The Collision

[Eric F]

I have heard it said lots of times that the barrel should be flung/launched/whipped at the ball, and force at the handle during impact is unnecessary. This seems to be accurate when speaking about a baseball and a 33"+, drop 3 wood bat.

Studies have been done about the physics of the collision between a baseball and a baseball bat, and the conclusion has been reached that what happens at the handle during collision makes no difference to the quality of impact. Offered alongside the scientific data is often this clip of Todd Frazier hitting a no-hands HR offering proof in real-world action.

I'm not smart enough to figure out the math, or resourceful enough to assemble my own experiment, but in my head, it seems that the increased mass of a softball, and decreased mass of a softball bat might change the impact equation dramatically.

This gets me wondering...Is this where there IS a difference between a baseball swing and a softball swing? Maybe force on the handle at impact is a good thing for hitting a softball. Maybe not.

I don't know the answer. I'm just curious. I'd love to hear what smart people think about this issue.

 

[riseball]

When I saw the title of the thread I didn't see that it was in the hitting forum. Thought someone ran into your DD at the plate. I will settle down now.

 

[GunnerShotgun]

I think the starting point should be the extremely small duration of the ball contacting the bat. Once you can wrap your mind around that everything else falls into place.

 

[JJsqueeze]

I am a firm believer that the physics shows that the handle force on a wood bat against a baseball is irrelevant. However, for a composite bat on a softball I don't know. When I hit a softball with a composite bat on the sweet spot, it sure does feel like the ball is there longer than it is when I hit a baseball with a wood bat. Maybe the physics change enough for handle forces to be able to act on the ball due to the impact time being longer.

Not sure if this thought got in your head because of that clip you posted Eric, maybe you noticed how her bat seems to stall at contact. I have a similar clip of my DD with her bat stalled 2 frames at impact. The shot on her hit was a rocket, line drive sweet spot hit that came off like a missile and when we talked about it she said barely felt the impact but the bat just died in her hands.

 

[rdbass]

What happens when ball meets bat?
Physics and Acoustics of Baseball and Softball Bats

The two movies below show the impact between a softball, with an initial velocity of approximately 90mph, impacting a stationary softball bat barrel segment.

Watching the movies (and comparing with the baseball movies above) we can notice several things:
The contact time between the softball and softball bat is longer than it is for a baseball (hardball) and bat. (a little less than two frames of the movie).
A softballs experiences an amazing amount of deformation during the collision, much more than the baseballs in the above movies. The amount of deformation is even more astounding when you consider how "hard" a softball feels when you hold it in your hands. The movies also show that, as was the case for the baseballs above, the softball is compressed (deformed) much more than the bat is. Furthermore the softball does not spring back to its original shape immediately after the collision with the bat. In fact, both movies show that the softball is still significantly deformed several milliseconds after the ball has separated from the bat.
As was the case for the baseballs, the speed of the softball is considerably less after the collision than it was before the collision. A significant portion of the initial kinetic energy was lost to friction forces during the compression and relaxation of the ball while is distorts during impact.
In this experimental setup the bat was simply supported at each end (which is different from the boundary conditions for a hand held bat). During the collision the bat flexes (bends slightly) and after the collision the bat oscillates back and forth indicating that some of the initial kinetic energy of the ball was transferred to vibrational energy in the bat.
During the collision the barrel of the bat compresses and expands, appearing to throw the ball away. This phenomenon is unique to hollow (metal and composite) bats and gives rise to what is called the "trampoline effect". In the two movies below I've isolated the two frames which show the barrel compression/expansion during the collision.

 

[pctrips]

Not sure if this thought got in your head because of that clip you posted Eric, maybe you noticed how her bat seems to stall at contact. I have a similar clip of my DD with her bat stalled 2 frames at impact. The shot on her hit was a rocket, line drive sweet spot hit that came off like a missile and when we talked about it she said barely felt the impact but the bat just died in her hands.

I've noticed this with my DD as well. I have always interpreted that as not finishing her swing but maybe that's not completely true.

 

[rdbass]

I've noticed this with my DD as well. I have always interpreted that as not finishing her swing but maybe that's not completely true.

Look more 'upstream'at how the swing was 'launched/loaded/unloaded'.

 

[Eric F]

When I saw the title of the thread I didn't see that it was in the hitting forum. Thought someone ran into your DD at the plate. I will settle down now.

I appreciate the concern. My DD doesn't lose that battle very often.

I am a firm believer that the physics shows that the handle force on a wood bat against a baseball is irrelevant. However, for a composite bat on a softball I don't know. When I hit a softball with a composite bat on the sweet spot, it sure does feel like the ball is there longer than it is when I hit a baseball with a wood bat. Maybe the physics change enough for handle forces to be able to act on the ball due to the impact time being longer.

Not sure if this thought got in your head because of that clip you posted Eric, maybe you noticed how her bat seems to stall at contact. I have a similar clip of my DD with her bat stalled 2 frames at impact. The shot on her hit was a rocket, line drive sweet spot hit that came off like a missile and when we talked about it she said barely felt the impact but the bat just died in her hands.

This is a thought/question that has been spinning around in my head for a number of months. The recent clip just reminded me about it.

Like you, I think the wood bat-baseball collision isn't affected by what goes on at the handle because of the very short duration of impact and rebound. It seems to me that there is enough change in the factors involved - bat compression, ball compression, bat mass, ball mass - that the baseball results might not apply to softball. If this is the case, this may require some of us to adjust our approach to specific issues within the swing for hitting a softball. It may also mean that those who advocate hands continuing to apply force through impact had it right all along.

As I said, I don't know the answer. I'm just investigating.

 

[JAD]

Once the ball leaves the bat after impact the bat has zero effect on the flight path or distance the ball will travel. Most hitting instructors try to teach proper follow through in an attempt to maximum the results of the impact.

 

[Eric F]

Once the ball leaves the bat after impact the bat has zero effect on the flight path or distance the ball will travel.

This is about what is happening during impact, and if it is affected by what is happening at the handle of the bat.

Most hitting instructors try to teach proper follow through in an attempt to maximum the results of the impact.

IMO, this is largely due to downstream affecting the upstream (and vice versa). Also, many hitting instructors are dumberer than me.