What sets apart a average swimmer from a truly great one?

I like this group of physical attributes. Let’s compare two Olympians, first the most awarded, Michael Phelps: Tall - Yes long arms - Famously yes long torso compared to legs - Yes wide shoulders - Yes ectomorph-to-mesomorph build - Yes big hands and feet - Yes big lung capacity - Yes flexible ankles, knees, and shoulders - Yes strong core - Yes high lactate threshold - Presumably high proportion of fast-twitch muscle - Yes And now Cody Miller: Tall - No long arms - No long torso compared to legs- No wide shoulders - Yes ectomorph-to-mesomorph build - Yes big hands and feet - No big lung capacity - No flexible ankles, knees, and shoulders - Yes strong core - Yes high lactate threshold - Presumably high proportion of fast-twitch muscle - Yes Corey Miller is a breaststroker and Breaststroker can be shorter. As for legs, My legs are so short that I have to go to petit. I'm also average height though and Breaststroke my best stroke.

I like this group of physical attributes. Let’s compare two Olympians, first the most awarded, Michael Phelps: Tall - Yes long arms - Famously yes long torso compared to legs - Yes wide shoulders - Yes ectomorph-to-mesomorph build - Yes big hands and feet - Yes big lung capacity - Yes flexible ankles, knees, and shoulders - Yes strong core - Yes high lactate threshold - Presumably high proportion of fast-twitch muscle - Yes And now Cody Miller: Tall - No long arms - No long torso compared to legs- No wide shoulders - Yes ectomorph-to-mesomorph build - Yes big hands and feet - No big lung capacity - No flexible ankles, knees, and shoulders - Yes strong core - Yes high lactate threshold - Presumably high proportion of fast-twitch muscle - Yes Corey Miller is a breaststroker and Breaststroker can be shorter. As for legs, My legs are so short that I have to go to petit. I'm also average height though and Breaststroke my best stroke.