I was just reading that Jose Bautista, the current MBL home run leader has popped 31 home runs, well behind the 50 or so that Mark McGuire was hitting by this time of year during the height of the Steroid Era. It got me thinking about the physics of the swing. A lot of people think that steroids help batters hit home runs because they can swing the bat faster and muscle the ball harder. But it seems to me that what muscle strength gets you is time. The key is that you can accelerate the bat faster, which means that you have a few more microseconds to watch the trajectory of the ball before you have to make a decision about hitting it. You get more data about if, when and where the ball will pass over the plate.
I think that was one of Barry Bonds greatest strengths. He seemed to be able to wait longer than anyone else. And then when he swung it was very quick, almost a pivot of his body and a flick of the bat (but then he always ended up jamming all that momentum onto his straightened right leg, which is where his knee problems came from).
Some have wondered if Bautista has been getting some chemical help because he has improved so quickly from last year, but he says that he is merely starting his swing earlier in the pitch. This makes sense–if you already have the bat moving you don’t have to accelerate so fast, and don’t need steroid-strength to get better home runs. Which made me wonder why more batters don’t do this. I think it might have to do with data. It’s easier to get reliable data about the flight of the ball if your head is still, so you want to wait. Of course if you could do the same body motion as you begin the swing, you could learn to get good data about the ball even while moving and beginning to accelerate the bat. I wonder if that is part of what Bautista is doing.