Autism spectrum disorders (ASD) are complex neurodevelopmental conditions characterised by deficits in communication and reciprocal social interactions, as well as restricted interests and repetitive behaviours. Although motor impairments have been recognised as limiting daily motor skills, they are not included in the DSM-5 diagnostic criteria for ASD. The Centers for Disease Control and Prevention published an estimate that the prevalence of ASD in the US population was approximately 1 in 54 eight-year-old children (around 1.85% of the child population). Furthermore, the World Health Organization (WHO) documented a worldwide prevalence of approximately 0.76% in 2010 (affecting nearly 1.16% of the entire child population).

Children with ASD underwent balance and foot measurement tests that they could perform only by following instructions.

Foot Posture Assessment: Children's foot posture will be assessed using the Foot Posture Index (FPI-6), which is valid for pediatric individuals. The Foot Posture Index is a scale consisting of a total of 6 items related to the posture of the rear foot and forefoot. These items are talar head palpation, the position of the inclinations above and below the lateral malleolus, the position of the calcaneus, ballooning in the talonavicular joint region, the structure of the medial longitudinal arch, and the abduction/adduction of the forefoot relative to the rearfoot. The total score in this assessment tool ranges from -12 to 12.

Timed Up and Go (TUG) test: For this test, individuals are seated in a chair. The individual is asked to stand up from the chair without assistance, walk three meters on the marked floor, walk back to the chair, and sit down again. The stopwatch is started with the "start" command and stopped when the individual sits down. The TUG time is recorded in seconds (s).

One-Leg Standing Test: During this test, which is used to assess an individual's static balance, the subject will be asked to lift one leg without touching the supporting leg, keeping their eyes open, and the time spent on one leg will be recorded in seconds.

Foot-Ankle Anthropometric Measurements: For the foot-ankle anthropometry of patients, foot length (cm), metatarsal width (cm), and navicular drop height (cm) will be assessed with and without body weight applied to the foot.