This article was downloaded by: [Ariel University Center of Samaria]On: 14 April 2013, At: 05:41Publisher: RoutledgeInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,37-41 Mortimer Street, London W1T 3JH, UK

Journal of Sports SciencesPublication details, including instructions for authors and subscription information:http://www.tandfonline.com/loi/rjsp20

Extrinsic and intrinsic risk factors associated withinjuries in young dancers aged 8–16 yearsNili Steinberg a e , Itzhak Siev-ner b , Smadar Peleg a , Gali Dar c , Youssef Masharawi d ,Aviva Zeev e & Israel Hershkovitz aa Anatomy and Anthropology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israelb Department of Orthopedic Rehabilitation, Sheba Medical Center, Tel Hashomer, Israelc Department of Physical Therapy, Haifa University, Haifa, Israeld Department of Physiotherapy, School of Health Professions, Tel-Aviv University, Te-Aviv,Israele Zinman College of Physical Education and Sports Sciences, Wingate Institute, Netanya,IsraelVersion of record first published: 30 Jan 2012.

To cite this article: Nili Steinberg , Itzhak Siev-ner , Smadar Peleg , Gali Dar , Youssef Masharawi , Aviva Zeev & IsraelHershkovitz (2012): Extrinsic and intrinsic risk factors associated with injuries in young dancers aged 8–16 years, Journal ofSports Sciences, 30:5, 485-495

To link to this article: http://dx.doi.org/10.1080/02640414.2011.647705

PLEASE SCROLL DOWN FOR ARTICLE

Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions

This article may be used for research, teaching, and private study purposes. Any substantial or systematicreproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form toanyone is expressly forbidden.

The publisher does not give any warranty express or implied or make any representation that the contentswill be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses shouldbe independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims,proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly inconnection with or arising out of the use of this material.

Extrinsic and intrinsic risk factors associated with injuries in youngdancers aged 8–16 years

NILI STEINBERG1,5, ITZHAK SIEV-NER2, SMADAR PELEG1, GALI DAR3,

YOUSSEF MASHARAWI4, AVIVA ZEEV5, & ISRAEL HERSHKOVITZ1

1Anatomy and Anthropology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel, 2Department of Orthopedic

Rehabilitation, Sheba Medical Center, Tel Hashomer, Israel, 3Department of Physical Therapy, Haifa University, Haifa,

Israel, 4Department of Physiotherapy, School of Health Professions, Tel-Aviv University, Te-Aviv, Israel and 5Zinman College

of Physical Education and Sports Sciences, Wingate Institute, Netanya, Israel

(Accepted 5 December 2011)

AbstractIn the present study, we tried to determine the association between joint ranges of motion, anatomical anomalies, bodystructure, dance discipline, and injuries in young female recreational dancers. A group of 1336 non-professional femaledancers (age 8–16 years), were screened. The risk factors considered for injuries were: range of motion, body structure,anatomical anomalies, dance technique, and dance discipline. Sixty-one different types of injuries and symptoms wereidentified and later classified into four major categories: knee injuries, foot or ankle tendinopathy, back injuries, and non-categorized injuries. We found that 569 (42.6%) out of the 1336 screened dancers, were injured.The following factors werefound to be associated with injuries (P5 0.05): (a) range of motion (e.g. dancers with hyper hip abduction are more prone tofoot or ankle tendinopathies than dancers with hypo range of motion; (b) anatomical anomalies (scoliotic dancers manifesteda higher rate of injuries than non-scoliotic dancers); (c) dance technique (dancers with incorrect technique of rolling-in werefound to have more injuries than dancers with correct technique); (d) dance discipline (an association between time ofpractice en pointe and injury was observed); and (e) early age of onset of menarche decreased risk for an injury. Noassociation between body structure and injury was found. Injuries among recreational dancers should not be overlooked, andtherefore precautionary steps should be taken to reduce the risk of injury, such as screening for joint range of motion andanatomical anomalies. Certain dance positions (e.g. en pointe) should be practised only when the dancer has alreadyacquired certain physical skills, and these practices should be time controlled.

Keywords: Dance, joint range of motion, anatomical anomalies, dance technique, injuries

Introduction

Dancing is one of the most popular physical activities

among young women, and as with other physical

activities, it involves risk of injury (Motta-Valencia,

2006). It has been found that as many as 60–90% of

dancers are injured during their career (Schoene,

2007). The rigours of dance training and the pursuit

of excellence and self-accomplishment entail poten-

tial risk for physical injury in young dancers (Askling,

Lund, Saartok, & Thorstensson, 2002; Motta-

Valencia, 2006). Injuries in non-professional dancers

may result, for example, from: inadequate experience

in proper balance and landing technique (Orishimo,

Kremenic, Pappas, Hagins, & Liederbach, 2009);

dancing positions that may result in extreme stress

on joints (e.g. the five classical positions of en pointe

that require excessive ‘‘turnout’’ of the lower limbs);

levels of selected physical fitness parameters (Kou-

tedakis, Khaloula, Pacy, Murphy, & Dunbar,

1997b); and repetitive movements in improper

positions that may impose high loads and strains on

muscles and ligaments (Shan, 2005).

Although most young women who are involved in

dancing are recreational dancers of a young age (8–

16 years), we know very little about risk factors

related to injury prevalence in this age group (Nunes,

Haddad, Bartlett, & Obright, 2002). Our knowledge

of risk factors pertains primarily to professional adult

dancers, and therefore may not be applicable to

young recreational dancers. This limited information

on major risk factors in young dancers may expose

them to injury, affect their health in the long run, and

negatively impact their future careers as dancers

(Hamilton, Hamilton, Marshall, & Molnar, 1992).

Correspondence: N. Steinberg, Anatomy and Anthropology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel.

E-mail: knopp@wincol.ac.il

Journal of Sports Sciences, March 2012; 30(5): 485–495

ISSN 0264-0414 print/ISSN 1466-447X online � 2012 Taylor & Francis

http://dx.doi.org/10.1080/02640414.2011.647705

Dow

nloa

ded

by [

Ari

el U

nive

rsity

Cen

ter

of S

amar

ia]

at 0

5:41

14

Apr

il 20

13

Past studies have made a distinction between

intrinsic (person-related) and extrinsic (environ-

ment-related) risk factors (Gleim & McHugh,

1997). Based on previous studies that have shown

that most injuries are sustained to the lower

extremities and back (Schoene, 2007; Shan, 2005),

intrinsic factors to be evaluated should include joint

range of motion of the hip, knee, and ankle, as well as

body structure, anatomical anomalies, and age. It has

already been documented that young recreational

dancers differ on many of these variables from the

non-dancer population (Steinberg et al., 2006). The

extrinsic factors to consider include dance discipline

(e.g. hours of dancing per week) and dance

technique (e.g. rolling in), which according to some

may also play a role in injury (Coplan, 2002; Negus,

Hopper, & Briffa, 2005).

The extremely high rate of injury among recrea-

tional dancers (Negus et al., 2005) attests to the strong

need for preventive action. Such prevention is possible

only if major risk factors are identified and studied.

Screening programmes have been developed in

many parts of the globe and they all share the same

goals: (a) to relate the physical fitness and physical

features (e.g. range of motion) of the dancer to the

extreme demands of dance practice and to specific

dance forms; (b) to determine the correct level of

practice and suggest exercises to overcome areas of

weakness; (c) to identify compensations for specific

positions; (d) to identify risk factors for injury; (e)

to increase the dancers’ self-awareness of their

physical limitations; and (f) to identify any existing

injuries (see Liederbach, 1997; Schon, Biddinger,

& Greenwood, 1994).

The purpose of this study was to investigate the

association between joint range of motion, anatomi-

cal anomalies, body structure, dance discipline, and

injuries in a large sample of female recreational

dancers aged 8–16 years, and to identify potential

risk factors for injury.

Materials and methods

Participants

A group of 1336 non-professional female dancers

(age 8–16 years), were screened for the study in the

Israel Performing Arts Medicine Center, Tel-Aviv,

Israel, over the past 15 years. The girls were active in

a variety of dance disciplines, including classical

ballet, modern dance, jazz, and composition. Data

on the physical characteristics of the participants are

given in Table I.

Screening

The individual screening consisted of six steps:

Step 1: Interview

Each girl was interviewed (by S.I. and S.N.) to

determine her biological profile (e.g. current age, age

of onset of menarche), and dance experience (e.g.

hours of practice per week).

Step 2: Estimation of joint range of motion

Measurements of ankle and foot en pointe, ankle

plantar flexion, hip external rotation, hip abduction,

and lower back and hamstring flexibility were taken

by S.I. and S.N. (Figure 1). All dancers were dressed

only in a body stocking, so that the body would be

exposed as much as possible. Range of motion was

measured bilaterally with a goniometer for the ankle/

foot and hip joints. Three measurements were taken

of each, with the mean value used for analysis. Joint

range of motion measurements were based on

previously recommended methodology (Hoppenfeld,

1976; Magee, 1992; Norkin & White, 1985; Siev-

Ner, Barak, Heim, Warshavsky, & Azaria, 1997), as

described by Steinberg et al. (2006).

Joint range of motion was classified using a

statistically based system (based on data obtained

in the current and our previous study [Steinberg

et al., 2006]). Within this system, three levels were

identified that were representative of decreased range

of motion (hypo range of motion; more than 1

standard deviation less than the mean), average

range of motion (+1 standard deviation from the

mean), and excessive range of motion (hyper range

of motion; more than 1 standard deviation greater

than the mean) (Table II).

Step 3: Body structure measures

Anthropometric measurements (weight and height)

were taken with standard anthropometric tools,

following the methods described by Lohman and

colleagues (Lohman, Roche, & Martorell, 1988).

Body mass index (BMI) was calculated.

Table I. Characteristics of the young dancers aged 8–16 years.

Weight

(kg) Height (cm)

BMI

(kg � m–2)

Dancing

per week

(h)

Age (years) mean s mean s mean s mean s

8 25.8 3.6 128.9 6.7 15.3 1.4 3 2

9 28.1 3.8 133.2 6.4 15.9 1.6 3 0

10 30.8 5.2 137.2 6.3 16.4 2.1 4 3

11 32.7 5.9 141.5 10.6 16.4 4.0 5 2

12 37.3 6.8 147.7 9.9 17.1 2.7 6 2

13 40.5 6.6 152.4 8.5 17.5 2.5 8 3

14 47.8 6.9 159.3 5.9 18.8 2.1 10 4

15 49.9 6.6 160.1 5.8 19.4 2.1 11 4

16 51.7 5.6 161.5 5.4 19.8 1.9 11 4

486 N. Steinberg et al.

Dow

nloa

ded

by [

Ari

el U

nive

rsity

Cen

ter

of S

amar

ia]

at 0

5:41

14

Apr

il 20

13

Step 4: Anatomical anomalies

Eleven anomalies (knee valgus, knee varum, hallux

valgus, splay foot, forefoot adduction, hindfoot

varum, hindfoot valgus, longitudinal arch cavus,

longitudinal arch planus, scoliosis, and lordosis)

were assessed by one of the authors (S.I.) for all

dancers, following previous definitions (Adams,

1965; Hoppenfeld, 1976; Liederbach, Spivak, &

Rose, 1997; Magee, 1992). All anomalies were

defined as either present or absent. Observations

were made when the dancers were standing in an

anatomical position.

Step 5: Dance technique

Evaluation of dance technique was performed for all

dancers by S.I., according to methods published by

Ryan and Stephens (1987). Each dancer was asked

to demonstrate each technique 1–3 times at her usual

speed, and a further 1–3 times as slowly as possible.

Technique movements were categorized either as

correct or incorrect: (a) The dancer was asked to

perform a releve: correct technique is when the

Figure 1. Measuring joint range of motion for: en pointe (a); ankle plantar flexion (b); hip external rotation (c); hip abduction (d); lower back

and hamstrings flexibility (e).

Table II. Three categories of joint range of motion (ROM), for

four movements.

ROM

Hypo

ROM (8)*Average

ROM (8)**

Hyper

ROM (8)***

Ankle & foot pointe �80 81–90 �91

Ankle plantar flexion �50 51–64 �65

Hip external rotation �50 51–64 �65

Hip abduction �45 46–59 �60

*More than 1 standard deviation below the mean. **Plus or minus

1 standard deviation from the mean. ***More than 1 standard

deviation above the mean.

Risk factors for injuries in young dancers 487

Dow

nloa

ded

by [

Ari

el U

nive

rsity

Cen

ter

of S

amar

ia]

at 0

5:41

14

Apr

il 20

13

dancer rises up on the ball of the foot and the weight

is in a straight line with the forefoot. Incorrect

technique is when the dancer places weight onto the

lateral (sickling out) or medial (sickling in) borders of

her feet. (b) The dancer was asked to perform a

‘‘turnout’’ position: correct technique is when the

dancer externally rotates her hips, legs, and foot,

without anterior pelvic tilt. Incorrect technique is

when the dancer tries to compensate for poor

‘‘turnout’’ by tilting the pelvis forward (hyperlordosis).

The examiner was looking for hyperlordosis and

poor body alignment. (c) The dancer was asked to

perform a plie in the first position: correct technique

is when the patella is above the second toe. Incorrect

technique is when the patella is above or medial to

the first toe (rolling in).

Step 6: Injuries

At the end of the physical examination (Steps 2–5),

all dancers were asked about any injury or pain

(Steinberg et al., 2011). When pain and/or injury was

indicated, the dancer was asked to describe the

dancing situation when the injury occurred – that is,

the movements or exercises involved in causing the

injury and the extent to which the injury affected her

dance practice and daily life activities. All dancers

who reported pain or dysfunction were examined by

S.I., an orthopaedic surgeon specializing in dance

medicine. When additional confirmation was re-

quired, radiographs, computed tomography or mag-

netic resonance imaging were performed. The

clinical examination was required to reveal repro-

duction of pain or signs of injury (such as swelling)

for an injury to be recorded.

As each dancer was recruited only once for

screening, only a current injury that was confirmed

and diagnosed by the dance physician (S.I.) during

the dancer’s clinical examination was included in the

current study. The injuries were later classified into

four major categories: knee injuries (e.g. patellofe-

moral pain syndrome), foot or ankle tendinopathies

(e.g. fibular [peroneal] tendinopathy), back injuries

(e.g. spondylolysis), and non-categorized injuries

(e.g. shin split).

The research received approval from the Univer-

sity of Tel-Aviv Human Subjects Review Board in

accordance with the Helsinki Declaration. Approval

was also obtained from the Ministry of Education

and the school’s administration. Each participant

and one of her parents signed a consent form.

Data analysis

To test for significant differences in hours of practice

and BMI between injured and non-injured dancers,

a t-test was used. To test for any association between

range of motion (three categories: hypo, average,

hyper), anatomical anomalies (present/absent),

dance technique (correct/incorrect), practice time

(two categories:5 60 min,4 60 min), age of onset

of menarche (three groups:5 12 years, 12–14

years,4 14 years), and injury (present/absent), chi-

square tests were performed. Cox regression (Ka-

plan–Meier survival curves) was used to estimate the

probability of a dancer with and without anatomical

anomalies reaching the age of 16 without an injury

(using ‘‘exact day of birth’’ and ‘‘exact day of injury’’

as the basic parameters for calculation). A logistic

regression (forward stepwise) was performed to

determine the major risk factors for each injury type.

Statistical significance was set at P5 0.05.

Repeatability

Repeated measurements were performed on 20

dancers sampled from the studied population.

Intra-tester reliability was determined for one author

who performed the examination of the dancers twice

at intervals of 3–5 days. Inter-tester reliability

involved two testers who performed the measure-

ments using the same method, within an hour of

each other. Both testers were blinded to the results of

the other’s measurements. Several tests have been

used to assess data repeatability: Kappa (non-metric

variables) and intraclass correlation coefficients

(metric variables) were calculated to determine intra-

and inter-tester reliability of observations and mea-

surements. In addition, we applied the Bland and

Altman (1986) method to calculate the ‘‘ratio limits

of agreement’’ (for details, see Nevill, 1996; Nevill &

Atkinson, 1997).

Results

Reliability

Intra-tester reliability. Intra-class correlation for the

joint range of motion measurements ranged between

0.896 and 0.964, and for body measurements

between 0.946 and 0.968. Kappa values for the

prevalence of anatomical anomalies ranged between

0.81 and 0.86, and for dance technique between 0.82

and 0.88.

Inter-tester reliability. Intra-class correlation for the

joint range of motion measurements ranged between

0.741 and 0.951, and for body measurements

between 0.902 and 0.951. Only the orthopaedic

surgeon evaluated anatomical anomalies and dance

technique, thus no inter-tester reliability data are

available. The ‘‘95% limits of agreement’’ between

repeated measurements appear in Table III.

488 N. Steinberg et al.

Dow

nloa

ded

by [

Ari

el U

nive

rsity

Cen

ter

of S

amar

ia]

at 0

5:41

14

Apr

il 20

13

Extrinsic risk factors for injury

Of the 1336 dancers examined, 569 (42.6%)

manifested an injury during her screening. No

significant association between total dance practice

per week and injury was noted, although the injured

girls tended to dance more hours than the non-

injured dancers (Figure 2). A significant association

between dance practice in a specific position (en

pointe) and injury was observed (P5 0.001): 43% of

the dancers who practised en pointe more than

60 min per week had an injury compared with just

29% of the dancers who practised this position for

less than 60 min per week. Although no association

between dance technique and injury was observed,

rate of injury among girls who manifested incorrect

technique when performing plie (rolling in) was higher

(48%) than for girls with correct technique (42%).

Intrinsic risk factors for injury

Age of onset of menarche. An association was found

between early age of onset of menarche (512 years)

and rate of injuries (P¼ 0.04): 38% of the dancers who

had an early age of onset of menarche were injured

versus 45% of the dancers with an average (12–14

years) or late (414 years) age of onset of menarche.

Range of motion. Distribution of dancers by range of

motion categories for the different movements is

presented in Table IV. The prevalence of injury

among dancers in four injury categories by hip

external rotation range of motion is shown in

Figure 3. Chi-square yielded significant results

(w2¼ 18.889; d.f.¼ 8; P¼ 0.015), implying different

distributions for the various injury categories. In-

jured dancers were almost equally distributed among

the three range of motion categories for knee injuries,

whereas for foot or ankle tendinopathies, the number

of injured dancers in the hyper range of motion

Table III. Sample size, the measurement means and differences, the absolute ‘‘limits of agreement’’, together with the correlation between

the absolute differences and the mean.

Measurement

Sample

size Mean I Mean II

Difference

(s)

Absolute

limits

Correlation

(abs. diff. vs. mean)

Intra-tester

En pointe 20 86.0 86.0 0 (1.62) 0 (3.18) 0.26

Plantar flexion 20 55.25 55.75 70.5 (2.76) 70.5 (5.41) 70.28

External rotation 20 54.75 55.50 70.75 (1.83) 70.75 (3.59) 0.06

Abduction 20 51.25 51.50 70.25 (1.97) 70.25 (3.86) 70.41

Weight 20 37.675 37.725 70.05 (0.534) 70.05 (1.05) 70.01

Height 20 144.60 144.65 70.04 (0.782) 70.04 (1.53) 0.06

Inter-tester

En pointe 20 86.0 85.75 0.25 (1.970) 0.25 (3.86) 0.25

Plantar flexion 20 55.25 55.25 0 (2.052) 0 (4.02) 0.18

External rotation 20 54.75 55.50 70.75 (3.726) 70.75 (7.30) 70.37

Abduction 20 51.25 52.75 71.5 (3.285) 71.50 (6.44) 70.38

Weight 20 37.68 37.65 0.02 (0.2863) 0.02 (0.56) 70.33

Height 20 144.61 144.85 70.24 (0.8401) 70.24 (1.65) 0.16

Figure 2. Hours of practice per week for injured and non-injured

dancers, by age.

Table IV. Distribution of dancers by range of motion (ROM)

category, for four movements#.

Hypo

ROM*

Average

ROM**

Hyper

ROM***

Movement n % n % n %

Ankle and foot en pointe 324 24.5 846 63.8 155 11.7

Ankle plantar flexion 280 21.3 712 54.1 323 24.6

Hip external rotation 287 21.6 746 56.2 295 22.2

Hip abduction 146 11.2 798 61.1 362 27.7

#Note: The total number of dancers varies among the four

movements. This is because a specific measurement could not

be made for some dancers.

*More than 1 standard deviation below the mean. **Plus or minus

1 standard deviation from the mean. ***More than 1 standard

deviation above the mean.

Risk factors for injuries in young dancers 489

Dow

nloa

ded

by [

Ari

el U

nive

rsity

Cen

ter

of S

amar

ia]

at 0

5:41

14

Apr

il 20

13

category greatly exceeded those in the other cate-

gories (hypo and average range of motion). Most of

the dancers with back injury presented hypo hip

external rotation range of motion; in contrast,

dancers with non-categorized injuries manifested

hyper hip external rotation range of motion.

Significant differences were also observed for hip

abduction range of motion (w2¼ 23.848; d.f.¼ 8;

P¼ 0.002), showing that most of the dancers with

foot or ankle tendinopathies, and dancers with non-

categorized injuries manifested hyper hip abduction

range of motion (Figure 4).

Anatomical anomalies. Of the 11 anatomical anoma-

lies studied, only scoliosis showed a significant

association with injury (Figure 5). There was a

significant association between scoliosis and injury

for two age bands: 8–12 years (w2¼ 12.379; d.f.¼ 1;

P5 0.01) and 13–16 years (w2¼ 30.8; d.f.¼ 1;

P5 0.01). The risk of injury for young (8–12 years)

dancers with scoliosis was 1.62 greater than for

young dancers without scoliosis, and 1.52 greater

than for adolescent (13–16) dancers (P5 0.001).

Survival analysis indicated that until the age of 12

years, dancers (both with and without scoliosis) were

at very high risk for injury. From age 13 years

onwards the risk declined sharply in both groups, yet

was more pronounced in the group of dancers with

scoliosis (Figure 6). In the group with scoliosis, the

most common injury was back injuries (47%),

followed by knee injuries (27%), while in the group

without scoliosis it was knee injuries (47%), followed

by non-categorized injuries (25.5%) (P5 0.001).

Body structure. With regard to the physical character-

istics of the dancers, no association was found between

BMI and injuries in all age cohorts (Figure 7).

Combined risk factors. The results of logistic regres-

sion analysis are shown in Table V. The most

important variables entered into the equation pre-

dicting knee injury were: ankle plantar flexion, hip

abduction, and age; for foot or ankle tendinopathies:

dancing time and hip abduction; for back injuries:

scoliosis, ankle plantar flexion, and dance technique

(rolling in); and for non-categorized injuries: dancing

time, ankle plantar flexion, hip abduction, dance

technique (rolling in), and age.

Figure 3. Prevalence of injured dancers in four injury categories by hip external rotation range of motion (ROM).

Figure 4. Prevalence of injured dancers in four injury categories by hip abduction range of motion (ROM).

490 N. Steinberg et al.

Dow

nloa

ded

by [

Ari

el U

nive

rsity

Cen

ter

of S

amar

ia]

at 0

5:41

14

Apr

il 20

13

Discussion

There is evidence that musculoskeletal injury is a

very common and important health issue in dancers

at all levels of skill (Hincapie, Morton, & Cassidy,

2008). Based on the present study, dance practice

time is associated with ankle or foot tendinopathy

and non-categorized injuries. This contrasts with the

results of other studies of different sports disciplines.

For example, Witvrouw and colleagues (Witvrouw,

Danneels, Asselman, D’Have, & Cambier, 2003)

found that duration of training did not increase the

rate of injury in soccer players. However, we found

that when considerable time was devoted to one

specific exercise (e.g. en pointe in dancers), the risk of

injury was increased. Dancing en pointe is a strenuous

and demanding exercise that may lead to some

common overuse syndromes unique to dancers, such

as chondromalacia patella and Achilles tendinopathy

(Motta-Valencia, 2006). In contrast, Nunes et al.

(2002) found that dancing en pointe did not promote

musculoskeletal injuries among young recreational

dancers. They suggested this was because young girls

generally begin dancing en pointe at around 11 years

of age, when they have already acquired sufficient

strength and considerable dance experience.

There is an association between joint range of

motion and injuries for many sport disciplines

(Gamboa, Roberts, Maring, & Fergus, 2008). The

present study showed significant associations be-

tween hypo and hyper joint range of motion and

injuries. The fact that hypo ankle plantar flexion,

hyper hip abduction, and hyper hip external rotationFigure 5. Prevalence of injured dancers with and without scoliosis

in two age groups.

Figure 6. Probability of dancers with and without scoliosis reaching the age of 16 without injury.

Figure 7. Body mass index (BMI) in injured and non-injured dancers, by age.

Risk factors for injuries in young dancers 491

Dow

nloa

ded

by [

Ari

el U

nive

rsity

Cen

ter

of S

amar

ia]

at 0

5:41

14

Apr

il 20

13

range of motion are significantly associated with

almost all types of injury needs some, albeit tentative,

explanation: Joint stability is important for dancers,

since they must rely heavily on the surrounding

ligaments and muscles (Ritter & Moore, 2008).

Hyper mobility of the hips in the frontal plane and

horizontal plane can increase the extent of the

‘‘turnout’’ position. Dancers with hyper ‘‘turnout’’

frequently tilt their pelvis and sickle in their foot, a

position that can cause injuries to the lower limbs,

such as foot and ankle tendinopathies (Figure 8). In

contrast, limited ankle plantar flexion was found to

be associated with a decreased risk for knee injuries,

back injuries, and non-categorized injuries. Although

Gamboa et al. (2008) found that an injured dancer is

50% more likely to have insufficient plantar flexion

than a non-injured dancer, Foss and colleagues

(Foss, Ford, Myer, & Hewett, 2009) suggested that

foot hyper mobility increases the stress that may rise

up the kinetic chain and possibly initiate injuries.

Hyper mobility of the ankle joint causes the forces at

the foot to be transferred proximally in an non-

optimal fashion, and hence may lead to injuries (Foss

et al., 2009).

We also found that dancers with hypo hip external

rotation range of motion tend to suffer from back

injuries. This explanation is indirectly supported by

the data of Fairbank and colleagues (Fairbank,

Pynsent, Van Poortvliet, & Phillips, 1984), who

found a correlation between lower limb joint hypo

mobility and back pain in adolescents. These authors

suggested that abnormalities within the lower ex-

tremities due to various mechanisms may cause

abnormal forces to be transmitted proximally to the

spine. One such mechanism may be a strength

imbalance between front and back thigh muscles

found in dancers (Koutedakis, Frischknecht, &

Murthy, 1997a). It is also possible that limited hip

external rotation range of motion can trigger com-

pensations (such as hyperlordosis of the lower back),

leading to injury (Hamilton et al., 1992). Both

hypotheses need further research. Kushner and

colleagues (Kushner, Saboe, Reid, Penrose, & Grace,

1990) claim that when dancers try to achieve perfect

‘‘turnout’’, they very often compensate for insuffi-

cient hip motion by rotating at the knees, everting the

heels, pronating the feet, and increasing the lordosis

Table V. Logistic regression analysis for four types of injury#.

Model components Variables in the equation Coefficient sx P-value Odds ratio 95% CI

Knee injuries Ankle plantar flexion 70.043 0.014 0.002 0.958 0.932–0.985

Hip abduction 0.047 0.022 0.033 1.049 1.004–1.095

Age 0.340 0.061 0.000 1.405 1.246–1.583

Tendinopathy Hours of practice 0.129 0.036 0.000 1.137 1.060–1.221

Hip abduction 0.129 0.037 0.000 1.138 1.058–1.223

Back injuries Scoliosis 3.068 0.345 0.000 21.51 10.45–38.83

Ankle plantar flexion 70.049 0.022 0.026 0.952 0.912–0.994

Rolling in 0.773 0.335 0.021 2.166 1.124–4.174

Non-categorized injuries Hours of practice 0.087 0.035 0.013 1.091 1.018–1.169

Ankle plantar flexion 70.046 0.019 0.017 0.955 0.919–0.992

Hip abduction 0.118 0.030 0.000 1.125 1.060–1.194

Rolling in 0.996 0.327 0.002 2.707 1.425–5.141

Age 0.229 0.094 0.015 1.258 1.045–1.514

#Comparison was made with non-injured dancers.

Figure 8. Excessive hyper ‘‘turnout’’, combined with spinal

hyperextension and sickling-in of the foot, is associated with foot

and ankle injuries.

492 N. Steinberg et al.

Dow

nloa

ded

by [

Ari

el U

nive

rsity

Cen

ter

of S

amar

ia]

at 0

5:41

14

Apr

il 20

13

in their lumbar spine. Thus, the emphasis placed on

‘‘turnout’’ may be the origin of some of the spinal and

lower extremity injuries seen in dancers (Coplan,

2002; Kushner et al., 1990).

It has been suggested that dance training that

emphasizes only certain movements, such as the

‘‘turnout’’ position (hip external rotation) or en pointe

position (ankle and foot plantar flexion), can lead to

adaptive shortening of soft tissue structures (e.g.

external rotator muscles and calf muscles), which in

turn increases the risk for local injuries (such as

Achilles tendonitis). Previous studies (e.g. Knapik,

Bauman, Jones, Harris, & Vaughan, 1991; Koute-

dakis & Jamurtas, 2004) reported that an imbalance

in flexibility (between agonist and antagonist mus-

cles) in young athletes is associated with injuries of

the lower extremities. Shan (2005), who compared a

high-speed, high-intensity sport (Tae-Kwon-Do)

with low-intensity dancing, both of which entailed

repetitive motions with large ranges of motion, found

that the rate and type of injuries differed markedly.

Shan (2005) suggested that reducing the frequency

and duration of repetitive movements, and extending

the time for recovery from micro-traumatic injuries

and strengthening the small muscles involved, can

significantly reduce the risk of injuries. Clinicians

often recommend active and passive stretching

techniques for joints with limited range of motion

and strengthening exercise for joints with excessive

range of motion, as a means of managing and

preventing injuries to athletes (Aalto, Airaksinen,

Harkonen, & Arokoski, 2005).

Low back pain is documented in as many as 75%

of young athletes, but especially in dancers (Omey,

Micheli, & Gerbino, 2000). Risk factors for back

injuries in dancers include limited flexibility, limb

length discrepancy, preseason training intensity, and

a history of back injuries (Harreby, Neergard,

Hesselsøe, & Kjer, 1995). In this study, dancers

with scoliosis were more likely to have back injuries

than dancers without scoliosis. Although scoliosis is

not painful, it might be that the reasons for back

injuries in young dancers with scoliosis are their

inability to properly control posture, and the

limitations they have in performing the demanding

body movements required for dancing (Harreby

et al., 1995; Omey et al., 2000). This may explain

why incorrect technique and hyper ankle plantar

flexion range of motion may expose dancers to back

injury.

We did not find any association between body

composition (weight, height, and BMI) and injuries,

as injured and non-injured dancers presented similar

measurements. This is not surprising, as in the

literature a relationship between BMI and injuries

was found only for dancers who had eating disorders

(Warren et al., 2002).

The body size and proportions of female dancers

experience radical changes during the adolescent

growth and development period (Steinberg et al.,

2008). Dancers are required to have a very specific

body type and shape (Hamilton et al., 1992), which

is reflected in the unusual patterns of musculoske-

letal development and special distribution of adipose

tissue (Hamilton, 1986). Nevertheless, Matthews

et al. (2006) found that the level of physical activity

to which young non-professional dancers are ex-

posed is not high enough to have any effect on their

growth. Their results suggest that moderate to high

levels of dance training do not affect linear growth

and maturation.

The fact that early age of onset of menarche (512

years) was found to be associated with a lower rate of

injuries is surprising in the light of the fact that

extensive involvement in sport may delay physical

development and menstrual function (Loucks,

1990), unless the activity is reduced (Twitchett

et al., 2010). Dancers who begin training before

menarche may experience a later menarche and have

an increased incidence of menstrual dysfunction

compared with girls who began training after me-

narche (Malina, 1983). In addition, young females

with delayed menarche often have low bone mass.

Warren and colleagues (Warren, Brooks-Gunn,

Hamilton, Warren, & Hamilton, 1986) showed that

dancers with delayed menarche manifested more

stress fractures than those with normal menarche.

These researchers suggested that the delay in sexual

development may adversely affect bone quality and

functional strength. The delayed reproductive devel-

opment may attenuate the well-known benefits of

weight-bearing exercise on bone mass accretion

during adolescence (Warren et al., 2002).

Incorrect technique (rolling in) may promote injury

among young dancers. Others have previously shown

that recreational dancers are at higher risk for acute

injuries, due to poor technique resulting from

inexperience or lack of physical prerequisites (Negus

et al., 2005). Compensation strategies are known to

be a common phenomenon among ballet dancers

and have been strongly linked to overuse injuries in

dancers (Coplan, 2002; Negus et al., 2005). Arendt

and Kerschbaumer (2003) observed that severe

overuse injuries were mostly found in the lower

extremities and lumbar spine, due to technical

deficiencies. When dancers try to achieve the ideal

‘‘turnout’’ position, they usually adopt a compensa-

tory strategy that involves anterior pelvic tilt, knee

screwing, and pronation (rolling in) of the feet

(Coplan, 2002). Dancers with limited ankle plantar

flexion compensate for this by using poor techniques

that shift much of the load to their adjacent

joints, including the knees (Hodgkins, Kennedy, &

O’Loughlin, 2008). Nevertheless, improving

Risk factors for injuries in young dancers 493

Dow

nloa

ded

by [

Ari

el U

nive

rsity

Cen

ter

of S

amar

ia]

at 0

5:41

14

Apr

il 20

13

technique (e.g. retroversion of the femur position,

thus increasing the dancer’s potential for external

rotation) and dance training (e.g. tasks that produces

highly skilled balance ability as well as neutral lower

extremity alignment, such as jumping tasks) may

reduce the need for compensatory strategies, and

therefore reduce the risk of injury (Liederbach,

Dilgen, & Rose, 2008).

Limitations of the study

The main limitation of this study is its cross-sectional

nature, in that some of the parameters examined

(such as rate of injury) may be affected by sampling

bias. The risk factors for injury among young non-

professional recreational dancers is difficult to

establish, because there are no uniform standards

for measuring or defining each dancer’s background

and previous experience, and no standard methodol-

ogy for assessing workload exposure (such as

intensity of dancing). Furthermore, we could not

control for the physical burden (as the volume of

training or the physiological demands of the dancers’

training were not accounted for in the analysis), as

the dancers were sampled from various schools and

studied with different teachers.

Methodological limitations. The study of anatomical

anomalies used dichotomous measures (present/

absent), implying that we did not use metric

parameters to evaluate the extent of the anomaly

(e.g. degree of scoliosis). The lack of standardized

measuring methods and limited number of joints

examined in other studies greatly limited our ability

to make comparisons.

Conclusions

Routine physical screening of young female recrea-

tional dancers should be mandatory for identifying

existing injury and decreasing their risk of future

injury. Furthermore, it can serve as a means for

increasing the dancers’ awareness of their physical

abilities, and can assist in the selection of exercises

that can help overcome physical limitations (e.g. by

strengthening specific muscles). Finally, physical

screening may assist in correcting poor techniques

(e.g. by preventing the use of compensation).

Acknowledgements

We gratefully acknowledge Dina Olswang for Eng-

lish editing, Zinman College of Physical Education

and Sports Sciences, Wingate Institute; Anna Bechar

for the drawings; Dan-David Prize, Tel-Aviv Uni-

versity; Vain Foundation, Zinman College of Physi-

cal Education and Sports Sciences, Wingate

Institute; Tassia and Dr Joseph Meychan, Chair of

the History and Philosophy of Medicine, Tel-Aviv

University, Israel.

References

Aalto, T. J., Airaksinen, O., Harkonen, T. M., & Arokoski, J. P.

(2005). Effect of passive stretch on reproducibility of hip range

of motion measurements. Archives of Physical Medicine and

Rehabilitation, 86, 549–557.

Adams, W. (1965). Lectures on the pathology and treatment of lateral

and other forms of curvature of the spine. London: Churchill

Livingstone.

Arendt, Y., & Kerschbaumer, F. (2003). Injury and overuse

pattern in professional ballet dancers. Zeitschrift fur Orthopadie

und ihre Grenzgebiete, 141, 349–356.

Askling, C., Lund, H., Saartok, T., & Thorstensson, A. (2002).

Self-reported hamstring injuries in student-dancers. Scandina-

vian Journal of Medicine and Science in Sports, 12, 230–235.

Bland, J. M., & Altman, D. G. (1986). Statistical methods for

assessing agreement between two methods of clinical measure-

ment. The Lancet, i, 307–310.

Coplan, J. A. (2002). Ballet dancers’ turnout and its relationship to

self-reported injury. Journal of Orthopedic and Sports Physical

Therapy, 32, 579–584.

Fairbank, J. C., Pynsent, P. B., Van Poortvliet, J. A., & Phillips, H.

(1984). Influence of anthropometric factors and joint laxity in

the incidence of adolescent back pain. Spine, 9, 461–464.

Foss, K. D., Ford, K. R., Myer, G. D., & Hewett, T. E. (2009).

Generalized joint laxity associated with increased medial foot

loading in female athletes. Journal of Athletic Training, 44, 356–

363.

Gamboa, J. M., Roberts, L. A., Maring, J., & Fergus, A. (2008).

Injury patterns in elite preprofessional ballet dancers and the

utility of screening programs to identify risk characteristics.

Journal of Orthopedic and Sports Physical Therapy, 38, 126–

136.

Gleim, G. W., & McHugh, M. P. (1997). Flexibility and its effects

on sports injury and performance. Sports Medicine, 24, 289–299.

Hamilton, W. (1986). Physical prerequisites for ballet dancers.

Journal of Musculoskeletal Medicine, 3, 61–66.

Hamilton, W., Hamilton, L., Marshall, P., & Molnar, M. (1992).

A profile of the musculoskeletal characteristics of elite profes-

sional ballet dancers. American Journal of Sports Medicine, 20,

267–273.

Harreby, M. R., Neergard, K., Hesselsøe, G., & Kjer, J. (1995).

Are radiologic changes in the thoracic and lumbar spine of

adolescents risk factors for low back pain in adults? A 25-year

prospective cohort study of 640 school children. Spine, 20,

2298–2302.

Hincapie, C. A., Morton, E. J., & Cassidy, J. D. (2008).

Musculoskeletal injuries and pain in dancers: A systematic

review. Archives of Physical Medicine and Rehabilitation, 89,

1819–1829.

Hodgkins, C. W., Kennedy, J. G., & O’Loughlin, P. F. (2008).

Tendon injuries in dance. Clinical Sports Medicine, 27, 279–288.

Hoppenfeld, S. (1976). Physical examination of the spine and

extremities. Norwalk, CT: Appleton-Century-Crofts.

Knapik, J. J., Bauman, C. L., Jones, B. H., Harris, J. M., &

Vaughan, L. (1991). Preseason strength and flexibility imbal-

ances associated with athletic injuries in female collegiate

athletes. American Journal of Sports Medicine, 19, 76–81.

Koutedakis, Y., Frischknecht, R., & Murthy, M. (1997a). Knee

flexion to extension peak torque ratios and low-back injuries in

highly active individuals. International Journal of Sports Medicine,

18, 290–295.

494 N. Steinberg et al.

Dow

nloa

ded

by [

Ari

el U

nive

rsity

Cen

ter

of S

amar

ia]

at 0

5:41

14

Apr

il 20

13

Koutedakis, Y., Khaloula, M., Pacy, P. J., Murphy, M., &

Dunbar, G. M. J. (1997b). Thigh peak torques and lower-body

injuries in dancers. Journal of Dance in Medicine and Science, 1,

12–15.

Koutedakis, Y., & Jamurtas, A. (2004). The dancer as a

performing athlete: Physiological consideration. Sports Medi-

cine, 34, 651–661.

Kushner, S., Saboe, L., Reid, D., Penrose, T., & Grace, M.

(1990). Relationship of turnout to hip abduction in professional

ballet dancers. American Journal of Sports Medicine, 18, 286–

291.

Liederbach, M. (1997). Screening for functional capacity in

dancers designing standardized, dance-specific injury preven-

tion screening tools. Journal of Dance in Medicine and Science, 1,

93–106.

Liederbach, M., Dilgen, F. E., & Rose, D. J. (2008). Incidence of

anterior cruciate ligament injuries among elite ballet and

modern dancers. American Journal of Sports Medicine, 36,

1779–1788.

Liederbach, M., Spivak, J., & Rose, D. (1997). Scoliosis in

dancers: A method of assessment in quick-screen settings.

Journal of Dance in Medicine and Science, 1, 107–112.

Lohman, T., Roche, A., & Martorell, R. (1988). Anthropometric

standardization reference manual. Champaign, IL: Human

Kinetics.

Loucks, A. B. (1990). Effects of exercise training on the menstrual

cycle: Existence and mechanisms. Medicine and Science in Sports

and Exercise, 22, 275–280.

Magee, D. (1992). Orthopedic physical assessment. Philadelphia, PA:

W. B. Saunders.

Malina, R. M. (1983). Menarche in athletes: A synthesis and

hypothesis. Annals of Human Biology, 10, 1–25.

Matthews, B., Bennell, K., Mckay, H. A., Khan, K. M., Baxter-

Jones, A. D., Mirwald, R. L. et al. (2006). The influence of

dance training on growth and maturation of young females: A

mixed longitudinal study. Annals of Human Biology, 33, 342–

356.

Motta-Valencia, K. (2006). Dance-related injury. Physical and

Medical Rehabilitation Clinics of North America, 17, 697–723.

Negus, V., Hopper, D., & Briffa, N. K. (2005). Associations

between turnout and lower extremity injuries in classical ballet

dancers. Journal of Orthopedic and Sports Physical Therapy, 35,

307–318.

Nevill, A. M. (1996). Validity and measurement agreement in

sports performance [Editorial]. Journal of Sports Sciences, 14,

199.

Nevill, A. M., & Atkinson, G. (1997). Assessing agreement

between measurements recorded on a ratio scale in sports

medicine and sports science. British Journal of Sports Medicine,

31, 314–318.

Norkin, C. C., & White, D. J. (1985). Measurement of joint motion:

A guide to goniometry. Philadelphia, PA: F. A. Davis.

Nunes, N., Haddad, J., Bartlett, D., & Obright, K. D. (2002).

Musculoskeletal injuries among young, recreational, female

dancers before and after dancing in Pointe shoes. Pediatric and

Physical Therapy, 14, 100–106.

Omey, M. L., Micheli, L. J., & Gerbino, P. G. (2000). Idiopathic

scoliosis and spondylolysis in the female athlete – tips for

treatment. Clinical Orthopaedics and Related Research, 372, 74–

84.

Orishimo, K. F., Kremenic, I. J., Pappas, E., Hagins, M., &

Liederbach, M. (2009). Comparison of landing biomechanics

between male and female professional dancers. American

Journal of Sports Medicine, 37, 2187–2193.

Ritter, S., & Moore, M. (2008). The relationship between lateral

ankle sprain and ankle tendinitis in ballet dancers. Journal of

Dance in Medicine and Science, 12, 23–31.

Ryan, A. J., & Stephens, R. E. (1987). Dance medicine: A

comprehensive guide. Chicago, IL: Pluribus Press.

Schoene, L. (2007). Biomechanical evaluation of dancers and

assessment of their risk of injury. Journal of the American

Podiatric Medical Association, 1, 75–80.

Schon, L. C., Biddinger, K. R., & Greenwood, P. (1994). Dance

screen programs and development of dance clinics. Clinics in

Sports Medicine, 13, 865–882.

Shan, G. (2005). Comparison of repetitive movements between

ballet dancers and martial artists: Risk assessment of muscle

overuse injuries and prevention strategies. Research in Sports

Medicine, 13, 63–76.

Siev-Ner, I., Barak, A., Heim, M., Warshavsky, M., & Azaria, A.

(1997). The value of screening. Journal of Dance in Medicine and

Science, 1, 87–92.

Steinberg, N., Hershkovitz, I., Peleg, S., Dar, G., Masharawi, Y.,

Heim, M. et al. (2006). Range of joint movement in female

dancers and non-dancers aged 8 to 16 years: Anatomical and

clinical implications. American Journal of Sports Medicine, 34,

814–823.

Steinberg, N., Siev-Ner, I., Peleg, S., Dar, G., Masharawi, Y., &

Hershkovitz, I. (2008). Growth and development of female

dancers aged 8–16 years. American Journal of Human Biology,

20, 299–307.

Steinberg, N., Siev-Ner, I., Peleg, S., Dar, G., Masharawi, Y.,

Zeev, A. et al. (2011). Injury pattern in young, non-professional

dancers. Journal of Sports Sciences, 29, 47–54.

Twitchett, E., Brodrick, A., Nevill, A. M., Koutedakis, Y., Angioi,

M., & Wyon, M. (2010). Does physical fitness affect injury

occurrence and time loss due to injury in elite vocational ballet

students. Journal of Dance in Medicine and Science, 14, 26–31.

Warren, M. P., Brooks-Gunn, J., Fox, R. P., Holderness, C. C.,

Hyle, E. P., & Hamilton, W. G. (2002). Osteopenia in exercise-

associated amenorrhea using ballet dancers as a model: A

longitudinal study. Journal of Clinical Endocrinology and Meta-

bolism, 87, 3162–3168.

Warren, M., Brooks-Gunn, J., Hamilton, L. H., Warren, L. F., &

Hamilton, W. G. (1986). Scoliosis and fractures in young ballet

dancers. New England Journal of Medicine, 314, 1348–1353.

Witvrouw, E., Danneels, L., Asselman, P., D’Have, T., &

Cambier, D. (2003). Muscle flexibility as a risk factor for

developing muscle injuries in male professional soccer players:

A prospective study. American Journal of Sports Medicine, 31,

41–46.

Risk factors for injuries in young dancers 495

Dow

nloa

ded

by [

Ari

el U

nive

rsity

Cen

ter

of S

amar

ia]

at 0

5:41

14

Apr

il 20

13