No, but getting research experience (not necessarily through SURF) would strengthen your application. You could also look into community service or teaching, or getting involved in campus leadership roles. As for what you 'need to do': a solid GPA/MCAT and clinical experience would top that list.
If you don't have a research experience, you'll need to be correspondingly stronger in some other EC area. Hopefully, you are working on/planning the essentials of clinical experience, shadowing, nonmedical community service, and maybe also leadership and/or teaching.
Keep in mind, since so much time is taken up by your sport, that there is no rush to get all this in before you graduate. Don't put unwarranted pressure on yourself to apply after junior or senior year when those of less traditional age are valued for their greater maturity. Enjoy each step of the journey.