The document discusses over-pronation, which is excessive or prolonged pronation of the foot during walking or running. Pronation is a normal motion where the foot turns inward to help absorb shock, but over-pronation is an extended period of this motion. It is caused by instability of the ankle bone on the hindfoot bones. This puts increased strain on foot ligaments and tendons and can lead to conditions like bunions, plantar fasciitis, and more. While often associated with flat feet, over-pronation can also occur in high-arched feet if the ankle bone is displaced from its proper position. Fixing over-pronation requires eliminating its underlying cause of ankle bone instability.
13. The foot moves in the opposite direction of the talus during walking.
14. Foot has to move in all three planes to pronate Slightly turns away from the mid-line of the body – lateral (abduction) transverse plane motion Sole of the foot slightly turns outward (everts) frontal plane Foot turns slightly up-wards (dorsiflexes) sagital plane.
19. Supination - Pronation Opposite movements between the ankle bone and the foot. Think of it as a winding and unwinding of the foot mechanism. A period of stability and less stability of the foot structures while walking.
21. These complex motions of the foot consist of a locking and unlocking of the joints within the foot.
22. Pronation unlocks the foot and turns it into a “Loose bag of bones” We have to be very careful using this term when describing the stability of the bones of the foot during pronation as it seems like there is no stability within the foot during this period. This is not the case, it is just that there is a period of slight joint motion as the foot is allowed to be a mobile adapter.
23. Mobile Adapter This is a very important aspect of the foot to allow slight accommodation to an uneven weightbearing surface below the foot. During this time there is a normal amount of adaptation that is acceptable and built into the mechanics of the foot.
25. It is determined by the motion of the ankle bone (talus) on two hindfoot bones (calcaneus-heel bone and navicular).
26. There is a specific point when the foot needs to be supinating.
27. During the contact phase of walking the hindfoot lands supinated, quickly pronates, and re-supinates for toe-off.
28. At mid-stance the foot transitions from its supinated motion into a pronating motion.
29. Finally, in order for the foot to function as it was designed, the hindfoot must stiffen/limit joint motion and transition back into supination in order to prepare the foot for lift-off.
39. How does the foot end up with too much or a prolonged amount of pronation?
40. Hind-foot stability has everything to do with the stability of the ankle bone on the hindfoot bones called the TaloTarsal Mechanism.
41. TaloTarsal Mechanism 3 bones Talus (ankle bone) Calcaneus (heel bone) Navicular (bone in front of the talus) This mechanism has the most complex motion of the body.
42. Talus sits on top of the back of the foot. 4 specific joints between the talus and the calcaneus and navicular bones. 4 3 2 1
43. TaloTarsal Motion There is a specific amount of motion that is supposed to occur between the talus on the hindfoot bones.
44. Normally, there should be twice the amount of supination compared to the amount of pronation.
46. As the saying goes, too much of anything is usually not a good thing.
47. A prolonged or excessive amountof foot pronation means there is instability of the ankle bone on the hindfoot bones.
48. This leads to excessive forces acting on the structures of the foot.Specifically, there are increased strains placed on certain ligaments and tendons of the foot.
49. A few conditions blamed on an excessive amount of foot pronation. Bunions Hammertoes Posterior tibial tendon dysfunction Plantar fasciitis/heel pain Tarsal tunnel syndrome
52. Answer In most cases there is a lower than normal arch of the foot. HOWEVER What determines a low or high arch is the inclination of the heel bone.
53. It is possible to have a high arched foot and still have hyperpronation? YES
54. Over-pronationis a result of the talus partially displacing off its normal position on top of the heel bone.
55. The angle of the heel has little to do with the displacement of the talus.
56. The bottom of the foot is notthe cause of over-pronation.