barrel/hand pivot point, a.k.a TTB

[Bobby Shirer]

I agree with everything there. I am replying with what I personally think the disconnect for some people.

You're saying the Active hands = "hands / wrists articulate but the force is supplied by the arm and shoulder movements." The hands and wrists are actively keeping all the angles

Where others are thinking Active = "hands / wrist assisting the drive backward via supination (???) in conjunction with the arm and shoulder".

Maybe I am wrong, perhaps it is just a disagreement on how....violent vs controlled the elbow slotting is. No one else has commented in our discussion so perhaps I am the only one whose idea of active vs passive is different than yours.

cmn

@fanboi22
I'm looking at my arm, bent at the elbow, elbow at my hip, hand extended as if to shake your hand, thumb up, wrist in a neutral position.
Palm down would be pronated. Palm up is supinated.
If I wrap my hand around the handle of a bat with the wrist in a neutral position, the barrel is vertical. With the palm up, the barrel is horizontal, and the wrist is supinated.
Just an observation.

 

[_MIA_]

His average acceleration measured over the entire swing is 82.3 mph in .17 seconds for an acceleration rate of 482mph/sec.
From the 90° elbow bend to contact his speed changes 8% or 6.1 mph in .08 seconds for an acceleration rate of 76.25 mph/sec.

Either your your units are off or there is a typo e.g. everywhere you say acceleration above you meant to say velocity..

 

[Shawn]

Mankin THT= early batspeed
BHT = late bat speed?

BHT isn’t late batspeed with regards to hitting out front. I think you could say BHT is being connected and not disconnected out front.

 

[Bobby Shirer]

Either your your units are off or there is a typo e.g. everywhere you say acceleration above you meant to say velocity..

I don't think so.
Velocity is distance over a period of time. That's not what I'm referring to.
No one swings 482mph.
I'm referring to the rate of change in velocity...acceleration rate.
0-82 miles/hr in .17 seconds....82m/h/.17 sec = 482 miles/hr/sec.
At the rate he's accelerating the barrel, if he accelerated for one entire second, he would reach 482mph.
When a force is applied to an object, acceleration happens.
More force= more acceleration
He's applying less force over the last .08 seconds and so the rate of change of velocity is less.
But you probably know that?

I've seen here where folks alude to applying a momentary pulse (aka force) to the bat.
I ask, if the swing from launch to contact is only .17 seconds, how short should the pulse be if it's not to be applied for the full time frame of the swing? And why is that better?

 

[_MIA_]

I don't think so.
Velocity is distance over a period of time. That's not what I'm referring to.
No one swings 482mph.
I'm referring to the rate of change in velocity...acceleration rate.
0-82 miles/hr in .17 seconds....82.3m/h/.17 sec = 482 miles/hr/sec.
At the rate he's accelerating the barrel, if he accelerated for one entire second, he would reach 482mph.
When a force is applied to an object, acceleration happens.
More force= more acceleration
He's applying less force over the last .08 seconds and so the rate of change of velocity is less.
But you probably know that?

I misread what you wrote..thought you were saying his average acceleration was 82.3 mph..

 

[Shawn]

L

Correa’s swing is just one way to swing a bat. He really isn’t having a HOF career. He is just an average hitter. Mankin’s study concluded that the best hitters didn’t generate bat speed out front. He said the best hitters used THT and BHT. Creating a transfer of torque over the entire arc. Correa has a long hand path out front, compared to a short hand path that comes from TTB. A short hand path as Mankin describes.

BHT isn’t late batspeed with regards to hitting out front. I think you could say BHT is being connected and not disconnected out front.

Anyone can and do create late batspeed at any given time, timing being a factor. There are few absolutes.

 

[Bonesaw]

The math says his rate of acceleration is slowing. He's still applying force and accelerating the barrel, just not as much.
His average acceleration measured over the entire swing is 82.3 mph in .17 seconds for an acceleration rate of 482mph/sec.
From the 90° elbow bend to contact his speed changes 8% or 6.1 mph in .08 seconds for an acceleration rate of 76.25 mph/sec.
He's losing his ability to apply force efficiently.
View attachment 17708View attachment 17709


The brush is aka internal rotation. He demonstrates the bend in the elbow as being crucial..... it allows the application of leverage, rotation, torque.
IR /wrist pronation is the fastest motion the human body can achieve.
It happens at the brush because of the direction the ball is thrown. The brush doesn't cause it.
Overhand throwing (baseball and football) also uses IR and there's no thigh to brush. Thumb turns down to pronate in overhand throw.
View attachment 17710

Bobby,
Interesting. Doesn't IR happen in the swing with the top hand?

Also, I think some might argue that this is closer to 90 degree elbow.



Im confused as to the units of the clock in the lower left. I think it has to be tenths of seconds. It looks like it starts registering his swing @ 3:00ish and contact at 4:70ish for 1.7 tenths of a second time to contact. I think that would make his acceleration from 79 to 85.2 happen in .008 seconds. Might be wrong about that.

Would be nice to have more pro swings. I'm sure others accelerate it earlier.

And Shawn, I'm not really a fan of correa, he is convenient to use as we have swings and video of him using a blast motion.

he has had some pretty good years and has pretty good bat speed.

If Barry Bonds had crystal clear slow motion and accompanying blast numbers I would look at that.

 

[Bobby Shirer]

Bobby,
Interesting. Doesn't IR happen in the swing with the top hand?

Also, I think some might argue that this is closer to 90 degree elbow.
View attachment 17717


Im confused as to the units of the clock in the lower left. I think it has to be tenths of seconds. It looks like it starts registering his swing @ 3:00ish and contact at 4:70ish for 1.7 tenths of a second time to contact. I think that would make his acceleration from 79 to 85.2 happen in .008 seconds. Might be wrong about that.

Would be nice to have more pro swings. I'm sure others accelerate it earlier.

And Shawn, I'm not really a fan of correa, he is convenient to use as we have swings and video of him using a blast motion.

he has had some pretty good years and has pretty good bat speed.

If Barry Bonds had crystal clear slow motion and accompanying blast numbers I would look at that.

Yes, IR is the bat tip but the motion at the downswing is supination (ER ?)
The supination is just used as a fulcrum/hinge with very little resistance and only some force added. Imo.

You are correct and I was wrong. I assumed the .17 number and the numbers on the clock were the same units. ( I admit I was suprised at the big disparity in acceleration rates. Should have checked the math) Looks like he accelerates the bat over the entire swing at 500mph/sec and at the end he's accelerating at 750mph/sec. Means one thing, he's more efficient at applying torque at the end of the swing. I do see the Mankin BHT (pulling rearward with the bottom hand while pushing his top hand forward) being applied late in the swing. Late barrel acceleration means he could have trouble if he's at all late to the ball.

FYI you use the formula the effect of gravity on the time of flight there's a way to approximate the ball exit speed using only video.
Assuming a 30 degree launch angle, if you take the time of flight x 22mph you'll get a pretty fair estimate of ball exit speed.
5 seconds of flight means 5x22 mph or 110mph exit speed.
If the angle changes the multiplier changes.
25 degrees = 26mph per second of flight time
30 degrees = 22mph per second
35 degrees = 19 mph per second
40 degrees = 17 mph per second
45 degrees = 15.5 mph per second of flight time
The more straight up you hit it, the less speed needed to keep it in the air for a few seconds....explains why popups stay up so long.

But someone should check my math.

 

[Shawn]

You are correct and I was wrong. I assumed the .17 number and the numbers on the clock were the same units. ( I admit I was suprised at the big disparity in acceleration rates. Should have checked the math) Looks like he accelerates the bat over the entire swing at 500mph/sec and at the end he's accelerating at 750mph/sec. Means one thing, he's more efficient at applying torque at the end of the swing. I do see the Mankin BHT (pulling rearward with the bottom hand while pushing his top hand forward) being applied late in the swing. Late barrel acceleration means he could have trouble if he's at all late to the ball.

BHT is a little different then posting the bottom hand and torquing around it out front. When there is to much extension you can lose the mechanical advantage of the front shoulder and arm connection to shoulder rotation. BHT defined by Mankin isn’t losing the mechanical advantage and the front shoulder is pulling back at contact.

 

[Bobby Shirer]

BHT is a little different then posting the bottom hand and torquing around it out front. When there is to much extension you can lose the mechanical advantage of the front shoulder and arm connection to shoulder rotation. BHT defined by Mankin isn’t losing the mechanical advantage and the front shoulder is pulling back at contact.

I think the way to build the swing is to get to positions that allow the batter to create mechanical advantage to torque the bat and reverse engineer from there.