I'm not far enough along in the process to have done ERAS yet. I was talking about my experience interviewing for med school and for summer positions. Re: putting experience from undergrad, if it is significant (e.g. a varsity sport; playing a sport competitively on the national, international, and/or professional level; significant humanitarian/volunteer experiences), I would certainly list it -- especially if undergrad was only four years ago. My rule is that if it has significantly affected my development and the choices I have made (e.g. to try to become an orthopod), I feel passionately about it to discuss it in an interview. And as such, I feel I should (and will) list it on ERAS.
I'm sure many others with more experience could chime in with their thoughts on this, and I would love to hear them.