Name: Running Index
Rating: 4.8 (46 reviews)
Author: Rider68

This Datafield calculates your 
-Running Index 
-Running Power in W
-Cardio Drift in %
 
based on your heart rate, elevation and speed data collected with your Garmin device. The Running Index shows you how efficient you are running and is close to the Running Index of Polar TM (see here https://support.polar.com/en/support/tips/Running_Index_feature). The higher the value, the better is your running performance. 

The following link helps you to estimate your best running pace for a given distance with Running Index: https://www.polar.com/en/smart_coaching/features/running_index/chart

For calculation of the Running Index, your maximum Heart Rate has to be entered in the settings. The value (default is 165 bpm) can be changed with Garmin Express on your desktop or with you mobile device Connect App (See the following link for more details https://apps.garmin.com/settingsHelp).

No index value is shown in the first five minutes as the result is not reliable. After that time, the index is shown and updated continuously. Ideally the value should reach a plateau. If not, additional HR drifting due to e.g. high (body) temperature or dehydration may cause changing of the running index with time. Also other factors like changing terrain could be a reason. Optionally, the Running Index can be adjusted by gradient and wind. With v1.8, wind data can be accessed automatically from the mobile phone when connected and supported by the device.

You can also use the data field indoor on a treadmill. In this case you should switch off GPS. You can enter the treadmill incline (in percent) in the settings. Acceptable range is from -5 to 35%. Only watches providing running cadence will support indoor use.

The Running Index, running power and Cardio drift will be recorded to the FIT file and is visualized on the Garmin Connect platform.

The Running Power is estimated based on your speed, incline, and wind/air drag. Make sure to setup your weight properly in athlete settings.

The cardiovascular drift is calculated by the ratio of the mean heart rate and the mean gradient adjusted pace at the given time (HR:GAP). The drift is shown in % change relative to a pre-defined basis or reference which can be selected in the settings. Default basis is the mean ratio measured between 5-10 min. The model compensates as much as possible effects of changing running speed, gradient and wind drag on the heart rate (the last two if checked in the settings). 

Finally, some useful summary statistic of the run is written to a log txt file on the device. This enables you to monitor your performance over time. You have to manually pre-create the log file in the folder garmin/apps/logs. The name of the txt file is (myapp).txt to match the running index datafield (myapp).prg. Unfortunately, the store assigns the prg name (8 characters and not consistent for different devices/users), so determining the correct prg file is tricky! The following data are stored:

Date, time, type of run [indoor or outdoor], distance, pace, pace adjusted, equivalent distance (gradient), equivalent distance (wind), elevation gain, mean HR, max HR, and Running Index.

How to install the datafield on your device?

Please note that Running Index is being only calculated if the corresponding "data field" was added to one of the activity's data pages.

A good explanation how to install a datafield on a garmin watch can be find here: https://tribeccato.com/2017/01/11/adding-data-fields-from-garmin-connect-iq/

Please contact me for any feedback, problems, suggestions, new features etc. !

Many thanks, when you consider the PayPal donation to my Connect IQ development here: http://www.paypal.me/ChristophK68