Effect of Trunk Stabilization Exercise on Dynamic Balance and Foot Function of Pronated Foot Posture

Pronation is the simultaneous calcaneal eversion with foot abduction and dorsiflexion. The range of motion (ROM) for subtalar joint during pronation was around 5 ° to 10°. Pronation is important for stabilization in standing and walking, but excessive ROM for this motion can lead to over pronation.

Foot pronation is a natural movement, necessary for the normal development of gait, since it contributes to the absorption of the ground reaction forces .

However, overpronation causes the collapse of the medial longitudinal arch of the foot, thus causing more tension in certain muscles of the foot and leg, i.e., posterior tibialis. Pronated feet present rearfoot eversion and dorsiflexion with abduction of the forefoot in a static position, and in addition, have a strong relationship with the medial longitudinal arch (MLA). It is suggested that maintaining the integrity of the MLA can prevent numerous musculoskeletal injuries .

Pronated foot posture is common in adulthood, with a prevalence of around 21%, and it may be related to deformities of the first ray of the foot, such as the hallux valgus. Furthermore, this biomechanical alteration can also affect other areas, such as the knee .Thus, pronation influences the time and intensity of lumbopelvic muscle activation, giving rise to low back pain or other dysfunctions at that level.

There are several methods to treat the pronated foot, such as custom foot orthoses, external modifications of the footwear, exercises to strength the muscles involved or even surgery .Strength exercises are a highly recommended method in the treatment of childhood flat foot, since muscle enhancement plays very important role in the development of the lower limbs in the growth of the child. The lack of treatment can often lead to short- and long-term problems with deformities in adolescence and adulthood .