system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do we remember some skills (e.g swimming and cycling) our whole lives?

Went to community pool yesterday with my friends after 5 years. Swam like a pro. Then this question struck me.
gpt
It's called procedural memory. More specifically, it's 'muscle memory' or 'motor learning' which is a type of procedural memory.

Your brain's cerebellum, in particular, is very good at encoding sequences of muscle movements into long-term memory storage.

Procedural memory is very robust. Even people with dementia and amnesia often still retain procedural memories for skills like playing a musical instrument or riding a bicycle without any conscious effort.

Interestingly, for people with anterograde amnesia (a condition characterized by the inability to form new memories), it's still possible for them to learn new motor skills and encode them as procedural memories.

In other words, you can have someone with anterograde amnesia learn to ride a bicycle (as just an example) for the first time in their life and each day you get them to ride they will have no recollection of ever riding before, but each day they will continue to get better and better at riding the bike.