December 01, 2019

A Treadmill Accuracy Test--Finally! (And 3-3-3 Week 9 Recap)

I finally got answers to the accuracy of my treadmill! I'll write more about that below. First, though, I hope everyone had a great Thanksgiving! Jerry was working, but my mom invited us to her house for dinner. Becky went with the kids (Brian was working) and Nathan went with his girlfriend, Alex.

That morning, I had the idea to invite Luke and Riley (my niece and nephew) to come over after dinner and stay the night. I'd invited them over for Saturday night, but on Thursday, we learned that Jerry's sister, Laura, was going to be induced into labor on Saturday evening. And I get to be in the delivery room! Of course, I was very excited about that, so I asked Becky about the change of plans, which was fine with her.

(Laura went in to the hospital last night as planned, but things are going very slowly. I'm hoping that it'll happen tonight! I'm ready to drive up there as soon as she lets me know.)

We ate dinner at my mom's, and it was delicious! My favorite dish is still my mom's sweet potato casserole. I could eat nothing but that and die happy.

Since Jerry was working, I had Luke and Riley to myself for a few hours. They are SO STINKIN' CUTE. Luke talks a mile a minute and asks so many questions I can hardly keep up. And Riley is one of the most adorable toddlers I've ever seen. She's very petite for her age--she's small but proportionate, so she looks like a little, drunk adult toddling around, hahaha.

And her smile. My heart just melts. She gets this grin on her face that stretches from ear to ear, and it's SO contagious. I tried so hard to get pictures of the kids, but they never hold still. There was one moment when Luke actually asked me to take a picture, though, which he never does. He was sitting on the floor with Riley. I wish you could see her huge smile!

Anyway, on to the treadmill... in my obsession with not knowing how accurate my treadmill's distance is (I think it's the thing I complain about the most on my blog--being a numbers nerd, it drives me CRAZY not to know!), I was doing some Googling about Garmin watches that are the most accurate on treadmills.

My Garmin is over five years old now; I don't need a new one, but I want accurate numbers on the treadmill. (When I do get a new watch, I don't want a fitness tracker or a wrist-based heart rate monitor--and they pretty much don't make them like that anymore.)

In searching, I came across DC Rainmaker's site (if you ever want to learn about fitness gadgets, he is my go-to), and he had a video that demonstrated accuracy of various tools for logging distance on a treadmill. To get a very accurate *actual* distance to compare the others to, he used a measuring wheel.

I cannot believe I didn't think to do that before! They are used for measuring long distances, typically for road marking, sports fields, paving, fencing, etc., so the accuracy is about as good as you can get. DC Rainmaker strapped a measuring wheel to his treadmill. I tried to do that, but it was very difficult to get it steady, so I had to do it the difficult way--holding it in place for a mile while my legs went totally numb from squatting on the floor.

I had Jerry start the treadmill (on 5.0 mph and leave it there) and read off distances throughout, writing down the number of feet measured at certain checkpoints--1/4 mile, 1/2 mile, then each 1/10 of a mile. I just wanted to see if it was consistent. Then when the treadmill hit exactly one mile, he told me to stop and I could record the exact number of feet that the wheel measured.

Ideally, the treadmill's distance would be spot-on with the measuring wheel. Worst case, I was hoping that the treadmill was going a bit longer than the display showed, so that at least I would know that I hadn't been cutting my runs short.

Here is what the result was:

The treadmill read 1.00 mile at the end. A mile is 5,280 feet or 1609 meters.
The measuring wheel, in the same amount of time, read 5,592 feet or 1704 meters.

This means that a mile on the treadmill's display is actually 312 feet (95 meters) shorter than the actual distance of a mile.

When I multiply that by the three miles that I run at a time, it works out to be an actual 3.177 miles that I've run. It also means that the pace I've been running has actually been a little faster than I thought!

I'm so glad to finally KNOW. I'm going to test it with a few different treadmill speeds, but I figured that 5.0 mph was a good start. Since I've been running until the treadmill reads 3.0 mph, I'll continue to do that, but I'll change the data on Garmin Connect to read 3.18 miles.

And since I'm going to do that from now on, I decided to go back to my runs over the last several weeks and change the distance for my treadmill runs to make it more accurate and consistent.

So, that done, here is my recap for Week 9 on my 3-3-3 running.

(For anyone new to the blog: 3-3-3 running is just my plan for getting back to running regularly. I run 3 miles, 3 times a week, for 3 months. I am doing MAF heart rate training, keeping my heart rate under 146 bpm for the entire duration of the run, no matter how slow I have to run in order to do that. It's a way of strengthening the aerobic system.)


Usually, after a run, I immediately write notes about it in Garmin Connect so that I remember what to write about in my recaps. I was in a huge hurry on Tuesday and forgot to do that. My memory is terrible, so I can't write much about it.

I had to pick up Noah early from school for a doctor's appointment, and I had to leave at 12:15. I wrote a blog post and finished a little before 11:00. I knew that getting ready to run, running three miles, and then showering would be enough time, but I was hoping I'd have time to cook some chicken and make a salad for lunch (I'm on a salad kick right now).

I quickly got dressed and hopped on the treadmill. I vaguely remember being happy that the run was definitely better than last week's runs, but my heart rate was still getting to 147 here and there.

I felt really good after this run! Afterward, I had to choose whether to make my salad or to take a shower. I was going to try to do both, but after trimming and cutting the (raw) chicken, I only had 10 minutes left, so I hopped in the shower instead before rushing out the door.

Garmin Connect only recently started showing my time spent in each of my heart rate zones. I love this! When I start doing speed work, it'll come in handy to make sure I'm doing 80% at MAF rate and 20% in zones 4 & 5.


This was the best run I've had in weeks--probably since the beginning of my training. I started the treadmill on 4.4 mph and then I wondered if starting it higher would allow me to run longer at a faster pace before my heart rate got too high.

Basically, I am so tired of running so slowly and I wanted to see if I could manage starting at a faster pace. After about 30 seconds at 4.4 mph, I bumped it up to 4.7 mph, expecting to hear the heart rate monitor alerting me to slow down at any moment.

But I left it there! I didn't have to lower the speed or the incline at all the entire run. After 2.5 miles, I was even able to run at 4.8 mph for a quarter mile. Running the faster pace felt so good! And my heart rate monitor only beeped 3-4 times during the whole run.

I was trying to think of reasons why this run went so well, and I think it may have something to do with my medication. I deliberately waited until after my run to take my bipolar meds. I think one of them makes my heart rate increase. I can't sleep when I take it in the evenings, so if my theory is correct, I'm going to have to become a morning runner again.

I have such a hard time getting motivated to run in the mornings! I do love how it feels to get it done early, though, and then not think about it all day. I'm going to try doing it for all three runs during Week 10 and I'll take my meds after the run. I'm curious to see if it makes a difference.

From the pic below, you can see that even though I was going faster, I was able to keep my heart rate in the correct range for 95% of the run (and only 3% was too high).


I was excited for today's run because I got a new pair of shoes and I wanted to test them out. I'll write about them next week after I've run in them a little more, but so far, so good.

Unfortunately, I forgot to run before taking my meds. I woke up at 6:15 and took them right away. Laura texted and said that there wasn't much happening as far as her labor, so I decided to give it a few hours before running.

I still wanted to try the speed that I did on my previous run, hoping for the same result. I started out at 4.8 mph this time, and less than a quarter mile in, I had to lower it because my heart rate was too high. Ultimately, I had to run at 4.6 mph, then 4.5 mph for most of the run, lowering it to 4.4 mph for only a few minutes.

Even though it wasn't a good as last time, it was still a big improvement from last week. I think the fact that I was sick last week is what made my runs so miserable and my heart rate so high.

I went back to watching 24 instead of Jack Ryan, because I need more action. I watched the whole series of 24 years ago, and I remember it being very fast paced, which is exactly what I need when I run on the treadmill.

So, that's the recap for Week 9. Today started my third month of the 3-3-3 plan. I'm two-thirds of the way through! And I haven't missed a single run. I'm pretty proud of myself :)

Well, I hope that tomorrow I'll be sharing a photo of my new niece!


  1. Riley looks so much like you!

  2. I can't believe you're going to have another new niece!! How exciting!! I hope all goes well! Hope you and your family had a wonderful Thanksgiving!

  3. I have a Fitbit and the distance reader SUCKS! I really wish I had bought another Garmin instead of this! Ugh, lesson learned.


  4. Slightly off topic, but have you seen Brittany Runs a Marathon? It was released in theaters over the summer and is available on Amazon now. I think you would love it.

  5. OMG My friend who owns the local running store and a timing company MUST have one of those wheels! I am going to ask to borrow it and do this! :)

  6. Since your measuring wheel measured 5592 ft when treadmill display said mile wouldn't that mean every mile ran on the treadmill is actually 1.059 miles or did I read wrong?

    1. Yes, that's correct. So the 1.059 miles, times 3 miles for each run, would be 3.177.


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