Step #2: Stated Weight Doesn't (really) Matter!

Previous: Step #1 Choosing a Legal Bat.

Next: Step #3 To Piece Or Not To To Piece

HOGWASH!

Now that we've narrowed the bats down by what is allowable, we need to start narrowing down even further the number of bats available and begging for your dollars.

The first way many suggest you do this is by using a "bat selection chart." These charts use some function of your player's age, height and weight to dictate what weight and length bat you should begin sorting through. This process is fundamentally INCORRECT.

You can delve into the next several paragraphs to learn why shopping by total bat weight doesn't make sense. You'll learn that choosing the right bat is a function of maximum swing weight and maximum swing speed--neither of which, it turns out, can be deciphered by looking at TOTAL bat weight or length. You learn below that it is the distribution of the weight which makes the difference the bats ability to be swung. This phenomenon is referred to as MOI (or Moment of Inertia or Swing Weight). Knowing that will make looking at bat sizing charts based on player age, weight and height (like here, here, here, here, here, here, here, here, etc. etc. etc.)) is a ridiculous exercise that too many folks get trapped into.

You can also NOT delve into the next several paragraphs, just accept those things out of hand, and move on to the next step: To Piece Or Not Two Piece.

To come to grips with the reality that total bat weight doesn't matter we need to break down the success of a hit into the two ways we increase power at the plate. The first is faster swing speed. A faster bat, assuming all other variables are the same, will create a faster batted ball speed. That seems obvious enough.

The second is a little less obvious. The amount of torque in the bat at impact, assuming all other things are equal, is the other variable that determines the speed of a batted ball. Torque, you may remember from High School Physics, is the energy a bat delivers to a pitch sending it in the opposite direction. Torque is NOT a measurement of the trampoline effect of the bats material (that is called Coefficient of Restitution or COR--which we will cover later) nor is it a measurement of the speed of the swing (that is called bat speed). Instead, torque is in reference to the amount of power in a bat at any given speed that resists the oncoming fast ball into a line-drive the other way.

To help make this clearer, imagine swinging a hammer. First hold the handle of the hammer and swing the head like a baseball bat. Now, turn the hammer around, put the head of the hammer in your hands and swing the handle like a baseball bat. Clearly swinging with the handle at the end, instead of the head at the end, changes the experience noticeably. While the total weight of the hammer never changes the weight of your swing (or swing weight) changes appreciably. Assuming you could swing both ends of the hammer with the same speed (possible depending on the size of the hammer) you'd have much more torque in the hammer while holding the handle and swinging the head.

So it goes with baseball bats. It turns out, like the sledge hammer idea, a bats comparative dead weight has virtually nothing to do with the torque or power in the swing. Instead it is much more a function of how the weight is distributed along the axis of the bat. Bats which tend to have more weight towards the end (called end loaded bats) have a higher swing weight. Bats which have weight evenly distributed along the axis (called balanced bats) have a moderate swing weight. Bats which have more weight in the handle (called speed bats) have very low swing weights.

Assuming two bats are being swung at the same speed, the bat with a higher swing weight will have more torque than a bat with the lower swing weight. That bat will, assuming the same swing speed, hit a ball further and faster than its low swing weight counterpart. Interestingly, and what happens often, a bat may have a higher swing weight yet a lower total weight than another bat. Such reality makes shopping bats by total weight as unsmart as the word unsmart.

The industry calls this principle of swing weight the Mass Moment of Inertia (or MOI). It is an objective measurement (which you can sort of do on your own) of the amount of mass required to force an object around a given point. (If you really want to dive into this, read this article from Professor Alan Nathan at the University of Illinois or this article from Dr. Daniel A. Russell at Penn State. I am not a physicist so I won't pretend to interpret them for you. But this much I am certain it says: the actual weight in ounces of the bat has between little and nothing to do with the success of a batted ball speed. And, as we've already discussed, batted ball speed isn't just a big deal it (and trajectory) are the only deal when it comes to getting our little tykes on base more often.)

19oz! Who Cares? You shouldn't.

Before I get too down on total bat weights, I do think they may not be entirely useless. Total weight may indeed be helpful if you are comparing bats of the same model. For example, we'd hope that a 32 inch is harder to swing (greater MOI) than the 30 inch of the same model. But, since we don't have published MOI, it is just a guess--and a good one at that. But we don't know how much more difficult relative to any other line of bats. It is a real shame bat companies don't publish their MOIs. If I were a small bat company trying to create a buzz, I'd let the world in on the secret.

As of today, the numbers in weight printed on the bat just don't correlate with the ability of a batter to put the ball in play with maximum velocity. Any sizing chart based on your players height or weight or online 'bat coach' that forces you to decide length and weight up front isn't doing you or your player any service. Avoid using those charts for a better experience in buying bats.

Next: Step #3 To Piece Or Not To To Piece
Previous: Step #1 Choosing a Legal Bat.