We have been beta testing the Rapsodo unit for several months. Following is our evaluation of the location accuracy - using the most recent hardware, firmware and software releases. (same version tested at Driveline).
How accurate is it?
We used our Hack Attack Pitching Machine and HitTrax system to provide the input and comparison measurements for Rapsodo. HitTrax has 3 hi-speed cameras to track the flight of the baseball on the way in (pitch) and way out (hit) using the triangulation method to determine where the baseball is.
Hi-Speed Video analysis has proven HitTrax to be accurate in reporting the location of the pitch. We will use this knowledge in our testing here and not re-confirm with video. Ten 77mph fastballs from the Hack Attack pitching machine were thrown and measured by each system. We have measured several hundred pitches of various types and spot checked the location on many which indicated the unit was in the ballpark but the focus was on determining if the other aspects of the unit were viable (spin rate, spin axis, true spin and movement). This small sample was used to put concrete numbers on location accuracy.
We have a couple of issues with the data that need to be discussed before looking at the results.
First: the strike zone itself and dimensions/location. We have no way to align both systems to have the exact same center point location of the strike zone for vertical and horizontal directions or size of the zone. Therefore, pictorial representations may be off.
Second: each system reports the location as above/below and left/right of a reference point. This reference point is not the same for each system. For HitTrax it’s from the middle/middle location of the strike zone. For Rapsodo, it’s the middle of the strike zone horizontally and appears to be from the bottom of the strike zone vertically (vertical reference point couldn’t be confirmed as of publication).
To address these issues, we used the first pitch as our primary reference point and then measured how far away each pitch was from that reference point. By doing this we are measuring how much each pitch is different from the original pitch for location as measured by each system. We can then compare the two systems to each other as we are looking at the relative relationship of one pitch to the next.
The first 4 columns of data show the difference in location from the first pitch for both systems in the vertical and horizontal directions.
The last 2 columns show the systems compared to each other.
The Rapsodo differed from HitTrax on average 1.3” horizontally and 1.8” vertically. The diameter of a baseball is just under 3” so the difference in location is roughly half of a baseball. However, a couple of the pitches differed by more than a baseball vertically.
Only using one camera as compared to three, we didn’t expect the Rapsodo to be as accurate as HitTrax. It turns out to be more accurate
than we expected. Having the catcher’s view with the camera certainly proves to be helpful in this regard.
Here are a couple of pictures from the two systems showing the location of the ten pitches. As you can see, visually they are very similar.
The differences of exact location with respect to the strike zone can be attributed to calibration (user dependent) and the actual dimensions of the different strike zones. The HitTrax strike zone dimensions in this case are 18” wide by 16.4” tall (varies by hitter). I don’t have the Rapsodo dimensions as of this posting.
HitTrax (shows hit speed, since we didn’t swing it all values are zero)
Is half a baseball close enough? Well, that’s really up to you. An error of 1.5" in this environment is reasonable in both a training or game situation; most umpires are not this good.
I would just like to reiterate some of the statements that Kyle made in his post. Rapsodo has been extremely responsive during all of our testing and very appreciative of the feedback. They are a pleasure to work with are very much interested in providing a product that is accurate and reliable. It’s not without it’s issues but I’m confident that not only will they be resolved but new enhancements and features will be added.
Teams and facilities should strongly consider adding this to their programs if they want to provide objective feedback to their players
to aid in their development.
Disclosure: we were provided a unit free of charge in exchange for beta testing and providing feedback to help them bring their product to market.
On August 29th, 2015 Liam Norris, an assuming 6’1”, 175 pound 14 year old, walked into the K-Zone Academy for an evaluation in order to begin our remote training program. His father, James Norris, had driven him in from Virginia some 3.5 hours away. We ran him through a battery of tests and showed him several drills and exercises he would be doing remotely. Liam is a good size (6’1”, 175lb) for his age and is a lefty thrower, lefty hitter to boot.
Below are his baseline numbers and hitting charts from his first couple of visits with us. (HitTrax system) Key statistics are highlighted.
All in all, not bad performance for someone entering the 8th grade. Liam’s goals at the time were to be like Clayton Kershaw (what lefty doesn’t), throw 84-85mph of the bump, hit the ball 90mph/350ft, be more aggressive at the plate and improve his command.
Those are some goals. So, we put together a plan and got to work.
Liam did most of the work at home with the help of his Dad. He trained 5-6 days a week and visited once a month sometimes more. It was challenging for Liam to stick to the training schedule and keep up on his school work, etc.
The visits to the K-Zone energized him each time. Competing against the high school and college athletes here drove him to improve and he developed some strong friendships in the process.
After 5 months of hard work Liam had reached some of his hitting goals.
91.5mph exit speed and 364ft. He was definitely more aggressive and was striking out far less. If you look closely at his early spray chart above, you will notice that he was hitting a lot of baseballs to the opposite field but there was nothing behind them. James liked to refer to his hitting style/profile as “Jeter” in reference to Derek Jeter’s inside/out approach to take the ball the other way. But at this time Liam was pulling the ball with authority. He was making significant progress on the throwing side too; increasing his pull-down to 89.7mph and feeling much stronger/healthier to boot.
By the time Liam’s season was ready to begin in the spring, he was ready to show off his newly developed skills. Unfortunately, his at bats were limited and pitched only 4 innings the entire season. Needless to say he was frustrated.
Being Liam, this fueled him to return to his training with a vengeance.
Liam and his family moved to the Raleigh area at the end of the school year and began to train full-time at the K-Zone. HE THRIVED!
Liam stopped doing specific velocity training in season (orange line) but continued to train in season. As a result, when he joined us in June he broke the 90mph barrier for the first time! His current record is 93.5mph; a 10+mph gain in a year.
Below is his velocity development to date from the beginning of his training.
This fall, Liam took his new skill set to the field entering a PG Showcase event and his life hasn’t been the same since.
He did so well at that event, he was invited to participate in a game with the top Forty 14 year olds in the country. His fastball now tops out at 87mph. He is ranked #5 in the country for the 2020 graduating class. The top collegiate programs are recruiting him aggressively. All this despite not being “good enough” to garner more than 4 innings of work for his HS JV team.
Liam is a great example of how important developing your skills and abilities through training is.
He didn’t play a bunch of games this year or attend several showcase tournaments or take weekly one on one lessons. He trained hard nearly every day for over a year and has turned himself into a top notch ball player.
So, when you see Liam out on the baseball diamond know that you are looking at someone who has worked very hard to be this good; he didn’t just wake up great.
Liam blasting a 387ft HR at 98.8mph
© K-ZONE BASEBALL SBA WWW.KZONEACADEMY.COM INFO@KZONEACADEMY.COM 919.619.0029
5205 Hillsborough St., Suite 103 Raleigh NC 27606
5205 Hillsborough St., Suite 103 Raleigh NC 27606