Roller derby players share more than sweat and grime as they jostle for rank in the rink.
A new study published in PeerJ in March 2013 shows that roller derby teams have distinct bacteria and may swap strains during gameplay.
"We could have picked out one player at random, and just by looking at the bacteria on her upper arm, we could have told you what team she played for," lead author James Meadow, a postdoctoral researcher at the Biology and the Built Environment Center at the University of Oregon, said to NPR.
However, once the players bumped elbows and brushed against each other, the bacteria swapped from player to player. It's not surprising considering that the sport involves a lot of shoving, and the players are allowed to make contact at the arms, chest, hips and thighs, according to the Women's Flat Track Derby Association.
"We could still tell which team she played for, but with a lot less accuracy," said Meadow.
The researchers looked at upper arm swabs from three roller derby teams from Washington D.C., the San Francisco Bay area and Eugene, Oregon. They sequenced the DNA to find bacteria that resided on the skins of players. Despite the fact that there was thousands of different bacteria, none jumped out as out-of-the-ordinary.
Meadow told NPR that the researchers didn't know why the teams had such diverse bacteria, but that it could because they were from different areas of the country which have their own climate, urban settings and wildlife. It could also be that the team shared a common environment, like locker rooms or a van.
But, after samples were taken from the same area after the game, it was discovered that the bacteria had moved from one player to another. It could be through direct contact, but sharing the same area or being in the same air could have also helped the swap, according to researchers.
They want to dig further to see how long these bacteria changes last. Finding out how long how bacteria can live on a different person can help scientists figure out what environmental changes make it easier or harder for a microbe to survive.
"One thing that we weren't able to do is to find out just how long these sorts of changes last. If you and I were to shake hands, some things would come off of my hands and onto yours, and some things would come off of your hands onto mine. But we don't know how long those things stick around and we don't know whether they have an impact on our health," Meadow explained to the Los Angeles Times.
Author Jessica Green, director of the Biology and the Built Environment Center at the University of Oregon and a roller derby player, added to Times that the researchers want to know more about the "human microbial cloud." This is the idea that if a person came into a room, others who enter that same area will pick up all those bacteria regardless if they make physical contact.
"That has a link to the roller derby study: Although we think that most of the microbes that were exchanged were due to skin-to-skin contact, some of what we saw could have been because the women were landing on the floor," she said.
The information not only may help fight off illness, but it may help people stay healthier. Some microbes actually provide beneficial factors that help fight off infections.
"In any case, I like to think of the similarity I share with my teammates in terms of skin microbial communities to be like an all-day bacterial hug," Kelly Grene wrote in Scientific American. She was one of the subjects swabbed for the study. "Even when I'm not with them, they're with me. As a jammer (scoring player), I couldn't ask for better protection from my pack."
To learn more about the study and see the players in action, check out the video below produced by the study authors.