*Reading this on mobile may cut off the charts. There is a lot of data and it is too wide. If you want to read it all please use a tablet but a computer is best. Sorry.
To build on my last couple posts and dive deeper into statcast data and calculating optimal contact and bat speeds I pulled data from Baseball Savant.
https://baseballsavant.mlb.com/hr_derby
I picked random rounds and Bryce Harper, Kyle Schwarber, and Alex Bregman to see if the assumptions line up to batting practice pitch speed (assuming 60 mph) and where the hitter is going all out to swing hard at grooved pitches.
- 1.2 0.2 Exp = Is what the optimal exit velo should be based on bat speed and pitch speed. = 1.2 x bat speed + 0.2 x pitch speed
- Opt Bat/Exit = Optimal ratios
Data
| Batter | Round | Exit Velo | Distance | Launch | Pitch Speed | Bat Speed | 1.2 0.2 Exp | Opt Bat/Exit |
| Alex Bregman | 1 | 103 | 422 | 23 | 60 | 76 | 103.2 | 1.358 |
| Alex Bregman | 1 | 100 | 401 | 27 | 60 | 73 | 99.6 | 1.364 |
| Alex Bregman | 1 | 98 | 399 | 28 | 60 | 72 | 98.4 | 1.367 |
| Alex Bregman | 1 | 100 | 385 | 24 | 60 | 73 | 99.6 | 1.364 |
| Alex Bregman | 1 | 95 | 386 | 33 | 60 | 69 | 94.8 | 1.374 |
| Alex Bregman | 1 | 100 | 416 | 25 | 60 | 73 | 99.6 | 1.364 |
| Alex Bregman | 1 | 99 | 404 | 30 | 60 | 73 | 99.6 | 1.364 |
| Alex Bregman | 1 | 98 | 390 | 33 | 60 | 72 | 98.4 | 1.367 |
| Alex Bregman | 1 | 98 | 377 | 35 | 60 | 72 | 98.4 | 1.367 |
| Alex Bregman | 1 | 102 | 413 | 27 | 60 | 75 | 102 | 1.360 |
| Alex Bregman | 1 | 100 | 409 | 23 | 60 | 73 | 99.6 | 1.364 |
| Alex Bregman | 1 | 98 | 404 | 31 | 60 | 72 | 98.4 | 1.367 |
| Alex Bregman | 1 | 98 | 406 | 29 | 60 | 72 | 98.4 | 1.367 |
| 99.154 | 400.923 | 28.308 | 60.000 | 72.692 | 99.231 | 1.365 |
| Batter | Round | Exit Velo | Distance | Launch | Pitch Speed | Bat Speed | 1.2 0.2 Exp | Opt Bat/Exit |
| Bryce Harper | 3 | 109 | 434 | 30 | 60 | 81 | 109.2 | 1.348 |
| Bryce Harper | 3 | 101 | 386 | 35 | 60 | 74 | 100.8 | 1.362 |
| Bryce Harper | 3 | 111 | 478 | 30 | 60 | 82 | 110.4 | 1.346 |
| Bryce Harper | 3 | 106 | 444 | 32 | 60 | 78 | 105.6 | 1.354 |
| Bryce Harper | 3 | 112 | 452 | 25 | 60 | 83 | 111.6 | 1.345 |
| Bryce Harper | 3 | 109 | 429 | 34 | 60 | 81 | 109.2 | 1.348 |
| Bryce Harper | 3 | 105 | 408 | 39 | 60 | 78 | 105.6 | 1.354 |
| Bryce Harper | 3 | 110 | 438 | 36 | 60 | 81 | 109.2 | 1.348 |
| Bryce Harper | 3 | 108 | 450 | 33 | 60 | 80 | 108 | 1.350 |
| Bryce Harper | 3 | 109 | 426 | 30 | 60 | 81 | 109.2 | 1.348 |
| Bryce Harper | 3 | 109 | 453 | 31 | 60 | 81 | 109.2 | 1.348 |
| Bryce Harper | 3 | 112 | 473 | 31 | 60 | 83 | 111.6 | 1.345 |
| Bryce Harper | 3 | 109 | 436 | 26 | 60 | 81 | 109.2 | 1.348 |
| Bryce Harper | 3 | 108 | 408 | 39 | 60 | 80 | 108 | 1.350 |
| Bryce Harper | 3 | 104 | 362 | 25 | 60 | 77 | 104.4 | 1.356 |
| Bryce Harper | 3 | 97 | 382 | 38 | 60 | 71 | 97.2 | 1.369 |
| Bryce Harper | 3 | 105 | 439 | 36 | 60 | 78 | 105.6 | 1.354 |
| Bryce Harper | 3 | 105 | 427 | 34 | 60 | 78 | 105.6 | 1.354 |
| 107.167 | 429.167 | 32.444 | 60.000 | 79.333 | 107.200 | 1.351 |
| Batter | Round | Exit Velo | Distance | Launch | Pitch Speed | Bat Speed | 1.2 0.2 Exp | Opt Bat/Exit |
| Kyle Schwarber | 3 | 108 | 446 | 24 | 60 | 80 | 108 | 1.350 |
| Kyle Schwarber | 3 | 105 | 422 | 32 | 60 | 78 | 105.6 | 1.354 |
| Kyle Schwarber | 3 | 109 | 446 | 26 | 60 | 81 | 109.2 | 1.348 |
| Kyle Schwarber | 3 | 110 | 442 | 26 | 60 | 82 | 110.4 | 1.346 |
| Kyle Schwarber | 3 | 110 | 446 | 30 | 60 | 82 | 110.4 | 1.346 |
| Kyle Schwarber | 3 | 109 | 430 | 25 | 60 | 81 | 109.2 | 1.348 |
| Kyle Schwarber | 3 | 105 | 433 | 30 | 60 | 78 | 105.6 | 1.354 |
| Kyle Schwarber | 3 | 107 | 442 | 29 | 60 | 79 | 106.8 | 1.352 |
| Kyle Schwarber | 3 | 111 | 435 | 22 | 60 | 83 | 111.6 | 1.345 |
| Kyle Schwarber | 3 | 105 | 413 | 34 | 60 | 78 | 105.6 | 1.354 |
| Kyle Schwarber | 3 | 112 | 393 | 18 | 60 | 83 | 111.6 | 1.345 |
| Kyle Schwarber | 3 | 109 | 430 | 23 | 60 | 81 | 109.2 | 1.348 |
| Kyle Schwarber | 3 | 104 | 416 | 34 | 60 | 77 | 104.4 | 1.356 |
| Kyle Schwarber | 3 | 107 | 441 | 27 | 60 | 79 | 106.8 | 1.352 |
| Kyle Schwarber | 3 | 98 | 397 | 26 | 60 | 72 | 98.4 | 1.367 |
| Kyle Schwarber | 3 | 104 | 435 | 27 | 60 | 77 | 104.4 | 1.356 |
| Kyle Schwarber | 3 | 104 | 428 | 33 | 60 | 77 | 104.4 | 1.356 |
| Kyle Schwarber | 3 | 110 | 453 | 26 | 60 | 82 | 110.4 | 1.346 |
| 107.056 | 430.444 | 27.333 | 60.000 | 79.444 | 107.333 | 1.351 |
We are assuming perfect contact on these home runs. We see that an Opt Bat/Exit or smash factor ratio of 1.35-1.365 on pitches 60 mph is accurate. Remember that as the pitch speed goes up, ratios go up keeping bat speed constant.
We can also see that as bat speed increases, Opt Bat/Exit or smash factor decrease slightly. Higher bat speeds are less efficient but higher pitch speeds also create higher ratios.
Here is that chart:
| 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 |
Results
As expected, Alex Bregman has a lower bat speed than Harper or Schwarber. Harper and Schwarber are basically identical. This lines up with in game performance as well.
| Exit Velo | Distance | Launch | Pitch Speed | Bat Speed | 1.2 0.2 Exp | Opt Bat/Exit | |
| Bryce Harper | 107.167 | 429.167 | 32.444 | 60.000 | 79.333 | 107.200 | 1.351 |
| Kyle Schwarber | 107.056 | 430.444 | 27.333 | 60.000 | 79.444 | 107.333 | 1.351 |
| Alex Bregman | 99.154 | 400.923 | 28.308 | 60.000 | 72.692 | 99.231 | 1.365 |
Conclusion
So far everything is checking out. These hitters are swinging as hard as they can in the home run derby and assuming a pitch speed of 60 mph its easy to look at the results. These numbers coincide with in game performance as well. Remember that in a game, hitters rarely swing as hard as they can.
We can actually dig into Harpers performance and see if his swing slowed down into later rounds. That’s for another time…