UDC: 793.3.071.2(669)
COBISS.SR-ID 258621708
Received:Dec 23, 2017/
Reviewed:Jan 17, 2018/
Accepted: Jan 25, 2018
Lower Limb Flexibility and Risk of Injury in Professional Dancers
A comparative study of Ballet, Hip-Hop and African traditional dances
Aiyegbusi Ayoola Ibifubara
Department of Physiotherapy, College of Medicine, University of Lagos
Odebiyi Daniel Olufemi
Department of Physiotherapy, College of Medicine, University of Lagos
Udegbeh Otito Stephen
Medical Rehabilitation Therapist Board of Nigeria
corresponding author:
[email protected]
Department of Physiotherapy, College of Medicine, University of Lagos
Odebiyi Daniel Olufemi
Department of Physiotherapy, College of Medicine, University of Lagos
Udegbeh Otito Stephen
Medical Rehabilitation Therapist Board of Nigeria
corresponding author:
[email protected]
Citation:
Aiyegbusi, Ibifubara A., Olufemi D. Odebiyi, and Stephen O. Udegbeh. 2018. "Lower Limb Flexibility and Risk of Injury in Professional Dancers: A comparative study of Ballet, Hip-Hop and African traditional dances." Accelerando Belgrade Journal of Music and Dance 3:10 |
Abstract
Background: Dancers are highly trained athletes who are at significant risk of injury due to the repetitive nature of their movement. It is hypothesized that injury patterns will be determined by the peculiar movement patterns and physical requirements of specific dance genres. This study was therefore undertaken to determine the association between the flexibility of the lower limb muscles and the pattern and risk of injury among professional dancers in three different dance genres. Methods: Eighty two professional dancers recruited from four (4) dance companies in Lagos State Nigeria presented as 28 indigenous African dancers, 26 ballet dancers and 28 hip hop dancers. A modified questionnaire on the epidemiology of dance injuries was administered to all participants and the degree of flexibility of the hip muscles measured by goniometry prior to warm up and stretching. Major Findings: There was a significant relationship between the flexibility of the hamstrings and injury occurrence in all the dance groups. The flexibility of the medial rotators, and the adductor group of muscles were significantly (p<0.05) related to injury occurrence respectively in the indigenous and ballet participants while a significant relationship (p<0.05) was seen between injury occurrence and flexibility of the adductors and medial rotators among hip-hop participants. Conclusion: The flexibility of the lower limb muscles is an intrinsic and a major factor contributing to injury among professional dancers. There is therefore a need to develop a stretching protocol for the different dance genres to prevent injury.
Keywords: body flexibility, injury occurrence, professional dancers, rotator muscles, hamstring muscles, gastrocnemius muscles. |
Introduction
Dance has been described as a rhythmic movement of the body usually to music and within a given space, for the purpose of expressing an idea or emotion (Mackrell 2015). It is performed in many cultures as a form of emotional expression, social interaction, or exercise in a spiritual or performance setting, and is sometimes used to express ideas or tell a story (William 1997). There are different types of dance genre which includes Ballet, Hip-hop, Jazz, various African traditional dances and a host of others. Professional dancers train many years, often from a young age, to attain one of the few positions available in professional dance companies and are subjected to fierce competition from other talented dancers as well as intense scrutiny from teachers, choreographers, and artistic directors, so they must possess innate talent, a high level of skill and physical ability (Craig et al. op. cit.).
Dancers are highly trained athletes who are at significant risk of injury due to intense competition and the repetitive nature of their movement patterns (Ibid.). Lower extremity and back injuries have been identified as being predominant while injury prevention includes identifying the risk factors for injury (Mackrell op. cit.). Though the lower extremities have been shown repeatedly to be the most commonly injured region of the body in dancers, the physical requirements of specific genres, however, may dictate injury location (Sides 2009, 43; Steinberg et al. 2012, 485). Injury or pain may impede dancers’ ability to attain or maintain their position or roles in a company and also at the extreme drastically shorten their career (Ramel 1999, 196). In one study comparing ballet to 61 other sports, it was deemed the second most demanding physical activity at par with bullfighting and second only to football (Nicholas 1975, 243). Professional dance companies have reported that as many as 67% to 95% of their dancers are injured annually and it has been estimated that approximately 90% of professional dancers will suffer at least one musculoskeletal injury during their career (Craig et al. op. cit.; Quirk 1983, 507) The type of injury sustained has been found to depend on the type of dance: for instance, ballet requires high levels of external rotation in the hip, therefore, poorly developed ‘turn-out’ is a leading cause of injury (Bird 2015, 21) and ballet dancers are more likely to suffer from ankle sprains due to the high demand on foot work, while African style dancers are more at risk of neck or back injuries due to the strong dynamics of movements executed with the spine (Naranjo 2016). Also, hip hop dancers have their knees at higher risk of injury because of the attacked flexion and screw-type extension performed with the legs often with unpredictable changes in speed and direction (Bird 2015, 21). Flexibility, which is the range of motion available in a joint is an important characteristic of physical and health related fitness since flexibility and stretching are recognized as the cornerstone of injury prevention, muscle recovery, and increased mobility for exercise enthusiasts (Brodowicz et al. 1996, 324; Alan 2013). Muscular tightness, the active resistance of a muscle to stretch is frequently postulated as an intrinsic risk factor for the development of a muscle injury (Reid et al. 1987, 347) as lack of flexibility may lead to early muscle fatigue or alter the normal biomechanics of movement predisposing to injury. Prior studies have shown the benefits of flexibility to include improved athletic performance, reduced injury risk, prevention or reduction of post exercise soreness and improved co-ordination (Hartig and Henderson 1999, 173). However, stretching for too long or too much can also give way to an injury (Witvrouw et al. 2001, 190) as there is the possibility that excessive stretching could decrease the stability of the joint which would also increase the possibility of injury (Alan 2013). Though some dance injuries are generally common, the type of dance determines its own risks (Ibid.) which is dependent on the different techniques that make up one’s personal training or choreographic engagements. These different techniques ultimately affect the flexibility of the lower limb muscles hence it is necessary to determine the relationship between lower limb flexibility and injury pattern among different dance genres in professional dancers. This will enable necessary proactive measures to be employed to minimize injuries in these groups of dancers. Presently, there is paucity of data comparing lower limb muscles flexibility and injury risk between Nigerian indigenous professional dancers and professional dancers in some other genres. Therefore, this study seeks to evaluate and compare lower limb flexibility and injury risk pattern among ballet, Hip hop and indigenous African professional dancers in Lagos State, Nigeria. Materials & Methods
Participants
Eighty two (82) participants who were all professional dancers between the ages of 18-35 years were selected by convenience from four dance companies in Lagos, Nigeria. Twenty eight participants performed one of the indigenous African dances (Bata, Odudu, Ekpekpe, Atilogwu, Egwu Odum, Jarawa, Maliki, Swange and Abang), while twenty six were professional ballet dancers, and twenty eight professional hip hop dancers. Student dancers were excluded from this study which affected the sample size because most of the dance companies had more students than professional dancers.
Research Procedure
A standard 360° goniometer (Baseline Company, U.S.A) was used to measure muscle group flexibility. Although there are different methods used to measure muscle flexibility, most studies utilize goniometry while a few used camera imaging. Arnheim and Prentice describe goniometry as the simplest and most widely used method for measuring muscle flexibility with an inter-rater relaibility of 0.830 and intra reliability of 0.896 (Hartig and Henderson op. cit., 173). An epidemiological investigation of dance injuries questionnaire which was developed in 2004 at Durban Institute of Technology was used to obtain data on demographics, dance history, present and previous dance injury history, and treatment of the injuries (Durban Institute of Technology, 2004).
Questionnaire Details
The questionnaire has 50 questions organized under sections 1-5. Section 1 (1-5) contains the demographic data, Section 2 (6-14) are questions on dance history and performance levels which are categorized into consistently (<10 hours a week), regularly (8-10 hours a week), irregularly (5-7 hours a week) and very irregularly (less than 2 hours a week) (Gleim and McHugh 1997, 289). Section 3 (15-37) has questions on history of previous dance injuries, Section 4 (39-45) are questions on history of present dance injuries, and Section 5 (46-50) are questions on treatment history.
Ethical Approval
Ethical approval was sought and obtained from the institutional Health Research and Ethics Committee. Letters of introduction and permission to recruit dancers were submitted to the management of the dance companies included in this study. An informed consent form was attached to each questionnaire to seek participant’s permission to participate in the study and to assure each participant that any information given would be confidential and would only be used for the purpose of the study. A total of 94 questionnaires were distributed but 82 were returned validly completed.
Evaluation of Flexibility
The degree of flexibility of the following muscles was evaluated: hip adductors, hip internal (medial) rotator muscles and external (lateral) rotator muscles, hamstring muscles and the gastrocnemius muscles. The range of motion was measured prior to warm up and stretching in order to maintain uniform procedure.
Hamstrings Muscles
Participants were positioned supine on exercise mats and their opposite lower limb was stabilized firmly on the mat to avoid pelvic tilt. The knee to be measured was maintained in extension. The goniometer was placed with the stationary arm parallel to the midline of the trunk, the moving arm along the lateral midline of the thigh, and the axis over the superior half of the greater trochanter. The lower limb to be measured was raised to the point in the range where a small amount of pelvic rocking movement was palpated by the researcher (Witvrouw et al. 2003, 41). The measurement was recorded at the point where the onset of posterior pelvic tilt was detected. The participants were instructed to relax the hamstring muscles during the procedure.
Adductor Muscles
The flexibility of the adductor muscles was measured with the participants lying supine on the exercise mat. The axis of the goniometer was aligned with the anterior superior iliac spine and the stationary arm was parallel to the midline line between the anterior superior iliac spines while the moving arm of the goniometer was aligned with the long axis of the femur. The lower limb was passively moved away from the midline until femoral rotation occurred, indicating the end of the adductor flexibility (Ibid).
Hip Medial and Lateral Rotators
Participants’ passive range of motion in internal and external rotation for hip was measured in sitting, with both knees flexed over the end of a plinth. The contralateral lower limb was abducted slightly to allow free movement of the tested limb, but it was not allowed to rest on the outside of the plinth. The axis of the goniometer was placed on the tibial tuberosity. The moving arm of the goniometer was aligned along the longitudinal axis of the tibia and the stationary arm was aligned vertically with the table leg. Passive hip internal and external rotation was measured at the point of the resistance (Heonsoo et al. 2015, 441).
Gastrocnemius Muscles
Participants were positioned prone on the plinth with their feet and ankles hanging over the edge of the plinth. The goniometer was placed with the stationary arm parallel to the lateral midline of the fibula, the moving arm along the lateral midline of fifth metatarsal bone, and the axis placed over the lateral malleoli. Passive ankle range of motion was performed by dorsiflexing the ankle to the end of the range, and then the measurements were recorded (Johanson et al. 2008, 172).
Data Analysis
Data collected was analyzed using SPSS 15.0 version. A descriptive statistics of mean, standard deviation and standard deviation were used to summarize the data. Chi-square was used to assess the association between type of dance and occurrence of injury and the association between gender and injury occurrence. Spearman’s rank correlation was used to determine the relationship among the body flexibility and injury occurrence among the selected dance professional dancers. The significant level of all the inferential statistic was p<0.05. Results
A total of 94 participants were recruited for this study, though 82 participated fully in the study (28 professional indigenous dancers, 26 professional ballet dancers, and 28 hip hop professional dancers). The gender distribution of the sample population was 45 (54.9%) for female professional dancers and 37 (45%) for male professional dancers. The mean years of experience as professional dancers was 3.29±1.16, with the least dancing experience to be 1.8 years and the highest dancing experience to be 7 years (Table 1). Majority of the participants were seen to perform very consistently, with 82.9% (n=68) performing very consistently, 9.8% (n=8) performing consistently, while 7.3% (n=6) performed irregularly.
Table 2 presents the frequency with which certain factors were reported to be the possible cause of injury with the participants being allowed to indicate more than one factor. Stretching (n= 41) was reported most often as the cause of injury, while other factors (e.g. tight underwear and foot wears) were reported the least precipitating factors for injury.
Table 3 shows responses of participants in the different dance groups to the frequency of injury and the chi-square analysis of the association between injury prevalence and type of dance.
Female participants recorded more injury than the male participants in the categories of 1 injury/month (66.7%), 1 injury/3months (64.3%) and 1 injury/6month (65.4%), while Chi-square analysis shows a significant association between gender and injury occurrence as presented in Table 4 below:
The relationship between the flexibility of the major muscles of the lower limbs and injury occurrence is expressed in Table 5:
Discussion
The purpose of this study was to compare the association between flexibility of the lower limbs muscles and injury risk and pattern among three different types of professional dances in Lagos, Nigeria. There were more female participants than male participants in this study in line with the trend in the literature and prior studies (Luke et al. 2002, 105; Ojofeitimi et al. 2010, 123; Jacobs 2010). One possible reason for this finding could be that female dancers often play the main role during dancing while the male dancers do more of back up dance (Hamilton and Hamilton 2002, 267).
Our findings show that injury occurrence among professional dancers was 89%, in line with the findings of some prior studies that reported a lifetime incidence of injuries among professional dancers to range from 50 -100% (Hamilton et al. 1989, Russell 1994, 12; Coplan 2002, 579). Injury occurrence among participants was highest (36.6%) at 1 injury/12months and lowest (3.7%) at 1 injury/1month. This outcome was same with the findings of Balding (2010) that showed 67.6% of participants suffered 1 injury/12months and 2.7% suffered 1injury/month. However, the higher percentage of the values as seen in Balding’s study (Ibid.) may be due to the fact that there were more student dancers as participants than professional dancers. The high prevalence of injury among our study population could also be explained by the fact that the dancers were between the ages of 21 to 34 years with a mean age of 24.94±2.73 years (Craig et al. 2016) which is in line with the findings of Hamilton (1986, 61) who reported that older dancers reported more injuries, major physical problems and required long recovery period than younger dancers. Findings from this study showed a significant association between type of dance and injury occurrence as it was found that ballet participants experienced the highest number of injuries. However, the indigenous participants had the least number of injuries though this is in contrast to the findings of Ojofeitimi et al. (2012, 347) who concluded that Hip hop dancers report injury rates that are higher than other dance forms but similar to gymnastics. The high prevalence of injury among ballet dancers may suggest that ballet choreography is more tasking than the other categories of dance which corroborates the fact that ballet and aerobic dances demand complex movement which requires the action of muscles in a kinetic chain movement that may result in tissue break down and injuries if the capacity of that chain is exceeded (Wainwright et al. 2005, 49). Another reason for the high prevalence of injury in dancers is that most dancers, especially ballet dancers, are so passionate about dancing that it is difficult for them to stop even by reason of injury. Though outside the scope of this study, another possible explanation is that Hip hop and ballet dancers exhibit increased flexibility and are required to perform at extremes of motion which is in line with prior studies that suggested that hypermobile dancers are at increased risk for injury (Bronner 2006, 21; Briggs et al. 2009, 1613). While ballet dancers rarely use the torso, African dancers and certain modern dancers have to be extraordinarily supple in the torso and pelvis in order to execute the ripples, twists, and percussive thrusts that their particular dances require (Mackrell 2015). Also, the ballet dancers’ age and the level and length of training may have played a role in the outcome among this group of participants (Zazulak et al. 2007, 1123). In addition, though beyond the scope of this study, poor core stability has been identified as a risk factor for lower extremity injury just as inadequate neuromuscular control in the trunk was specifically associated with increased athletic knee injuries in females in a prior study (Micheli 1983, 473; Reid 1988, 295). The significant association between gender and injury occurrence among all participants in this study may be due to the fact that females play different and more roles than males almost in all categories of dance which corroborates the findings of Hamilton and Hamilton (2002, 267) that the role of female dancers is completely different from that of the males, thereby explaining the injury pattern found between the genders. Females begin ballet training at an early age, often as young as 4 years of age and train for approximately 11years before turning professionals while in contrast, men start training later at close to 15years of age turning professionals after 7years of training (Hamilton et al. 1989; Micheli op. cit., 473; Reid op. cit., 295). This agrees with the report of Jacobs (op. cit.) who concluded that the number of years dancing and rank are associated with injury in professional ballet dancers. Our results showed a significant relationship between flexibility of the hamstring group of muscles and injury occurrence in all the dance types suggesting that in all these categories the hamstring muscles are more often stretched while dancing. This is not unexpected as prior studies have classified hamstring injury as the most common in sports and even more common in dance (Garret 1990, 436; Askling et al. 2002, 230). To maintain their balance, dancers need adequate flexibility in their lower extremity muscles (Bird 2015, 21; Gleim and McHugh op. cit., 289) as dancers stretch continuously in order to increase their height of leg and range of motion in order to become supple and overcome stiffness (Gelabert 1986, 181). However, if stretching techniques are incorrect, injuries may occur while stretching and resulting in damage and pain to the muscles involved. The findings from our study corroborates this fact because, as seen in table 2, more than half of the participants identified stretching as a precipitating factor for injury (Askling et al. 2000, 304). This underscores the need for dancers to employ proper stretching techniques to avoid injuries. More than half of the participants also cited insufficient warm up/cool down as a factor causing injury. A study by Amber (2013, 33) has extrapolated that preliminary exercise is important to prepare the body for more vigorous exercise and help reduce injury rates among dancers. Also for indigenous dancers, findings have shown a significant relationship between the flexibility of the medial rotators and occurrence of injury. This suggests that the medial rotator muscles may have suffered from injury due to muscle imbalance between the strong lateral rotators and the weak opposing medial rotators since this muscle group does not play a major role during dancing (Rist and Kemedy 1986). Observation has shown that in performing most of the indigenous dances, the lateral rotator muscle group plays more role than the opposing medial rotator group of muscles which is likely responsible for the increased risk of neck or back injuries seen in African style dancers (Naranjo 2016). It has been suggested by Volkmar (Volkmar 2013) that tight medial rotators predisposes a dancer to back and sacroiliac joint injury. For ballet participants, there was a significant relationship between injury occurrence and the flexibility of both the hamstrings and the adductor group of muscles suggesting that the hamstrings and adductor group of muscles are greatly stretched when performing the choreographies of ballet as seen in extreme turn-outs. For hip hop dancers, the prevalence of injury was significantly related to the flexibility of the hamstrings and both the adductor and medial rotator group of muscles. This may be due to difficult choreographying seen in hip hop dance which involves repetitive abduction and lateral rotation movements as reported earlier by Sohl and Bowling (1990, 317) that 12% of injuries reported by hip hop dancers are caused by difficult choreographies. In search of something completely new, choreographers can embark on routines that are very awkward and are incapable of being performed with any type of established technique. Also, dancers may either become injured from trying to develop a new technique in order to carry out the required routine or from sudden unaccustomed use of a particular area of the body (Quirk 1983, 507; Holloszy et al. 1995, 124). The significant relationship between the medial rotators and injury occurrence among hip hop participants may suggest that this set of muscle which is not highly needed while performing hip hop dance maybe suffering from muscle imbalance, this is in line with the findings of Rist and Kennedy (1986) who concluded that injuries may occur when a dancer has not corrected the alignment of the body and places strain on a weak set of muscles. Thus following muscle injury, atrophy of the fibres may occur from disuse resulting in muscle shortening (Holloszy et al. op. cit., 124). This study has thus been able to identify the flexibility of particular muscle groups as risk factors for injury in dancers of some selected genres in line with the suggestion of Wilson et al. (2015, 448) that identifying risk factors for injury is one of the preventive measures for injury in dancers. Relevance of Study to Dancers’ Health This study has been able to establish that flexibility of the lower limb muscles is a significant risk factor for injury. Also, the three dance genres involved in this study have peculiar flexibility risks associated with injury occurrence. To proactively minimize injury, dancers need to take part in regulated fitness training that is targeted at increasing the flexibility of the muscle groups involved in injury occurrence in the different genres. Conclusion
The findings from this study show that hamstring flexibility is crucial in preventing injury in all the three dance genres studied. The flexibility of the adductors is important in preventing injury in ballet and hip hop dancers while the medial rotators are important in hip hop and indigenous dancers. Thus, flexibility of the lower limb muscles is an intrinsic and one of the major factors contributing to injury among professional dancers.
Recommendation In view of the research evidence, it is recommended that dancers take part in general fitness training, not only as a helpful supplement to their technical training and performance, but as a means of decreasing their chances of injury (Wilson et al. 2015). Further studies are recommended with a larger sample size and also to develop an effective stretching protocol to prevent injury. References
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Belgrade Center for Music and Dance is the publisher of Accelerando: BJMD
Belgrade Center for Music and Dance is the publisher of Accelerando: BJMD