Sunday, November 30, 2008

Critical Thinking

Within the discipline of Critical Thinking, all the strategies that can be used to make arguments are well researched and documented. The fallacies of logic are clear. One of the false types of arguments is know as the straw man argument in which you define your opponents position as something that its not and then argue against that position. Wikipedia defines it as:

A straw man argument is an informal fallacy based on misrepresentation of an opponent's position. To "set up a straw man," one describes a position that superficially resembles an opponent's actual view, yet is easier to refute. Then, one attributes that position to the opponent. For example, someone might deliberately overstate the opponent's position. While a straw man argument may work as a rhetorical technique—and succeed in persuading people—it carries little or no real evidential weight, since the opponent's actual argument has not been refuted.

Here a some Podiatry Arena threads:
Challenging MASS
Challenging SALRE
Claims of Foot Orthoses Superiority

Have a read of them. Guess what? Spot the straw man arguments!

All this sums up the point that Steve the Footman made about Podiatry Arena: "What other profession has a forum that gives its members access to its most significant researchers and clinicians? You can ask any question you want and get informed and experienced replys that include links to multiple research papers. New research is discussed and critically appraised immediately. It is like having a blowtorch applied to the cherished beliefs of the profession. It is like having an academic review panel of 8000 people at your fingertips.And I think it is the major development in sports podiatry in 2008."

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Thursday, November 06, 2008

The abductory twist

During gait, in a number of patients, just as the heel comes off the ground, the foot often abducts. There is no doubt this happens and its called an abductory twist.

What is interesting about it, is that two different biologically plausible and theoretically coherent theories can be used to explain it:

1. Foot pronates beyond midstance--> internal rotation moment to leg; the opposite leg is swinging forward and rotating the pelvis --> externally rotation moment to leg on ground --> conflict between proximal external rotation and distal internal rotation moments -- initially the pronated foot causing the internal rotation moment wins the battle and foot does not resupinate to accommodate that proximal external rotation moment ..... eventually as heel comes off ground, friction between the ground and foot can no longer no longer resist the external rotation moment coming from above --> abductory twist

2. As heel starts to come off the ground a functional hallux limitus kicks in (for whatever reason); as the body has to move forward over the first MPJ, it can do so by a number of mechanisms; one of these is to abduct the foot to roll off the medial side of the blocked first MPJ --> abductory twist

This is a classic example of how a fact (the presence of an abductory twist during gait) can be explained by two competing theories (this is what make clinical biomechanics fun).

Lets wee what others think on the abductory twist.

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