There are some nuggets in this blog about instruction in practice and how it changes when you get into game situations. It's about a golf study but it applies in all sports.
I see it in games all the time. Batter swings and misses. Steps out of the box and looks down to the coach for the sign. Coach says to batter, "You're pulling your head out, or your shoulder out, or dropping your hands" or some other swing tip that is actually counterproductive when it comes to hitting the ball.Falls in line with what is commonly said around here; training is the time to tell your batter she's dropping her elbow. Gametime is when you tell your batter to give it a ride.