Perspectives of Ballet Dancers on Causes of Their Injuries and Implementation of Injury Preventive Measures by Ballet Teachers and Masters.

OBJECTIVES: Ballet dancers have a high injury risk. We aimed to gain insight into the causes for acute and overuse injuries in ballet dancers and the level of implementation of injury prevention by ballet teachers/masters, as perceived by dancers. METHODS: An international cross-sectional online-survey was based on the Fit-to-Dance Questionnaire and literature. Adult amateur, pre-professional, and professional ballet dancers reported the perceived causes of their injuries sustained in the previous 2 years. Multiple answers per injury were possible. Also, dancers rated the level of implementation of measures to prevent injury by their ballet teachers and ballet masters based on 21 items using a 5-point Likert scale. Causes were analyzed per-injury as well as per-dancer. RESULTS: 188 ballet ensembles and 51 dance organizations were contacted, from which 192 ballet dancers (mean age 27 ±7.8 yrs, 83% females) responded. 119 dancers (62%) reported 203 acute and 164 (85%) reported 469 overuse injuries. Fatigue was the most frequently perceived cause for acute injuries in the per-injury (n=89, 43.8%) and per-dancer analysis (n=63, 32.8%). For overuse injuries, pressure from the teacher/master was most frequently perceived as cause in the per-injury analysis (n=240, 51.2%), specifically in pre-/professional dancers (n=233, 61.3%). In the per-dancer analysis, fatigue/overtraining scored highest for overuse injuries (n=107; 55.7%). Other causes were previous/repetitive injuries (acute-per-injury 26.1%, acute-per-dancer 22.4%; overuse-per-injury 46.3%, overuse-per-dancer 53.1%) or erroneous dance technique (acute-per-injury 24.6%, acute-per-dancer 21.9%; overuse-per-injury 47.8%, overuse-per-dancer 45.3%). With regard to perceived level of implementation of injury preventive measures by ballet teachers/masters to prevent musculoskeletal injuries, 2 items received high ratings, 12 moderate ratings and 6 low ratings. CONCLUSIONS: Fatigue and pressure accounted for the majority of perceived causes for injuries. Perceived support by ballet teachers/masters regarding injury prevention was moderate to low. Future research should focus on the awareness, attitudes, and the important role of ballet teachers/masters for injury prevention in dancers.

Physical activity, sports participation and exercise-related constraints in adult women with primary hypothyroidism treated with thyroid hormone replacement therapy.

Awareness of physical activity (PA) constraints in patients with primary hypothyroidism on thyroid hormone replacement therapy (THR) is important. Hence, this cross-sectional matched case-control study aimed to determine PA and sports participation (SP) in patients with hypothyroidism on THR in comparison to control subjects. Accordingly, survey questions were selected from the National Survey on Injuries and Physical Activity in the Netherlands (IPAN), supplemented with questions related to self-reported clinical characteristics and exercise-related constraints (ERC) of patients. In total, 1,724 female patients (mean age 53.0 years ±11.6) and 1,802 controls (mean age 52.6 ± 13.2) were included. Compared to controls, patients were less likely to comply with the moderate-intensity PA guideline (OR 0.70; 95% CI: 0.611-0.803), although patients were more actively participating in sports (OR 1.40; 95% CI: 1.156-1.706). Two-thirds of patients reported that hypothyroidism was limiting their PA performance. These limitations were more pronounced in patients with autoimmune thyroiditis (AIT) than in patients with hypothyroidism from other aetiology (OR 1.93; 95% CI: 1.518-2.457), representing disease-specific exercise intolerance. In order to establish effective intervention programmes to encourage regular PA in hypothyroid patients on THR with exercise intolerance, further research is warranted to better understand PA barriers.

The impact of injury definitions on measures of injury occurrence in classical music students: a prospective cohort study.

BACKGROUND: Multiple definitions are used to investigate injuries in musicians, resulting in a wide range of prevalence rates. The aim of this study is to establish the impact of different injury definitions on the prevalence of injuries and disability in classical music students. Moreover, the practical implications of using different injury definitions are considered. METHODS: A prospective cohort study among first-year classical music students was performed using bi-monthly questionnaires focusing on injuries. Three injury definitions were used: 1) all MSK complaints injury (any MSK complaint resulting in a VAS pain score > 0 in the past eight weeks), 2) medical attention injury (any MSK complaint that resulted in a student consulting a health provider in the past eight weeks), 3) time-loss injury (any MSK complaint that resulted in partly/completely missing music classes or activities in the past eight weeks). For all injury definitions prevalences were calculated and compared. Furthermore, the Disabilities of the Arm, Shoulder and Hand performing arts module (DASH-pa) was used to calculate disability scores for all three injury definitions. RESULTS: Twenty-nine classical music students participated in the current study. The total response rate over one academic year was 85.3%. One year prevalences of all MSK complaints, medical attention and time-loss were 96.6, 17.2 and 13.8% respectively. The bi-monthly prevalences ranged from 74.1 to 96.0% for all MSK complaints, from 5.6 to 11.5% for medical attention injuries and from 0 to 11.5% for time loss injuries. Scores on the DASH-pa ranged from 15.6 to 26.9 for MSK complaints, 33.3 to 50 for medical attention and 47.9 to 62.5 for time-loss injuries. CONCLUSION: The choice of injury definition is a critical factor affecting the outcome of music injury surveillance studies. To reach a consensus, it is therefore important to consider the different injury definitions depending on the goal of the injury surveillance and the practical implications.

Risk Factors for Lower-Extremity Injuries Among Contemporary Dance Students.

OBJECTIVE: To determine whether student characteristics, lower-extremity kinematics, and strength are risk factors for sustaining lower-extremity injuries in preprofessional contemporary dancers. DESIGN: Prospective cohort study. SETTING: Codarts University of the Arts. PATIENTS: Forty-five first-year students of Bachelor Dance and Bachelor Dance Teacher. ASSESSMENT OF RISK FACTORS: At the beginning of the academic year, the injury history (only lower-extremity) and student characteristics (age, sex, educational program) were assessed using a questionnaire. Besides, lower-extremity kinematics [single-leg squat (SLS)], strength (countermovement jump) and height and weight (body mass index) were measured during a physical performance test. MAIN OUTCOME MEASURES: Substantial lower-extremity injuries during the academic year were defined as any problems leading to moderate or severe reductions in training volume or in performance, or complete inability to participate in dance at least once during follow-up as measured with the Oslo Sports Trauma Research Center (OSTRC) Questionnaire on Health Problems. Injuries were recorded on a monthly basis using a questionnaire. Analyses on leg-level were performed using generalized estimating equations to test the associations between substantial lower-extremity injuries and potential risk factors. RESULTS: The 1-year incidence of lower-extremity injuries was 82.2%. Of these, 51.4% was a substantial lower-extremity injury. Multivariate analyses identified that ankle dorsiflexion during the SLS (OR 1.25; 95% confidence interval, 1.03-1.52) was a risk factor for a substantial lower-extremity injury. CONCLUSIONS: The findings indicate that contemporary dance students are at high risk for lower-extremity injuries. Therefore, the identified risk factor (ankle dorsiflexion) should be considered for prevention purposes.

Characteristics, Properties, and Associations of Self-Assessed Pain Questionnaires: A Literature Review and Prospective Cohort Study Among Dance Students.

OBJECTIVES: To provide an overview of measurement properties of the Oslo Sports Trauma Research Center Questionnaire (OSTRCQ), pain visual analogue scale (VAS-pain) and Self-Estimated Functional Inability Because of Pain (SEFIP) scale in dance populations, and to investigate the relationship between these questionnaires in pre-professional contemporary dancers. METHODS: A search of PubMed was conducted and studies were included if they 1) used one of the three questionnaires within a dance population and 2) assessed the reliability, validity, or responsiveness of the questionnaire(s). 134 dance students (67.5% female; 19.4±1.5 yrs) were prospectively followed during 1 academic year. The OSTRCQ, VAS-pain, SEFIP, and injuries were self-assessed on a monthly basis. Pearson correlation analyses and repeated measures correlation analyses were performed to identify possible associations. RESULTS: The literature overview resulted in two studies describing measurement properties of the SEFIP (n=1) and OSTRCQ (n=1). Prevalence of injuries ranged from 23.1 to 42.6%. Weak monthly correlations (r=0.14-0.50) were found between OSTRCQ and SEFIP. Moderate monthly correlations (r=0.54-0.71) were found between OSTRCQ and VAS-pain, and weak/moderate monthly correlations (r=0.30-0.62) were found between SEFIP and VAS-pain. Repeated measures correlation demonstrated a moderate overall correlation between ORSTCQ and VAS-pain (r=0.57), with weak overall correlations between ORSTCQ and SEFIP (r=0.26) and SEFIP and VAS-pain (r=0.34). CONCLUSIONS: Studies on measurement properties of questionnaires in dance are scarce. Weak/moderate associations were found between the OSTRCQ, SEFIP, and the VAS-pain questionnaires. Future high-quality research should investigate measurement properties of these questionnaires within dance populations. The results contribute by substantiating choices when developing a surveillance system.

Health Problems in Conservatoire Students: A Retrospective Study Focusing on Playing-Related Musculoskeletal Disorders and Mental Health.

OBJECTIVE: To gain insight into the prevalence and characteristics of physical health problems and mental health problems in first-, second- and third-year conservatoire students of the classical music department. Also, differences in mental health and general health were investigated between students with playing-related musculoskeletal disorders (PRMDs) and students without PRMDs. METHODS: Eighty-nine classical music students of Codarts Rotterdam, University of the Arts, were asked to complete a questionnaire targeting PRMDs (components derived from Musculoskeletal Pain Intensity and Interference Questionnaire for Musicians, MPIIQM), mental health (Mental Health Inventory-5), and self-rated general health (SF-1 from Short Form health survey SF-12). RESULTS: The response rate was 52% (n=46). Of all participants, 17.8% (n=8) had experienced PRMDs in the past 12 months and 45.7% (n=21) of the students reported poor mental health (MHI-5≤60). Students experiencing PRMDs in the past 12 months reported poorer general health compared to students without PRMDs (43.8 vs 67.1 [range 0-100], p=0.012). No significant difference was found between the groups with regard to mental health (62.0 vs 66.5 [range 0-100], p=0.522). CONCLUSION: The burden of PRMD complaints in this population of conservatoire students seems relatively low. However, the number of students facing mental problems in this population is a cause for concern. Conservatoires should focus on the subject of mental health in their curricula to increase more awareness and prevent mental problems. To investigate possible causality between PRMDs and general health, prospective studies are needed.

Hip and groin injury is the most common non-time-loss injury in female amateur football.

PURPOSE: Hip and groin injuries in football are problematic due to their high incidence and risk of chronicity and recurrence. The use of only time-loss injury definitions may underestimate the burden of hip and groin injuries. Little is known about hip and groin injury epidemiology in female football. The first aim of this study was to examine the within-season (2014-2015) prevalence of total injury with and without time-loss in female amateur football players. The second aim was to study the within-season and preseason (2015-2016) prevalence of hip/groin injuries with and without time-loss. The third aim was to study the association between the duration of hip and groin injury in the 2014-2015 season and the severity of hip/groin problems during the 2015-2016 preseason. METHODS: During the preseason, 434 Dutch female amateur football players completed an online questionnaire based on the previous season and current preseason. The hip and groin outcome score (HAGOS) was used to assess the severity of hip and groin injuries. RESULTS: The hip/groin (17%), knee (14%), and ankle (12%) were the most frequent non-time-loss injury locations. The ankle (22%), knee (18%), hamstring (11%), thigh (10%), and hip/groin (9%) were the most common time-loss injury locations. The previous season prevalence of total injury was 93%, of which non-time-loss injury was 63% and time-loss injury was 37%. The prevalence of hip/groin injury was 40%, non-time-loss hip/groin injury was 36% and time-loss hip/groin injury was 11%. The preseason prevalence of hip/groin injury was 27%, non-time-loss hip/groin injury was 25%, and time-loss hip/groin injury was 4%. Players with longstanding hip/groin injury (> 28 days) in the previous season had lower HAGOS scores at the next preseason than players with short-term (1-7 days) or no hip/groin injury (p < 0.001). From all players with hip/groin injury from the previous season, 52% also sustained hip/groin injury in the following preseason, of which 73% were recurrent and 27% were chronic hip/groin injuries. CONCLUSION: Injury risk, and especially non-time-loss hip and groin injury risk, is high in female amateur football. Three-quarters of the players with longstanding hip and groin injuries in the previous season have residual problems at the start of the following season. LEVEL OF EVIDENCE: II.

Influence of Movement Quality on Heart Rate While Performing the Dance-Specific Aerobic Fitness Test (DAFT) in Preprofessional Contemporary Dancers.

OBJECTIVES: To explore whether movement quality has influence on heart rate (HR) frequency during the dance-specific aerobic fitness test (DAFT). METHODS: Thirteen contemporary university dance students (age 19 ± 1.46 yrs) underwent two trials performing the DAFT while wearing a Polar HR monitor (Kempele, Finland). During the first trial, dancers were asked to perform the movements as if they were performing on stage, whereas during the second trial, standardized verbal instructions were given to reduce the quality of movement (e.g., no need to perform technically correct pliés). The variables measured at each trial were HR for all five stages of the DAFT and HR recovery (1 and 2 min after finishing the DAFT), movement quality (MQ) score, and rate of perceived exertion score (RPE). RESULTS: There were significant differences in HR between Trial 1 and Trial 2. For all stages and the resting period, HR was lower during Trial 2 (p<0.001). Also, the RPE score was significantly lower and the MQ score was significantly higher, indicating a poorer performance, during Trial 2 (both p<0.001). CONCLUSION: The results suggest that DAFT performance with lower movement quality elicits lower HR frequency and RPE during the DAFT. We recommend that specific instructions be given to participants about executing the movement sequence during the DAFT before testing commences. Also, movement quality must be taken into account when interpreting HR results from the DAFT in order to distinguish if a dancer's low HR results from good aerobic fitness or from poor performance of the movement sequence.

Decreased physical activity, reduced QoL and presence of debilitating fatigue in patients with Addison's disease.

BACKGROUND: Health-related quality of life in patients with Addison's disease has been assessed in various European countries, indicating a reduced quality of life. However, no studies have addressed the impact of Addison's disease on physical activity. OBJECTIVE: The aim of this study was to investigate the quality of life in Dutch patients with Addison's disease particularly regarding the presence of fatigue and the ability to be physically active. METHODS: In this cross-sectional study, a postal survey was performed among Dutch patients with Addison's disease on stable glucocorticoid replacement therapy with hydrocortisone or cortisone acetate. For quality of life and physical activity assessment, patients completed general and health-related quality of life and physical activity questionnaires, and scores were compared to Dutch controls. RESULTS: A total of 328 patients with Addison's disease were studied. In patients with Addison's disease, only 45·7% met the standard of physical activity (Combinorm) compared to 67·8% of Dutch controls (P < 0·01). Forty-eight per cent of patients showed abnormal fatigue, while 61% had severe fatigue. The CIS fatigue scores were significantly higher compared to controls (P < 0·01). We found reduced general subjective health-related QoL scores in both male and female patients, especially in younger patients <65 years of age. CONCLUSION: Physical activity is decreased in patients with Addison's disease, combined with a reduced subjective health-related QoL and increased fatigue.

Soccer injuries and recovery in Dutch male amateur soccer players: results of a prospective cohort study.

OBJECTIVE: To describe characteristics of outdoor soccer injury and recovery among Dutch soccer players. DESIGN: Prospective cohort study. SETTING: The 2009-2010 competitive season (33 weeks). PARTICIPANTS: Four hundred fifty-six Dutch male soccer players of 23 amateur teams. MAIN OUTCOME MEASURES: Coaches recorded individual exposure to all soccer activities. Paramedics or sports trainers collected information on the occurrence (e.g., location, type, circumstances) and consequences (eg, absenteeism, medical treatment) of injuries. RESULTS: In total, 424 time-loss injuries were sustained by 60% (n = 274) of the players, with 23% (n = 105) having more than 1 injury. This corresponds to an overall density of 9.6 (8.7-10.5) injuries per 1000 player hours; 3.9 (3.3-4.7) in training sessions and 20.4 (18.1-23.1) in soccer matches. Almost 30% (n = 123) of the injuries lasted for more than 1 month, 14% (n = 58) were reinjuries (causing longer absence than new injuries), and 54% (n = 230) of the injuries were given medical treatment. The most common diagnoses were muscle/tendon (38%) or joint/ligament injuries (23%) of the lower extremities. After regaining the ability to fully take part in soccer training or matches, 27.4% of the players (n = 116) still reported complaints. CONCLUSIONS: Two recommendations based on the above-mentioned results are (1) prevention should primarily focus on these most common diagnoses and (2) players resuming soccer activities after an injury should be given special attention to resolve the remaining complaints and to prevent reinjuries.

Injury Prevalence Among Elite Adolescent Ballet Dancers is not Affected by Frequency of Questionnaire Administration: A 6-Month Exploratory Prospective Study.

INTRODUCTION: The Oslo Sports Trauma Research Centre Questionnaire on Health Problems (OSTRC-H) is a valid and reliable registration method for self-reported injuries and is regularly used among dancer populations. Monthly questionnaire administration is acceptable in athlete populations but has not been evaluated in dancers. The aim of this exploratory study was to assess the influence of weekly versus monthly administration of the OSTRC-H on estimated injury outcomes among elite adolescent ballet dancers. METHODS: Participants (n = 103) were prospectively followed for 6 months and completed the OSTRC-H online, evaluating perceived consequences of self-reported health problems during the previous week and the previous 4 weeks, respectively. Four definitions of dance-related injury were utilized: (1) all complaints, (2) substantial, (3) medical attention, and (4) time-loss injuries. Descriptive statistics estimated: (1) the number of injuries reported (count), (2) average injury prevalence [proportion, 95% confidence intervals (CI)], (3) average severity score (0-100), and (4) days of time loss (count) for each injury definition. The 4 outcome measures were then compared between weekly and monthly registration with paired sample t-tests (P < .05) and overlapping 95% CI. RESULTS: A significant difference between the number of all complaints injuries (weekly: 133; monthly: 94; P < .001) and substantial injuries (weekly: 64; monthly: 45; P = .012) was found. Regardless of injury definition, there were no significant differences between injury prevalence, severity scores, and days of time loss when reported weekly versus monthly. CONCLUSION: Monthly administration of the OSTRC-H is an acceptable method to estimate injury prevalence, severity scores, and days of time loss amongst elite adolescent ballet dancers.

Health consultations at a performing arts health centre among classical music students based on electronic health record data: a cross-sectional study.

Physical and mental health problems in music students are usually identified using self-reported data. The use of an Electronic Health Record database can avoid biases to give an overview of the extent of health problems in this population. Therefore, the aim of this study is to gain insight into both physical and mental health related issues in classical music students using this type of data collection. An Electronic Health Record database including five years of data from a Performing Arts Health Centre (PAHC) of a university or the arts, was used to analyze the number and characteristics of health consultations in music students. The total number of students, health consultations and the average number of visits per health consultation were calculated over five years. Furthermore, numbers and percentages of both physical and mental health consultations were registered. Also, the number and percentage of health consultations per instrument group were compared to the proportion of each instrument group within the specific sample. Over a period of five years, 230 students visited the PAHC and 417 health consultations were reported. 43.5% of the students who visited a health professional indicated at least one physical health consultation, 29.1% at least one mental health consultation and 27.4% at least one in both categories. An injury was the most frequently registered physical health consultation (40.2%), followed by performance improvement (9.8%) and stress (9.6%). Voice students registered relatively most health consultations. As far as we know, this is the first cross-sectional study using Electronic Health Record data from a PAHC to gain insight into both physical and mental health related issues in a population of classical music students. Looking at the variety of health consultations registered in the database, a multidisciplinary team and multidisciplinary approach are necessary to meet the needs of the students in terms of physical and mental health support and performance improvement.

A Systematic Review of Cardiorespiratory Fitness Tests Used in Dance.

Dancers need adequate cardiorespiratory fitness (CRF) levels in order to cope with the demands of dance classes and choreographies. Screening and monitoring of CRF is advised. The aim of this systematic review was to provide an overview of tests used to assess CRF in dancers and to examine the measurement properties of these tests. A literature search was performed in three online databases (PubMed, EMBASE, and SPORTDiscus) up until August 16, 2021. Study inclusion criteria were: 1. a CRF test was used; 2. participants were ballet, contemporary or modern, or jazz dancers; and 3. English full-text peer-reviewed article. General study information, participant information, CRF test used, and study outcome were extracted. If available, measurement property data were extracted (i.e., test reliability, validity, responsiveness, and interpretability). Of the 48 articles included in the review, most used a maximal treadmill test (n = 22) or the multistage Dance Specific Aerobic Fitness test (DAFT; n = 11). Out of the 48 included studies, only six examined the measurement properties of CRF tests: Aerobic Power Index (API), Ballet-specific Aerobic Fitness Test (B-DAFT), DAFT, High-Intensity Dance Performance Fitness Test (HIDT), Seifert Assessment of Functional Capactiy for Dancers (SAFD), and the 3-minute step test. Good test-retest reliability was found for the B-DAFT, DAFT, HIDT, and SAFD. Criterion validity was determined for the VO2peak of the API, the 3-MST, HIDT, and SAFD. For HRpeak, criterion validity was studied for the 3-MST, HIDT, and SAFD. While different CRF tests are being used in descriptive and experimental research within dance populations, the body of research supporting the measurement properties of such tests is very small. As many studies have methodological flaws (e.g., small participant numbers or no statistical analysis for validity or reliability), additional good quality research is required to re-examine and complement current measurement property results of the API, B-DAFT, DAFT, HIDT, SAFD, and 3-MST.

Aerobic and Anaerobic Fitness Levels of Pre-Professional Contemporary Dancers: An Exploration of 2 Dance-Specific Field Tests.

INTRODUCTION: The primary aim of this study was to present descriptive heart rate (HR), heart rate recovery (HRR) and RPE data for the DAFT and HIDT within one sample of contemporary dance students. The second aim was to explore if objective (HR) and subjective (RPE) data were correlated between tests. METHOD: 40 (11 males, 29 females) university dance students with a mean age of 18.8 ± 1.8 years performed the DAFT and HIDT on 2 separate occasions within 1 week. Measurements were HR after 4 minutes in all stages of the DAFT, the percentage of age-predicted maximal HR (%HRmax) of all stages of the DAFT and at the end of the HIDT, and peak HR (HRpeak) at the end of both tests. Subjective ratings of perceived exertion (RPE) and HR recovery after 1 minute of rest (HRR) were determined after the tests. RESULTS: HRpeak of the DAFT and HIDT were 188.1 ± 11.0 and 185.3 ± 7.3 beats·min-1, respectively. There were high positive correlations between HRpeak of the HIDT and stages 3 to 5 of the DAFT (r = 0.716-0.740, all P-values < .01). HRR (r = .678, P < .01) and %HRmax (r = .746, P < .01) showed moderate to high correlations between the DAFT and HIDT. The anaerobic training zone was reached in stages 4 and 5 of the DAFT and at the end of the HIDT. The subjective RPE scores did not significantly correlate between DAFT and HIDT, neither with objective HR data. CONCLUSION: Although the DAFT and HIDT differ in intensity and work-to-rest ratio, there were high correlations between HR and HRR data of both tests and both tests reached intensities above the anaerobic threshold (%HRmax > 85%).

An analysis of teachers' instructions and feedback at a contemporary dance university.

Background: Given the demands posed by excessive practice quantities in modern dance, physical and mental health can be compromised. Therefore, there is a need to consider how quality of practice may be improved and possibly even reduce training times. Sports literature has shown that instructions and feedback given by coaches can have an effect on the quality of training and influence self-regulation and the performance of athletes. However, currently little is known about the use of instructions and feedback by dance teachers. The aim of the current study was, therefore, to examine the type of instructions and feedback given by dance teachers during various dance classes. Methods: A total of six dance teachers participated in this study. Video and audio recordings were made of six dance classes and two rehearsals at a contemporary dance university. The dance teacher's coaching behavior was analyzed using the modified Coach Analysis and Intervention System (CAIS). Additionally, feedback and instructions were also examined in terms of their corresponding focus of attention. Absolute numbers, as well as times per minute (TPM) rates were calculated for each behavior before, during, and after an exercise. Absolute numbers were also used to calculate ratios of positive-negative feedback and open-closed questions. Results: Most feedback comments were given after an exercise (472 out of 986 total observed behaviors). Improvisation had the highest positive-negative feedback ratio (29) and open-closed questions ratio (1.56). Out of the focus of attention comments, internal focus of attention comments were used most frequently (572 out of 900). Discussion/conclusion: The results make clear that there is a large variability in instructions and feedback over teachers and classes. Overall, there is room for improvement toward a higher positive-negative feedback ratio, a higher open-closed question ratio and producing more comments eliciting an external focus of attention.

Predicting readiness for return to sport and performance after anterior cruciate ligament reconstruction rehabilitation.

BACKGROUND: Determining readiness to return to sport after anterior cruciate ligament (ACL) reconstruction is challenging. OBJECTIVES: To develop models to predict initial (directly after rehabilitation) and sustainable (one year after rehabilitation) return to sport and performance in individuals after ACL reconstruction. METHODS: We conducted a multicentre, prospective cohort study and included 208 participants. Potential predictors - demographics, pain, effusion, knee extension, muscle strength tests, jump tasks and three sport-specific questionnaires - were measured at the end of rehabilitation and 12 months post discharge from rehabilitation. Four prediction models were developed using backward logistic regression. All models were internally validated by bootstrapping. RESULTS: All 4 models shared 3 predictors: the participant's goal to return to their pre-injury level of sport, the participant's psychological readiness and ACL injury on the non-dominant leg. Another predictor for initial return to sport was no knee valgus, and, for sustainable return to sport, the single-leg side hop. Bootstrapping shrinkage factor was between 0.91 and 0.95, therefore the models' properties were similar before and after internal validation. The areas under the curve of the models ranged from 0.74 to 0.86. Nagelkerke's R2 varied from 0.23 to 0.43 and the Hosmer-Lemeshow test results varied from 2.7 (p = 0.95) to 8.2 (p = 0.41). CONCLUSION: Initial and sustainable return to sport and performance after anterior cruciate ligament reconstruction rehabilitation can be easily predicted by the sport goal formulated by the individual, the individual's psychological readiness, and whether the affected leg is the dominant or non-dominant leg.

Effectiveness of an injury prevention programme for adult male amateur soccer players: a cluster-randomised controlled trial.

BACKGROUND: The incidence rate of soccer injuries is among the highest in sports, particularly for adult male soccer players. PURPOSE: To investigate the effect of the 'The11' injury prevention programme on injury incidence and injury severity in adult male amateur soccer players. STUDY DESIGN: Cluster-randomised controlled trial. METHODS: Teams from two high-level amateur soccer competitions were randomly assigned to an intervention (n=11 teams, 223 players) or control group (n=12 teams, 233 players). The intervention group was instructed to perform The11 in each practice session during one soccer season. The11 focuses on core stability, eccentric training of thigh muscles, proprioceptive training, dynamic stabilisation and plyometrics with straight leg alignment. All participants of the control group continued their practice sessions as usual. RESULTS: In total, 427 injuries were recorded, affecting 274 of 456 players (60.1%). Compliance with the intervention programme was good (team compliance=73%, player compliance=71%). Contrary to the hypothesis, injury incidences were almost equal between the two study groups: 9.6 per 1000 sports hours (8.4-11.0) for the intervention group and 9.7 (8.5-11.1) for the control group. No significant differences were found in injury severity, but a significant difference was observed in the location of the injuries: players in the intervention group sustained significantly less knee injuries. CONCLUSIONS: This study did not find significant differences in the overall injury incidence or injury severity between the intervention and control group of adult male soccer players. More research is recommended, focusing on injury aetiology and risk factors in adult male amateur soccer players.

Multiple Factors Influencing Healthy Performance for Pre-professional and Professional Classical Violinists: An Exploratory Study Focusing on Physical Health.

Musculoskeletal complaints are common in pre-professional and professional classical violinists and these complaints can affect violinists' performance. Therefore, it is important to identify the factors that contribute to healthy performance in this population. Qualitative studies with a variety of stakeholders are able to provide insights from different perspectives into factors influencing healthy performance for the pre-professional and professional classical violinist. In the current small-scale, exploratory study, semi-structured interviews were conducted with various stakeholders; two classical violin students, one classical violin teacher, a physiotherapist, a professional classical violinist, who is also a performance coach, and a health specialist who also graduated as a professional classical violist. Thematic analysis was conducted using Atlas.ti 9. We identified six themes that were indicated as important by the participants in terms of ensuring healthy performance for the pre-professional and professional classical violinist. The themes were: (1) physical aspects (involved in playing the violin); (2) practice routine and techniques; (3) interaction between physical and mental aspects; (4) culture; (5) role of the main subject teacher; and (6) preventive measures. Furthermore, when asked specifically about the development of a physical screening tool, the participants indicated that such a tool should include multiple factors covering various regions of the body, the inclusion of a questionnaire on risk-factors, and follow-up measurements. Also, collaborations between health professionals and main subject teachers were recommended as part of the screening tool to increase commitment of participating students. The results of the current study are based on the opinions, attitudes, and ideas of a small, selected group of participants only and cannot be generalized to a wider group of violinists. More research is needed regarding factors influencing healthy performance, before conservatoires and professional orchestras can develop programs for a healthy playing environment for pre-professional and professional violinists.

Quantifying Internal Load in Pre-Professional Contemporary Dancers: The Association Between Objective Heart-Rate Derived Outcome Measures and Subjective Dancers' and Teachers' Perceptions.

BACKGROUND: Monitoring heart rate is one of the most common methods used to quantify internal training load (ITL) in athletes. The aim of this study was to determine whether subjective measurements can be used as a simple, non-invasive, and inexpensive method for assessing ITL in pre-professional contemporary dancers.
Method: A total of 16 first-year contemporary dance students participated in this study. Students wore heart rate monitors during 56 training sessions. After each session, students completed the rate of perceived exertion (RPE) scale and teachers completed the rate of observed exertion (ROE) scale. For each session, we calculated the session-RPEs (sRPE), session-ROEs (sROE), and heart-rate-derived ITLs [i. e., Banister TRaining IMPulse method (TRIMP) and Edwards TRIMP]. Pearson correlation coefficients were calculated to determine the association between sRPE, sROE, Banister TRIMP, and Edwards TRIMP.
Results: Between-individual correlation between Banister TRIMP and subjective dancers' (sRPE) and teachers' perceptions (sROE) were moderate (r = .49, p < 0.01) to large (r = .57, p < 0.01). Between-individual correlations between Edwards TRIMP and the subjective perceptions (sRPE and sROE) were very large (r = .74, p < 0.01; and r = .79, p < 0.01). There was a statistically significant large (r = 0.52, p < 0.01) to almost perfect (r = 0.93, p < 0.01) within-individual correlation between the sRPE and the two measured TRIMP methods. There was a statistically significant small (r = .29, p < 0.01) to almost perfect (r = .92, p < 0.01) within-individual correlation between the sROE and the two measured TRIMP methods.
Conclusion: The results of this study suggest that the sRPE is a simple, non-invasive, inexpensive, and valid method for quantifying ITL in pre-professional dancers.

Neuromuscular Warm-Up is Associated with Fewer Overuse Injuries in Ballet Dancers Compared to Traditional Ballet-Specific Warm-Up.

Neuromuscular warm-up exercises (NMWU) have been shown to prevent injuries. In dance, research on warming-up is scarce. We investigated warm-up habits among ballet dancers and the effects of NMWU and traditional ballet-specific warm-up (TBSWU) on injuries. Using a cross-sectional survey among ballet dancers over the age of 18 years, we recorded acute and overuse injuries sustained in the previous 2 years. Warm-up behavior was assessed through 28 items. Dancers were grouped into NMWU or TBSWU: NMWU was based on neuromuscular warm-up programs in sports science and included exercises improving strength, power, proprioception, sensorimotor control, or cardiovascular stimulus; and TBSWU consisted of stretching, dance-technical exercises, marking steps and running-through-choreographies, or stretching with tools. Separate linear regression analyses adjusted for confounding factors were performed for acute and overuse injuries. A total of 192 dancers (26.7 ± 7.82 years, 159 females, 132 professionals) reported 203 acute and 469 overuse injuries. In total, 47.4% of dancers always warmed up (mean duration 20.7 ± 13.2 minutes) based on stretching (63%), technical-exercises (58.9%), strength-training (54.7%), and the barre (53.6%); and 9.4% never warmed up. A total of 31 dancers (16.15%) were classified as TBSWU, 16 dancers (8.3%) for NMWU, and 145 dancers did combined exercises. Those in the NMWU group were associated with fewer overuse injuries compared to those in the TBSWU group (ß = -2.34; 95%CI -3.54 to -1.14). No association was found with acute injuries. As in other athletes, NMWU might be protective against overuse injuries in dancers. Large-scale prospective cohort studies are needed to gain more insight into NMWU as a possible component of injury prevention in ballet.