Imagine you’re a student and you have a practical exam coming up; in this test you’re asked to perform a specific skill and the instructors will not only be grading you for your ability to conceptualize what you are doing and why but to also that you can put it all together and actually get some results. I’ve been tested this way dozens of times as a undergraduate and graduate student and I can safely say that just because you know what you are doing and why doesn’t always mean you can do it in real life.
The same is true for football players; as instructors to the game, coaches often will be assessing a player’s ability to conceptualize what they are doing and why, but also how well they perform that skill. And just the same as any other student, just because you know what you are doing and why doesn’t always mean you can do it in real life. There are countless examples of players who have the mental aspect of football down pat but lack the technique required to be successful in the league.
Now imagine a practical exam where you can study and figure out what you need to do and why, but weren’t actually given a chance to practice that skill before the exam, how well do you think you would do? Again from experience I can tell you you often don’t get the desired results because while your mind knows what to do your body doesn’t have the muscle memory to successfully perform that skill.