iPhone tool for biomechanical measurements

For those who still do measurements as part of your biomechanical assessment (I stopped doing this a long time ago, except for measuring the tibial angle for the lunge test) and you have an iPhone, have you seen the iHandy Carpenter Tool (search for it at iTunes). It’s a cool way to do your measurements. It works really well for the Lunge Test.

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MASS Foot Position Theory for Foot Orthotics

MASS foot orthotic position theory has been proposed by Ed Glaser, DPM from Sole Supports Inc. MASS stands for Maximum Arch Subtalar Supination. It is a position of the foot that is much more supinated than the traditional subtalar joint neutral position, but also maintains the forefoot on the ground (no varus or valgus captured). Ed advocates the use of semi-weightbearing foam box as opposed to plaster (though it is not difficult to reproduce the position non-weightbearing with plaster bandage). The position results in a very different foot orthotic shape that is what is traditionally used. For more see comments on the Boot Camp site: MASS Foot Position Theory and the threads on Podiatry Arena tagged with MASS position theory (they do get a little heated).

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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.

Back to home page For more: http://www.fridayfitnessguru.com/i-just-learned-about-the-medial-heel-whip/ http://www.whatispodiatry.com/questions/what-is-an-abductory-twist/