This study showed that children with ASD had defects in all dimensions of executive function compared to children with typical development. In addition, executive function was correlated with social interaction disorder, and was closely related to working memory and emotional control of children with ASD, which was different from previous studies(9). Furthermore, all indexed of physical quality were basically correlated with executive function and social skill, in which balance quality had no correlation with each dimension, and there was a strong correlation between muscle strength and each dimension.
The study found that there was a close correlation between executive function and social interaction disorder, and there was the synchronization indexed between them. Daily executive function disorder was associated with increased feelings of isolation and reduced interaction with peers in children with ASD, and the common manifestations of executive function disorder appeared to reflect a comorbidity rather than individual disorder with distinct impairment(18, 19). The disorder of social interaction and communication in people with ASD could be explained by defects in "hot" executive function related to social emotion(20). In contrast, their stereotypic behavior, narrow interest and rigid style of action could be explained by the defects in "cold" executive function related to non-affective tasks(21, 22). Social interaction and communication behavior involved a variety of executive functions, including goal setting (interactional purpose, communicative intention), planning and organizing (interaction and communication strategy selecting and organizing), self-monitoring (interaction and communication process monitoring), outcome evaluation (interaction and communication outcome evaluation) and so on(7).
In addition, canonical correlation analysis showed that working memory and emotional control were more closely related to social perception, social cognition and autistic behavior. First of all, working memory, as a system for the temporary storage and information processing, was the core of high-level cognitive activities. Existing studies found that there was a relationship between visual working memory ability and social interaction disorder, and the stronger the visual working memory ability, the less significant the social interaction disorder(23, 24). For children with ASD, understanding other people's intentions might involve additional cognitive abilities(11, 25), such as deduction, reasoning and so on, which were inseparable from working memory. At the same time, executive function and language skills were also interrelated, and vocabulary, syntax, and pragmatics were also related to the areas of working memory, conversion, and inhibition in people with ASD(5, 26). Second, emotional control could help individuals make appropriate responses by controlling their immediate emotion in certain circumstances and reducing their impulse(10, 27). Children with ASD had poor emotional regulation and had difficulty in understanding others' emotion, which might lead to their autistic behavior in children with ASD(28). Some social interactions, such as putting themselves in others shoes, maintaining social reciprocity and initiative, were associated with emotional control. Therefore, the future studies can try to explain the relationship between executive function and social interaction disorder through the dimensions of working memory and emotional control.
This study found that physical quality was closely related to executive function and social skill, and muscle strength had the strongest correlation with them. The improvement of physical quality provided a guarantee for children's positive adaptive behavior, which to a certain extent, promoted the occurrence of their social behavior, and promoted the virtuous circle of children's social participation(29, 30). At the same time, the improvement of physical quality reduced the degree of motor dysfunction in children with ASD, which provided a basis for patients to participate in physical exercise and provided a pathway for exercise to improve executive function, which was helpful to cause plasticity changes in the functional connection of executive control network(31, 32). In addition, the social behavior of children with ASD was closely related to muscle strength ASD. There was a delay in the natural improvement of motor ability in children with ASD(33). Abilities such as reaching out and catching facilitated the manipulation of objects(34), and at the same time, these abilities also promoted joint engagement with objects and caregivers, increasing their sensitivity to the interaction of individual, environment, and behavior(35). Children with ASD communicated more frequently with family, peers, caregivers and others through vocalization and gestures(33), such as display, giving, and telepathy, thus having the opportunity to engage in rich social behaviors. Furthermore, Lower limb muscle strength played an important role in children's independent walking, which was associated with a series of changes in perception, cognition and social development. Visually, moving in an upright posture could create a new relaxed field of view (including remote objects and facial recognition) during movement(4), which increased visual connection to the world, thus promoting the social behavior.
In addition, this study found that children with ASD had their overall executive function impaired, and executive function was correlated with social skill, which was inconsistent with previous results. The possible reasons are as follows. 1. The evaluators was different. Previous studies used parents' evaluation(36), while this study used teachers' evaluation, which to some extent avoided parents' subjective will. 2. Executive function was classified differently(37, 38). A BRIEF scale was used to assess the executive function level of school-age children, which contained two dimensions (behavior management index and metacognitive index) and it was closer to the needs of daily life. 3. The participants were at different ages. Previous studies compared the executive function and social skill of preschool children(39), while this study compared the executive function and social skill of school-age children, because they had more abundant needs for social interaction and activities at this stage, which might expose the real situation of children with ASD.
4 Limitations and prospects: This paper adopted cross-sectional design, so the ability of causal inference was limited. In the future, longitudinal studies can be conducted to further verify the interaction pathway between executive function and social interaction disorder proposed in this paper. This study was applicable to the special population, and the assessment of executive function was assessed by the subjective scale. In the future, objective indexed applicable to children with ASD can be explored for assessment. Additionally, future study can further analyze the relationship between physical quality, motor function, executive function, and core symptoms. Furthermore, future study can try to establish an exercise intervention program based on physical quality as an outcome index, providing support for physical exercise to improve core symptoms of ASD.