Flat foot is caused by subtalar joint hypermobility which leads to changes in foot mechanics while walking. It results in increased load of the musculoskeletal system of the foot. It is proved by the literature which presents flat foot as an etiological factor responsible for numerous overuse injuries in this region. In particular, they concern the structures which support the longitudinal arch of the foot, i.e. Achilles tendon, tendons of tibialis posterior muscle, plantar fascia, sesamoid bones, hallux, metatarsal head and metatarsal bones. Due to the fact that foot loads and mechanics change during different gait phases, the magnitude of forces affecting particular tendons and ligaments also varies at its specific phases. Therefore, it is important that the findings of the latest studies on flat foot be collected in order to develop appropriate programmes of functional rehabilitation of the indicated deformity as well as therapeutic programmes for overuse injuries. Although this deformity and its consequences are a common problem, the foot still remains an unexplored area at the level of kinematics and kinetics. In particular, it is necessary to conduct research regarding correlations between the foot structure and its functions. It will be possible to broaden the knowledge in this field owing to the development or identification of the mathematical foot model taking into account common kinesiological problems with lower limbs that stem from flat foot.