Injury characteristics in professional modern dancers: A 15-year analysis of work-related injury rates and patterns.

We investigated work-related-musculoskeletal-injuries (WMSI) over 15-years in professional modern dancers to determine injury rate and pattern differences due to sex and professional-experience. Injuries were coded to allow analyses by tissue-type, body-region, severity, setting, mechanism, action-causation, and repertory-style. Injury prevalence (IP) was defined as average risk of injury/dancer. Injury incidence rate (IIR) was calculated per 1000-hrs exposure/block. Negative binomial logistic regression analyses were conducted with exposure-hrs to determine IIR, p < 0.05. Multinomial logistic regressions determined differences in tissue-type, body-region, action-causation and repertory-style; Poisson loglinear regressions determined differences in severity and mechanism, p < 0.05. Females were 15-times more likely to sustain bone-injuries, p = 0.016; males 8- and 15-times more likely to sustain muscle/tendon-injuries or lacerations/contusions, p ≤ 0.016. Females were more likely to sustain severe injury resulting in more lost-workdays and missed-performances, p < 0.001. In both sexes, more time-loss-injuries (TL-inj) occurred in performance , were traumatic in nature, with an action-causation of jumping/stomping/relevé. Dancers of moderate professional-experience were 1.3-times more likely to sustain TL-inj, p = 0.026;. Identifying context-specific activities and repertory-style relationships to injury can provide insight into casting and rehearsal scheduling. Comprehending sex-specific musculoskeletal health needs allows improved dancer health management and injury prevention planning.

Ukrainian Performing Artists Inspire.

Russia invaded the Ukraine on February 24, 2022. The atrocities perpetuated by invading Russian soldiers seized the world's attention in images captured by photojournalists on the ground in Bucha, Ukraine, in April 2022. We cannot look away. We must remember. Justice must prevail. … At the 2022 Grammy awards ceremony on April 3rd, President Zelensky introduced singer/songwriter John Legend, who performed with three Ukrainian artists. A masterful speech writer/performing artist in his own right, Zelensky began by saying "The War … what is more opposite to music? …".

Components of Pre-professional/Adolescent Dance Screens: What Should We Include?

Increasingly, best practice in dance healthcare includes preseason screening. But do preseason screenings give us useful information? Can they provide assessment of injury risk? Can we use a common screen for all athletes or need ones specific to dancers? What is the purpose of screening and what tests are appropriate for adolescent dancers? In this editorial, I make recommendations based on over 20 years of experience screening pre-professional and professional dancers.

The Dance Functional Outcome Survey: Cultural Adaptation and Psychometric Validation in Italian (DFOS-IT).

OBJECTIVE: To translate, culturally adapt, and validate the psychometric characteristics of the Italian version of the Dance Functional Outcome Survey (DFOS-IT) in adult dancers. DESIGN: Clinical measurement study. METHODS: The DFOS-IT was forward translated, reconciled, backward translated, and reviewed by an expert committee to establish optimal correspondence with the original English DFOS. We examined test-retest reliability in 58 dancers within a 10-day period, using intraclass correlation coefficients (ICC2,1). In a sample of 265 healthy and injured dancers, the following were examined: 1) construct validity, comparing the DFOS-IT to SF-36 using Pearson correlations; 2) exploratory factor analysis and internal consistency; and 3) sensitivity, by generating receiver operating characteristic curves and determining area under the curve (AUC). In a subgroup of 44 dancers, we determined internal responsiveness across three time-points using repeated measures ANOVA (p<0.05). Injured dancers' scores were analyzed for floor and ceiling effects. RESULTS: The DFOS-IT demonstrated very high test-retest reliability (ICC≥0.98). Single-factor loading in exploratory factor analysis supported unidimensionality of the scale, with high internal consistency (a=0.93). DFOS-IT total, activities of daily living (ADL), and Dance Technique scores had strong construct validity compared with scores on the SF-36 PCS (r≥0.71). There was excellent sensitivity, with high AUC values (AUC≥0.80). There were significant differences across time for DFOS-IT scores (p<0.001), demonstrating responsiveness to change, and no floor or ceiling effects. CONCLUSION: The DFOS-IT is a valid, reliable, and responsive tool that can be used as an outcome and screening measure for Italian adult ballet and modern dancers following lower extremity or low back injury.

Reliability of a Barre-Mounted Dynamometer-Stabilizing Device in Measuring Dance-Specific Muscle Performance.

BACKGROUND: Hand-held dynamometry is considered an efficient, effective, and portable means of objectively measuring lower extremity strength; however, it has yet to be studied specific to dance-relevant muscle performance. Also, dynamometry is often criticized for variability in results based on tester strength and sex. Use of an external stabilizing device has been suggested to minimize differences in outcomes between male and female testers by reducing variability associated with tester strength limitations. Therefore, this study used a barre-mounted, portable dynamometer stabilizing device to improve consistency of results among different testers for assessing hip and lower extremity muscle performance in dance-relevant positions. OBJECTIVE: To assess the intra and inter-rater reliability of a barre-mounted dynamometer stabilizing device in measuring muscle performance in common dance maneuvers. METHODS: Two testers assessed muscle performance of three common dance maneuvers--développé en avant, à la secondé, and arabesque--on 11 pre-professional and professional dancers on two separate occasions to establish intra- and inter-rater reliability of the barre-mounted dynamometer stabilizing device. RESULTS: Intra-rater reliability was moderate to high and inter-rater reliability of the device was excellent, with intraclass correlation coefficients ranging from 0.527-0.851 and 0.834-0.953, respectively, for all positions. CONCLUSIONS: The barre-mounted stabilizing device shows promise in mitigating tester strength or fatigue in assessing muscle performance of dancers. Initial assessment of the device suggests further study may be indicated to improve generalizability to applications of larger-scale muscle performance screening and assessment in dancers or other athletic populations who engage in movements that require extensive hip range of motion and multi-joint stability. CLINICAL RELEVANCE: Using a portable, barre-mounted stabilizing device in assessing multi-joint lower extremity muscle performance in dancers improves consistency of testing results. Application of this testing device into wider scale screenings could assist in developing normative data for a population that is lacking.

Here's To Our Community.

Memorialized in former Secretary of State Hillary Clinton's children's book entitled It Takes a Village, "it takes a village to raise a child" is an African proverb that means an entire community of people must interact with children for those children to experience and grow in a safe and healthy environment. The need of the artist to create is undeniable and their villages continue to support them. During these dark days of the COVID-10 pandemic, performing and fine artists have been denied their traditional communication with their public as theaters and museums closed down throughout the world. For those of us who live in New York City where the worst of Covid-19 hit last spring, it was no Broadway shows, no spring, summer or fall dance seasons, no summer festivals, no dance classes. Yet almost immediately, artists' resourcefulness shone as they continued to create, teach, and perform their art in new ways.

Intra- and Inter-Rater Reliability of a Ballet-based Dance Technique Screening Instrument.

OBJECTIVES: To investigate intra- and inter-rater reliability of a ballet-based Dance Technique Screening Instrument used by physical therapists (PTs) and student PTs (SPTs) with prior dance medicine or dance experience. METHODS: Ten pre-professional dancers were video-recorded in the sagittal and frontal planes while performing four dance sequences: 1) second position grand plié; 2) développé à la seconde; 3) single-limb passé relevé balance; and 4) jumps in first position. Dance videos and electronic versions of the demographics and scoring forms were provided through a secure online survey to 28 PTs and SPTs who served as raters. Raters reviewed a training video prior to scoring the 10 dancers. Raters were asked to repeat their assessments 1-2 wks later. Intraclass correlations (ICC) were assessed for all-raters, PTs, and SPTs for total and sequence scores. RESULTS: Twenty-eight raters assessed the videos one time. Inter-rater reliability was ICC=0.98 (CI95=0.96-0.99) (all-raters), with PTs and SPTs displaying similar values (ICC=0.96 and 0.96, respectively). Eighteen raters (11 PTs, 7 SPTs) repeated the video analysis. Intra-rater reliability was ICC=0.78 (CI95=0.72-0.83) with PTs ICC=0.81 and SPTs ICC=0.70. CONCLUSIONS: Correlations were high for all-raters. SPTs were as reliable as PTs in inter-rater comparisons. PTs exhibited higher intra-rater reliability compared to SPTs. These results substantiate the reliability of a standardized testing instrument to conduct dance technique assessment. Validity of this instrument was demonstrated in a previous study which found dancers with better technique were less likely to sustain injury. The ability to identify technique deficits can guide preventative programs that may reduce injury risk. LEVEL OF EVIDENCE: Level III.

Musculoskeletal injuries in professional modern dancers: a prospective cohort study of 15 years.

We analysed work-related musculoskeletal injuries (WMSI) in two modern dance companies to determine whether injury rates decreased and patterns altered compared to previous 3-yr and 6-yr audits (0.48 and 0.25/1000-hrs exposure respectively). In this prospectively designed 15-yr cohort study, data were collected in 30-dancer Company-1 and 12-dancer Company-2. In-house physical therapists tracked WMSI and time-loss-injuries for 159 dancers (42 dancers/yr). 15-yrs were grouped into five 3-yr blocks for comparison with prior audits. Negative binomial logistic regression analyses were conducted with exposure-hrs converted to the natural log and used as the offset variable. Block and company were categorical predictors for dependent variables: WMSI, time-loss-injuries, trauma-injuries and overuse-injuries (p < 0.05). 69% of dancers reported WMSI; 45% sustained at least one time-loss-injury. Company-1, with greater annual exposure, was 1.6-times more likely to sustain time-loss-injuries (p = 0.016, CI = 1.095-2.422) and 5.6-times more likely to sustain time-loss overuse-injuries (p = 0.003, CI = 1.812-17.327). Compared to Block-1, WMSI and time-loss-injuries decreased in Blocks-2, 3, and 5 (p ≤ 0.027). The ratio of time-loss overuse to trauma-injuries was reversed, with trauma-injuries accounting for over 80% of injuries by Block 5. Time-loss-injuries averaged 0.16 injuries/1000-hrs, lower than rates in ballet and sports. Decreased injury rates and changed injury patterns demonstrate efficacious injury management and prevention programming.

Removing Boundaries to Enhance Communication Between People.

Regardless of your view of national or global politics, we are living through an era of toxic partisan rhetoric. From belligerent tweets on Twitter to "fake news" on Facebook and Instagram, where is this taking us? It is so easy to misunderstand a text and even an email. I've been thinking about the artists we work with and what we do in our professional lives. Performance is a form of communication between the artist and audience. The artist on stage can feel the unspoken response by the audience (even before there is or isn't applause or boos). There is an energy, a connection.

Impact of touring, performance schedule, and definitions on 1-year injury rates in a modern dance company.

There is ongoing debate about how to define injury in dance: the most encompassing one or a time-loss definition. We examined the relationship between touring, performance schedule and injury definition on injury rates in a professional modern dance company over one-year. In-house healthcare management tracked 35 dancers for work-related musculoskeletal injuries (WMSI), time-loss injuries (TLinj), complaints, and exposure. The year was divided into 6 segments to allow comparison of effects of performance, rehearsal, and touring. Injuries/segment were converted into injuries/1000-h dance exposure. We conducted negative binomial regression analysis to determine differences between segments, P ≤ 0.05. Twenty WMSI, 0.44 injuries/1000-h, were sustained over one-year. WMSI were 6 times more likely to occur in Segment-6, compared with other segments (incident rate ratio = 6.055, P = 0.031). The highest rate of TLinj and traumatic injuries also occurred in Segment-6, reflecting concentrated rehearsal, New York season and performances abroad. More overuse injuries occurred in Segment-2, an international tour, attributed to raked stages. Lack of methods to quantify performance other than injury may mask effects of touring on dancer's well-being. Tracking complaints permits understanding of stressors to specific body regions and healthcare utilisation; however, TLinj remain the most important injuries to track because they impact other dancers and organisational costs.

Biomechanical metrics of aesthetic perception in dance.

The brain may be tuned to evaluate aesthetic perception through perceptual chunking when we observe the grace of the dancer. We modelled biomechanical metrics to explain biological determinants of aesthetic perception in dance. Eighteen expert (EXP) and intermediate (INT) dancers performed développé arabesque in three conditions: (1) slow tempo, (2) slow tempo with relevé, and (3) fast tempo. To compare biomechanical metrics of kinematic data, we calculated intra-excursion variability, principal component analysis (PCA), and dimensionless jerk for the gesture limb. Observers, all trained dancers, viewed motion capture stick figures of the trials and ranked each for aesthetic (1) proficiency and (2) movement smoothness. Statistical analyses included group by condition repeated-measures ANOVA for metric data; Mann-Whitney U rank and Friedman's rank tests for nonparametric rank data; Spearman's rho correlations to compare aesthetic rankings and metrics; and linear regression to examine which metric best quantified observers' aesthetic rankings, p < 0.05. The goodness of fit of the proposed models was determined using Akaike information criteria. Aesthetic proficiency and smoothness rankings of the dance movements revealed differences between groups and condition, p < 0.0001. EXP dancers were rated more aesthetically proficient than INT dancers. The slow and fast conditions were judged more aesthetically proficient than slow with relevé (p < 0.0001). Of the metrics, PCA best captured the differences due to group and condition. PCA also provided the most parsimonious model to explain aesthetic proficiency and smoothness rankings. By permitting organization of large data sets into simpler groupings, PCA may mirror the phenomenon of chunking in which the brain combines sensory motor elements into integrated units of behaviour. In this representation, the chunk of information which is remembered, and to which the observer reacts, is the elemental mode shape of the motion rather than physical displacements. This suggests that reduction in redundant information to a simplistic dimensionality is related to the experienced observer's aesthetic perception.

Extreme Kinematics in Selected Hip Hop Dance Sequences.

Hip hop dance has many styles including breakdance (breaking), house, popping and locking, funk, streetdance, krumping, Memphis jookin', and voguing. These movements combine the complexity of dance choreography with the challenges of gymnastics and acrobatic movements. Despite high injury rates in hip hop dance, particularly in breakdance, to date there are no published biomechanical studies in this population. The purpose of this study was to compare representative hip hop steps found in breakdance (toprock and breaking) and house and provide descriptive statistics of the angular displacements that occurred in these sequences. Six expert female hip hop dancers performed three choreographed dance sequences, top rock, breaking, and house, to standardized music-based tempos. Hip, knee, and ankle kinematics were collected during sequences that were 18 to 30 sec long. Hip, knee, and ankle three-dimensional peak joint angles were compared in repeated measures ANOVAs with post hoc tests where appropriate (p<0.01). Peak angles of the breaking sequence, which included floorwork, exceeded the other two sequences in the majority of planes and joints. Hip hop maximal joint angles exceeded reported activities of daily living and high injury sports such as gymnastics. Hip hop dancers work at weight-bearing joint end ranges where muscles are at a functional disadvantage. These results may explain why lower extremity injury rates are high in this population.

Frontotemporal oxyhemoglobin dynamics predict performance accuracy of dance simulation gameplay: temporal characteristics of top-down and bottom-up cortical activities.

We utilized the high temporal resolution of functional near-infrared spectroscopy to explore how sensory input (visual and rhythmic auditory cues) are processed in the cortical areas of multimodal integration to achieve coordinated motor output during unrestricted dance simulation gameplay. Using an open source clone of the dance simulation video game, Dance Dance Revolution, two cortical regions of interest were selected for study, the middle temporal gyrus (MTG) and the frontopolar cortex (FPC). We hypothesized that activity in the FPC would indicate top-down regulatory mechanisms of motor behavior; while that in the MTG would be sustained due to bottom-up integration of visual and auditory cues throughout the task. We also hypothesized that a correlation would exist between behavioral performance and the temporal patterns of the hemodynamic responses in these regions of interest. Results indicated that greater temporal accuracy of dance steps positively correlated with persistent activation of the MTG and with cumulative suppression of the FPC. When auditory cues were eliminated from the simulation, modifications in cortical responses were found depending on the gameplay performance. In the MTG, high-performance players showed an increase but low-performance players displayed a decrease in cumulative amount of the oxygenated hemoglobin response in the no music condition compared to that in the music condition. In the FPC, high-performance players showed relatively small variance in the activity regardless of the presence of auditory cues, while low-performance players showed larger differences in the activity between the no music and music conditions. These results suggest that the MTG plays an important role in the successful integration of visual and rhythmic cues and the FPC may work as top-down control to compensate for insufficient integrative ability of visual and rhythmic cues in the MTG. The relative relationships between these cortical areas indicated high- to low-performance levels when performing cued motor tasks. We propose that changes in these relationships can be monitored to gauge performance increases in motor learning and rehabilitation programs.

Activation of dorsolateral prefrontal cortex in a dual neuropsychological screening test: an fMRI approach.

BACKGROUND: The Kana Pick-out Test (KPT), which uses Kana or Japanese symbols that represent syllables, requires parallel processing of discrete (pick-out) and continuous (reading) dual tasks. As a dual task, the KPT is thought to test working memory and executive function, particularly in the prefrontal cortex (PFC), and is widely used in Japan as a clinical screen for dementia. Nevertheless, there has been little neurological investigation into PFC activity during this test. METHODS: We used functional magnetic resonance imaging (fMRI) to evaluate changes in the blood oxygenation level-dependent (BOLD) signal in young healthy adults during performance of a computerized KPT dual task (comprised of reading comprehension and picking out vowels) and compared it to its single task components (reading or vowel pick-out alone). RESULTS: Behavioral performance of the KPT degraded compared to its single task components. Performance of the KPT markedly increased BOLD signal intensity in the PFC, and also activated sensorimotor, parietal association, and visual cortex areas. In conjunction analyses, bilateral BOLD signal in the dorsolateral PFC (Brodmann's areas 45, 46) was present only in the KPT. CONCLUSIONS: Our results support the central bottleneck theory and suggest that the dorsolateral PFC is an important mediator of neural activity for both short-term storage and executive processes. Quantitative evaluation of the KPT with fMRI in healthy adults is the first step towards understanding the effects of aging or cognitive impairment on KPT performance.

Injury Characteristics in Pre-Professional Modern Dancers - Prospective Study of Differences Due to Sex, Training Year, and External Causal Mechanisms.

As efforts to improve surveillance and decrease injury rates in pre-professional dancer's progress, it is important to identify injury patterns and contexts. The aim of this study was to examine sex, training-based injury characteristics, and external causal mechanisms of injury among pre-professional modern dancers. Using a prospective cohort study design, 180 dancers (females = 140, males = 40, age 18.15 ± 0.68 years) were screened at freshman enrollment and followed for the 4 years of their college training. Injury, defined as medical attention injury (MAI) or time-loss injury (TLI), was classified by diagnosis, tissue category, body region, and incident event (action and dance environment). Negative binomial log-linear analyses evaluated injury rates by sex and training year. Multinomial regression compared injury characteristics and incident events, p < 0.05. Sex characteristics differed in height, mass, years of dance training, and previous injury (p ≤ 0.037). Total, traumatic, and overuse injuries per 1,000 hours decreased across training years for both injury definitions, p < 0.001, with no sex differences. In year 1, dancers were more likely to sustain muscle, tendon, and bone injuries (p ≤ 0.008) and to injure leg, ankle, foot, and hip, thigh, and knee regions (p ≤ 0.001). Jumping and running was the most commonly cited action mechanism in MAI and TLI in both sexes. Females were more likely to report alignment in MAI and TLI and jumping and running in TLI. Males were 1.4 times more likely to sustain muscle or tendon MAI (p = 0.006), while reporting partnering in MAI. Ballet class and rehearsals accounted for the majority of attributed dance environment mechanisms in MAI and TLI. Injury rates in pre-professional modern dancers decreased with training. Understanding sex, training, and external causal mechanisms will allow teachers to tailor programs to reduce injuries during training.

The Dance Functional Outcome Survey (DFOS) is Reliable, Valid, and Responsive in Pediatric Dancers.

The Dance Functional Outcome Survey (DFOS) is a dance-specific questionnaire developed for use with ballet and modern dancers at all training levels. To date, no study has assessed the psychometric properties of the DFOS in pediatric dancers. The purposes of this study were to determine: 1. the reliability of the DFOS when used with healthy and injured pediatric dancers; 2. the validity of the DFOS com- pared to a well-established generic scale, the Pediatric Quality of Life Inventory Physical Function Scale (PedsQL-PFS); and 3. the sensitivity and responsiveness to change of the DFOS in injured dancers. One hundred and two dancers completed the DFOS twice within 10 days. Intra-class correlation coefficients (ICCs) were used to assess test-retest reliability. In a sample of 148 dancers, construct validity was explored by comparing the DFOS to the PedsQL-PFS using Pearson correlations, and Exploratory Factor Analysis (EFA) and Cronbach's alpha were used for internal consistency analyses. A sub-set of 22 injured dancers was employed to examine responsiveness using repeated measures analysis of variance (p < 0.05). The DFOS demonstrated high test-retest reliability (ICC ≥ 0.90). The DFOS total score, activities of daily living (ADL), and dance technique sub-scores had strong construct validity compared to the PedsQL-PFS (r ≥ 0.79). Cronbach's alpha was high ( α = 0.92), indicating excellent internal consistency. There were significant differences across time in DFOS scores (p < 0.001), demonstrating responsiveness to change. There were no floor or ceiling effects. Thus, the DFOS demonstrates excellent reliability, strong validity, and good responsiveness over time and is a viable tool for assessing function in pediatric dancers.

Inter- and Intra-Rater Reliability of Handheld Dynamometry for Lower Extremity Strength Testing in Pre-Professional Dancers.

Handheld dynamometry (HHD) using external fixation has demonstrated high inter- and intra-rater reliability. Handheld dynamometry offers an objective way to quantify strength; however, setting up external stabilization devices for HHD can be time consuming. This study examined the reliability of HHD for lower extremity strength in dancers using body weight stabilization. Twenty-six pre-professional dancers (age: 20.64 ± 2.21 years) were recruited and assessed by three testers: an experienced physical therapist (ePT), a novice physical therapist (nPT), and a student physical therapist (SPT). To avoid testing fatigue, dancers were divided into two testing groups and were evaluated on separate weekends. Testers used HHD to test isometric force production of six muscle groups in the first cohort and seven dif- ferent muscle groups in the second cohort. Testing positions were standardized and utilized a "make" test protocol. Intra- class correlation coefficients (ICC), 95% confidence interval, and standard error of measurement were calculated for each position. Inter-rater reliability was > 0.75 for all ICC measures except knee extension and ankle eversion. Intra-rater reliability was > 0.75 for all ICC measures except the ePT (tester A) day 2 for hip extension, internal rotation seated, knee extension, and ankle dorsiflexion; nPT (tester B) day 1 knee flexion; and SPT (tester C) for day 1 knee extension and ankle eversion and days 1 and 2 for ankle dorsiflexion and inversion. It is concluded that HHD can reliably measure force production of hip, knee, and ankle muscle groups without use of external fixation devices.

Cross-Cultural Adaptation of the Dance Functional Outcome Survey (DFOS) for Spanish Dancers.

A growing number of research papers regarding Spanish-speaking dancers justifies the need for an adapted Spanish version of the Dance Functional Outcome Survey (DFOS). The objective of this study was to cross-culturally adapt and validate the DFOS for Spanish-speaking dancers. A sample of 127 healthy and injured professional and pre-professional dancers were recruited. Test-retest reliability of DFOS-Sp was examined using intraclass correlation coefficients. Construct validity compared DFOS-Sp to the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) using Pearson correlations. Principal component analysis identified factors and internal-item consistency. Sensitivity was evaluated by generating receiver operating characteristic and area under the curve analyses. A subgroup of 51 injured dancers were followed across three time-points to examine responsiveness using repeated measures analysis of variance. Injured scores were analyzed for floor and ceiling effects. The DFOS-Sp showed high test-retest reliability (ICC2,1 ≥ 0.92). DFOS-Sp scores had moderate construct validity compared with SF-36 physical component summary scores (r ≥ 0.56). Principal component analysis (PCA) supported uni-dimensionality explaining 58% of the variance with high internal consistency (α = 0.91).Area under the curve (AUC) sensitivity values were excellent (AUC ≥ 0.82). There were significant differences across time (p < 0.001), demonstrating responsiveness to change, with no floor or ceiling effects. The DFOS-Sp demonstrated acceptable test-retest reliability and validity in Spanish-speaking dancers, with comparable psychometric performance to the English-language version.

Ankle Injuries in Dancers.

The term dance encompasses a broad range of different styles; much of the orthopaedic literature has focused on ballet dancers. Injury is common in dancers at all levels, and many serious dancers sustain multiple injuries as they progress through their career. Foot and ankle injuries are among the most common injuries experienced by dancers. These injuries include those that are specific to dancers because of the unique physical maneuvers required to effectively perform, but they can also include common injuries that may require relatively different treatment because of the physical demands of the dancer. Os trigonum syndrome and flexor hallucis longus tenosynovitis generally fall into the former category as they are injuries that are more prevalent in dancers due to the extreme plantarflexion involved in dancing, especially ballet, and the relative demand placed on the toe flexors, most notably the flexor hallucis longus. On the other hand, anterior ankle impingement occurs both in dancers and in the general public. In many cases, a team approach to treatment with knowledgeable physical therapists can obviate the need for surgical treatment. If surgical treatment proves necessary, good results can be achieved with sound surgical technique and a well thought-out rehabilitation program.

Psychometric Properties of the Dance Functional Outcome Survey (DFOS): Reliability, Validity, and Responsiveness.

BACKGROUND: There are no outcomes measures that focus on the unique functional requirements of dancers. OBJECTIVES: To evaluate test-retest reliability, internal consistency, construct validity, sensitivity, and responsiveness of the Dance Functional Outcome Survey (DFOS) in professional and preprofessional adult dancers. METHODS: This prospective cohort study examined test-retest reliability of the DFOS in 198 healthy and injured dancers over 2 weeks, using intraclass correlation coefficients (ICC2,1). In a sample of 725 healthy and injured dancers, the following were examined: (1) construct validity, by comparing the DFOS to the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) using Pearson correlations; (2) exploratory factor analysis and internal consistency; and (3) sensitivity, by generating receiver operating characteristic curves and determining area under the curve (AUC). In a subgroup of 47 injured dancers, we determined internal responsiveness across 4 time points using repeated-measures analysis of variance (P<.05). Injured dancers' scores were analyzed for floor and ceiling effects. RESULTS: The DFOS demonstrated high test-retest reliability (ICC≥0.93). Single-factor loading in exploratory factor analysis supported unidimensionality of the scale, with high internal consistency (α = .96). The DFOS total score and activities-of-daily-living (ADL) and dance technique subscores had strong construct validity compared with scores on the SF-36 physical component summary (r≥0.77). This study found excellent sensitivity, with high AUC values (AUC≥0.91). There were significant differences across time for DFOS scores (P<.001), demonstrating responsiveness to change. There were no floor or ceiling effects. CONCLUSION: The DFOS demonstrates acceptable psychometric performance as an outcome and screening measure for dancers. The DFOS is a useful tool to monitor both healthy state and functional limitation following lower extremity or low back injury in adult ballet and modern dancers. J Orthop Sports Phys Ther 2019;49(2):64-79. Epub 27 Jul 2018. doi: 10.2519/jospt.2019.8247.