Idiopathic flat foot is a common condition in children and adolescents. After loading, the heel is adjusted in valgus, the medial longitudinal arch of the foot flattens, and the forefoot is positioned at abducted. Such deformation can be classified as flexible or rigid. The importance of shaping the longitudinal arch of the foot is one of the most controversial issues in orthopedics. A lowered flat foot arch is an undesirable feature.~The shape of the arch is determined by age and genetic conditions. The age of six is believed to be a critical moment for the development of the medial longitudinal arch, since it is the age when the development of the medial longitudinal foot arch slows down to finally stop at the age of 12-13. Therefore, it seems important to pay attention to the development of the medial longitudinal arch before adolescence in order to reduce the risk of perpetuating anomalies.~Incorrect arching can cause changes in the ankle, and pronative positioning of the foot influences the adjacent joints of the lower limb and the spine, which results in impaired control of body posture, kinetics and gait kinematics. The pain induced by the changes in body functioning increases the risk of injury.~The foot is the most distal segment of the lower limb bio-kinematic chain and represents a relatively small support base while maintaining balance. Even very small changes in this segment may be the reason of disturbances in posture control strategy. In addition, elimination of longitudinal arch of the foot and hypermobile metatarsus can be a challenge for neuromuscular system in terms of stabilization and maintenance of an upright posture. When medial longitudinal arch of the foot lowers it causes functional and consequently structural disturbances. Subsequently the ability to absorb impacts decreases and the feeling of balance can be lost leading to reduced stability~There are two reasons for the adverse effects of flat foot during gait:~Flat feet have a shortened lever arm compared to those with correct arches. Shortening lever arm is caused by abducted forefoot in the transverse plane, hindfoot valgus and metatarsal disturbances in the sagittal plane;~The lever (foot) becomes more elastic due to disturbances in the metatarsal and lowering of longitudinal arch in the sagittal plane. Because of loss of an appropriate degree of lever stiffness, the energy produced by the muscles in the push-off phase is not properly used.~Additional factors such as e.g. abnormal body weight, may have impact on the shape of medial longitudinal arch. The belief that overweight or obese children have flatter feet is based on research findings and may seem like an intuitive observation. Increasing evidence suggests that excess weight is inextricably linked to flatfoot and postural stability. Excessive body weight leads to a greater overall load, with a disproportionate effect on the midfoot area and the medial longitudinal arch. Childhood overweight and obesity are not compensated by the musculoskeletal system. Weight gain imposes additional biomechanical restrictions. Evans and coauthors demonstrated the existence of a correlation between the formation of the foot arch and body weight. According to Shiang and coauthors, flat feet of obese children may be the result of a decrease in the medial longitudinal arch due to overload, which is the result of overweight. Another consequence of abnormal weight can be balance disorders. Deforche et al. proved that overweight boys show reduced ability to perform tasks requiring static and dynamic balance. Comparative studies conducted using the Y Balance Test show differences in the range of forward movement of the lower limb, to the detriment of children with abnormal body weight, which is confirmed by studies on the correlation between postural stability and excessive body weight. In connection with the above-mentioned consequences, disorders of the muscles responsible for stabilizing the arches of the foot are noticed. Similar observations were made by Sung and coauthors and Murley and coauthors showing neuromuscular compensation associated with overloading medial longitudinal arch.~The mobility and stability of the foot arches is controlled by the internal and external muscles of the foot, but the former are often overlooked in therapy. The possibility of isolated internal muscle tension of the foot is provided by short foot exercises. Internal foot muscle training can improve foot function. Four-week training in adults with reduced foot arches, assessed by measuring the height of the navicular bone tuberosity and arch height index, improved balance. The results of the foot maneuver shortening test on children show that it is an effective method for increasing the arch and results in an improvement in the arch index. Short foot exercises are recommended as an improvement in foot arch parameters. Based on a meta-analysis carried out by Evans in 2008, it is believed that in the treatment of asymptomatic corrective flat feet and in disorders of their development in relation to the child's age, conservative treatment should be applied, including exercises to strengthen the intrinsic muscles of the feet. The participants will take part in the research with the written consent of their parents or legal guardians. The results will be used anonymously for scientific publications.~Hypothests: A six-week rehabilitation program for children with flat feet and excessive body weight will significantly affect the formation of the medial longitudinal arch, basic gait parameters and balance.
Idiopathic flat foot is a common condition in children and adolescents. After loading, the heel is adjusted in valgus, the medial longitudinal arch of the foot flattens, and the forefoot is positioned at abducted. Such deformation can be classified as flexible or rigid. A lowered flat foot arch is an undesirable feature.~Additional factors such as e.g. abnormal body weight, may have impact on the shape of medial longitudinal arch. Increasing evidence suggests that excess weight is inextricably linked to flatfoot and postural stability.~In connection with consequences, disorders of the muscles responsible for stabilizing the arches of the foot are noticed.~The mobility and stability of the foot arches is controlled by the internal and external muscles of the foot, but the former are often overlooked in therapy. Short foot exercises are recommended as an improvement in foot arch parameters. The participants will take part in the research with the written consent of their parents or legal guardians. The results will be used anonymously for scientific publications.