Does a GPX file record your interval sprint and rest splits?

The short answer

GPX 1.1 gives a track point a closed set of fields — latitude and longitude, usually elevation, usually a timestamp, plus a handful of others such as a name or a fix type. Nothing on that list marks a point as belonging to a sprint, a rest, or any other named segment of a workout. A file built from an interval hike and a file built from one steady, even walk look identical in structure: both are just a sequence of points, each carrying the same short list of fields, in the same order they were recorded.

What an interval hike actually looks like once it is a file

Sprint and rest are both still moving, from the recording's point of view, so both keep producing points the entire time — nothing pauses or restarts between one and the other the way it would if you had pressed pause by hand. That means the points logged during a hard sprint sit in the same unbroken sequence as the points logged during the rest right after it, with nothing attached to either batch to say which was which. Open the file in a plain text editor and a point from the middle of a sprint reads exactly the same, field for field, as a point from the middle of a rest — the only thing separating them is what the timestamps and positions happen to show once you already know where to look.

Where a label like that could theoretically live

GPX does leave one part of the schema open on purpose — an optional extensions block, attached to a point, a track, or the file as a whole, meant for exactly the kind of thing the core fields never defined a slot for. An app could, in principle, tag a point with something like a set number or a sprint/rest flag inside that block. Two things get in the way of relying on it. Not every app bothers writing anything into extensions in the first place. And even when one does, a different piece of software opening the same file is only obligated to understand the core fields — it is free to skip straight past extensions content written under a namespace it does not recognise, which is exactly what a well-behaved GPX reader is supposed to do. A label saved that way can look fine in the app that wrote it and simply be gone the moment the file is opened somewhere else.

Reconstructing the split after the fact

The one thing every point does keep is a timestamp, and that is enough to work backward if you already know, from some other source, roughly when each sprint and rest began and ended — a workout summary the app showed you at the time, or your own memory of the pattern. Matching those times against the timestamps in the file can tell you which points fell inside which segment. That is you doing the matching using information from outside the file, though, not the GPX track handing you the boundary on its own; a plain reading of the file, with nothing else to go on, gives no way to tell where one segment ended and the next began.

The one thing that does show through: pace

Even with no label anywhere in the file, a sprint and a rest are still, physically, just two different speeds, and speed is something any app can calculate afterward from the position and time already sitting in every point. Plot pace along the length of the track and the rhythm of a set often shows up on its own — a fast stretch, a slower one, a fast one again — even though nothing in the file says which is which. It will not come back labelled "sprint" or "rest," and short segments still carry the same GPS noise that makes any brief stretch of pace data a little jumpy, but the overall shape of an interval workout tends to be visible in the numbers even when the file carries no explicit record of it.

Where TrailCam fits in

TrailCam's interval sets are a feature of recording a hike, not of the file it produces afterward: set a sprint length and a rest length and it calls out each one aloud as you go, so a phone can stay in a pocket through the whole set. A route it exports, though, is a plain GPX 1.1 file — position, elevation and time on every point, the same fields every reader already knows how to open, without a proprietary extensions block carrying set boundaries that only TrailCam itself would know how to read back correctly. A sprint and a rest look the same once the file is out in the open, for the same reason anything else the format has no field for does not show up in it either. GPX export is part of the optional TrailCam Pro upgrade; the app itself is free to download.