In the human body, the base of support is the feet, it contains bones which are held together by muscles and ligaments. The foot includes three arches, the longitudinal medial arch, longitudinal lateral arch, and the transverse arch. The pressure of the weight of the body is absorbed by the medial longitudinal arch, and this arch length may shorten due to ligaments laxity or foot muscles weakness. (Pourghasem et al., 2016)The foot works as a lever, and it bears the weight of the body, normally in a foot center the weight and strain fall through it, and the muscular activity helps in balancing it.
The muscle which helped in balancing the weight will stop supporting the foot if it stops to act as a lever. This condition of the weak foot is called flatfoot, which is now no longer works as a lever but is causing pain and discomfort. There are three most visible deformity elements, the foot takes the valgus position, and the body weight falls on its inner side, the resting leg on the displaced talus changes its position and turns in while the foot turns out, this leads to shifting the strain line that transmits the power to the fulcrum to deviate from center of the foot to its inner side, in relation to the leg the foot is abducted or everted. The arch is becoming broad and flat, causing the foot to be flat.
(Whitman, 2010)Flatfoot is the most common type of the deformity in the foot, changes in the skeletal structure, ligaments, and muscles occur due to it, the change in the tarsal bones leads to transformation in its motion mechanism thus the fatigue is triggered, arthritis and a deformity which is secondary to it happens in the front part of the foot. Pain and fatigue are reproduced by walking or standing. The foot function is impaired when practicing sports or excessive activities, in flatfoot damage to the lower limb occurs due to the load on the tibia causing pain to it and the knees.(Seo and Park, 2014)The flatfoot condition can be categorized to congenital or acquired, and the congenital type can be divided into two flexible and rigid.
In flexible flatfoot, the medial longitudinal arch appears when the foot is in a non-weight bearing position and disappears while standing, in the rigid flatfoot the arch is absent even when the foot assumes a non-weight bearing position.(Pourghasem et al., 2016) The World Health Organization stated that less than 1% of the population is affected by Rigid flatfoot which causes pain and disability that may require surgery. While in the U.S. adult population between 2 to 23% is affected by flexible flatfoot.(Banwell et al.
, 2014)Symptomatic Flatfoot is considered pathological, the hindfoot medial region and the posterior tibial tendon is where the pain generally occurs, sometimes it may be associated with the tendon sheath effusion.(Toullec, 2015)Painful symptoms accompanying flexible flatfoot include, a wide distribution of pain and an increase in fatigue rate in lower limb area, osteoarthritis, achilles tendinopathy and patellofemoral disorders may appear. Other signs observed include the abnormal appearance of rearfoot kinematics such as a rearfoot excessive eversion or by an increase in the eversion range, abnormal kinetics of the foot and ankle such as joint moments elevated or loading forces abnormal values and change in the physical function by abnormal timing and activation of muscles or by raising consumption of energy. These functional consequences are the reason for