Running in the background (iPhone)
This article describes how CrewNerd works in the background on the iPhone. For the most part, the answer is "it just works", but there are some limitations and tips you may want to be aware of.
How it works
When CrewNerd goes into the background, your workout continues uninterrupted, with some exceptions (see details below). Any accessories you're using (heart rate monitor, Vaaka cadence sensor, external GPS receiver, or ActiveLook glasses) will continue to work normally.
There are some details that depend on whether the workout timer was running when the app went to the background. These differences are explained in the next two sections.
Timer running
If the timer is running when CrewNerd goes into the background, the timer is not paused and CrewNerd's "live tracking" continues normally. If you gave CrewNerd permission to access your location "Always", then your speed, distance, and path will continue to be recorded accurately.
Timer stopped
If the workout timer happens to be stopped when CrewNerd goes into the background, your workout data is immediately saved, and Live Tracking (or iCrew tracking) are suspended, since you may be simply ending your water session. To avoid unnecessary drain on your battery, CrewNerd minimizes its use of system resources in this scenario.
If you return to the foreground within 15 minutes, CrewNerd will take this as a continuation of the same practice, and any subsequent workouts will be grouped together with the workouts you did earlier. If Live Tracking (or iCrew tracking) was on previously, it will be restarted automatically.
If CrewNerd is in the background for more than 15 minutes (again, with the timer stopped) then when you start CrewNerd again, it considers that to be a new practice and subsequent workouts will be grouped accordingly.
Limitations
CrewNerd works as well as it possibly can in the background, but some limitations apply, due to the way that iOS works, as described here.
No stroke rates
The first thing to be aware of is that CrewNerd can't detect strokes when running in the background. This is because access to the accelerometer is not reliable unless the app is running in the foreground. The next two limitations follow directly from this.
The only exception to this is for paddlers using a Vaaka cadence sensor, which will work in the background. In that case, the following limitations also don't apply.
No stroke-based intervals
If you were in the middle of an interval based on stroke counts when CrewNerd goes into the background, the timer will be stopped. If, during a custom interval workout, you attempt to begin a stroke-based interval, the timer will be stopped.
These are the only scenarios where the state of the timer changes because the app went to the background or while in the background.
No auto start/stop
Because we can't detect strokes in the background, the "auto start/stop" feature is suspended until CrewNerd returns to the foreground. If the timer was running when CrewNerd went to the background, then the timer will continue to run until the app returns to the foreground. If the timer was stopped, it will remain stopped.
Tips
"Always" permission for location is recommended
If you give CrewNerd permission to access your location "Always", then it can remain in the background indefinitely, while continuing to record your speed and distance. If you selected "While using" for the location permission, then CrewNerd can access your location for only a limited time (about one minute) when sent to the background.
If CrewNerd loses access to your location while running in the background, it will stop the timer and then will display an alert message when it returns to the foreground so you know what happened.
Background activity indicator on iOS 17+
Some phones running iOS 17 or newer will display a blue location icon next to the dynamic island when CrewNerd is accessing your location in the background. This can be a helpful reminder that CrewNerd is still active, and tapping the icon will bring the app back to the foreground.
Stop the timer at the end of your water session
Remember to stop the timer at the end of your session. As soon as you leave CrewNerd, your data will be saved. If you don't stop the timer, it could auto-start as you put your phone and equipment away, and CrewNerd will continue running in the background without saving your data.