Dance regional interdependence

ABSTRACTDue to complex movements and high physical demands,dance is often associated with a multitude of impairmentsincluding pain of the low back, pelvis, leg, knee, and foot.This case report provides an exercise progression, empha-sizing enhancement of strength and neuromuscular per-formance using the concept of regional interdependencein a 17 year old female dancer with patellofemoral painsyndrome.

CORRESPONDENCEWilliam J. Hanney, PT, DPT, ATC/LUniversity of Central FloridaProgram in Physical TherapyHPA 1 D Suite 258Orlando, FL 32816Phone: 407-823-0217Email: [email protected]

CASE REPORTRehabilitation of a Female Dancer withPatellOfemoral Pain Syndrome: ApplyingConcepts of Regional Interdependence inPracticeCaitlyn Welsh, PT, MPTa

William J. Hanney, PT, DPT, ATC/La,b

Laura Podschun, PT, MPT, OCSa

Morey J. Kolber, PT, PhD, OCS, Cert MDTCc

a Florida Hospital Sports Medicine and Rehabilitationb University of Central Florida

Orlando, FL USAc Nova Southeastern University

North American Journal of Sports Physical Therapy | Volume 5, Number 2 | June 2010 | Page 85

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INTRODUCTIONDance often involves a complex sequence of movementsand high physical demands of strength, stability, and flex-ibility. Due to intricate choreography and challengingperformance schedules dancers are potentially at risk forinjury. These physical requirements of dance, whichinclude prolonged bouts of training and explicit physicalcontrol of their body, make physiologic training just asimportant as skill development for injury prevention.

The physical demands of dance often result in injury,which in turn limit a dancer's ability to perform. In a sur-vey of 324 professional dancers, almost 50% reportedmissing between one and twenty-one days of exercise dueto injury each year.1 Koutedakis and Jamuris1 reportedthat 90% of injuries in dancers involve the low back,pelvis, legs, knees, or feet. Prolonged bouts of trainingwith inadequate rest, unsuitable floors, difficult choreogra-phy, and insufficient warm-ups are among the factors thatcontribute to dance injuries.2 In their paper, Koutedakisand Jamuris1 reviewed studies on male and femaledancers, which suggested that supplementary exercisetraining, beyond that of dance training, can lead toimprovements in muscle balance and strength.

Strength training decreases incidence of dance injuries,without interfering with the key artistic and aestheticrequirements of a dancer.1 However, strength training hasgenerally not been considered a necessary component ofpreparation for success in dance.1 This idea is supportedby the view among dancers and choreographers thatstrength training may create a physique that is not com-plimentary to the typical dancer's aesthetic appearance.1

MacDougal et al3 found increases in muscle strength werenot necessarily accompanied by proportional changes inmuscle size. This finding suggests that strength training isclosely related to neural adaptations which increase mus-cle strength.3,4 These neural mechanisms responsible forstrength development include alterations in agonist-antag-onist co-activation, increases in motor unit firing rates(rate coding), and changes in descending drive to themotorneurons.3,4

Previous authors have suggested that proximal factorssuch as hip and core weakness may contribute to anteriorknee pain.5-7 Additionally, authors have demonstrated thatwomen exhibit movements associated with knee valgusand hip internal rotation when compared to men duringspecific movements.6,8,9 The ability of women to control


these motions may depend on the strength of proximalmuscle groups that are antagonistic to these movements.10

Proper hip strength and neuromuscular control, particu-larly of the gluteus medius and hip external rotators,enhances knee stability by controlling the pelvis and lim-iting hip adduction and internal rotation that result inincreased knee valgus during activity.11 In the absence ofsufficient proximal strength or muscular control, thefemur may adduct and internally rotate, exaggerating lat-eral patellar contact due to the valgus moment.12-14

Repetitive activities with this mal-alignment may eventu-ally lead to patellofemoral pain.10

Patellofemoral pain syndrome (PFPS), also known asanterior knee pain, remains a common orthopedic com-plaint2,6 occurring in approximately 1 in every 4 people.15

Those involved in athletics report an incidence ofpatellofemoral pain greater than 25%.10,15 The condition ismore common in women than men and most oftenaffects younger individuals between the ages of 10 and 35years.16 Unfortunately, this pain often becomes a chroniccondition that may fail to respond to conservative meas-ures.17

Symptoms of PFPS typically include the following: painwhile ascending and descending stairs, squatting, or pro-longed sitting. Swelling, popping or grinding sensationsmay be present, as well as incidences of knee buckling orgiving way.18,19 The spectrum of symptoms varies greatlyamong individuals, with complaints ranging from achypain after activity to severe pain when rising from a chairor climbing stairs.16

Many patients with anterior knee pain are eventuallyreferred to rehabilitation. Although PFPS is one of themost common clinical conditions treated by orthopedicand sports physical therapists, a consensus does not existregarding how these patients should be managed.16

Differential diagnostic skills must be utilized to rule out arange of inflammatory conditions, mechanical problems,and other conditions such as ligamentous injury,tendinopathy, bursitis, and muscle strain.18-20 Identifyingthe origin of the inflammation is important for developinga treatment plan that will result in prompt resolution ofsymptoms.16 Failure to do so may result in suboptimalcare and poor outcomes.16 Some of the various techniquescommonly used to treat PFPS include non-steroidal anti-inflammatory medication, ice, quadriceps strengthening,


hamstring and gastrocnemius stretching, patella taping orbracing, and orthotics.15,20

Vaughn21 highlighted the importance of a regionalexamination for a patient with non-specific knee pain,illustrating the concept of regional interdependence. Withrespect to musculoskeletal problems, regional interde-pendence refers to the concept that seemingly unrelatedimpairments in a remote anatomical region may con-tribute to, or be associated with, the patient's primarycomplaint.22 In some cases, knee pain may be the solepresenting symptom when a more proximal or distalstructure such as the pelvis, hip, ankle, or foot is at fault.23

In such cases, the pain may be referred from a more prox-imal structure or be consequential to a remotely locatedimpairment that produces excessive stress on structures ofthe knee, resulting in pain.21

The purpose of this case report is to demonstrate theimportance of strength and neuromuscular training in afemale dancer who presented with PFPS and highlight theimportance of a regional interdependence model of exam-ination to identify the origin of knee pain.

CASE DESCRIPTION AND HISTORYThe patient was a 17-year-old female high school studentwho participated in dance activities up to 18 hours a week.Pain was initially reported in the anterior/medial aspectof the left knee in December 2007 with no specific mech-anism of injury noted. The patient continued, despitepain in the left knee, to dance on a regular basis. Sheattempted to join the school cross-country team in the fallof 2008 but was unable to participate due to her kneesymptoms.

An orthopedic surgeon evaluated the patient in Decemberof 2008 with no significant findings related to fracture, dis-location, or meniscal involvement which is consistentwith the presentation of PFPS. Further diagnostic testingwith X-ray and MRI revealed a bone bruise on the medialfemoral condyle and thinning cartilage. The patient optedfor rest from dance and physical therapy.

INITIAL EXAMINATIONInitial PresentationThe patient was seen on December 31, 2008 for physicaltherapy examination with a chief complaint of left kneepain along the inferior and medial pole of the patella. Thepatient appeared to be a healthy and athletic 17 year old

female. She presented with a slender build, as well as alow waist-hip ratio of 0.7524,25 that is typically seen indancers. She had no swelling or erythema of her left kneewith visual inspection. The history of her current injurywas insidious onset of approximately one-year duration,as previously noted.

Functional StatusThe patient had stopped dancing 3 weeks prior toexamination, per the orthopedic surgeon's recommenda-tion. She reported difficulty walking or running forperiods longer than 10 minutes due to pain. She alsoreported that ascending and descending stairs at schoolcaused an increase in pain, which forced her to take theelevator some days. The patient demonstrated unilateralsquat with genu valgus collapse bilaterally with report ofmild retro patellar discomfort.

Systems ReviewAt evaluation the patient was 5'6" and 125 lbs with a bodymass index of 20.2 which is considered to be at the lowerend of a normal range.26 She reported a history of faintingdue to low blood sugar with no occurrences in the past twoyears. Also no previous injuries or surgeries were report-ed. An integumentary and neuromuscular screenrevealed no gross deficits. Family medical history wasunremarkable.

Tests and MeasuresPostureStanding postural assessment demonstrated the patient'sspine, hips, and knees were within normal limits (WNL)with exception of increased external rotation bilaterally inthe lower quarter. Supine postural assessment revealingan increase in femoral anteversion, which lead to com-pensations in weight-bearing. The patient also presentedwith a Q-angle of 8 degrees bilaterally and the patella washypo-mobile on the left with medial to lateral glides. Inprone the patient presented with rear foot varus of 5degrees bilaterally and a neutral forefoot when examinedin subtalar neutral. Gait was assessed with the patientambulating in bare feet at a self-selected pace for 30 feetand rapidly for 30 feet. No significant findings were foundduring gait analysis and the patient had no complaints ofpain.

Range Of MotionThe patient's active range of motion (AROM) for all hip,knee and ankle, measurements were WNL and symmetri-


cal bilaterally except for hip internal rotation with rightinternal rotation (IR) measured at 29 degrees and left IRmeasured at 39 degrees.

PainA 10 mm visual analog scale (VAS) was used to elicit anobjective description of the patient's pain level.26 Thepatient reported 8/10 pain during dance class, which wasthe activity that most aggravated the symptoms. Pain wasalleviated to 0/10 with sitting or resting. The patientreported 5/10 pain levels with walking more than 10 min-utes on even or uneven ground, as well as ascending ordescending 10 steps at school. Symptoms were localizedto the medial aspect of the knee around the medial jointline. No tenderness to palpation occurred during examina-tion.

Muscle StrengthThe patient's strength was measured using manualmuscle testing as described by Daniels andWorthingham.26 (Table 1) Abdominal (rectus abdominusand obliques) were measured at 4/5 in supine positionwith trunk flexion. The patient was unable to hold aprone plank greater than five seconds before increasingher lordotic curve suggesting weakness. All measure-ments were taken in a pain free manner.

Special Tests & and Muscle Length AssessmentsBased on the patient complaints of left knee pain severalspecial tests were performed to rule out ligamentous andmeniscal involvement. The patient tested negative bilat-erally for the following tests: Lachman's and anteriordrawer test for anterior cruciate ligament (ACL) stability,McMurray's test for medial and lateral meniscus, 90/90test for hamstring muscle length, Thomas test for iliop-soas and rectus femoris muscle length, and Ober's test foriliotibial band length.

Functional Outcome MeasurementsAt initial examination the patient scored a 49/80 on theLower Extremity Functional Scale (LEFS).27,28 She alsoscored a 3.7/10 on the Patient-Specific Functional Scale(PSFS)29 in which the patient identifies specific functionaltasks which are limited and rates them zero to ten withlower numbers reflecting greater levels of limitation.

ASSESSMENTThe patient's primary impairment was knee painsecondary to non-traumatic sports related injury. Thephysical therapy evaluation revealed an overall decreasein strength and muscle imbalances. This is particularlythe case for her hip musculature which is needed to per-form as a dancer. Weakness of the left hip abductor andexternal rotator muscles allowed for increased anterome-dial vector forces and disproportionate stress on theanterior/medial left knee. Due to pain while dancing, herorthopedic physician placed the patient on activity limita-tions and no return to dance until after the first 4 weeks oftreatment. The prescription was to evaluate and treat onetime a week for 6 weeks due to unusually high co-pay andfinancial limitations.After the initial examination, thepatient was treated once per week for three weeks, andthen once every other week, for six total sessions.

Plan of Care DesignThe rehabilitation program integrated aspects of aregional interdependence approach with a focus onimproving muscular strength and coordination, correctingmuscle imbalances, and enhancing neuromuscular con-trol. Physical therapy interventions were initiated with ahome exercise program (HEP) following initial examina-tion. The patient's initial home program included singleleg exercises for hamstring, gluteus medius and gluteusmaximus muscle strengthening, single leg squats, sideplanks with knees flexed, as well as instruction for trans-verse abdominus muscle contraction with all exercises.The patient was instructed to perform exercises daily,completing two sets of ten for each exercise.

Table 1. Reported hip and knee strength measures.


AssessmentThe patient reported pain intensity of 6/10 VAS the weekfollowing the initial examination, with the symptomsmost intense at night after performing exercises and nor-mal activity at school. She had not returned to dance buthad returned to teaching 3 children's dance classes whichwere 30 minutes in duration within the past week. Sheperformed her HEP every other day since examinationand described the pain as intense and achy after the exer-cises.

The treatment focus was on simple strengthening exercis-es for hip and core muscles necessary for activities of daily

living and progression to return to dance that could becarried over for home program due to limited visits. Thepatient externally rotated her lower extremities, a naturalposition for dancers, and demonstrated genu valgus dur-ing exercises. She also complained of pain with single legexercises. When cued to maintain her foot in a neutralposition with correct lower quarter alignment, the patientreported decreased knee pain during therapeutic exercis-es, especially with single leg exercises.

Table 2. Follow up visit 1 exercises performed in clinic.

INTERVENTIONFollow-up Visit 1

Figure 1. Unilateral leg press with elastic tubing.


Figure 2. Monster walk withelastic tubing around distal thigh.

Figure 3. Prone push up position withknee to chest at neutral and lateral andmedial angles with lower extremity move-ment.

Figure 4. Cable cord bilateral squatwith upper extremity row with elastictubing and abduction resistance.


AssessmentUpon return to treatment a week later the patient had min-imal to no pain at rest or with activity with most intensepain measured at a 2/10 on VAS. She had not increased heractivity but was able to ascend and descend stairs at school.Upon reassessment for strength the patient demonstratedbetter structural alignment of the lower quarter withdemonstration of bilateral squat and unilateral squat and adecrease in pain during performance of each. She contin-ued to demonstrate a genu valgus collapse with unilateralsquat.

Due to a decrease in overall pain intensity with exercise,the treatment focus was progressed to functionalmovements with strengthening to mimic simple dancemaneuvers. Elastic tubing was utilized for hip abductormuscle resistance during all single leg hip exercises to

decrease severe genu valgus collapse due to lack ofstrength of abductor and external rotator muscles. Thepatient complained of fatigue and cramping in stabilizinghip during exercises performed with foot in neutral hiprotation position. The patient was able to climb stairs with-out any pain and had no reports of knee pain during treat-ment. The patient was instructed to use elastic tubing dur-ing HEP for proper recruitment of abductor and externalrotator muscles and their ability to decrease vector forceson anterior/medial knee during closed chain activities.She continued HEP performance every other day duringthe week between treatments. HEP was expanded toinclude diagonal hops and single leg squats with ER of hipduring squat and IR of hip with rising.

Follow-up Visit 2


Figure 5. Unilateral leg press with circle board. Figure 6. Forward step ups.


Figure 7. Single leg squat with internal rotation (IR) of hip concentric motionand eternal rotation (ER) of hip with eccentric motion.

Follow-up Visit 3

AssessmentUpon return to therapy a week later the patient reportedhaving had no pain in her knee all week during ADL's butthat she had not returned to dance class. She did contin-ue to teach a children's class, which only required verysimple dance moves, all of which were pain free. She nolonger used the elevator at school and could ascend anddescend stairs without pain.

Due to the patient's report of no pain all week, treatmentexercises were advanced to mimic dance moves withmultiple planes and involvement of upper and lowerextremities in a sport specific preparation for return todancing. During treatment the patient demonstrated

improved abduction/ER strength during sagittal planeactivities by demonstrating decreased valgus collapsewith unilateral squatting. The patient continued to lackproper control in coronal plane activities and movementwith complaints of fatigue in hips. Over the next weekthe patient was allowed to return to tap class and joggingon pavement 1-2 miles a day. These activities were fol-lowed with return to ballet and contemporary danceclass the following week. She returned to therapy aftertwo weeks. Her HEP was advanced to include thecomplex activities she had performed during in-clinictreatment.



Figure 8. Side planks with knees flexed and single legabduction of top leg.

Figure 9. Crabwalk with squat andelastic tubing around distal thigh.


AssessmentThe patient reported a return to dance class 4 days a weekfor about 8 hours a week at 80% of pre-injury levels. Shereported only minimal pain during ballet class with certainmoves that required excessive external rotation. Thepatient was able run pain free on a treadmill for 2 miles forwarm-up. For re-examination prior to treatment the patientperformed bilateral jumps and unilateral hops on even anduneven surfaces to assess power and distance. She demon-

strated proper form with jumps and no compensations.Following pre-treatment re-examination the patient had nocomplaints of pain or fatigue with treatment exercises. TheHEP was advanced to focus on unilateral squats, jumps,and hops in an externally rotated position for return tosport training. The patient was to increase dance classhours and intensity and return to therapy in two weeks fordischarge.

Follow-up Visit 4


Follow-up Visit 5


AssessmentUpon return to therapy two weeks later the patientreported being 100% better. She returned to dance 5 days aweek for 9-10 hrs a week at 100% pre-injury level. She alsoreported jogging 3 miles twice a week on off dance days.Prior to physical therapy she could only perform one pirou-ette however now was able to perform three in succession.After re-examination for discharge the patient ran consecu-

tive 40-yard dashes at maximum speed and performedrepetitive jumping and skipping for 40 yards each. All activ-ities performed on pavement, with no reports of pain witheither activity.

OUTCOMESAt the discharge examination all hip and knee manual mus-cle tests were graded as 5/5. Overall pain level was a 0/10on VAS with all activities of daily living, school require-ments, ascending and descending stairs, as well as withdancing. The patient scored a 74/80 on the LowerExtremity Functional Scale and an 8.7/10 on the PSFS. Theone exception was a 1/10 pain on VAS, which the patientdescribed with certain ballet pliés and turnouts thatrequired maximal external rotation on both extremities.This limitation did not limit her performance in balletclass. She reported gradually increasing the amount of timeshe spent dancing each week, but was able to perform at100% of pre-injury level while in class. She was perform-ing and teaching dance class 5 days a week for up to 10-12hours a week at time of discharge.

DISCUSSIONWeakness of the hip abductor and external rotator musclemay be associated with poor eccentric control of femoraladduction and internal rotation during weight-bearingactivities. This lack of control can contribute to malalign-ment of the patellofemoral joint as the femur mediallyrotates under the patella.30,31 To reduce excessive lateralpatellar deviations during weight-bearing activities andpotentially reduce anterior knee pain, physical therapyintervention was necessary to address hip muscle perform-ance and control of the LE during activity.32,33 Decreasedhip stability due to muscular weakness, especially that ofthe gluteus medius and external rotator muscles, mayaffect the patellofemoral joint position in some patients.5

Decreased hip abductor and hip external rotation musclestrength may allow the pelvis to collapse under the weightof the body during single-leg stance which is a commonmaneuver in dance. When a dancer drops their hip, a val-gus stress at the knee can occur and that may aggravate apatellofemoral joint condition.5,17

Robinson and Nee34 demonstrated that females between 12and 35 years of age, presenting with unilateral PFPSdemonstrate significant impairments in the isometricstrength of their symptomatic limbs for hip abduction,extension, and external rotation when compared to unin-jured control subjects. Additional researchers have shownthat young females with PFPS demonstrate hip abductionand external rotation muscle weakness when compared tothat of age-matched non-symptomatic females.10 Subjectswith PFPS demonstrated 36% less external rotation muscle

strength and 26% less hip abductor muscle strength thancontrol subjects.10 Bogla et al35 also showed similar resultsfor subjects with PFPS, who demonstrated 24% less hipexternal rotator muscle strength and 26% less hip abductormuscle strength than controls. These studies support thetheory that hip abductor and hip external rotator muscleweakness may allow excessive hip adduction and hip inter-nal rotation during activity, thus contributing topatellofemoral joint stress.10,34,36 More importantly, severalauthors have reported favorable outcomes in patients whoparticipated in a rehabilitation program targeting the hipmusculature for the treatment of anterior knee pain.34, 37, 38

Authors have reported that female athletes land with lessknee flexion, less time to peak knee flexion, greater kneevalgus, greater vertical ground reaction forces, and lesshamstring activation than male athletes which may lead toACL injury.39 Jumping and landing is an integral part ofdance. Lephart et al,6,11 suggested that the neuromuscularcharacteristics of the lower extremity in female athletescan be improved with a basic exercise program of jumpsand single leg stance exercises which may reduce the riskfor injury. A reduction in injury rate after a strength-train-ing program alone was reported in those after ACL injury.6

Elevated neuromuscular control may account for some ofthe strength gains.40 Improvements in a muscle's ability togenerate force, appears to be a way for dancers to enhancetheir performance.1 The dancer presented in this casestudy demonstrated significant functional improvementsas reflected by the LEFS and PSFS scores with a primaryintervention of strengthening. An awareness of these fac-tors will assist dancers to improve training techniques andto employ effective injury prevention strategies.

CONCLUSIONThis case report outlines rehabilitation guidelines, atherapeutic exercise program, functional training interven-tions, and outcomes utilized with a female dancer withPFPS. The patient achieved a successful outcome, return-ing to full participation of dance training and employmentas a dance instructor. Critical to this case was implement-ing concepts associated with regional interdependence.Proximal weakness through the core and hip region of thisfemale dancer likely contributed to deficits in neuromuscu-lar control of the lower extremity kinetic chain duringsquatting, jumping, and hopping. Clinicians should consid-er the influence of proximal impairments when examiningand treating a patient with dysfunction of the lower limb.


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Dance regional interdependence