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× TRACK SPLITS automatically detects the intervals within a track workout recorded on a GPS device and reports the interval times and splits. The accuracy is generally +/- 2 seconds, so worse than hand timing, but better than raw GPS data. It accomplishes this by taking into account the actual length of the track. The input data is either a Strava activity or a GPX file. The output includes a shorthand description of the workout, a table recording the interval times and intermediate 400-meter splits, and an animation of the workout:



OUTPUT:

• The shorthand description of the Workout in the above example is "3x(2000,150),2000" which means 3 repeats of 2000 meters with a 150 meter recovery followed by a fourth and final 2000. The length of each interval and recovery is automatically determined based on speed changes. If they don't come out right, you can [Delete Activity] from the TRACK SPLITS database, adjust the SETTINGS and reload the activity.
• The average Pace of the workout divided into three speed zones, e.g. 5:316:328:18. The white zone is any interval within the Speed change threshold of the fastest interval. The gray zone is any interval slower than the white zone but faster than recovery, and the turquoise zone is recovery as defined by the Recovery threshold.
• The results table records for each interval: Distance (in meters), Time, Pace (in minutes per mile), and Lap split times. The recoveries are highlighted in turquoise.
• The animation allows you to visualize the workout. Click [Start Clock] to start the workout. A ball marks the athlete's location and the color and number in the ball indicates pace. You can [Pause Clock] or [Speed Up] the clock 5x. To start over, refresh the page. A in the results table tracks the athlete's progress in the workout.

To save a link to this report, copy the URL, e.g. https://roaringpython.com/tracksplits/index.htm?activity=gpx78 and paste it into your runner's log or other document or click [Share] to post it on Facebook.

Your results are kept private, unless someone knows or guesses your activity number.

INPUT:

The input GPS data can come from either a Strava activity or a GPX file. This data should contain the entire workout and may include the warm up and cool down, but if they are done away from the track, the reported distances of these segments will be inaccurate because distances are calculated by snapping the athlete's location to the closest point on the track.

• For Strava data, Enter Activity # and then click [Load Activity]. To find the activity number, go to the activity page in Strava and copy the activity number from the URL, e.g. https://www.strava.com/activities/867530900. (Also, if you have previously uploaded a GPX file and wish to view it again, enter the activity number assigned when you did this, e.g. http://roaringpython.com/tracksplits/index.htm?activity=gpx78.)
• If instead you choose to Upload GPX File, click [Browse...] to select the file. This file must contain latitude, longitude, and time. (If you wish to create a GPX file from Strava, you can use the "Strava to GPX" tool. To obtain this, go to https://mapstogpx.com/strava/ and drag the [Strava to GPX] button to your bookmark bar, following the instructions. Then go to a Strava activity page and click this [Strava to GPX] button on your bookmark bar. When the form comes up, click the Default button and [Yeah, GPX me!] to create a GPX file.)

It will take a minute for the activity to load the first time. If it doesn't load, you may receive the error message: "Failed to retrieve data. This is sometimes due to traffic. Try again later or try uploading a GPX file. Or try again tomorrow after Admin has had a look." Or the "Loading..." message will persist for more than a couple minutes and the report won't come up. Either way, I will be notified and will try to load the activity within 24 hours.

The more inaccuracies in the GPS data, the more likely it is the results will come out wonky, but tweeking the SETTINGS might help.

SETTINGS:

The settings help to determine where to break up the activity into intervals and recoveries. Ordinarily the default settings will produce exceptable results. When they don't, try tinkering with the settings or report the problem to me: Contact.

• Workout increment is the Greatest Common Factor of the lengths of all of your intervals. The unit of measure is either Meters or Seconds. Select Meters for distance-based intervals, e.g. 1200's & 200's, or select Seconds for time-beased intervals, e.g. Billat's. When the unit is Meters, recovery lengths should also be a multiple of the workout increment (or be zero, jogging in place). When the unit is Seconds, recovery lengths can be any time or distance. When the unit is Meters, also include the length of the track (400) when calculating the Greatest Common Factor. E.g. if the workout is 1200's & 200's with 200 and 400 recoveries, enter 200 (but 100 will usually work as well). If workout is 400's with 0 recovery (jogging around the start/finish), enter 400 (not 0), but 100 should work. If workout is 2000's with 150 recovery, enter 50 (since 50 is the largest number by which 2000, 150, and 400 are all divisible.)
• Speed change threshold is the minimum change in speed (as a percentage) that will trigger the beginning/end of an interval. E.g. with a 20% threshold, if you slow from 6min pace to a jog of 12min pace, your interval will end. When you increase back to 6min pace, the next interval will begin. If you only slow to 7min pace, it will be considered part of the same interval. So if the workout is de Castella's, with 400s at 6:00 and 200s at 7:00, try a threshold of 10%, but don't be surprised if some of the intervals get merged.
• Recovery threshold is the maximum speed of your recoveries relative to the speed of your fastest interval (as a percentage). Any interval slower than this threshold will be considered recovery and will be highlighted in turquoise in the workout table.
• [Fixed | Floating | GPS] specifies whether to:
  Fixed - start each interval at a fixed meter mark (as determined by the Workout increment in conjunction with the Speed change threshold) or to:
  Floating - only use the Speed change threshold. Use this option for time-based intervals, such as Billat's.
  GPS - is the same as Floating option, except that raw GPS distance is used instead of the distance derived from snapping the athlete's location to the track. GPS distances are typically overestimates.

LIMITATIONS: As indicated above, TRACK SPLITS will not always yield acceptable results. When it doesn't, you can let me know. Currently it only works on 400-meter tracks (or loops of any shape).

CONTACT: Any questions, problems, requests, suggestions, ideas for other tools, ...? Let me know: Contact. Thanks