Any GPS watches accurate enough for long intervals?

Standard Garmins are reasonably accurate for long straight stretches. Whenever there are turns the measurements/algorithm get worse. Typically they'll add about 1-2% on average.

Pretty much all of them are accurate enough for this purpose.

They're maybe a couple of a percent out - often less. The difference in training effect between doing e.g. 5 x 1000m in a given time and 5 x 1020m (or 980m) is neglibible.

Yes.

They will be as accurate for this type of training as they would be for you in a race. This creates an "apples vs apples" comparison that will help you align your training effort with race effort.

Bob Dobbs wrote:

Are there any GPS watches accurate enough for repeat kilometers or repeat miles? How about for shorter repeats?

are you serious, bro?

what the hell good would a gps be if it was inaccurate to the point of not measuring a km or mile?

what to you think people are doing with all this gps stuff nowadays?

thinks it's just for sh!ts and giggles?

this is a clown question, bro, come on!

I recently did a set of 800m repeats on my college's track. My garmin told me that my two lap intervals were .53miles. I went to my old coach and told him the workout that I did and that my findings concluded that the track was not 400m but longer. His reply was, "No wonder why you could never break 2 in the 800"

Ok that's not a true story, but way to many people take the word of the GPS as absolute truth.

What is a true story is that my college coach would often purposely measure out an interval course in the park as much as 20m +/- depending on what the team pshyci was for that week. We never knew that the huge confidence boost we got from "nailing" a key 1000 workout was actually due to the course being short. Maybe this philosophy is build into GPS watches?

If your running your workout on a track just use the GPS to track your time, not your distance. GPS is good enough for road workouts though.

For a road race, my watch pace is typically 2s per mile faster than actual splits (measured distance/time). This is a bias not a variance. The variance is low (though I've not measured it). So to remove the bias, just run 2s per mile faster during intervals and you will be running at the pace you should be. Because the variance is low, there will be little difference in actual pace from interval to interval, at least due to watch error.

Thanks much for all the helpful responses.

I'll be doing my intervals on riverside bike paths, so there won't be any sharp turns. Sounds like GPS will work fine for this purpose. Also sounds like any error is in one direction can be adjusted for.

I guess now I'll need to decide between Garmin and Nike.

The Nike HR monitor/watch I had several years ago was pretty shoddy. I had two of them stop working within a few months before I finally gave up. So I'm very reluctant to try Nike again.

metre stick wrote:

I recently did a set of 800m repeats on my college's track. My garmin told me that my two lap intervals were .53miles. I went to my old coach and told him the workout that I did and that my findings concluded that the track was not 400m but longer.

A few years ago, I started running what I thought were great interval times for me. I thought I'd had a breakthrough. After a few weeks of that, and now brimming with confidence, I ran the same workout on another track and couldn't approach my previous times. Turned out the first track* was short,and by quite a bit. Big bummer.

*It was the old Seattle Pacific University track on Queen Anne Hill, for those who know the area. Beware.

Bob Dobbs wrote:

Thanks much for all the helpful responses.

I'll be doing my intervals on riverside bike paths, so there won't be any sharp turns. Sounds like GPS will work fine for this purpose. Also sounds like any error is in one direction can be adjusted for.

I guess now I'll need to decide between Garmin and Nike.

The Nike HR monitor/watch I had several years ago was pretty shoddy. I had two of them stop working within a few months before I finally gave up. So I'm very reluctant to try Nike again.

Ok, the question about whether a GPS watch would work for long intervals was acceptable & forgivable.

But to consider a Nike gps over a Garmin? pu-lease.