In an earlier time, like the 20th century, young people grew up playing sports without a lot of detail in their way.
You learned how to position yourself in the field, how to get set before you threw a ball, maybe a pointer or two on the proper shooting technique in basketball or keeping your eyes on the ball all the way into your hands in football.
We lacked sophistication, among other things. If you played baseball, your best bet was to go watch a game in person somewhere, major league, minor league, college, high school, whatever was available, just to pick up a pointer here or there.