The Effect Subtalar Joint Pronation on Postural Stability and Lower Extremity Alignment

The lower extremity consists of sequent columns. The deviation of one segment from its normal alignment in the lower extremity also affects the alignment of the other segments. The alignment of the parts of the foot during weight bearing is called foot posture. Foot posture is divided into neutral, pronation, and supination. Foot posture varies significantly from person to person, and deviations from normal foot posture are associated with lower extremity injuries. Increased or prolonged pronation has been identified as both a risk factor and etiologic factor for increased navicular drop, a lower extremity malalignment pattern. In pronation posture, the foot may not adequately adapt to the ground, and there is increased movement of the lower extremity in the frontal plane. As a result, the person's postural stability is compromised. The fact that the foot is the most distal segment of the lower extremity chain indicates that even small biomechanical changes in the bearing surface can significantly affect postural control strategies. There are studies in the literature that examine the effect of foot pronation on dynamic balance and postural stability in individuals with different foot postures. However, to our knowledge, there is no study that examines differences in postural stabilization and lower extremity alignment by classifying individuals with varying degrees of subtalar joint pronation into pronation and hyper pronation groups.

Examination of the biomechanics of the foot and ankle is an important aspect in the evaluation of human movement. The purpose of this study is to divide healthy subjects into pronation and hyperpronation foot postures and investigate the effects of differences subtalar pronation amounts in lower extremity alignment and postural stabilization. The part of the foot where the subtalar joint is located is called the hindfoot. The anatomy and alignment of the hindfoot is a critical factor in the biomechanics of the lower extremities and the function of human locomotion. Pronation of the foot causes tibial internal rotation and femoral internal rotation through the mechanism of the kinetic chain, resulting in valgus alignment of the knee when the foot is on the ground. The valgus alignment changes the position of the pelvis. Alternations in pelvic position increases the tension on the hip and pelvic muscles because it changes the force lever. In addition, increased femoral internal rotation of the lower extremity relative to the tibia has been shown to increase stress on the weight-bearing tissues of the tibio-femoral compartments and increase tibial internal rotation in individuals with pronated foot posture. Normal pronation motion is necessary for proper foot function, but increased and excessive pronation of the subtalar joint is a condition that should be investigated because it presents several problems with lower extremity alignment. The fact that foot pronation is important for the lower extremity kinetic chain during dynamic tasks prompts us to investigate foot pronation by measuring it in various ways. The purpose of this study is to divide healthy subjects into pronators and hyper pronators and to investigate the effects of differences in lower extremity kinetic chain alignment and postural stabilization and in healthy subjects.

Eligibility Criteria:
Inclusion Criteria:

* Being between 18 and 40 years old
* Not to have pain and function loss
* Foot posture index value between 6-12
* No orthopedic disease
* Not be visually or hearing impaired
* Not have participated in a physical therapy program in the past 6 months
* Not have undergone any surgical procedure on the lower extremity
* No intake of pain medication during the examination period and within the specified treatment days

Exclusion Criteria:

* Having congenital anomaly of the lower extremity
* Having a history of lower extremity surgery or lower extremity surgery planned within the next 12 months
* Having ligament hyperlaxity
* Having a history of tendon or cartilage injury
* Having metabolic disease, cancer
* Using any kind of support/orthosis in the shoe
* Having knee injections in the past 3 months
* Any neurological or systemic inflammatory arthritis disorder