You can use a sync service as Dropbox to share your Workouts between computers. Redirect your Documents folder to a folder in the Dropbox folder. Or another way is to just email them to your own email account and save it to your other computer.
The same also works if you’re using workouts on your iOS device such as an iPad or iPhone. You can copy workouts off of the device, or create custom workouts and copy them to the device. Here’s a short video I did, describing exactly how to do that: