In this case there is, but Garmin seems to have closed the Feature Requests part, including the threads in there. So since I cannot support this feature request* in it's original thread, and do think it is a useful feature I decided to start a new thread on this request.
* Quote Feature Request:
In Garmin connect one can select a range of an activity graph. For example, I am heading to Central Park, and I want to select from the moment I enter the CP loop to the moment I exit it, 2 laps later. Right now you can do that selection, but the calculation of average speed, and other metrics, is not recalculated for the selected range. Strava does that in a very neat way.
Please, implement such calculation.
So a +1 by me :D
Please add this feature to Garmin Connect to improve the analysis capabilities.