Here is a way to export a TCX file from MapMyRide (MMR) and then convert it to a GPX file that Strava will accept. Strava does not accept GPX files that are directly exported from MMR because MMR is being a jerk and will not provide all the info needed for Strava or Strava is being a jerk and won't accepting basic GPS information for plotting just the route. So here's a solution:

1. Make your MMR workout privacy "Public" or called "everyone" in the mobile version.
2. Use the TCX button and export the TCX file of your workout and save somewhere on your computer.
3. You need an intermediate application to take in the TCX file and spit out a GPX file. Here are two options, login (free sign up) to website GPSies.com OR login (free sign up) to Garmin Connect (you don't need a Garmin device).
4. Import your TCX file to either one of these websites and use their export GPX function to create and export a GPX file.
5. Go to Strava and use the Upload Activity function (a "+" inside a circle) icon and follow prompts to select the new GPX file. Or, in my case, I needed a GPX file that I can upload onto my device so I can follow a new route.

I don't know how to do a batch of MMR files, but I hope this helps if you just want to get a GPX file out of MMR to upload to Strava or just some GPS device for navigation.