1. http://www.wmgh.net/article/foot-orthotics-72.asp

2.  Many people think of orthotics based on the off-the-shelf brands and do not realize how the orthotic works

3.  Prevents abnormal movement  Various conditions can be relieved › Back, hip, knee, and ankle pain  Increase stability in joints  Increase biomechanical efficiency Right leg posterior view http://www.wellfeet.com/orthoticswork.htm

4.  Anatomically designed to flex and extend in the sagital plane (hinge joint)  Abnormal alignment at the foot can alter the forces when standing, walking, running, etc. to a transverse component

5.  70% have over- pronation  Low arches  Effects travel up http://healthyfeetforlife.com/

6. Example: 150 lb person standing with the foot 20 ⁰ over- pronated Vertical Component: cos 20 ⁰ = (v / 150) v = 140.95 lb Transverse Component: sin 20 ⁰ = (t / 150) t = 51.3 lb

7.  Force directed at the ankle into the posted orthotic http://www.orthoticsandal.com/AboutOS_Technology.html

8. http://www.trcc.com/au/solution/orthotics.html http://www.wellfeet.com/orthoticswork.htm

9.  Authors: › Dorsey S. Williams III › Irene McClay Davis › Stephen P. Baitch  Journal: › Medicine & Science in Sports & Exercise

10.  11 runners participated  All previously wore standard orthotics  Inversion orthotics posted at 15 ⁰ or 25 ⁰  3-D gait analysis › Joint motion › Joint kinetics  Ran at 3.35 m/s

11.  Results › Eversion moment not present before › Peak inversion moment significantly decreased › Increase in peak knee adduction  Other factors › Takes 5 ⁰ of change in post in order to have 1 ⁰ change effect

13.  Corrected with 54% improvement 20 ⁰ x.54 = 10.8 ⁰ cos 10.8 ⁰ = (v c / 150) v c = 147.34 lb Sin 10.8 ⁰ = (t c / 150) t c = 28.11 lb (28.11-51.3) x 100% = 45% decrease 51.3

14.  Impact of Padding › Decreases the force due to the compression of the padding › Orthotics have various amounts of padding depending on the person’s needs  At the ankle › Muscles affect stability  Rear foot movement and stress on the lateral knee needs to be studied more

15.  These results suggest that an inversion orthotic may be more suitable than a standard orthotic for those with excess pronation http://www.syracuseorthotics.com/