bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrating Historical Ecology and Environmental Justice
Authors: Wolverton Steve , Figueroa Robert Melchior , Armstrong Chelsey Geralda
Published: May 2023

Environmental justice studies (EJS) provides a framework for interdisciplinary research and advocacy in the realm of cultural heritage research and management. Ethnobiologists, in particular those who focus on environmental archaeology, are no strangers to the heritage arena as our scholarship commonly concerns “cultural keystone places,” which are rich with meaning for one or more groups of people. Three dimensions and three core concepts of EJS can serve as guideposts to research centering on these significant places. These EJS concepts align and intersect with core principles of historical ecology (HE), particularly through the study of landscapes as complex systems. This paper highlights how environmental justice and HE can be conceptually integrated. This EJS-HE framework is relevant to research design in environmental archaeology and more broadly ethnobiology, a framing to be adopted at the beginning of the research process that explicitly considers whether a research question is ethical to approach within a particular heritage context.
Guatemalan Maya Q’eqchi’ Seasonal Calendar: Methods to Monitor Climate Change Locally
Authors: Thiel Amanda M. , Medinaceli Armando
Published: May 2023

Maya Q’eqchi’ villagers of Alta Verapaz, Guatemala fathom local indicators of climate change keenly. In a small-holder, maize-based, horticultural village, ethnographic interviews with village experts in hunting, agricultural production, and animal husbandry, and with non-expert/lay villagers recounted that many local climate- and subsistence-related activities and some traditional ecological knowledge (TEK) correspond to annual cycles or seasons. This research documents the local queues and timing of residents’ practices as a baseline for monitoring subsequent years’ activities and climate-related observations based on our interpretation of emic views, practices, and traditions. Using focus groups, we collected such traditional indicators to design a visual representation of a seasonal calendar, which we present herein. This seasonal calendar is a locally accessible tool to document monthly climate observations, agricultural and home garden activities, hunting, animal raising, and cultural activities during a complete annual cycle. We supplement observational and focus group data with semi-structured interview data about subsequent changes in weather patterns, which villagers identify as resulting from climate change. We suggest that Maya Q’eqchi’ villagers are active in their acknowledgment of climate change and are taking steps to document its effects on locally significant cultural activities, exemplifying Q’eqchi’ cultural capacity to adapt to ecological changes and to promote local resilience and cultural vitality. We demonstrate how seasonal calendars and the methods to create them may contribute to local and global understandings of TEK and climate change and annotate conventional anthropological methods as considerations for creating seasonal calendars in other cultural and ecological communities.
Factors that Influence Preferences for Defined Benefit Plans Versus Defined Contribution Plans
Authors: Ryan Michael P. , Cude Brenda J.
Published: May 2023

The majority of public sector employees in the United States still have access to defined benefit (DB) retirement plans, with some retaining a choice between a defined benefit plan and a defined contribution (DC) plan when hired. This research was based on a survey assessing individuals’ financial literacy, risk tolerance, and time orientation and the influence those three variables had on preferences for DB versus DC plans. Greater financial skill and risk tolerance were associated with a preference for DC plans, while a time orientation focused on the present was associated with a preference for DB plans. This research could benefit employers as they determine retirement plan options that they choose to offer employees. Employers who offer both plan types may benefit from informing employees about the factors associated with preferences for each plan type as greater awareness of such factors could improve employee satisfaction and increase retention.

JEL Codes: J32, H75, G53, G32
Analysis of tensile properties of geogrids for different morphology parameters
Authors: Gao Junli , Liu Lu , Zhu Guoliang
Published: May 2023

Following the emergence of new morphology geogrids, tensile tests on some of the new morphology geogrids were conducted in this paper for practical engineering options. The study focuses on the tensile testing of 3D printed geogrids to analyze the effects of morphology differences (material, planar structure, filling rate, rib width and rib height) on the tensile properties of geogrids. The test results show that the tensile properties of high density polyethylene geogrids are stronger than those of polylactic acid geogrids. Increasing the filling rate of geogrid can increase the tensile performance while decreasing the rate of tensile performance improvement. In contrast to the elongation at the break of the geogrid, the maximum tensile strength and the maximum tensile modulus increase in the order of bidirectional, triaxial and quadaxial geogrids. When the rib width and the rib height increase by the same amount, the rib height increases the maximum tensile strength of the geogrid more than that of the rib width.
Study on the influence of running parameters on the temperature field of disc brake on long downhill road
Authors: Gang Wu , Tian Chen , ZhiPeng Liu
Published: May 2023

The braking system of the vehicle is liable to fail due to the high temperature of frequent braking in the downhill road. This paper analyzes the influence of the main operating parameters of the vehicle on the maximum temperature of the brake disc surface. Firstly, the mechanical characteristics of the vehicle on the long downhill road are analysed, and the Finite Element Model of the brake disc/friction plate is established; Secondly, the effects of gradient, vehicle weight, brake speed threshold and brake pressure on the braking cycle and disc brake temperature field on long downhill roads are studied. The results show that when the gradient increases from 3° to 9°, the maximum temperature of the brake disc increases by 41.6%, while when the vehicle weight increases from 4 to 7 tons, the brake disc temperature only increases by 16.7%. For the braking speed threshold and braking force that the driver can control, selecting a smaller braking force and a lower braking speed threshold can better inhibit the temperature rise of the brake disc. Finally, the effectiveness of the simulation method is verified by the real vehicle test. It is found that the average measured temperature is 9.2%–11.8% lower than the simulated average temperature. It is considered that the modified temperature value can be obtained by reducing the maximum temperature of the simulation model by 5%–6%.
Fuzzy proportional–integral–derivative control system of electric drive downhole cutting tool based on genetic algorithm
Authors: Zhu Xiaohua , Zhong Jiahang , Jing Jun , Ye Wenyong , Zhou Bowen , Shan Hongbin
Published: May 2023

An electric drive downhole tubing cutting tool is the key equipment for tubing cutting in pressurized gas well workover operation. Cutting force control in radial feed movement of the cutting blade is the key to ensuring the successful cutting of tubing. In this article, the relationship model between cutting blade feed speed and cutting force is established by Matlab. Based on the mathematical model of cutting head rotation and blade feed movement, combined with the relationship between blade feed and cutting force obtained from cutting experiments. To keep the cutting force of the blade constant in the cutting process. Genetic algorithm was used to optimize the fuzzy proportional–integral–derivative control, and the automatic control scheme of the electric drive downhole tubing cutting tool was constructed. Based on Matlab/Simulink, the cutting force control simulation of the tubing cutting process is carried out. The performance of fuzzy proportional–integral–derivative control optimized by the genetic algorithm is compared with that of other standard controllers. The results show that the response speed and stability of the fuzzy proportional–integral–derivative control system are better than other algorithms. The steady-state error of the controller in the steady-cutting stage is < 5% based on the ground-cutting experiment of tubing, which meets the actual engineering needs and verifies the reliability and accuracy of the control system.
Generalization of Costly Pain-Related Avoidance Based on Real-Life Categorical Knowledge
Authors: Glogan Eveliina , Liu Peixin , Meulders Ann
Published: May 2023

Avoiding activities posing bodily threat is adaptive. However, spreading of avoidance to safe activities may cause functional disability in people with chronic pain. We investigated whether costly pain-related avoidance would generalize from one activity to another on the basis of real-life categorical knowledge in 40 pain-free people (30 female; mean age = 25 years; university students and public of Maastricht, The Netherlands). In a computer task, participants moved a joystick to complete activities from two categories (gardening and cleaning). During activities from the avoidance category, pain could be avoided at the cost of task efficiency by deviating from a short, pain-associated joystick movement. Activities from the safe category were never painful. Subsequently, we tested generalization of avoidance to novel pain-free activities from both categories. Participants generalized avoidance to novel activities from the avoidance category despite the novel activities not being paired with pain and despite avoidance costs, suggesting that costly (pain-related) avoidance generalizes from one activity to another on the basis of category knowledge and can thus be wide reaching, creating detrimental consequences.
Optimization of functionally graded plates under Thermo-elastic free vibration using nature-based algorithms
Authors: Rout Mrutyunjay , Bagal Dilip Kumar
Published: May 2023

This article presents the parametric optimization of the free vibration characteristics of a functionally graded material (FGM) plate exposed to nonlinear thermal loading using the finite element method and nature-based algorithms. The one-dimensional (1D) Fourier heat conduction equation is used to calculate temperature distributions over the thickness of the plate. Using Lagrange’s equation, we get the dynamic equation of motion for the plate. An eight-noded iso-parametric plate element with five degrees of freedom per node is used in the finite element formulation based on first-order shear deformation theory. Rectangular plates have temperature-dependent material characteristics; the thickness of the plates is scaled using a straightforward power law distribution. Here, the investigation of the FGM plate is conducted with two different boundary conditions, such as simple support and fully clamped. Additionally, new hybrid optimization approaches, namely RSM-Composite Desirability Optimization (RSM-CDO), Whale Optimization Algorithm (WOA), Corrected Moth Search Optimization (CMSO), Lichtenberg Algorithm Optimization (LAO), Sunflower Optimization Algorithm (SFO), and Forensic-Based Investigation Algorithm (FBI), are utilised to determine the best optimal solution, and the obtained findings are validated using confirmatory tests.
High precision localisation of the sources of noise of a bent-axis motor
Authors: Xu Chen , Xiangming Meng , Qinghong Gong , Hui Huang , Shumei Chen , Heng Du , Yuzheng Li , Xiufang Lin
Published: May 2023

The hydraulic motor will generate noise in operation and it has fluid-structure coupling and compact internal structure. The sound intensity measurement is difficult to distinguish the noise sources of motor. In this paper, a high-precision localization method for noise sources of bent-axis motor is studied to improve the resolution of the sound intensity images to locate noise sources accurately. Firstly, the structural characteristics of the motor are analyzed, and the sound intensity images are obtained through the experiment. Then the high-resolution optimization method based on compressed sensing is designed according to the characteristics of the sound intensity field. Finally, the sound intensity images with high resolution are constructed. The high-resolution images can distinguish the position of the prominent points, and the error is less than 0.4 dB. The identification distance of noise sources can reach 30 mm, and it breaks through the highest resolution of the traditional sound intensity test.
Can the welfare state reduce youth poverty? The determinants of material deprivation and subjective poverty among young people in Europe
Authors: Chevalier Tom
Published: May 2023

As an age-group, young people are most at risk of poverty. Yet significant cross-national variation persists, which seems puzzling: the countries displaying the highest levels of youth poverty are (uncharacteristically) Nordic. How can such diversity be accounted for? Is the welfare state part of the story? First, I argue, unlike most studies, that in order to measure youth poverty it is better to use material deprivation and subjective poverty indicators, rather than income poverty. Second, I hypothesize that the welfare state has two potential routes to the alleviation of youth poverty. On the one hand, via ‘individualization’ of claims (allowing young people to claim benefits as full adult citizens), access to income support leads to lower levels of youth poverty. On the other, youth poverty levels can also be reduced through investment in young people’s human capital, in line with the ‘social investment’ strategy. These claims are confirmed by multilevel logistic regressions on three waves and across 23 European countries of the Eurofound’s European Quality of Life Survey.
“Speaking as a mother”: A membership categorisation analysis of child-centric talk in a UK daytime television talk show
Authors: Foster Emily , Kilby Laura
Published: May 2023

In this study, we explore motherhood as an interactionally emergent identity category that speakers construct and lay claim to in talk, and as a category that is imbued with moral expectations of how incumbents should behave. We analyse 18 child-focussed debates from British daytime television talk show, This Morning. Engaging a postfeminist framework, we use membership categorisation analysis to explore how, and to what effect, women deploy claims to motherhood. We report three main findings: (a) Speakers routinely quantify their motherhood credentials in the development of a “mother-cum-expert” identity; (b) speakers who construct motherhood in accordance with neoliberal norms of “good motherhood” habitually trump the arguments offered by other speakers, including those with professional expertise; (c) any challenge to essentialist norms of womanhood and/or motherhood become accountable matters. We conclude that whilst there is power in motherhood insomuch as it vests some women with expertise and elevates their rights to be heard on child-focussed matters, the speakers in our study nevertheless construct motherhood in a manner that (re)produces and elevates essentialised notions of gender and narrow versions of motherhood.
Transplanting Microglia for Treating CNS Injuries and Neurological Diseases and Disorders, and Prospects for Generating Exogenic Microglia
Authors: Var Susanna R. , Strell Phoebe , Johnson Sether T. , Roman Alex , Vasilakos Zoey , Low Walter C.
Published: May 2023

Microglia are associated with a wide range of both neuroprotective and neuroinflammatory functions in the central nervous system (CNS) during development and throughout lifespan. Chronically activated and dysfunctional microglia are found in many diseases and disorders, such as Alzheimer’s disease, Parkinson’s disease, and CNS-related injuries, and can accelerate or worsen the condition. Transplantation studies designed to replace and supplement dysfunctional microglia with healthy microglia offer a promising strategy for addressing microglia-mediated neuroinflammation and pathologies. This review will cover microglial involvement in neurological diseases and disorders and CNS-related injuries, current microglial transplantation strategies, and different approaches and considerations for generating exogenic microglia.
Characteristics of a good nurse as perceived by nurses
Authors: Abedin Samireh , Khademi Zahra , Kamalzadeh Hesamaddin , Beigi Broujeni Razieh
Published: May 2023

Background

Nursing is a humanitarian and social field that provides health services. It combines science and art and has a rich history. Despite fundamental changes in the provision of medical services and nursing education, the concept of “good nurse” is still unclear.

Purpose

The purpose of this article is to investigate the characteristics of a good nurse from the nurses’ perspective.

Research design and method

A qualitative study was applied using conventional content analysis. The participants were 30 nurses that selected with purposive sampling method. Data were collected through unstructured interviews and simultaneously analyzed via the conventional content analysis approach of Graneheim and Lundman.

Ethical considerations

This study was approved by the Research Ethics Committee of Hormozgan University of Medical Sciences, Iran.

Findings

The study revealed that personal characteristics (Adherence to ethical and human principles, Physical health, Attractive appearance, and Ability to communicate properly); and professional characteristics (knowledge - clinical skill - nursing roles) are essential to being a good nurse.

Conclusion

Coming to know the distinctive features of a good nurse as perceived by nurses themselves creates an opportunity for nurses to rethink their profession and to reflect on the characteristics of the good nurse.
Associations Between Certificate of Need Policies and Hospice Quality Outcomes
Authors: Gaines Arlen G. , Cagle John G.
Published: May 2023

Background

Certificate of need (CON) laws are state-based regulations requiring approval of new healthcare entities and capital expenditures. Varying by state, these regulations impact hospices in 14 states and DC, with several states re-examining provisions.

Aim

This cross-sectional study examined the association of CON status on hospice quality outcomes using the hospice item set metric (HIS).

Design

Data from the February 2022 Medicare Hospice Provider and General Information reports of 4870 US hospices were used to compare group means of the 8 HIS measures across CON status. Multiple regression analysis was used to predict HIS outcomes by CON status while controlling for ownership and size.

Results

Approximately 86% of hospices are in states without a hospice CON provision. The unadjusted mean HIS scores for all measures were higher in CON states (M range 94.40-99.59) than Non-CON (M range 90.50-99.53) with significant differences in all except treatment preferences. In the adjusted model, linear regression analyses showed hospice CON states had significantly higher HIS ratings than those from Non-CON states for beliefs and values addressed (β = .05, P = .009), pain assessment (β = .05, P = .009), dyspnea treatment (β = .08, P < .001) and the composite measure (β = .09, P < .001). Treatment preferences, pain screening, dyspnea screening, and opioid bowel treatment were not statistically significant ( P > .05).

Conclusion

The study suggests that CON regulations may have a modest, but beneficial impact on hospice-reported quality outcomes, particularly for small and medium-sized hospices. Further research is needed to explore other factors that contribute to HIS outcomes.
Child Welfare System-Level Factors Associated with All-Cause Mortality Among Children in Foster Care in the United States, 2009–2018
Authors: Lee Joyce Y. , Steelesmith Danielle L. , Chaiyachati Barbara H. , Kirsch Jaclyn , Rao Smitha , Fontanella Cynthia A.
Published: May 2023

Little is known about the impact of child welfare system-level factors on child mortality as an outcome within foster care. Using data from the Adoption and Foster Care Analysis and Reporting System, 2009–2018, we examined the associations between county-level sociodemographic, foster care performance, and judicial reform characteristics with all-cause mortality rates. Results of random effects negative binomial regression analyses showed that higher proportions of younger children (<1 year: IRR = 1.06, 95% CI [1.02, 1.11]; 5–9 years: IRR = 1.05, 95% CI [1.01, 1.09]); children of color (i.e., non-Hispanic Asian: IRR = 1.07, 95% CI [1.01, 1.13]; multiracial: IRR = 1.03, 95% CI [1.01, 1.04]; non-Hispanic Black: IRR = 1.02, 95% CI [1.01, 1.02]; Hispanic: IRR = 1.01, 95% CI [1.01, 1.02]); and male children (IRR = 1.10, 95% CI [1.05, 1.15]) were associated with higher mortality risks at the county level. Current class action lawsuits (IRR = 0.79, 95% CI [0.63, 0.99]) and active consent decrees (IRR = 0.77, 95% CI [0.63, 0.94]) were associated with lower mortality risks. None of the foster care performance characteristics (e.g., foster care entry, placement stability, permanency) were associated with mortality risks. These findings have implications for addressing health disparities and reforming foster care systems through programmatic and policy efforts.
Hip and Knee Injuries in Dancers
Authors: Teitz Carol C.
Published: May 2023

Common hip injuries in dancers include tendon problems, stress fractures, and torn acetabular labra. Problems in the knee are frequently related to patellar alignment, inflamed plicae, or torn menisci. Ligament injuries are less common in dancers but are discussed as well since their management differs from that in other athletes. Emphasis is placed on identifying technical errors and anatomical variations that may have contributed to the injuries. Recommendations for rehabilitating the injured dancer often include changes in technique in order to maximize the chances for full recovery and minimize the risk for the recurrence of the injury.
Further Effects of Somatic Training on Pelvic Tilt and Lumbar Lordosis Alignment during Quiet Stance and Dynamic Dance Movement
Authors: Gamboian Nancy , Chatfield Steven J. , Woollacott Marjorie H.
Published: May 2023

The effectiveness of somatic training in the improvement of pelvic tilt (PelT) and lumbar lordosis (LL) alignment has been examined by Gamboian and colleagues.1 Further investigation is needed to continue analyzing the effect of somatic training on more subjects with repeated measurements across days. The purpose of this study was two fold: 1. to use repeated measures across more days and subjects to continue assessing whether alignment improvements from somatic training have a larger magnitude than day-to-day variability and a testing effect and 2. to determine whether improvements (if found) can be retained two weeks after training. Six female undergraduate subjects, who were dancing as a hobby, participated in four weeks of somatic training. Subjects began at different weeks for PelT and LL baseline measurements (weeks 1 to 3), then all subjects were assessed for posttest (week 7), and retention (week 9). The results revealed measurable LL improvements for almost all the subjects. An independent relationship between PelT and LL was also found in many of the subjects, since variability or changes were found with one measure and not the other. The presence of a testing effect and day-to-day variability suggest that future studies should continue to use multiple repeated measures, while also controlling arm position during conditions, the effect of conditions, and use of same foot position tracing after training.
The Effect of Conditioning on the Height of Dancer's Extension in à la Seconde
Authors: Grossman Gayanne , Wilmerding M. Virginia
Published: May 2023

The purpose of this study was to document the effects on the height of the gesture leg in dancer's extension in à la seconde (the combined actions of hip flexion, external rotation, and abduction) following a six-week regimen of conditioning aimed specifically at the hip flexors. Sixteen intermediate and advanced college age female dancers in a university dance program were invited to participate as a convenience sample on a volunteer basis. The subjects were divided in half, eight serving as the control group and eight serving as the treatment group. The control group continued their usual dance regimen for the six-week period. The treatment group added five minutes of therapeutic exercise three times per week following their usual dance regimen for the six-week period. T-tests served to compare the pre-test and post-test scores for the control and experimental groups. There was a significant difference in the mean height of the gesture leg in the experimental group (+ 6.25 inches, p = 0.001). There was no significant difference in the mean height of the gesture leg in the control group. Extra conditioning targeting hip flexion has been shown to be beneficial in this small sample of intermediate and advanced university dancers. Potentially, adequate strength in this vital area of the dancer's body may enhance performance and help reduce compensations that can lead to injury.
Acute Disruption of the Tarsometatarsal (Lisfranc's) Joints in a Ballet Dancer
Authors: Della Valle Craig J. , Su Edward , Nihal Aneel , Rosenberg Zehava S. , Trepman Elly
Published: May 2023

A 15-year-old female ballet dancer suffered acute midfoot pain when landing from a jump. Physical examination and imaging studies revealed acute disruption of the tarsometatarsal (Lisfranc's) joints with rupture of Lisfranc's ligament. Fluo-roscopic examination under anesthesia confirmed instability of the first, second, and third tarsometatarsal joints. Treatment included operative open reduction and rigid internal fixation to re-establish stable alignment, and postoperative protection (non-weightbearing) in a bivalved cast. The screws were removed 14 weeks after fixation, and weightbearing and physiotherapy were advanced. Follow-up evaluation at 10 months after initial treatment showed maintenance of stable alignment. The patient had no pain at the tarsometatarsal joints, but there was pain at the metatarsal heads after dance activity. She was able to plié, tendu, and work on demi-pointe, and had achieved her age level of dance, but had not resumed pointe work because of limitation in plantar flexion. Acute tarsometatarsal disruption is rare in young dancers and may be difficult to diagnose. Recognition of this type of injury is important because delay in the diagnosis and treatment may be associated with residual instability and poor prognosis.
Activity Monitors and Dance-Based Exercise: Estimating Caloric Expenditure
Authors: O'Mailia Shawn P. , Scharff-Olson Michele , Williford Henry N.
Published: May 2023

The purpose of this study was to determine the validity of the Caltrac and Tritrac-R3D activity monitors in predicting the caloric cost of dance based exercise modalities with regard to the CDC 150 kcal criterion. Ten women volunteered to participate in a repeated measures study. The subjects had the following (mean ± SD) characteristics: age: 26.6 ± 8.1 years; weight: 54.8 ± 8.1 kg; height: 162.8 ± 6.3 cm; and VO2max: 45.0 ± 3.9 ml-kg-1.min-1. All participants performed three 20-minute dance-exercise routines while being measured for predicted energy expenditure with two caloric monitors: The Caltrac and Tritrac-R3D. The subjects were also concurrently measured for actual caloric expenditure with verified laboratory methodology (e.g., open-circuit spirometry). Specifically, the three exercise routines consisted of the following: 1. a “dance style” (DS) step workout, 2. a choreographed “high/low impact” routine (HL), and 3. a repeating and building “high/low impact interval” style “peak performance” (PP) workout. The predicted values of energy expenditure were significantly lower than the actual values (repeated measures ANOVA, p < 0.05). Specifically, the monitors underestimated caloric expenditure by as much as 41% to 52% depending on the particular dance-exercise style. As with many activity monitors, the Caltrac and Tritrac-R3D predict energy cost largely in terms of lower extremity movement/translation. However, in dance-related activities, the upper body and arms provide a great deal of choreographic variety and, as such, are additive to the energy cost delivered by the legs. Therefore, the Caltrac and Tritrac-R3D may not provide appropriate technology for use in accurately determining the energy cost of dance-based exercise modalities or dance performance.
Prospective Analysis of Body Composition and SF36 Profiles in Professional Dancers over a 7-Month Season: Is There a Correlation to Injury?
Authors: Beriet Gregory C. , Kiebzak Gary M. , Dandar Alicia , Wooten Christin , Box Jane H. , Anderson Robert B. , Davis W. Hodges
Published: May 2023

This IRB-approved, prospective study evaluated body composition, strength, diet, lifestyle factors, and the incidence of injuries in professional dancers. Measurements were obtained from 15 dancers (6 males, 9 females) before a 7-month dance season and 13 dancers (5 males, 8 females) at the end of the season. Body composition was analyzed using dual x-ray absorptiometry. Quality-of-life variables were measured using the SF36 general health status survey. Post-season bone mineral density (BMD) for arms, trunk, ribs, pelvis, and total body for females was statistically significantly greater than preseason values. Total tissue mass for arms decreased significantly. No other body composition changes for females or males were observed, though striking differences were found when comparing dancers to age-matched and weight-matched non-dancers. Total body percent fat for female dancers was 43% lower than non-dancers, while lean mass was greater. Arm and spine BMD was lower than non-dancers but BMD for legs was significantly higher. For male dancers, there was significantly lower total body fat, greater lean mass in legs, and greater total body BMD than non-dancers. Grip strength did not change (preseason to post-season). Dietary profiles varied greatly, although most dancers met estimated minimum caloric requirements. Eleven dancers (85%) suffered injuries during the course of the season. There were no significant correlations between injury rate and body composition or lifestyle variables. All dancers scored significantly lower than population norms for the perception of pain. In summary, dancers maintained their body composition profiles despite the physical and emotional rigors of the dance season, and BMD actually increased significantly in females. The bodily pain score on the SF36 documents the impact of chronic injuries.
Management of Posterior Ankle Impingement as a Result of Ankle Instability a Case Report
Authors: DiStefano Andrea , Schon Lew C.
Published: May 2023

Dancers may suffer from either anterolateral ankle instability secondary to recurrent inversion ankle sprains or posterior ankle impingement syndrome secondary to a large trigonal process or os trigonum. Ankle instability may cause posterior impingement syndrome by allowing the forward shift of the talus in the mortise during plantar flexion. Identifying the interrelationship between instability and impingement is a key step in returning the patient to dance. We describe the results of a dancer who presented with both anterolateral ankle instability and posterior ankle impingement, the surgical procedure used, and the comprehensive, dance-specific treatment protocol implemented to achieve a successful outcome.
Strengths and Vífeaknesses of Current Methods for Evaluating the Aerobic Power of Dancers
Authors: Redding Emma , Wyon Matthew
Published: May 2023

The methods of measuring aerobic power in dance is reviewed. The underlying metabolic pathways used during dance class and performance are examined and, in conclusion, dance has been classified as an intermittent form of exercise. The relevancy of measuring maximal oxygen uptake (VO2max) in relation to intermit-tent exercise is discussed with regard to other sports. Previous dance VO2max data is examined in relationship to other exercise forms and it is shown to be comparable to results in other non-endurance sports. The limitations of graded exercise tests with regards to extrapolating oxygen data from heart rates during dance has been highlighted as a flaw in a number of previous research studies and a limitation to be aware of in future re-search. Due to the infancy of dance science, the availability of valid and reliable laboratory and field tests are limited and, therefore, until further research is done, there needs to be a reliance on tests de-veloped in the health and sport environ-ments. Such tests should be graded, either in speed or gradient, with stages of at least 3 minutes and be weight-bearing. Even though no research to date has shown that dancers with improved VO2max perform better, the review suggests that both the aerobic and anaerobic systems need to be stressed to a greater extent than seen presently within dance class.
Energy Balance and Physical Activity Patterns in University Ballet Dancers
Authors: Hirsch Nicole M. , Eisenmann Joey C. , Moore Sylvia J. , Winnail Scott D. , Stalder Margaret A.
Published: May 2023

This study estimates daily energy expenditure (DEE) and the amount and relative intensity of daily activity energy expenditure (AEE) and compares DEE with self-reported daily energy intake (DEI) among university ballet dancers. Three male and eleven female university-level ballet dancers, ranging from 19 to 24 years of age, participated in the study. Daily energy expenditure and physical activity intensity were assessed by minute-to-minute heart rate monitoring during two weekdays and one weekend day. Prior to the assessment of energy expenditure, heart rate-oxygen consumption measurements during sedentary activity and submaximal and maximal exercise were established for each individual. Estimated DEE in male and female dancers was 4,617 ± 1,244 and 2,945 ± 823 kilocalories per day (kcals.day1), respectively. Male dancers accumulated 450 ± 162 min-day-1and female dancers accumulated 296 ±198 min-day-1in moderate-to-very hard physical activity (greater than 50% maximal heart rate). Reported DEI was 1,949 kcals-day-1and 938 kcals-day-1less than DEE in male and female dancers, respectively (p < 0.05). This information provides a guide to the energy demands of ballet dancers that nutritionists and instructors can use to optimize performance without compromising the health of the dancer.
Physiological Comparison between Female University Ballet and Modern Dance Students
Authors: Susan B. White , Philpot Alisha , Green Amanda , Bemben Michael G.
Published: May 2023

Generally, dance is an activity in which performers desire lower body weights in order to increase their ability to perform or to enhance their aesthetic appeal. Modern, or contemporary dance, requires far more movement of the upper body and more floor work than ballet. Since both forms of dance have apparent differences in training regimes, it was thought that there might be differences in some physiological factors that might ultimately influence the overall health of these athletes. Therefore, this study compared the aerobic capacity, body composition, and bone mineral density of female university ballet and modern dancers. Seventeen university dance students volunteered to participate in the study, ten ballet dancers, and seven modern dancers. Maximal aerobic capacity was assessed on a treadmill using the Bruce protocol, while total and regional body composition and bone mineral densities (total, hip, and spine) were measured by dual energy x-ray absorptiometry (DEXA, Lunar DPX-IQ). There were no statistically significant differences between the two groups of dancers for any of the measured physiological parameters. The VO2max of the ballet dancers was 40.8 ±1.6 ml·kg-1·min-1 compared to the modern dancers 39.2 ±1.9 ml·kg-1·min-1. Total body fat of the ballet dancers was 19.8 ± 1.5% while the modern dancers were measured at 19.3 ± 1.4%. The bone mineral density for the total body, total hip, and L2-L4 of the spine for the ballet dancers was 1.165 ± 0.002 g/cm2, 1.082 ± 0.004 g/cm2, and 1.183 ± 0.004 g/cm2, respectively, while the modern dancers were measured at 1.170 ± 0.002 g/cm2, 1.107 ± 0.003 g/cm2, and 1.231 ± 0.004 g/cm2, respectively. These finding suggest that no differences exist between the physiological profiles of university modern and ballet dancers. Even though the dancers had lower percentages of body fat than the average female university student, the dancers were not low enough to be considered at increased risk for any major health problems. Also, the dancers low body weights and lower percentages of body fat did not seem to affect bone mineral densities, since both groups of dancers had values that were about 10% better than age-matched normal subjects. Finally, although both groups perform rigorous training regimens, their aerobic capacities were lower than other elite female athletes but higher than the average published norms for this age group.
Recognizing Eating Disorders
Authors: Glace Beth
Published: May 2023

As many as one quarter of ballet dancers are estimated to suffer from either anorexia nervosa or bulimia. These diseases represent the most extreme end in a spectrum of eating pathology. Since the long-term mortality rate is quite high in anorexia and increases with duration of the disease, it is crucial that eating pathology be recognized, and intervention begun, as early as possible. There are both physical and behavioral changes associated with eating disorders that may aid concerned professionals, friends, or family members in distinguishing between illness and thinness, and dedication and compulsion.
Psychological Factors Associated with Performance-Limiting Injuries in Professional Ballet Dancers
Authors: Adam Maya U. , Brassington Glenn S. , Matheson Gordon O.
Published: May 2023

The purpose of this study was to assess the relationship between a broad range of psychosocial variables and performance-limiting physical injuries in a sample of elite ballet dancers in order to identify potential factors that could be included in interventions to prevent and treat dance injuries. Participants were asked to complete a battery of questionnaires assessing psychological well-being and social support. Participants also participated in a structured interview designed to solicit information about dance-related injuries in the 10-month period preceding the study. Study was conducted at the workplace of a 60-member professional ballet company. The company is part of a large, government-funded state theatre in Germany. Participants were 30 female and 24 male (mean age: 26.59 years; SD: 6.2 years) ballet dancers, representing 20 countries. Participants were employed in the company for the 2000-2001 performance season and were not injured at the time of participation in the study. Participants were asked to complete a battery of questionnaires including: a demographics questionnaire, the Cohen Perceived Stress Scale, the Social Support Appraisal Scale, the Profile of Mood States, and the Pittsburgh Sleep Quality Index. Percent of performance and rehearsal days missed due to injury was computed as follows: (number of days missed due to injury/scheduled days) X 100. To identify potential correlates of injuries, Pearson Product-moment Correlation Coefficients were computed between the injury variable and each of the psychosocial variables. Absence due to injury was significantly positively correlated with stress, sleep disturbances, daytime sleepiness, and negative mood states (i.e., tension, depression, anger, fatigue, and confusion). However, absence due to injury was significantly negatively associated with social support. Future interventions designed to prevent and treat injuries in elite ballet dancers should include the assessment and treatment of psychological distress (i.e., perceived stress, negative mood states, sleep problems) as well as the enhancement of social support in their programs.
Validity of Using Heart Rate as a Predictor of Oxygen Consumption in Dance
Authors: Redding Emma , Wyon Matthew , Shearman Jeremy , Doggart Lance
Published: May 2023

The validity of predicting oxygen uptake (VO2) from heart rate (HR) was examined in 19 professional modern dancers of both genders ranging in age from 21 to 29 years. The subjects were measured on two occasions; once during a multi-stage graded treadmill test and again during their usual modern dance class. The data showed significant differences during both the treadmill test or dance class at lower intensities of less than 20 ml·kg-1·min-1 (p ≤ 0.03) and paradoxically no significant differences between the relationships at intensities greater than 20 ml·kg-1·min-1. However results also identified large individual variability and when taken into account the great variability, it would seem unacceptable to predict the VO2 from HR values in dance, based on the HR-VO2 relationship established from a progressive treadmill protocol. Furthermore, given that dance is a non-steady-state activity and is executed at low to moderate intensities with occasional anaerobic bursts, it seems unlikely that the HR-VO2 relationship established from a steady-state laboratory test can be relied upon as a predictor of VO2 in dance.
Study of Muscle Activity during Relevé in First and Sixth Positions
Authors: Massó Nuria , Germán Ana , Rey Ferran , Costa Lluis L. , Romero Daniel , Guitart Silvia
Published: May 2023

To assess differences in the muscular activation related to position when performing relevé, a kinetic and kinematic analysis was performed on 18 professional classical ballet dancers aged 14 to 32. The degree of plantar flexion and the involvement of the peroneus longus, soleus, gastrocnemius, and abductor hallucis muscles were analyzed. The results in sixth position (parallel) against external rotation of the hip or turnout and the correct first position against first position with foot pronation were compared. All comparisons were evaluated using the Wilcoxon test. When in relevé, the plantar flexion values were greater in sixth position than in first and also greater in the correct first position than in first with pronated feet. The medial gastrocnemius muscle had more electromyo-graphical activity when the relevé is done in first position. However, the abductor hallucis exerted greater activity when in the sixth position. The low activity of this muscle when in first position may reflect deficient stability of the internal arch and the first ray, thereby leading to increased risk of injury. With foot pronation, the peroneus longus and gastrocnemius muscles presented their highest activity levels.
A Three-Dimensional Kinematic Analysis of Grand Rond de Jambe en l'air
Authors: Wilson Margaret , Lim Bee-Oh , Kwon Young-Hoo
Published: May 2023

The purpose of this study was twofold: to perform an in-depth three-dimensional kinematic analysis of grand rond de jambe en l'air en dehors and to identify different strategies employed between the skilled and novice dancers in performing grand rond de jambe. Ten female college dance students, ranked as skilled (N = 5) or novice (N = 5), performed grand rond de jambe while videotaped for three-dimensional motion analysis in a six-camera setup (60 Hz). Events and phases for the movement were determined to establish a protocol for biomechanic analysis of this movement. Orientation angles of the trunk and pelvis and horizontal and vertical angles of the gesture leg were computed for inter-group comparison. The results of this investigation show differences between skilled and novice dancers in terms of the vertical angle (height) of the gesture leg, horizontal angle of the leg at the transition of pelvic rotation, and increased pelvic motion in all three planes. No significant difference was observed in the trunk motion and orientation. It was concluded that the skilled group secured the required gesture leg motion via a pelvic strategy.
The Significance of Muscular Strength in Dance
Authors: Koutedakis Yiannis , Stavropoulos-Kalinoglou Antonis , Metsios Giorgos
Published: May 2023

The physical demands placed on dancers make their physiology and fitness just as important as skill development. However, dancers’ muscular strength and bone and joint integrity seem to suffer as a result of the dance-only selection and training system. This partly reflects the unfounded view that exercise training that is not directly related to dance would diminish dancers’ aesthetic appearances and destroy muscle flexibility. Nevertheless, data on male and female dancers have demonstrated that supplemental strength training can lead to better dancing and reduced incidents of dance injuries without interfering with key artistic and aesthetic requirements. An awareness of these factors will assist dancers and their teachers in improving training techniques, employing more effective injury prevention program, and in determining better physical conditioning strategies.
Preseason to Postseason Changes in Body Composition of Professional Ballet Dancers
Authors: Micheli Lyle J. , Cassella Michelina , Faigenbaum Avery D. , Southwick Heather , Ho Vanessa
Published: May 2023

Assessment of body composition in dancers as part of a pre-participation evaluation is controversial — it is strongly supported as an important monitor test by some health professionals, but condemned by others as increasing the potential for the development of eating disorders. A number of studies have documented normative values of body composition for dancers at the student, pre-professional, and professional levels. To the best of our knowledge, no study has ever assessed body composition changes that occur during a professional performance season. The present investigation evaluated male (n = 29) and female (n = 39) professional dancers before and after a performance season. While no significant changes in body composition in the males was noted, a significant decrease in both body weight and percentage of body weight as fat was found in the female dancers [Fat %, Pre: 12.8 ± 2.7; Post: 11.5 ±2.1 (p < 0.05)]. These data suggest that both preseason and postseason assessments of body composition are necessary in order to screen for dancers who require further medical assessment and nutritional counseling to maintain optimal health.
Do Professional Dancers Have Medical Insurance?
Authors: Requa Ralph K. , Garrick James G.
Published: May 2023

A variety of dance companies were surveyed to document the medical insurance coverage they provide for their dancers. Various dance and theater arts directories available in San Francisco, California, yielded approximately 100 dance companies, ranging from traditional ballet through many ethnic, folk, eclectic, and modern dance forms. Twenty-eight dance companies provided information about their dancers and medical insurance status. The dancers were not contacted directly so no information about outside sources of medical insurance is available. A total of 292 dancers were listed by the 28 companies. Most were ages 21 to 30 (152, 58.7%) and 31 to 40 (64, 24.7%) years. Just over half (157, 53.8%) of the dancers were covered by Workers Compensation (WC) insurance, while slightly less than half (124, 42.5%) were in companies that offered to contribute to a private insurance plan. A expected, dancers in smaller companies were less likely to have medical insurance. If the two large, professional companies are excluded, out of 187 dancers in the remaining 26 companies, only 52 (27.8%) had WC insurance and only 19 (10.2%) had private insurance at least partially provided by their companies. Only 13.5% of the dancers in companies dancing less than half-time in season had WC insurance, and none had even partial support for private insurance. It is clear that dancers performing in small companies and those performing on a part-time basis rarely have medical insurance provided even in part by their dance companies. Some may have had medical insurance provided by outside sources, but this information was not available from our data collection method.