Intrinsic Factors affecting Navicular Drop
I don’t really have too much to say about this article, because it’s more suited towards experimental research, however I did find it interesting and thought the info might be helpful.. Here’s the link, from the Journal of Foot and Ankle Research:
http://www.jfootankleres.com/content/2/1/12
So we're on the same page.
In case you didn't feel like reading it, the key surprise from this for me was that BMI did not influence dynamic navicular drop. Two possible considerations, one perhaps more important than the other: there was no one in the study with a BMI over 30.5, which means that a very small number of the participants barely met the cut-off for obesity of BMI >30. Perhaps a study with heavier subjects would show a correlation. The other consideration, and I’m just throwing this out there, is that when I think of Danish men---which I do all the time---I tend to think of solidly built Viking types (with flowing blonde hair). As we know, BMI doesn’t differentiate between the fat and the muscular and perhaps some of the folks with higher BMI numbers in this study were fit, and thus blessed with stronger dynamic support of their lower extremities.
You can see how he would skew the results.
Yes, in fact we do stereotype here.
A correlation the researchers did find was that both gender and foot length affected navicular drop, with males having an increase in dynamic navicular drop by 0.4mm for every 10 mm of increased foot length, and females having an increase of 0.31 mm for each additional 10 mm.
Why is this important? There are some studies that show correlations between static navicular drop and various lower extremity injuries. There are some that don’t but this study points out that failure to group subjects by gender and foot length may have corrupted the results of those studies and suggests that studies in the future should control for those differences. If they do, we may find more consistent associations (or non-associations) between navicular drop and incidence of injury.