Swing Quality: An Interview with the Blast Biomechanics Team


We recently sat down with the Blast Biomechanics Team to discuss the three major components of a quality swing – Plane, Connection and Rotation.


How would you define swing quality?


We look at swing quality in two parts: the performance output, which gets to the quality of contact, and the mechanical part, which addresses how consistently a player reduces variability in the actual swing. 


Blast provides insights into the mechanical quality of the swing, based on the motion and the measurements we capture. In terms of performance outcomes, they are always going to matter, but there’s a high dependency on the quality of the swing itself.


If a player’s in their goal range for Plane, Connection and Rotation, could you say that they have a high-swing quality, independent of the outcome?


Exactly right. Conversely, you could also have a mechanically poor swing, but flare it over the first baseman’s head and get a hit. What we’re really trying to do in any sports performance is reduce variability. (Now variability, specifically functional variability, for human performance is always there. We never move exactly the same.)


What we are trying to determine is in the major concepts of the swing: Plane, Connection and Rotation, how consistent we are for all types of swings. This is important because in baseball and softball, we have variability of the pitch. 


With our latest release, Blast has unveiled new functionality where we automatically assess every swing and provide insights and drills for further development, initially for baseball and softball. Specifically, we’ve categorized the three major components of the swing: Plane, Connection, and Rotation, with additional metric details available for coaches that want to dive into the specifics for each of these areas.  


Starting with Plane, can you explain the difference between On-Plane Efficiency and Plane Score?


Sure. On-Plane Efficiency is how consistently a player maintains their arm and wrist throughout the swing, or the percentage of the swing where the bat is on-plane. The score shows you where you fall within your skill level, so both of them matter. The value of the On-Plane Efficiency metric is obviously going to drive your score; The higher it is, the higher your score. 


At the end of the day, it comes back to the actual metric value that we have. The data’s important to show us how consistent you are in your movement patterns, and it provides a better indicator for your performance. 


We are trying to look at it from the perspective of simplifying the swing. If my On-Plane Efficiency is high, that means that I’m much more consistently able to put the sweet spot of the bat where I want and think it needs it to go. 


The score helps coaches and players understand where they fall relative to their peers. It’s important to know where that is because as part of any development program or process, we first need to measure and assess the right things. Second, we need to know where a player needs to be for a particular skill level. And third, we need to know the prescriptive training plan–how do we get there?  

How about Connection?


Connection links together what your body and your bat are doing. It sounds simple, but Connection really affects your plate coverage. Where On-Plane Efficiency and Rotation values are on a swing by swing basis, Connection is measured throughout the zone, specifically, are we connected throughout that coverage?


A lot of hitters will be strong in one area but have a deficiency in others. At the Major League levels, you’ll see the hot/cold zone maps that they show in games. Cold zones are where swings fall apart or get disconnected. 


Connection also provides information about whether a hitter is adjusting with the body or the hands and arms. The difficulty of adjusting with the hands and arms is that there’s a lot more variability there, so consistently hitting the ball on the barrel is reduced. We measure both Connection at Impact and at the beginning of the swing. 


Early Connection is important because there is a lot of variability at that point in the swing. Players who are connected early have a better chance of being connected at impact. 


Connection at Impact is important because it’s the end of the result of that dynamic motion. 


How is the Connection score calculated?


We combine the Connection at Impact and the Early Connection values, and then we look at where you fall against the population at your level of play. 

Third category, Rotation. What is the difference between Rotational Acceleration and Rotation score?


Rotational Acceleration is extremely important because it’s a big differentiator, especially at the professional levels. We see a very consistent trend in Rotational Acceleration values increasing between rookie league and Major League Baseball. 


Major League Baseball players have, by far, the highest Rotational Acceleration average. At the Major League level, if you don’t have the ability to accelerate into Rotation very quickly, you’re never going to catch up to the pitches due to the combination of speed and movement. At the lower levels, it’s not as important, but yet it still is predictive of performance. It goes all the way back to the youth levels. The better you learn to rotate and use rotation to your advantage to build bat speed, the better you are as your level of play advances. 

Looking at it from a coach’s perspective, how can I use these main categories of Plane, Connection, and Rotation to help improve my hitters?


This goes back to the Swing Quality. Plane, Connection, and Rotation provides coaches with deep insights into swing mechanics, which are going to be directly tied to the performance outcome. A lot of coaches are familiar with the concepts of exit velocity and launch angle. Plane, Connection, and Rotation map directly to those values.


What we see with Rotational Acceleration, again at the Major League levels, is the players with the highest Rotational Acceleration have the highest exit velocities and they hit those exit velocities more consistently. 


So, you can always tell the relationship between the two. 


On-Plane Efficiency speaks directly to the launch angle, but there are a couple of different factors involved. You’ve got the pitch plane coming in on a slightly downward trajectory. You hopefully have an attack angle that is positive so that they match the plane. The On-Plane Efficiency is how consistently a player is getting the sweet spot of the bat to the ball. The higher the On-Plane Efficiency, the less variability you’ll see in launch angle.

You talked about Plane and Rotation leading to exit velocity and launch angle. Is there a direct correlation to Connection in the performance outcome?


Yes. Connection’s really is looking at how consistent On-Plane Efficiency and Rotational Acceleration are. If you look at that barrel concept of exit velocity versus launch, we want to keep that high throughout the zone. Connection is really what ties that together.


Good Connection means you’re using the body to adjust throughout the zone, while maintaining our Rotational Acceleration and On-Plane Efficiency.


Coaches can work with players on those specific categories, then there are drills provided to help them further develop their skills?


Yes. If you are only looking at outcomes, you may see lots of variability and not know why. Plane, Connection, and Rotation actually provide the insights as to why there’s that variability.


If I’m looking at my app, am I looking at concentrating on the score or am I drilling into the individual metrics making up those scores? What do you think is the best path?


I think this has more to do with the type of coach. If you’re coaching a 12-U team, the scores provide a lot of insight because now you’re not having players spanning across different levels. If I’m an academy coach where I work with a 12-U player, then a 16-U player, sometimes the metrics, at least initially, provide a little more insight because then they are not as dependent on the population.


As you get familiar with what the metrics are, and the scores based on the level of play, the scores at the end of the day will provide you the insight you need. 


Final question. Starting at the youth level all the way through Major League, do the drills that we prescribe help you continually work on Plane, Connection, and Rotation? 


Yes. That’s where the prescriptive drills help because they’re categorized by Plane, Connection, and Rotation. Going through all the drills will help you improve the areas where your score is low and maintain in the areas where you’re strong.  


– Blast Biomechanics Team

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