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

 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

 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

 70% have over- pronation  Low arches  Effects travel up

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

 Force directed at the ankle into the posted orthotic

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

 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

 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

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

 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

 These results suggest that an inversion orthotic may be more suitable than a standard orthotic for those with excess pronation