Can I import a single workout to my forerunner 310xt unit? Or, how do I restore deleted activities to my unit - they are saved in the training centre and on garmin connect?
Why do you want to do that? Normally you have to delete activities from the 310xt to make room for more. The 310xt (or any of the Garmin fitness devices) are not really meant for long-term storage -- once you've transferred the activity to Training Center or Connect, you can delete from the 310xt.