outdoors. If you are in the market to purchase a running watch, I can only advise that Garmin outperforms all others that I've previously owned. (And there have been several throughout the years).
Additional data you can actually use with your treadmill conversion (I've highlighted my setup as described earlier in the chart below):
Keep on running STRAVA family. PEACE & Good Health to you!
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