Humiliation in gym class left many adults with a life-long aversion to physical activity. (CBC)Humiliation in physical education class as a child can turn people off fitness for good, according to a University of Alberta researcher.

Decades later, some people are still scarred from sitting on the bench, stumbling through drills or trying to keep up with other kids around the track, according to a study by Billy Strean, a professor with the university's faculty of physical education and recreation.

"If you have that sense of humiliation — of being incompetent — then it can really cause you to stay away from that activity," Strean told CBC News.

Until kids reach their teens, Strean said, there should little attention paid to winners, losers and statistics.

"We're better off keeping things a lot less structured — a lot more fun, equal playing time and letting them take the lead a little bit," he said.

"Kids will change the teams if one team is winning by too much — so that it's more fun for everybody — whereas adults, once we've got them structured in a league, we'd never think of doing such a thing."

During his research, Strean said, he heard from people who are still suffering, years after bad experiences with coaches and instructors.

"I am a 51-year-old-woman whose childhood experiences with sports, particularly as handled in school, were so negative that even as I write this my hands are sweating and I feel on the verge of tears," one of the participants in the study wrote. "I have never experienced the humiliation nor felt the antipathy toward any other aspect of life as I do toward sports."

Strean said his study found that participants had better experiences from minimally organized games such as street hockey, compared with more-organized activities. That means adults should allow children to explore sporting activities on their own, with minimal rules and no scorekeeping.

Strean's research was recently published in Qualitative Research in Sport and Exercise.