Introduction: Autism Spectrum Disorder (ASD) is characterized as a neurodevelopmental disorder, with motor symptoms that may predispose to falls and gait changes. Exercises through virtual reality (exergaming) showed good results in children with ASD, but no studies were found that evaluated the effects of exergaming on gait and the risk of falls. Objective: To evaluate the effects of exergaming on motor performance during gait and the risk of falls in children with ASD. Method: Pilot study of a clinical trial. There will be 22 participants, diagnosed with ASD, level I or II; age: 5 to 9 years old; that they do not use medications that interfere with postural balance and falls; without physiotherapy care for at least 2 months. They will be divided into Exergaming Group (EG, n=11) and Control Group (GC, n=11). The GC will receive guidance through booklets. The EG will be submitted to a treatment with exergaming for 3 months, with 2 weekly sessions of 45 min each (initial 10 min, 25-30 of exergaming with the Xbox360 console with Kinect sensor and game "Kinect Adventures!", 5 min of cool down ). They will be assessed using CARS-BR (Childhood Autism Rating Scale - Brazilian version), DCDQ (Developmental Coordination Disorder Questionnaire), EEP (Pediatric Equilibrium Scale), a semi-structured questionnaire to assess the history of falls and prevalence of falls, an adapted motivational scale for ASD, a satisfaction survey, and three-dimensional assessment of gait through the Gait Laboratory. Descriptive analysis will be performed and continuous variables will be summarized in mean and standard deviation, and categorical variables in absolute and relative frequencies. To compare the independent and paired variables, parametric tests will be used and a significance level of 5% will be considered (p <0.05). Pearson's correlation will be used to assess correlations between continuous variables and the Chi square test to assess the relationship between categorical variables. Expected results: It is expected that children from the EG will obtain better results than the CG on gait variables and the risk of falling, with clinical and statistical significance.

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder with altered motor aspects, present among 50-88% of children with ASD1. They can present difficulties in motor planning, altered gait, postural imbalance, and decreasing postural control, thus increasing the risk of falls.

Children with ASD have variability in gait patterns intra-individually, considering stride length, stride time, and walking speed5. The gait kinematic alteration includes wider step width, decrease in gait velocity, increase in stance time, gait cycle and step time, and differences in cadence and gait cycle compared to children without ASD5. A study showed that children with ASD have a more severely impaired postural balance than other neurodevelopmental disorders and typical children.

The impaired gait patterns can lead to pain, fatigue, and joint stress, affecting the functional capacity of children with ASD and impacting their quality of life. Also, it has been suggested that the motor alterations present in children with ASD are related to difficulties in communication and socialization, difficulties in the development of cognitive abilities, contribute to adaptative dysfunction, decrease the physical functional capacity, and increase the chance of obesity. The motor abilities are strongly related to adaptative function and quality of life of children with ASD, anticipating the deficits in social communication.

Although there is evidence in the literature concerning motor difficulties in children with ASD, it is estimated that 1,34% of them are diagnosed with motor alteration. Besides, it is an underestimated diagnostic among physical therapists in clinical practice. This highlights the importance of functional diagnostics and the study of possible interventions that can be useful in clinical practice in treating motor alterations, especially gait, and the risk of falls.

Exergaming (EXG) has been used as a treatment in children with ASD, demonstrating positive results. Among the effects of EXG in children with ASD are an improvement in explosive strength, better performance in velocity and agility, improvement of aerobic capacity, better work memory capacity, better strength and agility, improved perception of competence, reduced stereotypical behaviors, improved measurement of executive function, reduced aimless arm movements, and decreased body mass index.

Thus, EXG is a valuable tool to treat children with ASD. However, few studies have used EXG to treat motor aspects, especially those related to gait or balance performance. This highlights the following question: Could EXG improve the gait and lessen the risk of falls in children with ASD? Therefore, the primary objective of this study is to describe a randomized and controlled clinical trial protocol to verify the effect of EXG on gait and risk of falls in children with ASD. The secondary objective is to describe the gait measurement and the risk of falls to assess the effect of exergaming in children with ASD. The hypothesis is that the EXG will lessen gait alterations in children with ASD and improve postural balance, lessening the risk of falls.

Inclusion Criteria:

• Children with ASD levels I or II;
• Age 5 to 9 years
• No use of medications that interfere with balance and falls;
• Who have not been undergoing physiotherapeutic care in the last 2 months
• Who present some gait alteration.

Exclusion Criteria:

• Children with genetic syndromes duly diagnosed in association with ASD, based on the medical report;
• Physical disability, respiratory disease, or cardiac complications that prevent exercise;
• Proven hearing or visual loss without the use of hearing aids or eyeglasses respectively;
• With a history of epilepsy/seizures in the last six months and without the use of specific medication;
• Children who, even with the formal consent of those responsible for them, do not accept to participate in the research.

Both assessors participating in the study will be masking for the group of the participant.