If you’re doing speedwork on a track, and trying to maintain a certain pace on speedwork reps… with some basic math, you can use each 100-200 meter sections on the track to monitor how fast you’re going.
For example, let’s say you’re trying to run 400 meters in 2 minutes (2:00). Your GPS watch will probably give inaccurate pace readings. This is not only because of the GPS margin for error, but because going in circles in the same location can lead your watch to believe you’re not moving much at all.
However, you can use the time reading and the markings on a track to keep pace.
To run a 2:00 rep for 400 meters, you need to travel 100 meters in 30 seconds (100 meters x 4 = 400 meters. 30 seconds x 4 = 2:00).
On most modern tracks, the 100 meter mark, 200 meter mark, and 300 meter mark will be indicated, along with of course the finish line at 400 meters.
At every one of those marks, you can look at your running time and see if more or less than 30 seconds has passed since your last measuring point. More than 30 seconds, and you need to pick up the pace. Less than 30 seconds, and you’re exceeding your projected pace (whether or not you need to slow down depends on your goals for the rep).
If you struggle with doing math on the fly, you can use your watch’s lap function to get your time between time-points.
This approach is similar to occasionally reviewing your speedometer while driving to make sure you’re not speeding. You can check your watch and make sure you’re on track for your desired pace.
So, if you wanted to run 400’s in 1:45, then you check to make sure you’re running every 100 in about 26 seconds (1:44 total).
If you’re running 800 meter repeats and trying to do them in 3:50, you can check every 200 meters to make sure you’re crossing at 56-57 seconds… or every 100 meters at 28-29 seconds.
And of course, if you’re not on a track but out and about on the roads or trails, you can do some math using measurements from Gmap-Pedometer to assess your time at certain timepoints. It’s not as even as the track, but will still help you in the same way.
Of course you don’t need to check your pace every 100-200 meters. Maybe you only check occasionally, or for the first couple and last couple segments, to make sure you’re on pace. But this approach will help you monitor your pace on reps and guide you towards speeding up or slowing down as needed.