Google”Orthotics” = Wikipedia
Proprioceptive orthotics
While most conventional orthotics relies on passively supporting and immobilizing the feet, proprioceptive orthotics is a new type of less costly orthotics that relies on the proprioceptive system. The proprioceptive system is the brain processing mechanical stresses received from nerve endings in the skin, joints, ligaments, tendons and muscles and providing motor output to control (tense and relax) muscles to maintain body equilibrium and intended motion. A proprioceptive approach to orthotics is particularly suited for people who have Morton’s Foot Syndrome or an elevated first metatarsal (usually, but not necessarily associated with MFS). Morton’s Foot Syndrome is characterized by a deeper cut web space between the first and second toe and/or a longer appearing second (Morton’s) toe. Morton’s Foot Syndrome is also defined to include a hyper mobile first metatarsal and is often associated with calluses underneath the 2nd and 3rd metatarsals (Morton). An elevated first metatarsal is characterized by the first metatarsal not being weight bearing when the weight bearing foot is positioned in its subtalar neutral position (where the heel bone is perpendicular to the floor). This can be observed by mapping the pressures underneath the sole of the foot. It is thought (Rothbart) that this condition is associated with retention in talar torsion (a structural variation) as described by (Sewell) who documented that a talar head rotation in the frontal plane may vary by as much as 20 degrees from person to person. The result is that in “normal subjects” the first metatarsal does not become fully weight bearing until 88% of the contact stance phase of gait is complete (Cornwall, McPoil), causing the foot to substantially hyperpronate through mid-stance and most of the propulsion cycle. The theory behind proprioceptive orthotics revolves around the natural response of the foot and body in response to how the ground is felt by the feet. Travell and Simons stated that Morton’s Foot Syndrome causes an unstable foot where the main pressures are focused on the heel and at the area at the base of the second toe causing walking (presumably because the associated elevated first metatarsal) to be akin to walking in ice skates. This instability by all appearances causes one of two different proprioceptive responses. The foot is either freely released to roll in (hyperpronators = inside outsole shoe wear), or this action is partially or fully resisted through bracing the muscles to prevent it by forced (conscious or subconscious) supination (outside outsole wear). Since supination is most often a proprioceptive response (compensatory response) to hyperpronation, hence supinators are typically hyperpronators in disguise. Proprioceptive insoles are designed to alter how the foot feels the ground, particularly the timing of the first metatarsal ground contact. When ground contact is felt underneath the first metatarsal, muscles are naturally activated to push against the ground forces. When the ground is purposefully elevated underneath the first metatarsal, this muscle response is thought to happen sooner hence bringing the first metatarsal to bear more weight earlier in the contact gait cycle and stabilizing the forefoot. This controls hyperpronation, and, as a result, natural proprioception reduces the subconscious urge to compensate by supinating the foot. Proprioceptive orthotics may therefore be applied to eliminate or reduce both foot and general postural musculoskeletal pain in both hyperpronators and supinators. Proprioceptive orthotics may be combined with passive arch support in cases of severe hyper mobility, and temporarily while healing Plantar Fasciitis injury. Because proprioceptive orthotics only requires small dimensions to influence the neuromuscular system, they are thin, flexible and virtually unnoticeable in footwear. The foot remains free to move naturally and comfortably.