Injury Profile of Hip-Hop Dancers

Home , Footwork (genre), House dance, Locking (dance), Popping

Olga Tjukov, MA, Tobias Engeroff, PhD, Lutz Vogt, PhD, Winfried Banzer, PhD, MD, and Daniel Niederer, PhD

Abstract dancers only involved the lower extremi- Hip-hop is characterized by moves This study assessed the injury incidence, ties. In house, the lower extremities were such as bouncing the body, bending mechanisms, and associated potential risk affected most frequently, followed by the the knees, jumping, turning, twisting, factors for hip-hop, popping, locking, trunk. A total of 65.3% of the dancers isolated extremity movements, and an house, and breaking dance styles. Data experienced time loss, with a duration of extreme involvement of the torso. The were collected from June to November 12.7 ± 21.3 weeks. Breakers experience significantly more injuries than dancers of characteristics of popping are short 2015. The retrospective cohort study and fast muscle contractions, which included 146 dancers (female: N = 67; the other styles. Injury risk among dancers of all the styles studied can be considered are performed with different body age = 20 ± 4.2 years; males: N = 79; age parts to the rhythms of the music. The = 22.9 ± 5.8 years) who completed a low compared to soccer players, swimmers, and long-distance runners. dancer looks robotic and can incorpo- questionnaire that collected data concern- 6 ing training hours, injuries, self-reported rate wave and illusion techniques. In the dance style locking, many basic injury causes, treatment, and recovery ompetitive dancing has been movements are executed with the time over the last 5 years. For the last 5 associated with a high risk arms and wrists, which are “locked” years, 52% (N = 76) of the dancers re- of injury.1 While injuries in ported 159 injuries and, in the year prior or paused to point. Furthermore, Cballet, breaking (breakdance), and to the survey, 31.5% (N = 46) reported a dancers go into the squat position, modern and contemporary dance total of 75 injuries. Overall, 0.61 injuries pull up their knees, perform artistic have already been investigated quite (5 years) and 1.156 injuries (1 year) per jumps into half splits, and drop with thoroughly,2 there are popular con- 1,000 hours exposure time occurred. For their knees on the ground (“knee temporary dance styles that are largely breaking, 1.286 injuries (5 years) and drops”). House has its focus on the 2.456 injuries (1 year) per 1,000 hours neglected in this context, such as feet, which are almost constantly mov- exposure time were calculated, while the hip-hop. The term “hip-hop” is used ing to a rhythm of 120 to 130 beats other dance styles accumulatively reached both to differentiate a specific dance per minute,6 while the arms are usu- 0.151 injuries (5 years) and 0.318 injuries style and as an umbrella term for a ally just taken along. Finally, breaking (1 year) per 1,000 hours of exposure time. subculture that includes such styles as consists of fast footwork and acrobatic Breakers reported most injuries at the popping, locking, house, and hip-hop upper extremities, followed by the lower movements. The dancers spend most itself. Thus, although all dance styles extremities, trunk, and head and neck re- of the dancing time on the ground that are investigated in this study be- gion. Most injuries in hip-hop occurred at in positions where the hands have long to the hip-hop subculture, they the lower extremities, mainly affecting the contact with the floor and carry part differ significantly in their movement knees, followed by groin and ankle. Inju- of the body’s weight. patterns and physical demands.3-5 ries experienced by popping and locking Currently there is only one study that reports overall injury incidence for a compilation of hip-hop dance Olga Tjukov, MA, Tobias Engeroff, PhD, Lutz Vogt, PhD, Winfried Banzer, PhD, 5 MD, and Daniel Niederer, PhD, Goethe University Frankfurt, Department of styles. Ojofeitimi et al. performed Sports Medicine, Frankfurt am Main, Germany. research on injuries in popping and locking and a category that the au- Correspondence: Olga Tjukov, MA, Department of Sports Medicine, Goethe- thors refer to as “new school” (includ- University Frankfurt, Ginnheimer Landstraße 39, 60487 Frankfurt am Main, ing house, street jazz, krumping, and Germany; [email protected]. Harlem shake). From the 312 dancers

Copyright © 2020 J. Michael Ryan Publishing, Inc. 66 https://doi.org/10.12678/1089-313X.24.2.66 Journal of Dance Medicine & Science • Volume 24, Number 2, 2020 67 included in that study, 232 reported good clinical practice in the conduct residence. The second part consisted a total of 738 injuries. The most and reporting of survey research.7 All of dance-related questions. The par- frequently reported injures for pop- participants gave written informed ticipants were asked what dance ping and locking affected the lower consent and all data were treated styles they practiced, for how long extremities (62%), upper extremities anonymously. they had been practicing each style, (25%), and trunk (8%). “New school- and how many hours per week they ers” were most frequently affected at Study Population were currently practicing each style. the lower extremities (69%), upper Participants (21.6 ± 5.2 years of age) Participants were also asked whether extremities (12%), and trunk (8%).5 in the survey were German residents, they participate in dance competitions The grouping of the dance styles, how- females (N = 67) and males (N = 79), and performances and, if so, how ever, does not allow for differentiating who practice at least one of the dance often per year, whether they worked injury locations and mechanisms for styles considered in this study for a as dance teachers, choreographers, or any one dance style in particular. minimum of 1 year and for at least both, and whether dance was their Therefore, despite the high-quality re- 1.5 hours per week. Potential subjects main source of income. Then there search design of this study, the subsets were identified at dance practices, were questions about their warm up lack detailed information such as 1. dance battles, and dance jam sessions habits, use of protective equipment, overall hip-hop injury rates, 2. simi- and came from 46 different cities in and participation in other types of larities and differences in movement Germany. All dancers who met the sport. The last question asked whether patterns, and 3. hip-hop as a unique inclusion criteria could participate in the dancer had experienced acute inju- dance style in its own right. the survey. ries or overuse damage from dancing. Accurately categorized informa- Those who answered affirmatively to tion concerning injury risk in the Data Collection this last question completed a third dance styles that constitute hip-hop Data were collected from June to part of the questionnaire. This third is of interest to dancers, coaches, and November 2015 by means of a ret- part asked for detailed information health care professionals. Based on rospective questionnaire with a recall regarding their dance-related injury or an increasingly profound knowledge period of 5 years. After a thorough multiple injuries: when did the injury of injury types and causes, effective literature review and in accordance occur (date); where did the injury prevention strategies for dance-related with the authors’ practical experience, take place (training, battle, jam, per- injuries may be developed. Moreover, an initial version of the questionnaire formance) and at what point in time insight into recovery times after inju- was generated. The pilot version of the during the dance activity (beginning, ries could be used to optimize current questionnaire was tested on 10 danc- middle, end); where was the injury rehabilitation programs. Therefore, ers involved in hip-hop dance styles. located, descriptive and indicated on this study systematically analyzes in- In accordance with the responses, all a diagram of a human body ventral, jury incidences, types, and causes, as unclear questions were rephrased. The dorsal, and lateral (left, right); did the well as injury recovery times, therapy revised questionnaire was then tested dancer seek medical help; what was regimens, and prevention for the on 10 different dancers and the fol- the diagnosis and therapy that the different hip-hop dance styles (hip- low-up procedure was repeated. The dancer received; in cases of overuse in- hop, popping, locking, house, and final questionnaire was distributed jury, how did the injury develop; and breaking), all as influenced by such to dancers who participated at dance what, in the dancer’s opinion, were potential contributors as age, sex, and practices, dance battles, and dance jam the causes of the injury. Subsequently, financial considerations. sessions in different cities in Germany. the dance style being practiced when Participants self-administered the the incident happened, the type of Materials and Methods questionnaire and handed it back to floor being used, and whether other Study Design and Ethical the investigator (OT). The investi- hobbies or activities could have led Standards gator was always close by to clarify to the overuse injury were assessed. This research project was designed as a potential questions and immediately The last questions concentrated on retrospective cohort study. A six-page checked each questionnaire after it consequences and time loss following questionnaire (available from the au- was returned for missing and unclear the injury. Injuries could be attributed thors on request) was used to survey data. In cases of missing information to a specific dance style in cases of dancers of the five different hip-hop or unclear descriptions, the researcher acute injury or when participants only styles about their dance habits and asked for the missing details to prevent practiced one dance style. injuries from dancing. The data col- incomplete data. Injury was defined according to the lection was done via self-report. The The questionnaire consisted of time-loss concept; the injury had to study was approved by the ethics three parts. The first part was com- restrict the dancer for at least 24 hours committee of Goethe University, posed of general and demographic beyond the report of the injury.8 Based case number 2018-76. The study questions, such as age, sex, height, on the definition of the International followed the recommendations for weight, ethnic origin, and place of Association for the Study of Pain, pain 68 Volume 24, Number 2, 2020 • Journal of Dance Medicine & Science was defined as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage….”9 Based on our injury research, we excluded pain caused by social and cognitive components. Chronic pain was defined as pain that “persists past normal healing time” and “persists or recurs for more than 3 to 6 months.”10 Statistical Analysis After descriptive displaying of demographic information, the obtained data were shown as sums, means, maximum, minimum, or percentage distributions. Injury occurrence was calculated per 1,000 hours of exposure (training and battles) for both 1- and 5-year incidence. All statistical analyses were based on the results of the initial data, checking for relevant underlying assumptions (data structure, normality distribution, variance homogeneity) and for parametric (or rather nonparametric) statistical testing. A multivariate logistic regression was performed with injury occurrence as the dependent variable and body mass index (interval scaling), sex (nominal, dichotomized), reported weekly dance hours (interval), and earning money from dancing Figure 1 Participants flow and characteristics, N = Number, SD = standard deviation. (ordinal, dichotomized) factors as the independent variables. The non- care systems), one because the dancer of the dance styles. For 18 of those 81 dichotomized nominal scaled variable’s did not train in any of the included dancers, it was their main profession, (dance style) impact on injury occur- dance styles, and one due to missing and their economic activities as danc- rence was evaluated using cross tables information. The compilation rate was ers were their main source of income. for comparing expected and observed 100% and the cumulative response numerical distributions (chi-square rate was 94%. Figure 1 displays the Injury Incidence comparisons for statistical analyses). All participants’ flow and characteristics. Overall, 31.5 % (46 dancers) reported statistical calculations were conducted The average years of dancing hip- 75 injuries for a 1-year incidence using IBM SPSS Statistics software hop was 5.8 ± 3.8, popping 5 ± 4.9, period. The mean exposure time per version 23 (IBM, Armonk, New York, locking 5.2 ± 4.7, house 4 ± 3.3, and injury was 863 hours (Table 1); thus, USA). An alpha-error level of 5% was breaking 6.3 ± 4.9. The majority of the total injury incidence was 1.156 considered to be a relevant cut-off value dancers practiced not just one but injuries per 1,000 hours of exposure. for significance testing. several of the surveyed dance styles; For the 5-year incidence, 52% (76 e.g., of the 112 participants dancing dancers) reported 159 injuries during Results hip-hop, 33 exclusively practiced this a mean exposure time of 1,794 hours, Participants’ Flow and dance style and the other 82 at least reaching a total injury incidence of Characteristics two different dance styles. Of 61 0.61 injuries per 1,000 hours of ex- Of the 156 questionnaires that were popping dancers, six solely danced posure (Table 1). distributed and returned, 146 were popping, and among 57 breakers, 23 included in the analyses. Eight ques- only practiced breaking. There were Injury Locations tionnaires could not be considered no dancers in the sample who exclu- The majority of injuries in the hip- because the participants were not sively danced locking or house. hop dance style occurred at the lower German residents (to avoid bias due to In total, 81 participants stated that extremities (82.6%), beginning with differences in other countries’ health they earned money from one or more the knees (52%), continuing with the Journal of Dance Medicine & Science • Volume 24, Number 2, 2020 69

Table 1 Total Number of Dancers, Injured Dancers, Injuries, and Injuries per 1,000 Hours Exposure Time Injuries Per Number of 1,000 Hours Dance Style Dancers Number of Injured Dancers Difference Testing Number of Injuries Exposure Time 1 Year 5 Years 1 Year 5 Years 1 Year 5 Years All 146 46 (31.5%) 76 (52%) 75 (100%) 159 (100%) 1.156 0.61 Hip-hop 112 7 (6.25%) 18 (16%) Chi square = 51.3 6 (8%) 23 (14.5%) 0.318 0.151 p < 0.001 Popping 61 6 (9.8%) 8 (13.1%) 6 (8%) 8 (5%) Locking 36 3 (8.3%) 3 (8.3%) 3 (4%) 3 (1.9%) House 57 5 (8.8%) 5 (8.8%) 5 (6.7%) 5 (3.1%) Breaking 64 21 (32.8%) 33 (51.6%) 45 (60%) 109 (68.6%) 2.456 1.286 Mixed* 6 7 10 (13.3%) 11 (6.9%) *Injuries that could not be related to only one dance style. groin (13%), ankle (9%), thigh (9%), Additionally, “fatigue,” “anatomical “knee pad slipped down” (locking), trunk (13%), and upper extremities factors,” “not sufficient warm up,” and “no protective gear” (breaking) (4.3%). Popping and locking dancers “bad floor surface,” “previous injury,” were also reported. In locking, two only reported injuries affecting the lower extremities (100%). In popping, the knee was affected in 85.7% and the thigh in 14.3% of the cases. In house, the lower extremities were most frequently affected by injuries (80%), followed by the trunk (20%). Breakers reported most injuries at the upper extremities (43%), followed by the lower extremities (36%), the trunk (12%), and the head and neck region (9%). Taking all dance styles together, the lower extremities were indicated most frequently (60%), the upper extremities second (23%), followed by the trunk (13%). The head and neck region was reported least frequently (9%). The total number of injuries per Figure 2 Injury location distribution for each dance style. location and dance style are displayed in Figure 2. Injury Mechanisms and Circumstances Among all dance styles, the majority of injuries occurred during training, followed by dance battles and jam sessions. The point in time of injury was most often in the middle (59.3%) and lower at the end (25.9%) or the beginning (14.8%) of a dancing activity (training, battle, jam, performance). In 84.5% of all cases, the injury was traumatic (acute). The two possible injury causes (all styles) that were most frequently as- sumed and reported by the dancers were “overuse” and “false technique.” Figure 3 Self-reported injury causes according to different dance styles. 70 Volume 24, Number 2, 2020 • Journal of Dance Medicine & Science

Figure 4 illustrates the use of reported therapy regimens by dance styles. Discussion Style Specificity The results show that there are differences in injury incidence among the dance styles, as breaking had the highest rate of reported injuries followed by hip-hop, popping, locking, and house, which is in accordance with Ojofeitimi et al.5 However, it needs to be taken into consideration that the number of locking and house dancers represented in this study was much smaller compared to the other Figure 4 Use of therapy regimens by dancers of the different dance styles. dance styles. Hip-hop showed a larger range of injured body parts, while out of three injuries occurred during 32.7%, 5 to 12 weeks by 18.4%, and house dancers had more diversity the dance style’s unique move, “knee a time loss of more than 12 weeks of injuries to the lower extremities. drop,” while in popping the most was reported by 11.8% of the injured In locking, two out of three injuries frequently reported injury causes were dancers. After being cleared to return occurred during the style-specific the dance specific moves “knee rolls” to dance, 53.7% of the dancers still move “knee drop,” while in popping and “shoot downs.” Figure 3 gives felt pain, 14.7% reported movement the most frequently reported injury a more detailed illustration of these restrictions, and 9.5% had chronic causes were the dance-specific moves results. pain. After full recovery from injury, “knee rolls” and “shoot downs.” These The respective impacts of potential training volume was reduced at least findings point out that although the predictors and risk factors on injury temporarily by 17.7% of the dancers injured region is the same (the knee occurrence are displayed in Table 2. and training intensity by 30.5%. A in this case), different style-specific The factors training hours per week, total of 36.8% of our cohort needed moves can cause the injury. economic income from dancing, sex, to reduce their training intensity and body mass index did not have an permanently. All other participants Injury Incidence impact on injury. Overall Nagelkerkes maintained or increased training vol- The injury incidents for hip-hop, R2 was .096 (p = 0.048). ume and intensity. popping, locking, and house were Recurrence preventive measures calculated jointly due to the low Time Loss, Therapy Regimen, and were taken by 43.2% after injury number of reported injuries in these Recurrence Prevention healing: 18.9% engaged in strength dance styles. Our finding of an injury Overall, 61.8% of the injured danc- training, 15.8% used knee pads or incidence of 0.318 injuries per 1,000 ers reported a time loss of 12.7 ± bandages, 3.2% used taping, and hours of training and competition for 21.3 weeks of dancing caused by 1.1% used insoles. The post-injury the dance styles hip-hop, popping, the reported injuries. A time loss of therapies received most frequently locking, and house, for the period 0.5 to 1 week was reported by 2.6% by all dancers were physical therapy, of 1 year, are much lower compared of the dancers, 1.5 to 4 weeks by medication, and strength training. to 2.456 injuries per 1,000 hours for breaking. For the period of 5 years, we found an injury incidence of 0.151 Table 2 Injury Predictors and Risk Factors injuries per 1,000 hours of training Quasi-OR 95% CI and competition for the four dance Quasi-OR styles compared to 1.286 injuries per P-value Exp(B) LL UL 1,000 hours for breaking. Overall, BMI (kg/m2) 0.170 .918 .813 1.037 the 1-year incidence is considerably Earning money with dancing 0.073 .508 .247 1.064 higher than the 5-year incidence. That can definitely be attributed to the Training duration (minutes/week) 0.227 1.029 .982 1.078 passage of time, during which many Sex 0.179 1.654 .795 3.445 dancers have no doubt forgotten some Quasi-OR Exp(B) = quasi odds ratio, calculated for binary logistic regression. Quasi- OR of the injuries. The 5-year incidence is 95% CI LL Exp(B), 95% CI UL Exp(B) = 95% confidence interval of Exp(B) with upper thus only minimally valid. The injury and lower limits. rates we found for the different dance Journal of Dance Medicine & Science • Volume 24, Number 2, 2020 71 styles are lower compared to those fitness.15,16 Consequently, these results ers engaged in more than one of the in soccer (5.12), basketball (1.68),11 support use of some of the frequently styles surveyed. swimming (2.64), and long-distance applied preventive approaches, such as running (2.79).12 strengthening of important muscles. Conclusion The lower extremities were af- Further strategies could incorporate To date, no longitudinal data are avail- fected by injuries most frequently dance-specific flexibility and endur- able that subdivide the hip-hop dance in hip-hop, popping, and locking. ance training. culture into specific dance styles. The Whereas these findings are in line with False technique was also frequently current study reveals differences in Ojofeitimi et al.,5 we cannot confirm reported as a cause of injury in all technique that lead to injuries among their hypothesis that the most injuries dance styles. This study identified the hip-hop, popping, locking, and house of breakers are located in the lower “knee drop” as an injury-producing styles. These findings can raise aware- extremities. In contrast, our results move for locking dancers. Preventive ness of potentially injurious moves indicate that injuries of the upper approaches could focus on proper and related preventive measures. Due extremities are most frequent in break- technique combined with protective to small sample size, low volume of in- ing. This assumption is supported by equipment. juries, and an overly long recall period, Cho et al.,13 who reported the upper The injured popping dancers of this we were unable to determine defini- extremities to be the most frequently study frequently reported “knee rolls,” tive injury rates for three of the styles injured region in a comparable co- “knee twists,” and “shoot downs” as studied. Future studies should record hort to ours. On the other hand, causes of injury. For “knee rolls,” it is training hours, performance hours, Kauther et al.14 reported the spine to advisable to be well warmed up before and injury incidence in hip-hop dance be the most frequently injured region performing this high intensity move- styles over 1 year, using a standard- in breaking. Since Cho et al. and ment on the knee joints. Similarly, in ized surveillance tool, to gather more Kauther et al. reported differences in the house dance style, two out of four detailed data on this subject. injury distribution between amateurs injuries affecting the lower extremities and professionals, the differences we occurred during jumps. This finding References found may be attributable to skill could be explained by the dominance 1. Wanke EM, Arendt M, Mill H, level. Furthermore, Kauther et al. of footwork and constant bouncing on Groneberg DA. Occupational ac- report sex-specific differences whereas the feet to a fast rhythm in these dance cidents in professional dance with Cho et al. only surveyed male dancers styles. A preventive approach should focus on gender differences. J Occup and Kauther et al. had 13.4% female again include technique training Med Toxicol. 2013 Dec 17;8(1):35. 2. Allen N, Ribbans WJ, Nevill AM, breakers. With 40.4%, this study had along with development of a strong Wyon M. 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