Your examples, surfing, swimming, riding a bike, throwing a baseball, shooting hoops, playing tennis are simple actions, requiring only you controling you, and nothing else. The first time you go on a surf board you fall, and continue to fall until you get used to it, as the surf is relatively the same, everywhere you go, depending on the intensity of it. If you fall in love with surfing you will become more skilled at staying on top of your board, eventually being able to surf the wave for as long as it lasts. This is very different from preventing someone from hurting you in fight while attacking them as well, you should know this...
Physical skills are just that, physical skills.
While I understand your comparison to being a doctor and med school, being a doctor is NOT a physical skill per say, though a surgeon would argue with that
As for your above example in regards to control, while the control issue is an issue, I think T point was well made, wanna use/train WC to be effective in a fight it may be counter-productive to view WC training as different than what is need to be effective in a fight.
Psalms 144:1
Praise be my Lord my Rock,
He trains my hands for war, my fingers for battle !