I might be wrong but... I'm pretty sure your body doesn't need to be trained(unless certai...

I might be wrong but... I'm pretty sure your body doesn't need to be trained(unless certain circumstances), just to know how to swim..

Don't you just need to know what to do to know how to swim? Not actually just rely on muscle memory or something??

I'm sure the mc knew or atleast, swam before when he wasn't Yoo Hajin..