Theta Orthotics

I have not suggested stacking prefab and custom devices anywhere. I have said that if I section either prefab or custom devices at this point in the the orthoses many of them will have angulation greater than 40 degrees given the application of your 4 node segmentation. Brent, don't try and talk to me like I'm a fool, instead consider me as someone who may actually know more out podiatric biomechanics and foot orthoses than yourself. Try instead answering my questions to recap, and there have been many, but let's start with:

How do foot orthoses work?
Next, lets try: why is the trigonometrical function you are using tan theta = opp / 0.5 adj?

Then we can go back to that coupling argument and you providing data to support your contentions.

 

simon,
this was the part that was most difficult for me to figue out and any attempt to relate orthotic design to function did not work until I did. If was an arbitrary choice, but as long as the medial point used excluded the "medial flange" portion of the device and the lateral point was defined consistently it realy would not matter...when you look at my diagram you see P1, P2 P3, the copy that refers to those points suggest that the angular measurment would be different depending on which of those three points was used, when this portion of the curve is eliminate from the measurment a the point defined arbitrarily as 25 percent of the horizontal distance, I could consistently relate the angle measured to functional results...probably why no one has ever done this before...

additionally you are correct that you could use the calculas to determine the slope at the designated point on the curve and forget about the trig functions...ultimately the quantifying measurment has to be simple enough for all to do and granted the trig method is not necessarly practicle for most either...

I have some photos of a light box that I would set an orthotic in and align the point and read quickly the Theta angular measurement...

You could also use calipers to measure the distance between the point on the horizontal plane and the superior surface of the orhtoic. brent

 

simon
I dont think I ever implied that you were a fool, that was your jugement of me yesterday. I must have read your question wrong...first off either you are not yet understanding how I measure or you are just totaly wron as youi will finno orthotic anywhere tht is even close to 40 degrees...

It is not .5 adj the adj is .5 total width of the plate...

judge not that ye be not judged...brent

 

I could also just have the orthotic model in my CAD program, section and measure the angles. Regardless my points remain. You assume that this one sectional plane is key, it is not. It is one of any unknown number of other sectional planes upon which the foot has a reaction force with at a given instant in time. You cannot ignore the other areas of that one sectional plane any more than you can ignore any other of the other sectional planes that the foot is in contact with, since these will all contribute to the net ground reaction force vector. This will ultimately determine the external moments acting about the joint axes produced for a given point of time during the foots weightbearing interaction with the orthotic. Please tell me why my above assertion is incorrect.

You still haven't answered my question: why theta = opp / 0.5 adj?

& I will ask for the fourth time: How do foot orthoses work?

Brent, you really should try to answer this in order for us to continue here. And given that you make your living from selling foot orthoses, if you can't answer this simple question, as a customer i would be really put off by your apparent lack of knowledge.

 

simon,
to further clarify...the only judgement I made about you was that you were a jerk off, and looke funny with your hat and stach...the fool part is probably a judgement you hold against yourself, and now attempt to project on me...you may know more biomechanics than I, but you have not spent the last 30 years of your life working with the Theta, so get off your high horse...brent

 

t

Come on Craig! Enough is enough. Get rid of this guy, Please:craig:?!

 

Which should be a concern for you Brent, given that this thread is on the first page when you google 'theta orthotics'.

Don't forget my last question in post #119 on page 4

 

I have answered it you just don't understant it yet...I could care less what you think about me as a physician or otherwise...brent

 

No, just the last 20. Yet it seems that I have learned more than you with a decade less thought.

Keep him here Craig, I like him.

 

I responded to that question go back and look...I am through here for the day...perhaps you should discontinue pretending your my advocate and understand that right this moment, at the least, I am your teacher...brent

 

No you haven't. If you feel you have then indulge me, explain it again since I must have missed it: how do foot orthoses work? Focus on this one question in your answer........

 

Who? Me or Brent?

 

http://www.pcopco.com/html/how_do_orthotics_work.html

 

Sorry Brent, I've looked and looked again and you definately haven't answered it. Since post #119 you have only been exchanging posts with Simon. The question (regarding treatment of peroneal tendinopathy and tibialis posterior tendinopathy) was this:

So... if I have this right (and please correct me if I have not) is your treatment for these two pathologies essentially the same? That is, it will be a varus post either at the forefoot, rearfoot or both?

I am not pretending anything - I am merely asking you quite reasonable questions. How can you claim to be my teacher when it takes so much effort to get an answer?

 

simon, that would be me, brent

 

Perhaps you should read Carl Rogers views on teaching then.

 

Ok, so it's all about kinematics with you. Now I see. What drives motion, Brent?

 

Ian,
mostly the treatment is allways the same, reduce pronation throughout the gait cycle by the most effective method possible and symptoms will resolve...brent...with almost 50 postings this morning I too have had problems keeping track of were I am as I did not know were to access the first part of the thread until just a bit ago...

 

mechanical design, gravity and energy...brent

 

right...what ever...

 

so who is craig, the man who kicks everyone off the site who has something to say that you don't agree with?

 

As suspected. Irrespective of presenting pathology everyone gets the same treatment. Awesome. Pronation is the aetiology of all symptoms. Wicked. What year is this by the way??? No more energy for this. It's late here and I have an early tee off time tomorrow. All the best

IG

 

thank you...brent

 

Forces drive motion, Brent. Forces. How do foot orthoses work, ultimately they alter the forces beneath the foot. How do they do this? By altering the geometry and / or load deformation characteristics at the foot interface with the ground (orthotic, shoe, whatever). So how does the geometry, as I believe that is the key to your argument (theta orthotics and all of that) add up to create an alteration in the ground reaction forces beneath the foot, is it in a singular area within of a uniplanar section as you advocate? No.

Carl Rogers said this of teaching (I'm paraphrasing): when I try to teach, I achieve one of two things: either nothing, or harm is done. For these reasons, I have stopped trying to teach. Lesson there for all. Hence, I have attempted this evening to ask questions of you which might have led you to the answers for yourself, such that your learning might have been self-appropriated and as such, a much deeper-learning. Never-mind.

Next.... Or, "what ever".

Bill Hicks, sitting in a waffle house reading a book, waffle waitress walks over "what are you reading for?"...... this discussion, this evening tells me everything I need to know about why I give up several hours a day, reading and researching upon a subject which I have devoted my life's work to... so I don't end up as a waffle waitress. Y'all know what I'm saying.

 

He's the bloke who created this wonderful world and keeps an order to all of this without payment, under difficult circumstances, when the likes of you and I shoot our mouth's off. Think of him as the Wonderful Wizard now in Oz.

 

when the geometry of the interface is changed so do the vectors of all the forces...correctly as you stated above...brent

 

... thanks...I like that thought toto...

 

So who's the wicked witch? Lion and tigers and barefoot, oh my! I too will be off for golf starting tomorrow (two days worth!) and for a little target shooting (S&W 38 special) in the wonderful Sierra Nevada mountains. Can't wait to try an catch up on this thread come Sunday!:wacko: But I still have until tomorrow to follow along.

 

Yes that's right, so if we section our orthoses into X number of frontal planes sections and take the reaction forces acting at every discreet point upon the orthoses at a given instant in time, and take moments about these forces, we can calculate the centre of the force in one direction. If we repeat the process but section the orthoses in the sagittal plane we can repeat the process to calculate moments in this plane and find the centre of pressure. When combined with our frontal plane data, this will give us our net position for the centre of force and theoretically the direction and magnitude of the net vector. This may be anywhere within or without the surface of the orthotic and will move from one given moment in time to the next. It may lie somewhere within your "important" orthotic frontal plane cross-sectional segment for a single instant in time, it may or may not be within the area of the orthosis that you deem important within this cross-section, it may be right up on one side or the other, regardless it will only be there for an instant and yet will be defined by the whole area of the orthosis that the foot is in contact with, not simply one 2D slice through the orthotic.

Tired now. Bed. I've been looking at how orthotics work for many years now, if only it was as simple as taking a single 2d slice and prescribing an angle of 40 degrees...

Still don't know why it should be theta = opp x 0.5 adj, in your mind though Brent, I'm sure it makes sense

 

I was going to use just one word to describe the ideas behind this product; Cowpie!

Now that I see that Theta orthotics are sold via the internet one word will not suffice, so let me add: Internet Cowpie!

Watch your feet people....

 

It is a function of frontal plane geometry projected througoutht the entire sagital plane of the orthotic...but the frontal plane section throughout the entire sagital plane is defined mathematically by the curve at the apex or highest point.

if your truly up to speed with your algebra I won't need to explain that any further... If biomechanics it cant be simplified, which it can, then even with e dimencial imiging it is unlikely that we will make no more advances in human biomechanics than we have in the last 100 years...brent

 

david...you funny...brent

 

Not really Brent but thank you. I bet if you put high heels on those things and sold them to the right people (runway models, movie stars) you could get rich quicker AND create an increased demand for Podiatric services!

You altruist/inventor/humanitarian, you had no idea what you had till you met me now did you?

 

David:

Good one!:good:

Internet Cowpie with Flies......

 

My production manager just asked me why we don't charge $100 for a pair of top covers.
http://www.pcopco.com/html/total_control_orthotics_progre.html

 

AGHAAAAAAAAAAAAAAA!:craig::craig::craig::craig::craig::craig:

 

Jeff is that what I think it is, molded plastazote? And it is suggested to be put underneath the removable shoe liner? This is a horrible joke right?

Oh and Brent the Propulsive Stage Theta:

http://www.pcopco.com/html/propulsive_gait_control.html

I really don't care what the idea behind it is or material because it is just reprobate. In an already equine position are you seriously promoting the idea of supinating the forefoot or MTP joint further?

 

David, according to Dr. Jarrett's earlier reply, the material is urethane rubber. I'm not sure what the durometer is.

 

What is?

No its not.

No, I was always rubbish at algebra, so I think you'll need to explain further.

 

Let me see if I've got this right, we've had Glaser's Spikethotic, Kiper's Bladder Bag, Shavelson's Leaning Tower-of-absent-scientific-Support, Butterworth's Applied Crapology Insole, Rothbart's Contraceptive-feel-the-love-thotic and now....the Jarrett Shoe Condom?

:craig: