Epidemiology of Women’s Flat Track Roller Derby Injuries in Kansas City

Abstract

This cross-sectional descriptive retrospective epidemiological pilot study determined the frequency, circumstances, type, and outcome of injuries in the members of a Kansas City women’s flat track roller derby league. Injuries were reported by 79% of the respondents, with 50% having sustained multiple injuries. Medical attention was required by 64%. The risk of injury in the sport is high. Further study is needed to identify specific factors that can be modified to decrease the injury rate.

Introduction

Women’s flat track roller derby is an established and growing sport in the United States. Once known for its gratuitous showmanship, the sport has evolved into a popular form of recreation and entertainment. The Kansas City Roller Warriors (KCRW), formed in 2004, is a member of the Women’s Flat Track Derby Association (WFTDA). The WFTDA now governs over 301 member leagues and 99 apprentice leagues in the U.S., Canada, United Kingdom, Australia, and a growing number of countries in Europe, Asia and South America. In the U.S., over 50,000 women currently participate in WFTDA teams. The KCRW currently consist of four home teams and two traveling teams and encompasses over eighty active skaters. About 250 women have participated over the course of its ten year existence.¹

Despite the growth and popularity of the sport, the epidemiology of injury is not well-defined. The purpose of this epidemiologic pilot study was to determine the frequency, circumstances, type, and outcome of injury in the members of a women’s flat track roller derby league.

Materials and Methods

This cross-sectional study was conducted on members of the Kansas City Roller Warriors. An invitation to participate in a REDCap survey was administered via e-mail to the past and present members of the KCRW league as of December 31, 2014. A total of 208 invitations were sent out with a response rate of 80 (38%). Participants ranged from ages 24 to 49, with a mean of 35 years.

Demographic information was obtained. The primary measures of the study were the total incidence and frequency of injury to the neck, trunk/spine, upper extremity, lower extremity, the need for medical care, and the severity of injury as measured by discontinuation of participation. Secondary measures of the study included the relationship of injury to age, pre-existing medical conditions, medication use, skating experience, derby position, and supplemental equipment use. Participants took part in the survey on a voluntary basis. This protocol was reviewed and approved by the institutional review board. Statistical analysis was performed using unpaired t-tests and chi-square analysis. Significance level was set at α < .05.

Results

The demographic information is listed in Table 1. As seen in Table 2, injuries more serious than contusions were reported by 79% of the respondents, with 50% having sustained multiple injuries. For those that were injured, time lost in playing the sport due to injury was less than 2 weeks for 20% and greater than 4 weeks for 40%. Injury forced 19% to permanently stop participating in the sport. Specific sites of injury are listed in Table 3.

Table 1.

Demographic Data

	Mean	Range
Age	35	24–49
seasons with KCRW	3.7	1–9
age start roller derby	29	18–45
	Number	%
active 2014	34	42.5
retired due to injury	15	19
previous skating experience (years)	30	37.5
figure skating	8	10
non-WFTDA team	8	10
WFTDA team	8	10
known medical problems while participating	13	16
lower extremity injury	5	6
trunk/back injury	3	4
asthma	3	4
other	7	9
smoke	9	11
ever on all star team	39	49

Table 2.

Injury

	Number	%
injury	63	79
required medical care	51	64
required surgery	14	18
stop skating due to injury
no	5	6
1–2 weeks	8	10
2–4 weeks	12	15
1–2 months	14	17
> 4 months	12	15
cause
pile-up	5	6
skater-skater	28	35
skater-object	5	6
equipment malfunction	3	4
missing equipment	1	1.25
other	21	26
> 1 injury	39	49
derby related infection	5	6
require antibiotics	3	4
methicillin resistant staph	1	1.25

Table 3.

Specific Injuries Reported

	Number	%
head - concussion	3	5
body/trunk	9	15
rib fracture	1	2
strain	1	2
clavicle	1	2
other	6	10
upper extremity	12	21
shoulder	1	2
fracture humerus	2	3
fracture finger	3	5
dislocation finger	1	2
other	5	8
lower extremity	35	59
knee	14	24
fracture tibia/fibula	3	5
fracture ankle	5	8
other	13	22

Skaters with previous skating experience were more likely to be injured (P=.002). There were no statistically significant differences in injury rate based on smoking status, age, position, wearing additional padding, being an all-star, age starting, or current medical problems. Active skaters had an injury rate of 20%, while 22% of the retired skaters reported an injury.

Discussion

This epidemiologic pilot study of injury on women’s flat track roller derby discovered high rates of injury, multiple injuries, and the need for medical care and surgery. A typical year-long season involves approximately 65 practices and 5 bouts per year for the home teams, and 150 practices and 20 bouts for the travels team. Detailed description of the rules, regulations and bouts is available from the WFTDA website.¹ Information on more than two injuries was not collected in order to limit the time required to complete the survey. Assuming the skaters participated in all the practices and games, a conservative estimate is 2 – 5 injuries per 1000 athlete exposures.

In this study, the lower extremity was the body region with the most injuries. This was different from other skating sports. Current literature describes roller-skating injuries as primarily occurring in the upper extremity. ^{2, 5, 7–9} Studies on ice-skating also show a predominance of upper extremity injuries, and a higher incidence of head injuries.⁷ Skateboarding and Heelys (roller-shoes) mostly describe wrist and forearm injuries.^{6, 10, 13} These studies reported on predominantly pediatric patient groups, with the skating injuries are often due to falls on outstretched hands. While upper extremity injuries still occured, our data suggests that roller derby predisposes participants to more lower extremity injuries. This may be due to the rules governing contact between skaters.¹ Lower extremity injuries were also more common in men’s professional roller hockey.¹²

The derby population is required to wear certain safety equipment, including wrist guards, mouth guard, elbow pads, knee pads, and a helmet. While the literature on roller skating shows that wearing of wrist guards reduces the incidence of wrist fractures, forearm fractures are still common.² In women’s roller derby, all pads are required to be worn at all times during practice and gameplay. The use of wrist guards and elbow pads may help to reduce upper extremity injuries. In our study, wearing extra, non-required padding was not protective against the more severe injuries, but they may have reduced the incidence of contusion.

The training and experience of skaters in WFTDA leagues may account for differences in injury pattern compared to other skating groups. Skaters must pass a yearly minimum skills test before contact skating is allowed. This test assesses the ability to stop, block, hit, and fall safely while skating in close proximity in a pack. Injury does not seem to be a deterrent to skating, with the same number of active and retired skaters reporting at least one injury from skating.

In comparison to other women’s sports, flat track roller derby has frequent injuries.⁴ For example, women’s collegiate lacrosse injury rates range from 3–7 injuries per 1000 athlete exposures.³ Women’s rugby studies show a rate of 3 per 1000 exposures.¹¹

It is unclear why skaters with more experience were prone to more injuries. Experienced skaters may skate faster, attempt more complex maneuvers, skate more often, or be more competitive.

A limitation of this study is the low response rate. The low rate may have skewed the data toward skaters that had been injured. Given a best case scenario, which assumes that all of the skaters that did not respond to the survey had never sustained an injury, the overall injury rate would still be greater than 30%. Other limitations include potential recall bias due to the retrospective nature of the survey that covered many years of participation. The studied population may not reflect the injury rate in other communities due to differences in practice attendance, bout frequency and competitive level. Exposures per year were not directly measured but estimated based on a typical schedule. We also did not measure whether injuries occurred during practice or bouts, nor did we collect the total number of injuries. The actual number of injuries per exposure may be higher. Studies on leagues in other cities need to be performed to confirm our findings. A follow-up study is also needed to define the exact injuries, especially the high number of injuries that required surgery.

The photo above depicts the typical type of contact and falls that occur in women’s flat track roller derby. Photo by Phil Peterson www.phil-peterson.com

The risk of serious injury in the sport of women’s flat track roller derby is significant. The results of this pilot study suggest that additional studies need to be performed to more specifically identify the injury rate per encounter along with rules, training, or equipment that can be changed to help reduce the injury rate.

Biography

Sadie M. Markey, MD, is in the Department of Orthopaedic Surgery, University of Missouri – Kansas City, Mo. A PGY-2 from UMKC School of Medicine, Dr. Markey skated for the Kansas City Roller Warriors Women’s Flat Track Roller Derby league and volunteered as ringside physician/aide at local MMA fights. Richard L. Hutchison, MD, MSMA member since 2016, is an Assistant Professor of Pediatric Orthopaedic Surgery, in the Section of Hand Surgery, Children’s Mercy Hospitals and Clinics, Kansas City, Mo.

Contact: rlhutchison@cmh.edu