4D Swing - Wrist Data?

[cwdlaw223]

Tapio -

Does 4D swing capture lead and trail wrist data?

[teeace]

Dec 6, 2013 14:28:26 GMT -5 cwdlaw223 said:

Tapio -

Does 4D swing capture lead and trail wrist data?

If so, I believe 4D would be the first non-markerless, video based 3D system in the world that captures wrist data.

Not directly and it's almost impossible also for those sensor systems as there is so many ways to get those sensors to be lined.

We can calculate those actions by relations between elbows, wrists and club head, but I don't think it's that important at all as there is so many more relevant things to follow.

But for example supination is pretty easy to calculate and see from graphs, DF and PF are those which are very complicated.

[cwdlaw223]

Tapio -

Thanks. Does 4D capture forearm data? I presume it does since the forearms are much larger.

[teeace]

Dec 6, 2013 15:06:59 GMT -5 cwdlaw223 said:

Tapio -

Thanks. Does 4D capture forearm data? I presume it does since the forearms are much larger.

Few basic things first:

There is no data captured from any that kind of part. Not in one device in this world. So i.e. if someone says they capture wrist data or forearm data it's not really true. It's same with speeds, there is no device to measure speed directly

So there is always two or more points that are captured and everything els is just math and calculation. Speed is distance-time related, positions are relations between two measured points.

After that there is general knowledge about joints and which directions they got range of motion. i.e. elbow can bend only to one direction, wrist got four directions etc. So when understanding those it's possible to create model between few points to understand how they move and specially when most of those are well captured. By that it's also pretty easy to calculate wrist movements when orientation of the arm is known and also the angle between arm and shaft.

But... after we see what happens, we have to go deeper and find why. In 90% of things we see in golf swing happens because something else happens at inner circle (like speed or direction changes). By that if someone seems to flip, I check his hand speed graph and how much it changes. If it drops a lot, I go to shoulder speeds and also lateral speeds to see what happens there. I about never start to talk about wrist. Also if I see CH passing (in 3D space) hands and coming early to the same line (path in our definitions) with hands I know there is lot of forearm rotation going on and I have to go and see if the hand path is in to out as it usually is in these cases.

To understand these things is very hard work and takes years and I have to say every day I find more open questions than real answers. Just when you find something that seems to be loud and clear, something else pops out and you find that some other good player does it differently... it's golf

[cwdlaw223]

Does your system generate or present data regarding forearm movement or not as a regular graph? Are there numbers like your other graphs or do you yourself need to perform the calculations?

You seem to be making a distinction without a difference when it comes to the word capture. I understand math is involved (I certainly don't know the math or algorithms) and am at the mercy of the math. There is no system without the math, software and algorithms.

I understand this stuff takes years which is why I consult with Tyler Ferrell who has seen more AMM graphs of tour pros than anyone except Cheatem or Rose. He's spent years with these graphs. Good guy and teacher.

[teeace]

Dec 6, 2013 17:53:04 GMT -5 cwdlaw223 said:

Does your system generate or present data regarding forearm movement or not as a regular graph? Are there numbers like your other graphs or do you yourself need to perform the calculations?

You seem to be making a distinction without a difference when it comes to the word capture. I understand math is involved (I certainly don't know the math or algorithms) and am at the mercy of the math. There is no system without the math, software and algorithms.

I understand this stuff takes years which is why I consult with Tyler Ferrell who has seen more AMM graphs of tour pros than anyone except Cheatem or Rose. He's spent years with these graphs. Good guy and teacher.

No, there is no direct one line graph for that as well there is not for many other things. We use combinations to see that kind of things. It would be lets say middle complicated to do but possible anyway if we would see it important. I don't see it that important and don't want to spend time and money for that.

Actually what I was explaining is that only 2 points are known, or many times estimated as in AMM case when they digitalize those points, Now relation between those two points are measured and then math steps in with some assumptions and there can be the mistake, like we saw when Kelvin showed that measuring of supination when doing PF.

Tyler is good guy and he has learned to read those well as far I know. The problem when digitalizing points is that you give fixed coordinates to them in relation to the sensor and that doesn't stay like it. There is for example way to turn your waist about 30 degrees without turning your hips at all and that was the big mistake for sensor systems when publishing that kinetic chain theory and hip deceleration measurements. If you are interested to really understand it, I can write another post about it and explain it clearly, but there is good reason why we see about 20-30 degree hip turn at BSW and other devices 45

But as said, wrist action can be seen in combinations at the level it's need to be seen, then also reasons for that as it all comes from directions of movements and acceleration/ deceleration profiles

[cwdlaw223]

Taipio -

Good post and another thread would be appreciated on your general thoughts about 3D systems.

[teeace]

This is one simple graph that pretty much demonstrates arm rotation around impact area and if left forearm is really supinating or not.

First of all the definition "orientation" as we use it. It's degrees around the vertical axis where zero (black line) presents ball position at address and the origo of that rotation is at the center of player body (from neck down) In other words its top down image of relation between hands and club head as they move around the body.

So in this first image you can see those lines getting together about at impact and then red line getting higher than the blue one. It tells that club head is passing the hands from that projection and there is no other anatomical way to get that happen than supination or supination combined with whole left arm rotation around its own axis. i.e. cross over release or combination of that and flipping.



At the second image you see those lines get together much later and it happens after about 50 degrees of rotation after impact.



This is not perfect way to find scientific truth, but I don't think we need that anyway. What we need to understand is that at the second image shaft, and by that also the club face stays longer pointing to the target and when understanding human movements behind those two ways we can guide our students to get better.

I have been doing calculations to be more precise and deeper.. and thrown all that away after awhile. Too much detailed information doesn't help anyone to get better and for the moment it seems people who are working with different devices are about in same situation where I was few years ago when trying to find that silver bullet. Getting too deep, analyzing too much, making assumptions from few shots and few players and then speaking out loud how things should be done.Strong opinions like "all good players do this or that" are faraway from scientific view or specially from golf teaching. We have to find few important things and range of values for those that can work. It's far away from discussions of pages about if all got their hips decelerate even 1% before impact and specially when used systems that measure more waist than hips (.. another story to write)

For me this presented graph is one of the 10 I check with student for the moment and those give me enough information in few minutes what happens in the swing. When those things start to be at decent level, it's time to go out and learn how to play this game

[cwdlaw223]

Thanks for posting!