Launch Differences between Mats and Grass

[Lihu]

The spin axis number sticks out. -0.9 means it drew. If it hit towards the toe that means more draw and lost distance.

Are there other ways to draw the ball?

[boogielicious]

Gonna take a wild guess here:  Pain or discomfort.

Hitting the mats too hard or too steeply hurts, and people are subconsciously, or consciously, avoiding that by "sweeping" more on the mats.

If not that, then I'm guessing that it's the reaction of the mats on slightly fat shots.  (Actually, forget my original guess, let's skip straight to this one (I'll leave it there as a hedge, though, on the off chance that its right ;))  With grass, the club will keep going down through the turf, but with mats the club will bounce up off the concrete.

I'm with Drew on this with the addition of type of mat.  The more rigid mats seem to help the irons bounce a bit if they are slightly fat.  Better mats won't do this.

[Ernest Jones]

I'm with Drew on this with the addition of type of mat.  The more rigid mats seem to help the irons bounce a bit if they are slightly fat.  Better mats won't do this.

These are averaging 186y of carry for a 7 iron off the mat, I'm guessing they are being struck pretty cleanly.

[Lihu]

Quote:

Originally Posted by Golfingdad

Gonna take a wild guess here:  Pain or discomfort.

Hitting the mats too hard or too steeply hurts, and people are subconsciously, or consciously, avoiding that by "sweeping" more on the mats.

If not that, then I'm guessing that it's the reaction of the mats on slightly fat shots.  (Actually, forget my original guess, let's skip straight to this one (I'll leave it there as a hedge, though, on the off chance that its right ;))  With grass, the club will keep going down through the turf, but with mats the club will bounce up off the concrete.

I'm with Drew on this with the addition of type of mat.  The more rigid mats seem to help the irons bounce a bit if they are slightly fat.  Better mats won't do this.

This is my gut feeling as well.

On grass, I use the divots to tell where I am hitting the ground, and on a mat it is hard to tell exactly where I hit the ground. So, hitting fat on the mat makes some sense.

[iacas]

I need to check again but are these averages of multiple shots or just one swing? Because… I don't know many club fitters that would take one swing and make any sweeping conclusions.

I've assumed to this point it was multiple swings but comments here make me doubt that; I seem to be the only one thinking it was multiple averaged swings.

[Lihu]

I need to check again but are these averages of multiple shots or just one swing? Because… I don't know many club fitters that would take one swing and make any sweeping conclusions.

I've assumed to this point it was multiple swings but comments here make me doubt that; I seem to be the only one thinking it was multiple averaged swings.

You are correct.

Below is the data that we have collected from our test. There are a total of 10 shots from each surface.

[Ernest Jones]

I need to check again but are these averages of multiple shots or just one swing? Because… I don't know many club fitters that would take one swing and make any sweeping conclusions.

I've assumed to this point it was multiple swings but comments here make me doubt that; I seem to be the only one thinking it was multiple averaged swings.

Yeah, I assumed it was multiple swings too.

These are averaging 186y of carry for a 7 iron off the mat, I'm guessing they are being struck pretty cleanly.

[nevets88]

Oy, I assumed it was one swing each, I didn't read the article. I'm a dope. Still, why is the average spin axis so different between mats and grass for all those swings? What's causing the ball to draw (albeit a little) repeatedly?

[billchao]

Oy, I assumed it was one swing each, I didn't read the article. I'm a dope. Still, why is the average spin axis so different between mats and grass for all those swings? What's causing the ball to draw (albeit a little) repeatedly?

The face to path delta is a little bit more pronounced on the grass data, as is the downward AoA. [Rule] My theory is that the ball is struck with a small part of the club digging down into the dirt. It allows the clubhead to travel a bit more down and outwards at impact. You can't do that on a mat as much (not if it's made out of something durable enough to be used as a golf mat). So instead of continuing to travel down and out slightly, the clubhead begins to bounce just enough to change the impact numbers.

[iacas]

The face to path delta is a little bit more pronounced on the grass data, as is the downward AoA.

Yes but that would produce a fade. The face is reported to be right of the path.

[nevets88]

Test player is a +2. Really, I read the piece this time. :-) Here are the individual swing numbers.

[billchao]

Yes but that would produce a fade. The face is reported to be right of the path.

Right. Duh. I'm really, really, really, thick sometimes.

[nevets88]

[quote name="iacas" url="/t/78417/launch-differences-between-mats-and-grass#post_1080873"] Yes but that would produce a fade. The face is reported to be right of the path.

Right. Duh. I'm really, really, really, thick sometimes.[/quote] Ball flight laws wording crosses me up occasionally. Still. I understand them, but I have to be careful speaking about them.

[rehmwa]

I'm more interested if it's the most impactful example (rock hard mat, like you find at a cheap and crappy driving range)

or if it's a nice 1.5 to 2 inch thick crimped material type of mat

maybe better to find out if the quality mats are very close to nice soft turf, and how much a difference it makes vs those horrible mats I find most everywhere

I swing different if the mat is a bad one.  But I'll go after it just as thoroughly on a really nice mat

[natureboy]

The things I noticed are the higher launch angle / lower spin off the mat and the lower launch angle / higher spin off the grass. Here's my $.02:

Could it have something to do with the compressibility of a grass surface relative to mats?

On grass the ball will tend to 'float' slightly above the surface, while the much heavier body-weight-bearing feet will sink closer to the surface of the ground. Could this higher ball position on the club face relative to a mat swing put the ball effectively back along the clubhead path? This seems unlikely with such a small change, though.

Another thought is some kind of 'flinch' instinct that changes swing shapes on golfers who know from experience that mats are not as forgiving to the wrists as turf even with ball-first contact.

[iacas]

Gave it a few minutes of thought today.

I think a human being was hitting the ball, so… one of or both of these things seem likely to me:

• The player swung differently when the ball was on the mat versus on the grass.
• The ball sat up higher on the mat than it did when sitting on the grass.

The latter goes to explain the higher launch angle with less backspin (vertical gear effect) on the mat shot. The player also probably didn't feel quite as much need to get the handle forward.

[mvmac]

Gave it a few minutes of thought today.

I think a human being was hitting the ball, so… one of or both of these things seem likely to me:

The player swung differently when the ball was on the mat versus on the grass.

The ball sat up higher on the mat than it did when sitting on the grass.

The latter goes to explain the higher launch angle with less backspin (vertical gear effect) on the mat shot. The player also probably didn't feel quite as much need to get the handle forward.

Yes agree, gotta be the vertical gear effect.

[nevets88]

I'm more interested if it's the most impactful example (rock hard mat, like you find at a cheap and crappy driving range) or if it's a nice 1.5 to 2 inch thick crimped material type of mat maybe better to find out if the quality mats are very close to nice soft turf, and how much a difference it makes vs those horrible mats I find most everywhere I swing different if the mat is a bad one.  But I'll go after it just as thoroughly on a really nice mat

The piece mentions the exact model name of the mat. Dunno if it's the bristle type or astro turf like type. It didn't sound like your typical range mat though.