Yes you can; how to do it may differ for different cloud services.
iCloud: Tap a cma7 or cmr7 file, tap the Download button and select Copy to Coach 7. Coach 7 App starts and opens the activity.
Dropbox: Tap a cma7 or cmr7 file, tap the Menu icon, select Export and Select Open In … then select Copy to Coach 7. Coach 7 App starts and opens the activity.
GoogleDrive: Go to My Files or Google Drive, tap a cma7 or cmr7 file, Coach 7 App starts and opens the activity (notice that Coach 7 App has to be closed first otherwise you may get an error).