My team does a lot together. We work out. We practice and scrimmage. We swap recipes and cook food together. We watch footage and we hold meetings. We try to listen and then talk all over each other. We squabble. We love.

Roller derby is the most brutal, yet most fun, sport I have ever played. The degree of contact between skaters is high, as we hold on to our teammates' hips, shoulders, arms, sometimes whatever we can grab to provide stability, form a wall, or sometimes throw one of our players at an opponent. We need to trust and respect each other, to listen and communicate. Despite its violence, derby is my safe space: there are no anonymous peer reviews, no opaque promotion and tenure policies. My experience has been that the greater your effort, the greater your results, and compared to the stressful experience of academia where the uncontrollable factors are what can ruin your research trajectory, this is an exhilarating feeling. I love my team and I know they love me, warts and all.

I don’t know everything going on in my teammates’ lives outside of derby, but because of the camaraderie formed by doing something dangerous, competitive, and gloriously fun together, we are very close. We know our menstrual cycles aren’t synchronizing, despite occasional coincidences in timing. But perhaps there are other ways we are physiologically in sync.

Protect your jammer!

To my mind, the most important job a blocker can do is hold back the opposing jammer as long as possible to help their jammer get lead and make a scoring pass. Related goals include playing offense to help your jammer through, and protecting her from the worst hits. As someone who jams pretty often, I am most at ease when I know my blockers are keeping the other jammer from making it through the pack, because it frees me up from worrying about where she is, so I can do what I need to do to score.

A roller derby pack is not unlike a microbial community. Diversity of strategies and skills are key – some of our blockers are better at containment, some at big hits, others at offense, even if pack coordination is the primary goal. And a diverse microbiome tends to be correlated with better health outcomes, provided the main bacterial types are the “good” kind (think Lactobacillus, found in cultured food like yogurt, but also our guts and our vaginas). This diversity is what makes it possible for the “good” bacteria to outcompete the “bad.”

In a paper out today at the new open access journal PeerJ, Meadow et al (2013) explore the ways in which the contact sport of roller derby provides a great test scenario for understanding variation in and transmission of skin microbes. One of the authors is a former skater, and their materials and methods indicate they understand the sport well. My favorite quote:

"Flat track roller derby is a contact sport; blockers are allowed to initiate contact with another player tocompete for track position using any of the following body parts: upper arm (shoulder to elbow), torso, hips, “booty” (official WFTDA nomenclature), and mid to upper thigh" (Meadow et al 2013: 3, emphasis mine).

The authors used a tournament happening at Eugene, Oregon with the Emerald City Roller Girls (the host, from Eugene), DC Roller Girls (Washington, DC) and Silicon Valley Roller Girls (San Jose, CA). They were able to test a few conditions: the teams’ microbial communities before playing, after playing one bout, and after playing two bouts, to see change over time and over contact with different team microbial communities. They sampled from the upper arm, because it’s probably the body part with the most universal exposure across players.

Meadow et al (2013) hypothesized that individual skin microbial communities would be similar within teams, but after bouts opposing teams would also bear some similarities, given the substantial skin contact involved in the sport.

Bacteria that skates together, stays together

The authors found that team membership predicted individuals’ skin microbial communities. They also found a significant difference in the composition of each team’s microbial communities, but also that their microbial communities of each individual within a team became more similar, after bouts.

Differences between individuals did not seem to be predicted by the amount of time each skater played in a bout. The way they measured time played was to assign each skater 2 minutes of playing time for every jam they were in. 2 minutes is the maximum amount of time a jam can take, and is by no means the average, so skating time, which can be anywhere from 10 seconds to 2 minutes per jam, was not well represented. Further, they didn’t differentiate between jammer and blocker positions in each jam, which carry very different kinds of contact risk. This was perhaps the only methodological wrinkle for me, and the authors are careful to note it themselves as well. And unless the authors planned to take copious observational data and ask for post-bout stats, it would have been hard for them to do better than what they did. What this means though, is that their lack of a correlation is just as likely a false negative as it is accurate.

Finally, the Meadow et al (2013) found that Emerald City skaters’ microbial communities were similar to the track where the tournament was held, which also happens to be their practice track. The authors then point out (I may have LOLed):

“it is perhaps unsurprising that EC players share some of their microbiome with the track surface since they shed skin cells and frequently come into direct contact with the floor” (Meadow et al 2013: 12-13).

Bacterial hugs, on and off the track

There are a lot of reasons each of these roller derby teams have microbial community similarities. They are from the same geographic region, they probably practice and live in the same area, some skaters may even live together. There is a high amount of skin contact when they practice, scrimmage and bout together. And, as the authors also point out, exercise produces changes in microbial communities, and these are all pretty highly ranked teams, with elite athletes (Emerald City is ranked 58th, DC Rollers are 48th, and Silicon Valley is 74th out of 161 teams as of this writing… <cough cough> my own Twin City Derby Girls are 72nd).

The authors suggest direct contact is the most effective means of bacterial transmission, given the present evidence, which means the skin contact of roller derby is the best predictor for team and post-bout similarities. It would be interesting to test their hypotheses among other sports, or at different times of the year, and to compare hand microbial communities to upper arm communities. Or what about shifts along the menstrual cycle or with or without hormonal contraceptive use? I would also wonder about non-skating teammates and coaches: coaches get quite a lot of sweaty contact from their team, but not with their opponents. How much of a shift might happen to their microbial communities between bouts?

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. Even when I’m not with them, they’re with me. As a jammer, I couldn’t ask for better protection from my pack.

Bonus footage!

Check out this video that lead author James Meadow shared with me from the tournament where they sampled skaters (a little hokey, but then, I did just talk about being hugged by my team via bacteria).


Meadow et al. (2013), Significant changes in the skin microbiome mediated by the sport of roller derby. PeerJ 1:e53; DOI 10.7717/peerj.53