How much does a strong extracurricular spike matter for top schools?

At top schools, an extracurricular spike can be extremely important. It is certainly possible to get in without one, but it is much more difficult.

It's a little difficult to answer this question just from numbers of activities alone. On paper, having 4-5 non-STEM activities and 4-5 non-STEM activities sounds fine to me. However, what really matters is how impressive these activities are. If you have one or two extremely impressive STEM activities (IE. being a finalist at the Intel Science and Engineering Fair and/or getting a research paper you co-authored published and having it cited in many other important papers), the rest of your extracurriculars are much less important. You've already built your spike. If it's 4-5 more passive activities (you're a member of your Science Olympiad team but the team hasn't won any competitions, you shadowed a doctor once, you're in robotics club but don't have a leadership position, you attended a hackathon, etc.), then it's a rather less impressive spike. What also matters is how closely related the activities are. If most of these 4-5 activities are all directly related to biology or biomed, then it may be easier to build a clear spike than if they're spread out across various STEM fields.

It is always good to add an impressive activity or achievement to your extracurricular list, and winning competitions is a great way to prove to admissions officers that you have real skills and talent.

That's a lot of extracurriculars! Getting involved in science/STEM activities are a great way to get started in pursuing a career in biology or medicine. I'd say that the amount of extracurriculars you have is enough for now. It might not be the best idea to take on too many activities. I know it's tempting to make ourselves look extra good for college applications, but you shouldn't push yourself too hard. Consider how much free time you have and how new extracurriculars may affect your schoolwork, job, or social life before starting anything else. It's great that you have activities in other fields, as colleges like to see someone with a wide variety of interests and skills. Ultimately, it's up to you to decide how much you can handle. Good luck!

So for top schools, having a spike is good because it shows that you're already focusing on your interest with your extra curriculums, especially if you're intending on majoring on that. It is great that you have 4-5 extra curriculums related to your interest! It would also be good to have other extra curriculums that show interest outside of STEM.