Endomondo Sports Tracker, one of the most popular exercise tracking apps, has added support for background GPS tracking in its latest version 8.1 update, for devices running Windows Phone 8. This means the app will continue tracking your position by GPS, even when the app is running in the background (e.g. if you switch to another app, or receive a phone call during your exercise activity). This is enabled by API support that was introduced in Windows Phone 8 and Endomondo is one of the first of the major activity tracker apps to take advantage of it.

Previously, In Windows Phone 7.5, it was only possible to have active GPS tracking when the app was in the foreground or active under the lockscreen. This limited the usefulness of such applications as it generally required users to remember users to switch their tracking app back to the foreground, if it it were interrupted for any reason.

Endomondo is a comprehensive activity tracker, with strong social features, designed to "record" walking, running, cycling, or any other distance based sport. It can keep a track of where you go on an exercise route, how long it takes, and estimate how many calories you burn. The history section of the app will keep a record of any recorded exercise activity, with the key stats shown on screen, and the ability to view the route of the exercise on a map.

Endomondo is promoted as "a free personal trainer and fitness partner", reflecting both a number of features in the app (audio feedback for every mile while exercising, optional distance goal with audio coach, lap times and split times) and the strong social features on the app (sharing workout activities, receive social pop talks). When you sign up to Endomondo all data is automatically sent to a personal training diary on www.endomondo.com, essentially providing a web version of the history element (previous workouts) of the Endomondo app, but also making  it easier find and follow friends, and be part of the wider Endomondo community.

Windows Phone Store description:

Use your mobile as a free personal trainer and fitness partner! Using the built-in GPS, Endomondo Sports Tracker tracks your fitness - running, cycling, walking and any other distance based sport! On top, you get audio feedback on your performance during your workout and your friends can follow you live and send you peptalks in real-time.

Endomondo Sports Tracker can be downloaded for free from the Windows Phone Store. Versions are available for both Windows Phone 7.5 and Windows Phone 8, but only the latter has the background GPS tracking functionality.