Showing posts with label measurement. Show all posts
Showing posts with label measurement. Show all posts

Friday, July 4, 2014

My Garmin lied and the truth hurts

My Garmin made up most of this route
Today's run (street): 3.75 miles

Halfway through today's run, I glanced at my Garmin and saw that I had covered two miles in about 17 minutes. That would have put me on track for my best training run in memory. I was puzzled because my perceived effort was nowhere near what I'd expect for that pace. I tried to rationalize the reasons for such a dramatic improvement in my performance compared to yesterday. It was 10 degrees cooler and cloudy, but could that account for running over a minute per mile faster?

When I got home and saw my time and mileage on the Garmin, I thought I'd rocked it. Maybe I was turning a corner with my training. After all, I used to regularly average 8:45 paces on my daily runs. Breaking 9:00 minutes on a run these days is a notable achievement for me. I hoped it was accurate and not some weird Garmin fail.

Despite that wishful thinking, it did turn out to be a badly confused GPS. For some odd reason, the Garmin put my starting point 3 miles north of where I began my run. Looking at the run data through Garmin Connect, my course appeared to have frequent 50-foot elevation changes. That's definitely not the case for my relatively flat route. I'm guessing that the low cloud cover may have interfered with the GPS signal and caused it to skip.

I Gmapped my route and was disappointed to see that I'd only covered 3.75 miles, rather than the 4.35 that the Garmin said I'd run. I wanted to run 4-5 miles today and thought I'd met my objective. The good news is that I beat yesterday's pace by 42 second per mile. The other good news is that it's a long weekend and tomorrow we're hosting a Runsketeer pool party. If the weather reports are accurate, the skies will be clear and I'll be able to get in a longer run in the morning.

Sunday, June 8, 2014

Not a step back, but not what you'd call progress

Disappointing cadence
Today's run (street): 4.6 miles

I wasn't sure what to expect on today's run but I hoped I would find it easier to reach my targeted performance numbers after seeing some improvement yesterday. To my dismay, I felt less energy this morning and I hoped that I'd rebound during the run. Although I did quickly get into rhythm, I found even the first couple of miles difficult. I wasn't sure if I'd started too fast, or if I was simply too tired.

I've read numerous times that an ideal (non-competitive) pace will allow a runner to maintain a conversation while still providing some level of challenge. For most people, that's 75-85% of max heart rate. A check of the data from today's run showed that I stayed primarily between 76 and 79% of max for the first 3.75 miles. Even though I was primarily at the lower end of the HR scale, the going felt difficult.

My response was to pick up the pace and, for the last 3/4 of a mile, I kept heart rate between 80-86% of max. In terms of technique, I adopted an almost bouncing stride that I hoped would translate to greater speed. It did, but it still fell short of today's expectations. My cadence, even after using my new form, never got out of the middling range. The one upside is that getting my HR into the higher 80% range is good preparation for harder workouts.

I don't know if I can return to doing 8:00 minute range training paces, but even if I can't, I still have lots of room for improvement.

Saturday, September 28, 2013

Measure for measure, I don't like this change

New and improved?
Today's run (street): 5 miles

In business, many people subscribe to the idea that, "if it ain't broke, don't fix it." I made my career challenging that notion and I firmly believe (at least in technology) that complacency is the enemy of success. Okay, no more clich├ęs, but I do believe that open source technologies further the cause of progress. So am I a hypocrite to condemn the new Gmaps version that just went up, using OpenLayers in place of the Google Maps API?

I've relied on Gmaps for years as a tool to precisely measure my routes. Foot pods and GPS watches/apps both fall short due to calibration, route angles or weather. I always use mapping, combined with time, to calculate my exact pace. This morning I was surprised to see a new interface for Gmaps. I also discovered that Gmaps is now an open source supported framework, and will now be called Milermeter. It wasn't until I tried mapping this morning's run that I started to grumble.

I won't go into the specific issues that I had, but I will say that the interface can use some refinement. I'm not sure of the reason, but items flicker on screen and the tools behaved inconsistently. I'm also unsure about the accuracy. I mapped my route using "Milermeter" with both Chrome and Firefox and saw a 1.5% difference in distance between them. Both measurements fell short of what my Garmin captured, surprising because that usually under-counts distance.

Forgetting the technology issues for a moment, this morning's run turned out to be a really good workout. I ran over to the business park to run the loop a few times. This route offers either a steady uphill for almost a mile, or a shorter but steeper section if you run it in the opposite direction. I took the steeper option and made three circuits before heading home.

I used my metronome app and set it to 87 SPM. Although I felt I was coordinating my steps with metronome, I didn't end up with a particularly fast pace. To be fair, except for the hill, I didn't push that hard, although I kept a steady stride throughout the run. Right now, I care more about managing up my cadence than speed. If I understand how this all works, better paces should follow

Friday, April 6, 2012

The declining accuracy of my Garmin FR210

I'd add 3% just to be safe
Today's run (street): 2.53 miles (Gmaps measured)

I'm not sure why, but my Garmin FR 210 has been under-performing lately. It was especially bad this morning. I generally run the same route every day at 4:00 AM and, after careful measurement, I know that the distance is exactly 2.53 miles. The Garmin's margin of error is generally -3%, which means that it under-counts to that degree fairly consistently. Since it is consistant, I accept that variance and correct for it in my pace calculation.

It's no mystery why this happens. Looking at my run captured in Garmin Connect, I can see that the watch will vectorize corners and straighten out curves. This is due to the capture time between GPS signals (approximately one sample per second). If the signal was captured continuously, the course would be displayed accurately, with no corners cut, etc. When it's cloudy, the signal can get interrupted. When that happens, the watch interpolates the distance between signals as a straight line. Enough of those and your accuracy really suffers.

Lately my FR210 has been under-reporting by about 5% and this morning it came in at -7%. It was cloudy, but clear enough to see some stars. My run could only be described as slow, and with the under-counted distance, my watch recorded my pace as glacial. Correcting for the true distance, it was still the slowest 4:00 AM run in memory.

I'm puzzled as to why my Garmin's GPS has become less accurate of late. Perhaps it's just going through a bad spell. The GPS accuracy tends to be better when I run a mostly straight course like at Bethpage. I'll see how it does tomorrow.

Thursday, December 22, 2011

News flash - GPS watches aren't accurate



Graphic from 12/19 NY Times article
Photo credit: Martin Strauss, via Garmin and Microsoft
 Today's run (street): 2.5 miles
There was an article in Tuesday's New York Times about the accuracy (or should I say, inaccuracy?) of GPS watches. The writer made the same point that I've been making for years, that GPS technology does not provide exact measurement. The same can be said for smartphone GPS apps that show lots of metrics and graphics, but also under-count distance. The thing is, if your distance is off, so is everything else, including pace.

I'm a bit of a belt and suspenders guy when it comes to tracking my runs. I use a Garmin FR210 GPS watch to capture my run metrics and route. But later, I usually measure where I had run using Gmaps to get the most accurate distance. This way I can calculate my true pace. Why use the Garmin if I know it's inaccurate? Good question. But just try taking my Garmin away from me...

This morning I got back outside for my early run and was rewarded with dry roads and mild temperatures. There was wind coming from the north that, when traveling head-on, made things chilly. Most of my route went either south or east so it wasn't a problem. I managed an average pace, though my PE (perceived effort) was higher than that result. Then again, when you get your performance information from a GPS watch, you never know what to believe!

Monday, November 1, 2010

Extra work just to stay the same

I recently read an article stating that men past the age of 40 will lose muscle mass even if their rate of activity and exercise remains constant. The trick to maintain a specified base level is to increase the amount of effort incrementally over time. Working more just to keep from losing what I already have is not an appealing thought. I love to run and this activity helps me maintain a healthy body and mind. However, I do wonder why my paces seem to average closer to mid 9's rather than low 9's over the last year. It was a hot summer and I know that factored into my performance. I figured as the weather cooled off my run times would begin to improve. Prior to the Dirty Sock 10K I was focusing on faster paces over short distances and was regularly nailing mid to high 8's on runs below 5 miles. More recently, I've focused on longer distances (6+ miles) for my weekend runs and when I do that I find that I'm back in the 9:30-9:50 range.

The last week isn't representative of my potential because I've been fighting a bad cold. The previous weekend, when I reran the Cow Harbor 10K course, I was only able to manage a 9:33 pace for the 6.2 miles under ideal conditions. I'll agree that regularly meeting last year's numbers will require some extra work. It may be time to re-engineer my training and add more strength and speed work. Or maybe I'll just run longer and hope for the best.

Wednesday, April 21, 2010

Central Park: once around for good measure

Central Park Reservoir (1.58 miles around)
Yesterday's run (Central Park): 4.8 miles at 9:18/mile

Today's run (street): 2.16 miles at 9:37/mile

Yesterday  afternoon I ran in Central Park for the second time in less than a week. I met my friend CK at the statue of the Maine in Columbus Circle and we set off with a vague plan to cover the distance to the reservoir and back. CK is still dealing with a foot injury that has forced him to scale back on his running in favor of other sports and activities. Like the last time we ran, he said he'd need to take it easy due to the foot injury. This time I knew not to believe him. CK laughed at me as I prepared the Garmin for the start. He's more old school, relying on time from his stopwatch rather than using an over-engineered running watch that captured distance, pace, etc. However, I noticed that he asked me more than once how far we'd gone during the run.

The sun was high in the sky but the heat was moderate. By the midway point I did find myself gravitating to the side of the road that had the most shade. By the time we reached the reservoir I began to feel the effort. CK managed to subtly push the pace past my default comfort zone. I wasn't exactly hurting but I felt like I was running at race pace although the Garmin's display did not reflect that. By the time we'd circled the reservoir and headed toward the east side of the upper loop I was ready to slow down. We ended our 4.8 mile run near the outlet to Central Park South and then grabbed some water to cool down. Once again I had a great Central Park run and CK pushed me hard, as always.

I tossed and turned last night and I believe that related to being so wired from the midday run. My plan for this morning was to cover two miles at an easy pace to balance the hard work from yesterday. I was suspicious that my recent recalibration of the Garmin led to under-counting my distance so I used this morning's run as a benchmark, comparing the Garmin numbers to Gmaps. Both came out exactly the same: 2.16 miles. I was hoping the Garmin was off which would explain why I felt I worked so hard yesterday and only managed a 9:18 pace. I guess I need to work a little more on speed. The hills didn't help but I can't blame them. What goes up one also comes down and it probably evened out in the end..

Thursday, February 12, 2009

Measure twice, cut one

Shortly before I left the office yesterday my wife sent me an email that said "Good News, I think your new watch thingy came today." I got home and was very excited to see that it had, in fact, arrived.

The watch thingy is a Garmin Forerunner 50 with data linking, heart rate monitor and foot pod. Theoretically, this watch has everything I need to capture the metrics from my runs and wirelessly transmit the data to my PC. Compared to my Nike+ Sportband it does quite a lot. That's partially due to the Sportband's tendency to self destruct, usually within two months of receipt. The Sportband's display has become increasingly difficult to read (apparently the design has big problems with corrosion) and it no longer shares well with others. By this I mean that when I try to upload my run data to the Nike+ site it refuses to acknowledge that there is any available data. For that last two weeks I've had to record all my run data manually.

Now that the 50 has arrived I'm anticipating the opportunity to capture my training information in all different ways. The 50 has a stopwatch so, at the very least I can accurately time outdoor running and compare distance from Gmaps for pace. The watch also calculates splits and times intervals. The HRM captures length of workout pulse rate and the foot pod captures speed, pace and distance.

So theoretically I'm set. But what about reality? Experience has shown that running technologies often sound better than they perform. I've had a continuously bad experience with the Sportband but yet I continue to use it because it does one thing very well; capture run distance very accurately. This weekend I plan to perform a faceoff between the Nike+ Sportband and the Garmin 50. I'll wear them both and compare the distance data they report. I'll then compare that data to the benchmark of Google Earth measurement.

One will win and the other will be returned. I really hope the Garmin's capability is more than theoretical.

Friday, December 26, 2008

That darn metric system



Earlier this week I had a conversation with my nephew, a member of the local High School track team, about the actual diameter of the HS track. I discovered that I had made a bad assumption about the distances I was running as I had assumed the measurements were in quarter mile increments. He told me the track is measured at 1600 meters around. That explained why my Nike+ Sportband was off when I thought I was running my measured distances. What's puzzling is that when I measure the track using the extremely accurate Google Earth ruler tool the distance around is actually .26 miles or about 4% longer than a quarter mile. It should actually be shorter than a quarter mile, not longer. Either way I now know the actual distance so I can calibrate accordingly but I'm obviously missing something.

Today I did 25 minutes of upper body work to rest my legs but later in the day I went over to the track with my wife and kids because the kids wanted to run. Instead of doing laps I did sprints to work on my fast twitch muscles and anaerobic conditioning. I'm not used to running that fast and started to develop some tightness in my leg (different from my previous muscle pull). I stopped right away and iced it when I got home. I'm not taking any chances. Tomorrow I plan to run 3+ miles as my training for the April race continues.
 

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