THE members of the swim team at Bloomington High School South in central Indiana cheer wildly every time Nathan Buffie races. In his two years on the team, Nathan has never won first place at a meet. Often, he finishes far behind.

But it is the fact that Nathan even goes into the water and manages to compete at all that his teammates find so remarkable. Nathan, a trim 16-year-old with a boyish smile, has autism, the devastating developmental disorder that makes his participation in any sport or social activity a struggle.

“He is probably the worst swimmer on the team, but he keeps getting better and he wants to win,” said his mother, Penny Githens. “He tells his teammates this, and they just get so excited for him.”

For years, children with autism were left on the sidelines, a consequence of a widespread belief that they were incapable of participation in athletics. But while it is true that autistic children can be difficult to motivate and resistant to exercise, they are now being pushed to take part in physical education programs, encouraged by experts who say that certain sports can ease repetitive behaviors like pacing and head-banging as well as provide a social outlet.