Proof is meaningless.
If I say that I spoke with kids and they then went on to set a new school home run record, did I hit any home runs?
If I offer that a hitter should keep his weight back, or extend his arms further into the swing or complete his follow through and that leads to success, did I hit any balls?
If I offer that a batter should hold the bat higher to have a greater range of motion and that eliminates strike outs and leads to a higher average, did I hold a bat?
What is proof if a batter uses one scintilla of a suggestion?