Once you have connected your Strava account with this website, all future activites that you upload to Strava are also sent here.
We have a look at the segments in the current challenges you have joined and check to see if the uploaded ride contains efforts on any of the same segments. If they are then we check to see if the new time is better than your existing best time, and add it to the leaderboard if it is.
Sometimes you may join a challenge that has already been running for some time and you may wish to include your previous rides. Although we have the ability to scan all your past rides, we have found that this uses up our quota on the Strava API too quickly.
So if you do want to include past rides, then please just go on to Strava and find the ride you want to include and make a simple edit, such as a slight edit to the activity name. Then Strava will resend the activity to us and we can analyse it. It goes without saying that only rides that occured within the challenge dates will be included!