Skip to main content

88 replies

Zepp Data -- Hand Speed, Bat Speed, Time to Impact

BogeyorparBogeyorpar1,000+ posts
Originally Posted by 2019Dad:
Originally Posted by Bogeyorpar:

I'm still a little skeptical of the numbers reported by Zepp. I recently went to watch a showcase. The showcase reports Zepp readings for all players. We saw many bat speed listed in the 90+, but we also saw their swing in the real games. Some were really weak hitters, couldn't even hit the ball out of the infield. I read somewhere that bat exit speed of 85 should produce a home run on a typical HS field. However, I haven't seen those 90+ guys done one yet. There may be a way to trick the Zepp system ... not sure how coaches/scouts use this data.

This is not Zepp-related but along the same lines. 

 

When you see a kid hit a ball 325 ft., can you assume the exit speed was ~90 mph or better (absent any wind)?

 

It should work the same as a throw, and I know that 90 mph is the approximation of the release velocity of a throw that travels 325 feet. And that 85 mph equates to approximately 300 feet.

 

Does that make sense? Am I thinking about this right? 

If the ball was sitting on a tee, and the batter was using a 32/29 wood bat, yes. If it was a pitched ball, the velocity of the pitch will affect the bat exit velocity greatly. The size/weight of the bat will also affect exit velocity. That's why at showcases, exit velocity is measure by hitting teed up balls with a fixed size wood bat to make it equitable.  

D 2020dad
But the poster simply asked is 85 85 and is 90 90.  And the answer is yes.  Whether it is thrown, hit off a tee or hit off a pitxh if it comes out at the same speed with the same launch angle it will go the same distance.  Keep in mind launch angle.  If the launch angle is too steep that ball that goes 325 feet could theoretically be at 100mph to go 300 feet.  But yes safe to say that if it goes 300 feet at.minimum it was going 80 or so.

Screenshot_2015-05-08-16-35-03

Attachments

Hide
Images (1)
  • Screenshot_2015-05-08-16-35-03
D 2019Dad10,000+ posts
Originally Posted by 2020dad:
But the poster simply asked is 85 85 and is 90 90.  And the answer is yes.  Whether it is thrown, hit off a tee or hit off a pitxh if it comes out at the same speed with the same launch angle it will go the same distance.  Keep in mind launch angle.  If the launch angle is too steep that ball that goes 325 feet could theoretically be at 100mph to go 300 feet.  But yes safe to say that if it goes 300 feet at.minimum it was going 80 or so.

Screenshot_2015-05-08-16-35-03

That's very cool, thanks.

 

Regarding the tee vs. pitch thing, I understand why a tee is used to get an apples-to-apples comparisons of different kids, and I have always believed that the velocity of the pitch made a tremendous difference in how far the ball goes when hit. It made sense to me. But a couple months ago I read an article that was pretty persuasive that it makes very little difference: www.diamondkinetics.com/dispel...tery-of-pitch-speed/

 

D 2020dad
There is a difference but as you say not nearly as much as people think.  And as I have states before the faster it comes in the faster.it goes out is mostly a myth.  However there is some correlation due to the fact it is human nature to swing a little harder (faster) when a high velo guy is throwing.  But it is the speed of the bat not the speed of the pitch in that case that makes most of the difference.
BogeyorparBogeyorpar1,000+ posts

I read the diamondkinetics article but did not see scientific proofs. However, even in the article they said that each mph of pitch add 0.2mph of batted ball speed. If we accept this formula, a pitch comes in at 80mph will add 16mph to ball speed. That's a lot. If 85mph is the speed needed to make a home run, it means that a person with 69mph static exit speed can hit homeruns.

 

Let's go back to the Zepp data collected at showcases. Virtually everyone gets more than 69mph on teed ball. My point was that we should have seen many more home runs if the data is correct.

D 2019Dad10,000+ posts
Originally Posted by Bogeyorpar:

I read the diamondkinetics article but did not see scientific proofs. However, even in the article they said that each mph of pitch add 0.2mph of batted ball speed. If we accept this formula, a pitch comes in at 80mph will add 16mph to ball speed. That's a lot. If 85mph is the speed needed to make a home run, it means that a person with 69mph static exit speed can hit homeruns.

 

Let's go back to the Zepp data collected at showcases. Virtually everyone gets more than 69mph on teed ball. My point was that we should have seen many more home runs if the data is correct.

Each mph of pitch speed doesn't add 0.2 mph of exit velocity; it adds 0.2 feet of distance. So the difference between hitting off a tee and hitting a 100 mph fastball is 20 feet of distance. The point they made about 440 ft. bombs hit on home run derbies or Stanton's blast off a Jamie Moyer 66 mph pitch made sense to me.

 

As to the home runs, I'm not really disagreeing with you. Our high school field is 330 ft. down the lines and 380 to the deepest part. Kids with exit velocities off a tee of 85 mph would not be able to hit a home run or even hit the fence, even with optimal launch, and even off a 100 mph pitch (not saying they could hit that pitch, just that it would add 20 feet of distance if they could hit it). But my question was the flip side -- if we see x distance, can we assume y exit velocity. Like for our high school field, if I see a kid hit it out, I know that on that hit, there was 90+ exit velocity (assuming no wind). And I think 2020dad's data answered that question.

GovGovMember since 2015

Hitting the sweet spot of the bat against the ball at the right launch angle should also be considered.  If the hitter doesn't have the right launch angle of the bat he may or may not produce sufficient backspin (carry/lift) to get out of the infield or over the fence.  

 

High bat speeds and high exit speeds but at topspin producing bat launch angle's may or may not get out of the infield.  

 

Some of the slower pitching speeds that produced a home run out of the park were likely with curve balls.  A hitters ability to sit on a curve ball can create greater backspin than off a fastball.  Credo's to any hitter than can make an adjustment in .10 of a sec to get the right angle on a quickly dropping pitch.  

D 2020dad
85mph will get you 330 ft.  67mph exit velo won't get you much.  So wherever the 67mph exit velos are I would certainly expect to see zero home runs unless there is a gale blowing out, a short porch and a perfectly squared ball at the perfect launch angle.  Even with all that not sure its possible.  Basically once you get in the low to mid 80's you become at least a threat to grease one over.  Once you are 90's you are a legit power threat.
D 2020dad
P.s. also don't confuse bat speed (zepp data) with exit velocity - zepp has no idea if you squared it up or to what degree so renders no exit velocity data however you can enter it on your own which is a nice feature.  Exit velocity can be more or less than bat speed.  If you really square it up though exit velocity is higher than bat speed   have not been able to find an exact ratio although I have looked.  If anyone has one I would love to see it.  For example: at an 80mph swing speed (zepp data) what is MAXIMUM possible exit velocity...  in any case I don't think the difference is as much as I thought it was and I find it hard to believe 67 swing speed will get you over a fence.
BogeyorparBogeyorpar1,000+ posts

Found another, slightly more scientific, article about BBS (Batted Ball Speed):

 

http://www.popularmechanics.co...ports/a4569/4216783/

 

This article explains the "sweet zone", the ideal bat weight, why people hit 78mph curve balls further than 94mph fast balls, and the theoretical limit of the distance a batted ball can travel (475 feet.)

 

He also has a "Batted Ball Speed vs. Swing Speed" chart. Here I suspect his definition of Swing Speed is the hand speed, since a 30mph hand speed can roughly create a 72mph BBS.

D 2019Dad10,000+ posts
Originally Posted by 2020dad:
P.s. also don't confuse bat speed (zepp data) with exit velocity - zepp has no idea if you squared it up or to what degree so renders no exit velocity data however you can enter it on your own which is a nice feature.  Exit velocity can be more or less than bat speed.  If you really square it up though exit velocity is higher than bat speed   have not been able to find an exact ratio although I have looked.  If anyone has one I would love to see it.  For example: at an 80mph swing speed (zepp data) what is MAXIMUM possible exit velocity...  in any case I don't think the difference is as much as I thought it was and I find it hard to believe 67 swing speed will get you over a fence.

Now that PG has been using zepp for awhile, more data is starting to become available. For example, for the 2016 class, a bat speed of 90 mph is roughly the 90th percentile of the kids tested. As you said, that is not the same thing as exit velocity (and thus, distance, assuming a good launch angle).

 

I looked at the PG Zepp page (www.perfectgame.org/Partners/Zepp.aspx) and the max exit velocity leaderboard for MLB (www.baseballsavant.com/apps/hit_leader.php) and it seems like exit velocity for the pros tops out at around 15%-25% higher than the highest swing speed. For example:

 

Trout -- 99 mph swing speed; 118 mph exit velocity

Ortiz -- 94 mph swings speed; 114 mph exit velocity

Altuve -- 86 mph swing speed; 106 mph exit velocity

Myers -- 91 mph swing speed; 112 mph exit velocity

Donaldson -- 98 mph swing speed; 114 exit velocity

Rizzo -- 95 mph swing speed; 112 exit velocity

Springer -- 97 mph swing speed; 114 exit velocity

Stanton -- 96 mph swing speed; 120 exit velocity

 

The exception is Pence, who has reached a 106 mph swing speed, but *only* a 113 mph exit velocity. Perhaps that has something to do with his swing mechanics? Also, I'm not sure if they all used the same weight bat.

 

Anyway, for high school players, it will likely be somewhat less than 15%-25%, because they are not swinging as heavy a bat as the pros (32/29; thus their swing speeds will be higher than they would be with a heavier bat -- college uses 33/30 in the zepp testing; not sure about the pros).

 

This doesn't precisely answer your question about an exact ratio between swing speed and exit velocity, but I think it's fair to say that the high school kids who are above 90 mph swing speed can generate exit velocities over 100 mph, assuming they square up the ball.

C Cap217100+ posts

IMG_5923I'm new here but have read your threads for a while. Glad to be posting.

Can someone explain this please?  I use zepp on my swing and I get in the 80s range on my best. Hit 90 a few times. I have a friend who plays MLB ball and he hit on my sensor after I was hitting and getting low average numbers. He ripped off a 109 swing speed and a few 105s. He averaged high 90s. This was with jeans on and dress shoes and not warming up. Pretty impressive but my question is, how can he get a 109 speed?  All the data I see doesn't show many speeds that high.  These were off a tee or soft tossed. 

Attachments

Hide
Images (1)
  • IMG_5923
D Dominik8510,000+ posts

I believe zepp definitely reads high above 80 mph or so. 

my best batspeeds with the swingspeed radar have been 82-83 and with the zepp I am often upper 80s and sometimes up to mid 90s (one time it even read 100).

not sure if the new zepp is more accurate. 

I use it for swing plane but I don't think the batspeeds and especially time to  impact (I had many swings around 0.10 which is probably too low too) are all accurate . 

Last edited by Dominik85
D Dominik8510,000+ posts

don't confuse launch angle and attack angle. you can hit fly balls with a zero or negative attack angle if you hit it below center enough but then you might get too much backspin and not hit it flush enough. some backspin is good but Nathan said above 2000 RPM backspin actually becomes detrimental plus you lose exit speed if you cut the ball too much. 

Last edited by Dominik85
D 2020dad
Dominik85 posted:

don't confuse launch angle and attack angle. you can hit fly balls with a zero or negative attack angle if you hit it below center enough but then you might get too much backspin and not hit it flush enough. some backspin is good but Nathan said above 2000 RPM backspin actually becomes detrimental plus you lose exit speed if you cut the ball too much. 

Spot on

C Cap217100+ posts

I understand. I am saying that if we assume the swing bat path angle is 0' the ball can go anywhere from 90' straight down to 90' straight up. Since the ball and bat are round it will matter where it makes contact on the barrel. 

This can get complicated but the more positive the attack angle the less margin there is on the + exit angle.  The ball can never go backwards although foul tips come at the edges of the 90'. Pictures are easier to explain. 

D Dominik8510,000+ posts

The top Exit Speeds in MLB are on average around  plus 5-15 degrees, because that is the average attack angle. Exit Velo is highest when attack and Launch angle match, basically when you hit a "knuckleball" (not considering the incoming spin which is almost never Zero).

HRs are hit at higher Launch angles and often have a couple mph less than the hardest hit balls because there is some undercutting.

in theory a higher attack angle would produce longer HRs but then it would be harder to square up 90+ fastballs which tend to be "flatter" than slower pitches (around  5-8 degrees downward I think), so attack angle is always a compromise for sluggers, usually they swing a Little steeper than the average pitch but it can't be too much.

 

here is the leaderboard and most of the hardest hit balls are hit below the HR range (20-40)

http://m.mlb.com/statcast/lead...ard#exit-velo,r,2016

that is one of the things that makes slugging HRs consistently hard. It is much easier to achieve high Exit velos on 5-10 degrees than it is on 25-35 degrees, many Players can't carry their good Exit Speeds in higher angles because they Need to get under the ball too much to elevate meaning they hit mostly sliced FBs, often the other way.

so hitting balls really hard at 25+ degrees is a really tough Thing, especially if you want to do it against plus Velo (you can of course lean back to the catcher more to create more lift and even make it work against BP fastballs but doing that and getting behind 90+ is really hard).

there are some sluggers who use steeper attack angles around 20 degrees or even a Little higher (Chris davis seems to be like that) but those guys usually have astronomical Strikeout rates and low average.

Last edited by Dominik85
D 2020dad

I am all about numbers and the physics of baseball. But at some point it is paralysis by analysis.  Main take aways from this science should be:

1. Need an uppercut somewhere in the 5 to 15 degree range.  Can someone succeed at zero?  Sure it's just harder. Same for 20 and above. 

2. Need to hit the ball center to just under center - but easier said than done. 

3. Swing as hard as we can without losing total control. 

4. Find a REPEATABLE set of mechanics that allows you to do the above. 

5. Once you establish the above its time to move on to some finer points like pitch recognition, situational hitting and hitting the count. 

T teddy9100+ posts

nice thread, what led me here was trying to understand my Son's recent PG Zepp showcase numbers (young 15yr old sophomore in HS):

Bat Speed at Impact 83mph (79.5% for 2019 in 2016)

Hand Speed Max 37.5mph (97% 2019 class in 2016)

Time to Impact 0.146 (14% 2019 in 2016)

Exit Velo (rocket radar), off tee 80mph

Trackman Exit Velo off live ball 87mph

 

So what does this tell me? 

1) Maybe he should be a boxer with that hand speed?

2) Force should equal Mass x Acceleration, right?  How does a bat moving at 83mph only transfer a force of 80 mph? weak contact? no benefit from the mass (bat?)  

3) "Time to Impact" really is useless (IMO) in a vacuum, or singularly, especially when hitting a stationary ball.; maybe gathering this reading verse live pitching then trying to determine the optimal "time to impact" to best read and stay back on different speeds.  Or maybe the higher numbers mean the swing is too long, or hitter starts too early...

I'm interested, so I bought a ZEPP. I'm going to start collecting data here and there. After accumulating a larger sample, maybe then the relative numbers may mean a little more.  

D Dominik8510,000+ posts

I'm honest, with you, that plane is really bad. he basically is taking a straight downward hack.

 

however the batspeed is solid and it can be corrected.you want a path more like a nike swoosh sign, bottoming out around the rear hip and then going up slightly.

https://www.youtube.com/watch?v=Ehs-H2V6N5o

best is you would upload a swing Video. without guessing with a swing plane downward that I assume there is a lunging (hips and head flexing Forward and not staying behind the front side axis) and dropping arms issue but you can't say that without Video.

Last edited by Dominik85
C Cap217100+ posts

Do this:

-go to the zepp app

-go to a swing you are looking at and look at the numbers

-click on HAND SPEED or BAT SPEED number

-toggle to chart if its not on chart

-take a screen shot of the chart

 

I am going to assume your max bat speed is higher somewhere other than impact.  

 

For your swing.  I see that you lung forward then rotate and start the swing.  I would suggest staying back on the ball.  Starting your swing from your back right hip and rotate off the back leg.  Drop the hands to the swing plane so you have a positive attack angle.  Rotate through and keep your head still.  It seems that you stride, move laterally a lot, and start rotation on your front foot.  

 

 

Can you also take screen shots of your numbers screen?  From the 3d model it looks like you would have a -30' attack angle and the only way to hit the ball up is to be creating a lot of backspin.  This would mean that you are not squaring up on the ball and that can be why exit velo numbers are low. 

Last edited by Cap217
D Dominik8510,000+ posts
teddy9 posted:

nice thread, what led me here was trying to understand my Son's recent PG Zepp showcase numbers (young 15yr old sophomore in HS):

Bat Speed at Impact 83mph (79.5% for 2019 in 2016)

Hand Speed Max 37.5mph (97% 2019 class in 2016)

Time to Impact 0.146 (14% 2019 in 2016)

Exit Velo (rocket radar), off tee 80mph

Trackman Exit Velo off live ball 87mph

 

So what does this tell me? 

1) Maybe he should be a boxer with that hand speed?

2) Force should equal Mass x Acceleration, right?  How does a bat moving at 83mph only transfer a force of 80 mph? weak contact? no benefit from the mass (bat?)  

3) "Time to Impact" really is useless (IMO) in a vacuum, or singularly, especially when hitting a stationary ball.; maybe gathering this reading verse live pitching then trying to determine the optimal "time to impact" to best read and stay back on different speeds.  Or maybe the higher numbers mean the swing is too long, or hitter starts too early...

I'm interested, so I bought a ZEPP. I'm going to start collecting data here and there. After accumulating a larger sample, maybe then the relative numbers may mean a little more.  

teee 

teddy9 posted:

I'm thinking the Zepp data, or more likely the swings were not "normal"; here's the swings at the same showcase event during BP, and a couple swings vs game pitching. His recent tee work has been shirtless, I rather not post that

Thanks for your input, much appreciated!!!

there is some lunging and also front elbow collapsing. on chest high pitches the plane was kinda acceptable but the few waist high pitches the plane looked bad. 

 

BTW don't throw as many chest high pitches, in games most pitches will be knee to waist high. 

Last edited by Dominik85
Linedrive_07Linedrive_07100+ posts

Adding my 2-cents.  First there is a difference in an end-loaded bat vs. a balanced bat when it comes to exit velocity.  An end loaded bat at a bat speed of say 75mph would have a greater exit velocity than a balanced bat because the weight is in the end of the barrel creating a higher MOI.  I am not sure which bat type is used for the PG stats or if they let you use your own.  I just wanted to throw that out there so when exit velocity is discussed, we are comparing apples to apples.  My 2019 is planning to attend one next year, so it will be interesting to see.

Here is another interesting observation based on our personal experience, which Im curious if others are seeing.  My son (2019 Grad) and I both swing his bat per the Zepp around 76mph, but there is a huge difference in our exit velo.  My exit velo tops at 90mph (Im 43 and hardly ever pick up a bat so my mechanics are horrible for those wondering about hitting the sweet spot).  A couple swings and I can hit 88mph no problem.  My son on the other hand is only hitting 73mph off the Tee.  Again, SAME bat speed, but to complicate things more, his hand speed is averaging around 33-34mph where mine is around 30-31mph.  What gives??  Here is the difference, I'm 6'0, 200lb, and he is 5'7, 120lb (late bloomer as I was).  His mechanics are pretty sound as he works hard, so I have to take the sweet spot excuse out of the equation.  I doubt height comes into play because we are talking bat speed which is the same, but I absolutely think the player weight has to be a HUGE factor greatly increasing the MOI.  It seems projections from PG and PBR put a lot of weight on Exit Velocity, but it seems to me that more should be put on Bat Speed Vs Player size.  Thoughts???

C Cap217100+ posts
IMG_6083IMG_6082Linedrive_07 posted:

Adding my 2-cents.  First there is a difference in an end-loaded bat vs. a balanced bat when it comes to exit velocity.  An end loaded bat at a bat speed of say 75mph would have a greater exit velocity than a balanced bat because the weight is in the end of the barrel creating a higher MOI.  I am not sure which bat type is used for the PG stats or if they let you use your own.  I just wanted to throw that out there so when exit velocity is discussed, we are comparing apples to apples.  My 2019 is planning to attend one next year, so it will be interesting to see.

Here is another interesting observation based on our personal experience, which Im curious if others are seeing.  My son (2019 Grad) and I both swing his bat per the Zepp around 76mph, but there is a huge difference in our exit velo.  My exit velo tops at 90mph (Im 43 and hardly ever pick up a bat so my mechanics are horrible for those wondering about hitting the sweet spot).  A couple swings and I can hit 88mph no problem.  My son on the other hand is only hitting 73mph off the Tee.  Again, SAME bat speed, but to complicate things more, his hand speed is averaging around 33-34mph where mine is around 30-31mph.  What gives??  Here is the difference, I'm 6'0, 200lb, and he is 5'7, 120lb (late bloomer as I was).  His mechanics are pretty sound as he works hard, so I have to take the sweet spot excuse out of the equation.  I doubt height comes into play because we are talking bat speed which is the same, but I absolutely think the player weight has to be a HUGE factor greatly increasing the MOI.  It seems projections from PG and PBR put a lot of weight on Exit Velocity, but it seems to me that more should be put on Bat Speed Vs Player size.  Thoughts???

I always wonder the same thing. I have experimented with a balanced bat vs a heavy end loaded bat and my swing speed seems consistent. I don't measure exit velo bc my radar gun for some reason doesn't pick up the ball consistantly. 

Im 34. Been working in my swing for a while now after taking years off after college ball. Feel like I crush the ball and my bat speed is low. I can get good hand speed numbers but my bat speed seems to be in the 80s. I also feel that I hit up on the ball and it gives me a negative attack angle. That's my main project now, hit up. 

Here are my recent stats.  I feel like my swing speed should be higher. And yes peak is at impact.  Here is a pic of me at impact. I am 100% hitting up on the ball. 

Attachments

Hide
Images (2)
  • IMG_6082
  • IMG_6083
Last edited by Cap217
T teddy9100+ posts

Catching up, thanks for the pointers. I need to upload some zep numbers a couple requested, plan to do that soon. 

It PG Showcase all kids use the same bat for zep and the bat length is dependent upon Grad class. They have the bat size in their site. So it's apples to apples. The wood bat in the video is top loaded, good eye! 

Thanks everyone for the responses. 

Linedrive_07Linedrive_07100+ posts

As far as your gun being inconsistent, it probably has to do with the distance.  Some guns wont give very good readings unless the ball is able to travel say 25+ feet.  My guess is you are hitting into a net a few feet away.  

As far as your bat speed, I think when you have a big upper cut for instance you are competing against gravity slowing your bat speed.  If you hacked down for instance it would jump.. My little guy can top out at 82mph with a steep downward swing which is not realistic.  Below is what that looks like.  On a plane it is 75-76mph, so I would guess if he was swinging at the up angle you have it would really drop as well.

 

 

IMG_4228IMG_4229

Attachments

Hide
Images (2)
  • IMG_4228
  • IMG_4229
PreviousNext

Add Reply

Post
.

Membership Required

We're sorry. You must be signed in to continue. Sign In or Register
×
Are you sure you want to remove from your Block List?
×
Loading...
×
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .
×
Advanced Search
Advanced Search
Link copied to your clipboard.
×