Baseball Bat – Ball Collision Using Blast, Diamond Kinetics, and Hit Trax – How Can We Use Data for Bat Fittings?

About a year ago I started to get interested in bat/ball collision and what perfect impact would look like and how we could tell as baseball players, instructors, and in analyzing data.  I reached out to Dr. Alan Nathan who is considered the leader in the baseball field.  We went back and forth and he settled on basically saying I should dig into this more if I have access to real life data.  So I did…

There is a lot of scientific information and formulas that he and others have spent a lot of time on but it gets very confusing and data overload.  I wanted to dig into this in a real world way with Blast, Diamond Kinetics, and Hit Trax.  I collected data and I had others send me verified data that is trusted.  All the work is on metal bats, bbcor, -3 (we can get into wood bats another time but I found that there isn’t much of a difference).  The goal was to come up with some ratios and metrics that could be used to verify solid contact.  Lets get into the data and remember I am keeping this straight forward and simple.  You can get lost digging into this stuff.


Base Information

Calculations used from Dr Nathan and can be dove into here:

Exit velo = (Bat Speed x 1.2) + (Pitch Speed x 0.2)

So a bat speed from Blast of 61.7 mph and a pitch speed of 68 mph should equal an optimal exit velo of 87.64 mph.  Thats (61.7×1.2)+(68×0.2)= 83.64 or (74.04) + (13.6) = 87.64.  This is ignoring launch angle which is a whole other discussion and factor that changes everything.  We are only worried about pure max exit velo based on bat speed and pitch speed.

What is Smash Factor – Golf

You should probably understand smash factor as well.  Golf again was ahead of baseball.  If you ever did a driver/shaft fitting, you know that the smash factor is one of the most important numbers.  Also keep in mind that a golf ball sits on a tee vs a pitch coming in at 90 mph and in different locations with different movements.  In golf we can discuss absolute optimal numbers.  In baseball these rarely happen and when they do we hit home runs.

Here is a definition and link.

Smash factor is a golf term that might sound intimidating, but to me it is the most important metric for ball striking. It is simply defined as the ball speed divided by clubhead speed. I like to think of it as how efficiently you are hitting the golf ball. For example, if your swing speed was 100mph and your ball speed was 135mph, then your smash factor would be 1.35.

Every player wants to know how to hit a golf ball farther. It is all we read about and hear about from the mainstream golf media. Essentially you have two options:

  1. Swing faster
  2. Increase your strike efficiency



The data random bat/ball speeds collected.  All of these were the best contact and best outcomes of a hitters session based on exit velo, not distance.  Although those do line up for some (ideally they always would).  It would  include Blast lining up with Hit Trax on that swing.  We collected:

Bat Speed – Hand Speed – Exit Velo – Launch Angle – Distance – Pitch Speed

Bat Bat Speed Hand Speed Exit Velo Launch Distance Pitch Speed
metal 61.7 21.4 82.9 22 267 68
metal 65.4 19.3 82.1 17 250 33
metal 60.3 18.9 76.9 11 136 39
metal 70.2 24.7 97 19 300 36
metal 73.1 23.1 91.1 20 299 38
metal 68.1 23.1 88.1 10 195 36


Data Breakdown

  • Bat/Exit = is basically the smash factor in golf.   This is the ratio that would be the easiest to determine optimal contact.  It is bat speed divided by exit velo.
  • 1.2 0.2 Exp = is just what the optimal exit velo should be based on bat speed and pitch speed.
  • Act – Exp = is Actual exit velo minus expected optimal velo.
  • Opt Bat/Exit = Optimal ratios
Bat Bat Speed Hand Speed Exit Velo Launch Distance Pitch Speed Bat/Exit 1.2 0.2 Exp Act – Exp Opt Bat/Exit
metal 61.7 21.4 82.9 22 267 68 1.34 87.64 -4.74 1.420
metal 65.4 19.3 82.1 17 250 33 1.26 85.08 -2.98 1.301
metal 60.3 18.9 76.9 11 136 39 1.28 80.16 -3.26 1.329
metal 70.2 24.7 97 19 300 36 1.38 91.44 5.56 1.303
metal 73.1 23.1 91.1 20 299 38 1.25 95.32 -4.22 1.304
metal 68.1 23.1 88.1 10 195 36 1.29 88.92 -0.82 1.306


Analyzing this data made it clear that the ratio we should be looking at is Bat/Exit and comparing that to Opt Bat/Exit.  The challenge here is that the Opt Bat/Exit changes based on bat speed and pitch speed.  These ratios get bigger as those go up.  Here is a chart to explain.

Bat Speed Pitch Speed 1.2 0.2 Exp Opt Bat/Exit
62 40 82.4 1.329
65 40 86 1.323
68 40 89.6 1.318
72 40 94.4 1.311
76 40 99.2 1.305
62 70 88.4 1.426
65 70 92 1.415
68 70 95.6 1.406
72 70 100.4 1.394
76 70 105.2 1.384
62 80 90.4 1.458
65 80 94 1.446
68 80 97.6 1.435
72 80 102.4 1.422
76 80 107.2 1.411
62 90 92.4 1.490
65 90 96 1.477
68 90 99.6 1.465
72 90 104.4 1.450
76 90 109.2 1.437
62 95 93.4 1.506
65 95 97 1.492
68 95 100.6 1.479
72 95 105.4 1.464
76 95 110.2 1.450

This clearly shows that when speeds increase, optimal contact ratios increase.  We simply cant use the same ratio for tee work as flips as machine pitches.  We also have to factor in the players swing speed.  I imagine we can take thousands of swings and categorize them in contact as A+, A, B, C, D F and then work from there to learn how to equate expected performance based on players average bat speed and pitchers average pitch speed per pitch (we are only discussing fastballs here, curves change these ratios).

What is also interesting is as swing speed increases, Opt Bat/Exit decreases.  A slower bat speed at the same pitch speed should actually be more optimal vs a faster bat speed.  For example:

90 mph pitch.  62 mph bat speed has the ability to hit a ball 92.4 mph which is a 1.490 ratio vs a 76 mph bat speed, 109.2 mph exit, and 1.437 ratio.


So what is an optimal swing and how do we know?  We need both bat speed and exit velo then we look at these formulas to determine where that bat speed should fall and then we calculate the ratio.  Remember, the ratio is simply exit velo divided by bat speed.  But these changes as each speed changes.  At the MLB level, you would like to see a ratio in the 1.425-1.475 range vs 90+ pitching.  Do not use this ratio for BP.  A ratio of 1.3 or more would be ideal for BP.


Side Note

I have seen some exit velos that do not correlate with the swing speed. I don’t know why this happens but these don’t translate into real in game results.  This will be a learning experience so what I post today may change when more data is collected.

I also want to test exit velos off tees but I never have. I’d like to gather a bunch of mlb results with blast connected.