1 Topic by Justien

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Dear All,

I am a Belgian student and for my master essay, I am investigation the flexibility of the foot during the underwater dolphin kick.
We shot a lot movies in the swimming pool and our plan was to analyse the movies with kinovea.

For the moment I am calculating the angels of the hip-knee-foot in side-view.
I have also a movie in the back view (the feet of the swimmer), so first I synchronize the two movies.
In the back view I have to measure the supination of the foot, and that is where my problem is. The supination is an 3D movement, while the perspective of the camera is not changing. Now my question, How can I find the maximal supination during the downward movement of the feet of the swimmer with the correct perspective?

Do I have to calculatie the angles myself, or can I use the perspective grid in Kinovea and how I have to use that grid?

With kind regards and hoping for a little help
Justien

2 Reply by joan

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The perspective grid is more a visual aid than a measurement tool. You can do rough positionning with it but for measuring supination angle in 3D space you will have to use a more elaborate technique. I don't think Kinovea is currently tooled to measure such angles on arbitrary axes. Maybe exporting the trajectories of joints from both views and feeding them to another software to recompute the spatial trajectory.

3 Reply by Chas Tennis (edited by Chas Tennis 2011-12-14 19:22:36)

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I don't know how to measure foot supination nor have I successfully measured similar rotatory body motions.

I have a similar problem - to measure wrist pronation during a tennis serve.    To see pronation (between the elbow and wrist) and to separate it from upper arm rotation (internal shoulder rotation) the angular difference between the elbow and wrist must be measured (in this case from a single viewpoint camera).  I have videos that show internal shoulder rotation very well but it is difficult to get the wrist position from the videos without markers because of the quality of the videos.  I cannot place markers.

If I could place markers and duplicate the set up after the original videos were taken - and maybe you can? - I might use markers as placed in this report on baseball pitchers.

Look at the markers used to indicate shoulder angular positions for baseball pitchers, photos page 51. 

http://www.jssm.org/vol7/n1/7/v7n1-7pdf.pdf

Place the swimmer and camera in the pool as originally taken and place very clear markers on the swimmer's foot, leg, etc.. Of course you can do most work to develop and try out the technique without the pool.  Calibrate marker position vs foot supination in the video.  Maybe you can get a reasonable estimate using the markers and then use that as a guide/template to estimate the foot supination in your data videos.  Could Kinovea lines be used to construct a calibrated scale for supination given the set up is nearly the same.

[Term Usage Pronation. I recently realized that my understanding of anatomical pronation was uncertain for the hand.  I believe, but am not certain, that pronation for the hand is defined as the angular position in degrees from an anatomically neutral position.  Bend elbow, thumb straight up/vertical.  Rotation of thumb in medial direction gives degree of pronation but in lateral direction degree of supination. In other words, I'm still unclear if by definition pronation is only an angular position (degrees) and if used for a direction of motion (counter clockwise) the term is not being correctly used.  Uncertain of usage..?.. The sloppy usages of the term "pronation" in tennis is ridiculous.]

4 Reply by Archer4

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Chas Tennis wrote:

[Term Usage Pronation. I recently realized that my understanding of anatomical pronation was uncertain for the hand.  I believe, but am not certain, that pronation for the hand is defined as the angular position in degrees from an anatomically neutral position.  Bend elbow, thumb straight up/vertical.  Rotation of thumb in medial direction gives degree of pronation but in lateral direction degree of supination. In other words, I'm still unclear if by definition pronation is only an angular position (degrees) and if used for a direction of motion (counter clockwise) the term is not being correctly used.  Uncertain of usage..?.. The sloppy usages of the term "pronation" in tennis is ridiculous.]

You're quite right that, anatomically, upper limb pronation is purely forearm rotation ie rotation at the radioulnar joints and specifically excludes shoulder rotation, the anatomically neutral position being full supination - so standing with the elbow flexed at 90 held in to the side and thumb straight up is 90 pronation rather than zero. The direction of movement is also pronation - for the part that is pronation. Where terminology slips is if you start in the same fully supinated positon and abduct your shoulder to 90 your thumb is now straight up but you're right, there's no pronation there at all. Similarly if you start as above with your elbow at 90 and in to your side and fully pronate (making sure to keep your thumb in the same plane as your hand) then extend your elbow you'll gain a futher 90+ degrees of movement in the same direction from internal shoulder rotation - but that extra movement isn't correctly pronation in either sense. Or, if you point your thumb forwards with elbow extended by your side that can be 90 pronation, zero pronation if you achieve it purely by internal shoulder rotation or anywhere between zero and 90 if you mix it.
Your useage is correct in that what you are trying to measure is rotation between elbow and wrist so your degree of pronation would by definition be correct as you're excluding internal shoulder rotation and the direction of movement you would be measuring is also correctly pronation, if there is any, internal rotation if there isn't

5 Reply by Chas Tennis

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Archer4 wrote:
Chas Tennis wrote:

[Term Usage Pronation. ..............................

.............the anatomically neutral position being full supination - so standing with the elbow flexed at 90 held in to the side and thumb straight up is 90 pronation rather than zero. ..................................

Thanks so much for the information.  You clarified many points.

There is still one point that I am unclear about.   It might involve conventions in certain countries - definitions of pronation and supination that could be different between the US and your country.  It also might involve a difference between the absolute angle of pronation that you have discussed and angles discussed for measuring range of motion for pronation.

You say above that with the thumb straight up pronation angle is 90°.    The usage in the videos below for measuring range of motion of pronation & supination I would interpret to indicate that the pronation angle is 0° for the thumb straight up.   For measuring ROM the difference between two angular reference points is measured so the absolute scale might not play a part. ? Still, they set their goniometers to 0° to begin ROM measurements with the thumb up.

http://videos.rehabstudents.com/measuri … upination/

Beginning half of the video as the last part covers very limited ranges of motion for injuries.
http://www.cdc.gov/NCBDDD/video/JointRO … index.html

My issue is to simply measure and time pronation in videos of tennis serves like this one.

http://vimeo.com/27528701

I can see internal shoulder rotation very clearly by movement of the elbow features but the quality of the video for seeing the wrist position without markers makes me very uncertain about the angle of pronation. 

I’d appreciate any observations, comments or suggestions. 

The OP wants to measure foot supination.  The ROM for foot supination is probably much less than the ROM for wrist pronation in the tennis serves that I’m having difficulty with.  Measuring foot supination angle seems like a very challenging goal.

6 Reply by Archer4

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How interesting
There seems to be a glitch in the semantics in that an "anatomically neutral position" is full supination ie with radius and ulna parallel however there does indeed seem to be a convention of measuring pronation and supination from a "neutral position" ie mid pronation, certainly in all of the US/Canadian papers I've skimmed. Logical I suppose in that that would best reflect the clinically significant movements ie 50° pronation and supination from neutral/thumb up/mid pronation to maintain useful function whereas the same range of 100° but from full supination would leave you short of sufficient pronation to eg use a keyboard comfortably. In my day job (in the UK) I was brought up referring to degrees of pronation or supination lost - as that would indicate the functional effect of the restriction and the correction aspired to which would be independant of the start position in the same way as the neutral/thumb up zero. For your purposes a thumb up zero would certainly be correct and most useful as the range of motion measured would be unaffected but it would be the correct way to localise where in rotation the forearm was for the purposes of assessing expected torque, pronating muscles involved at that angle etc
Back to Kinovea - no I can't see how you could usefully measure pronation without markers and susoect that a retro-fit duplicate set up with markers would be at best a guide limited by inherent variability

Regards

7 Reply by Chas Tennis (edited by Chas Tennis 2011-12-16 21:57:54)

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Interesting discussion on the term pronation and I think that we can agree something is still missing in how we both see the usage of the term. 

In USA tennis I believe that most average players don't have any idea of what the term 'pronation' invloves. To make matters worse many informed tennis parties, instructors, etc. incorrectly use the term 'pronation' to describe a combination of pronation and internal shoulder rotation because both add to turn the forearm/wrist.  Since internal shoulder rotation uses entirely different muscles than pronation and contributes much more power to the serve, it is a very detrimental misuse of terms.  I was misled for decades............ 

As for now, to me pronation is CCW rotary motion [between elbow & wrist] when looking at my right hand regardless of the angular position.  I have a big uncertainty as to the absolute angle to be assigned.   ROM (usually around 90°) is measured with the thumbs up arrangement as described with a "0" degree at the top as a reference. That reference "0" may possibly only be used for ROM measurements. ? ( To me there is a term inconsistency if the wrist is in the supination side of the circle but is rotating CCW, still pronation? For example, 'The wrist is in supination and pronating.'?)

I hope that the OP does not have any similar issues with foot supination.  With a small ROM and no markers that measurement from video seems very challenging.   (Would attaching a laser pointer on the bottom of the foot and videoing the pool scattering of the beam be a useful marker after the fact?)