Teenage boys who played football, basketball or both were about twice as likely as other boys to have recently abused their girlfriends in a new study from California.
Researchers say the "hypermasculine" attitudes encouraged in some sports may foster aggression off the field, but the locker room can also be a place to teach boys about healthy relationships and avoiding violence.
"We need to create a safe place for our youth to discuss healthy masculinity, healthy relationships and the idea that violence never equals strength," said Heather McCauley, a researcher at University of Pittsburgh School of Medicine and the Children's Hospital of Pittsburgh of UPMC, who led the study.
In the U.S., women experience 2 million injuries from intimate partner violence each year, and nearly one quarter of women experience violence by a current or former spouse or boyfriend at some point in their lives, according to the Centers for Disease Control and Prevention.
Recent research suggests that one in three youth experience physical, psychological or sexual violence in romantic relationships, McCauley and her coauthors note in the Journal of Adolescent Health.
Violent sports and dating abuse have been linked among college athletes, but McCauley's team wanted to know if the association could be seen in even younger athletes.
They analyzed data from 16 Northern California high schools that had participated in surveys for another study.
A total of 1,648 male high school athletes who indicated they had been in at least one relationship with a girl for more than one week were included in the analysis.
The boys, who were in ninth, tenth, eleventh and twelfth grades, were asked about their attitudes toward gender and what's expected from males and females in relationships.
They were also asked if they had physically, verbally or sexually abused their dating partners during the previous three months.
The boys were asked about their participation in high school sports, including basketball, football, soccer, volleyball, wrestling, baseball, tennis, golf, swimming, cross-country or track and field.
The researchers found that 276 boys reported being involved in some type of relationship abuse.
When the researchers compared the survey answers about gender attitudes and rates of relationship abuse among athletes in different sports, they found "boys who had hypermasculine attitudes were three times more likely to have recently abused their female dating partners," McCauley said. "That's in the entire sample and it's a pretty strong association."
Moreover, football and basketball players tended to have more hyper-masculine attitudes about gender and relationships than wrestlers, swimmers and tennis players, who held more equitable attitudes about males and females.
Overall, boys who played both football and basketball were twice as likely to have abused their dating partners as the other boys, while boys who only played football were about 50 percent more likely to have abused their partners.
"It was really fascinating - boys who play football and basketball were more likely to hold hypermasculine attitudes compared to their peers playing in other sports," McCauley said.
"But interestingly, even after accounting for these attitudes, boys who played football or both football and basketball were more likely to have recently abused their dating partners," McCauley said.
"So this indicates that there's something in the environment of these youths even beyond these gender attitudes that is sending the message that it's acceptable to use aggression and violence off the field and in their dating relationships," she said.
In past research, McCauley has also studied the Coaching Boys into Men program, created by the organization Futures Without Violence to engage men and boys in the prevention of violence against women and girls.
"We found that one year later, boys who were exposed to the Coaching Boys into Men program reported less abuse perpetration against their dating partners, so it certainly is an exciting program for sure," she said.
Coaches present the program to student-athletes throughout the season, McCauley said. Lessons include how to step in and say something when students see peers doing something they shouldn't be doing, and promoting nonviolence and discussing healthy masculinity.
Michael Merten told Reuters Health that he isn't surprised McCauley and her colleagues found that football players perpetrated more violence. "You're telling these football players to hit someone or knock him out - is that spilling over into relationships?" he asked rhetorically.
Merten, from the Youth and Family Health Research lab at Oklahoma State University in Tulsa, was not involved in the new study. But he has previously examined the role of sports participation and competitive attitudes on acceptance of dating violence in teens.
He said there's a "spillover theory" that says "what you do in your everyday life tends to spillover" into relationships.
"So it's kind of like mixed messages - and this is what is happening early with youth sports - (kids are told) to do one thing in the sport, yet when you're in the context of relationships, that behavior's not acceptable," Merten said.
Still, it's up to coaches to teach the kids that while it's okay to be aggressive in the sport, they still have to do the right things away from the game, he said.
Athletes who have a win-at-all-costs attitude, or a 'high win orientation' might be more prone to violence, Merten added.
"I think we are dealing with some of these athletes - it's probably that attitude that leads to more violence," he said
"But the thing I found in my work in this area was that just because someone participates in sports doesn't make them more likely to perpetrate violence or have worse attitudes - you have to look more specifically at each individual."