**PITTSBURGH** *(UPDATED, 6 min read)*– Last week we analyzed approach angle and trigger to impact, in terms of swing optimization, to see how those specific metrics could affect the outcome of two different swings.

With the help of Dr. Alan Nathan, we learned how approach angle not only affects batting average and home run probability, but also how much it affects timing and results – relative to making contact with the ball at a specific point during the swing.

The two case studies Dr. Nathan looked at involved a swing with an approach angle of +6° and +24°.

He surmised…

“*The level swing is one where the attack angle coincides with the descent angle of the ball, which in our case is 6°. That angle is very close to the optimum angle for high BABIP. The home run swing is one where the attack angle maximizes the probability of hitting a home run, which we have just found to be 24°.”*

In terms of someone’s approach at the plate, this poses an interesting question.

Which approach angle should you strive for?

As Dr. Nathan discussed in his article on this subject (emphasis ours):

“…

if the batter is going for a line drive single, the offset (the amount of distance the batter is off from making contact with the ball right at the front edge of home plate) might be about 0.5 inches; if he is going for a home run, it will be around one inch. Now suppose that the batter is a little late with the swing (say, a bit over three milliseconds late), so that the contact occurs four inches behind the front plane of home plate. If the attack angle is level, the actual offset will be identical to the desired offset.Such a swing is therefore very forgiving for small errors in timing.

However things are very different if the batter has a home run swing. Over those four inches, the ball will be about 0.4 inches lower and the bat will be about 1.8 inches lower. The net effect is that the offset will be larger than the desired offset by 1.4 inches. Likewise if the swing were too early by the same four inches, the offset would be smaller than desired by 1.4 inches. Think about that for a minute: 1.4 inches is about half the diameter of a baseball. It is huge! For example, if you are aiming for one inch and are late by three milliseconds, your offset will be 2.4 inches, which gives you a on-base probability of close to zero. Indeed, if the offset is larger as 2.7 inches (the sum of the ball and bat radii), the bat will miss the ball altogether.”

We now see the difficulty the batter faces. The margin for error severely decreases as the approach angle increases (~ >20° degrees)

However, the payoff can be immense.

Daren Willman, Director of Baseball Research and Development for MLB.com, recently shared the Statcast data of the launch angle of the ball after impact, relative to results, of over 15,000 at-bats.

We have highlighted the top batting averages with their corresponding launch angles, as well as the top home run swings with their corresponding launch angles. Below is the chart with the complete data.

**Home Run Launch Angle & Results**

1) 25° – 29°: 1,407 HR’s

2) 20° – 24°: 976 HR’s

3) 30° – 34°: 889 HR’s

4) 35° – 39°: 362 HR’s

5) 15° – 19°: 134 HR’s

**Batting Average Launch Angle & Results**

1) 10° – 14°: .775 BA

2) 15° – 19°: .619 BA

3) 5° – 9°: .569 BA

4) 20° – 24°: .538 BA

5) 25° – 29°: .438 BA

Last summer we took an initial look into this, singling out home runs by Todd Frazier, Ryan Howard, Justin Upton and Andrew McCutchen that had launch angles between 15° and 19° – see video of Frazier’s below:

As Mr. Willman’s chart has shown us, we can see the results of all balls hit with those specific launch angles. With this knowledge in hand, we now know that home runs with launch angles between 15° and 19° have accounted for 3.4% of home runs measured by Statcast data**¹**.

But getting back to the question at hand, which approach should we use, relative to approach angle at the plate?

While the type of pitch the batter sees certainly has a huge effect on the approach and path to the ball, assuming we see a pitch that is more or less ‘down the middle’, how should the approach angle look.

Here’s a suggestion from Dr. Nathan (emphasis ours):

“A possible compromise is to pick some intermediate attack angle. For example,an attack angle of 12° reduces the home run probability by about 35 percentbut also reduces the four-inch timing error to be about 0.4 inches. Moreover,such an attack angle is actually “level” for a typical curveball, which has a larger descent angle than a fastball.”

Furthermore, here is further explanation of how to approach swing plane angle from Diamond Kinetics’ own Jeff Leach:

Perfect Swing?

Is the perfect swing getting the bat to line up w/ the ball path resulting in direct central impact? pic.twitter.com/gVRvNg8lCt

— Jeff Leach (@CoachJeffLeach) January 28, 2016

A: Perfect on plane swing (bat path +6* to ball -6* would = +6* ball exit after contact w/low spin & NO home run! pic.twitter.com/HrokVrPXWJ

— Jeff Leach (@CoachJeffLeach) January 29, 2016

**Conclusion: **

As we discussed last week, timing (hand speed, trigger to impact and quickness) certainly has an effect on the outcome of each particular swing, relative to launch angle.

However, we can at least discern – within a given set of parameters – what the results of a specific launch angle are, and from that, learn how to make one’s swing fall within that framework.

**Footnotes:**

1. The two home runs – by Ryan Rua of the Rangers and Aaron Altherr of the Phillies – that had a launch angle between 10° – 14° were both inside-the-park home runs as seen in the video below:

**#DKBaseball**