In addition to developmental delays, many Autistic Children have low muscle tone and experience difficulty with gross motor coordination (running, kicking, throwing, etc.). These issues can interfere with basic day-to-day functioning, and they’re almost certain to interfere with social and physical development.

Physical therapists are trained to help with these issues. Not only can physical therapists help your autistic child to build muscle strength and coordination, but they can do so in many contexts such as sports, play time and motor planning. As a result, physical therapy can improve functioning and social skills at the same time.
Physical therapists help to build or rebuild strength, mobility and motor skills.

Physical traits that may be treated by physical therapist range from difficulty with coordination to lack of muscular strength. Balance may be an issue: autistic children can find it very hard to ride a bike.
Physical therapists may work with very young children on basic motor skills such as sitting, rolling, standing, and running. They may also work with parents to teach them some techniques for helping their child to build muscle strength, coordination, and gross motor skills.
They may work on more sophisticated skills such as skipping, kicking, throwing and catching. These skills are not only important for physical development, but also for social engagement in sports, and general play.