Two-thirds of parents say they have witnessed bullying and intimidation on the school sports field, a survey suggests.
A poll of 1,250 eight to 16-year-old pupils and 1,010 parents for cricket charity Chance to Shine suggests some pupils are put off sport as a result.
More than half of the pupils surveyed say they have been subjected to teasing, taunts and physical threats.
Nearly 55% say they have witnessed physical violence.
The research suggests such "psychological warfare" is sapping children's love of sport.
Some 42% of parents say their child has lost confidence after being bullied on the playing field.
A fifth say their child is reluctant to take part in sport as a result, and one in 10 says their child has given up at least one sport entirely.
Previous surveys for the charity have suggested many pupils are bad sports, willing to elbow, headbutt and argue their way to victory. They have also suggested some youngsters are unable to lose or win gracefully.
The Chance to Shine cricket education charity works with 4,000 UK state schools to encourage fair play and good sportsmanship through cricket.
Its chief executive Wasim Khan said: "It is worrying to hear that this kind of psychological warfare is being waged on our school playing fields.
"We are teaching children from a young age to play competitively, but to respect the opposition as well as their team-mates. We need to stamp out this bullying in school sport."
And John Stephenson, head of cricket at Marylebone Cricket Club, which jointly commissioned the survey, said: "The results from the survey highlight an alarming trend in school sport, which needs to be proactively addressed."
He added that pupils needed to learn how to play hard but fair.