You can synchronise the activity of Runtastic through Apple Health.

How to connect Runtastic with Apple Health:

When you complete an activity with the Runtastic app, Apple Health will be able to display useful information like walking and running distance and calories burned.These stats then form part of your daily activity statistics in Apple Health. Steps:

1- Go to the Runtastic app

2- Go to ‘Settings’ 

3- Go to ‘Partner Accounts’ and click ‘Connect’ next to Apple Health. 

Once you have linked Runtastic and Apple Health, you simply have to add Apple Health in your WeFitter connections as indicated here.