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Abstracts from the Current Literature.

Amorim T, Koutedakis Y, Nevill A, Wyon M, Maia J, Machado JC, Marques F, Metsios GS, Flouris AD, Adubeiro N, Nogueira L, Dimitriou L. Bone mineral density in vocational and professional ballet dancers. Osteoporos Int. 2017 Oct;28(10):2903-12.

According to existing literature, bone health in ballet dancers is controversial. We have verified that, compared to controls, young female and male vocational ballet dancers have lower bone mineral density (BMD) at both impact and non-impact sites, whereas female professional ballet dancers have lower BMD only at non-impact sites. The aims of this study were to (a) assess BMD in vocational (VBD) and professional (PBD) ballet dancers and (b) investigate its association with body mass (BM), fat mass (FM), lean mass (LM), maturation and menarche. A total of 152 VBD (13 [+ or -] 2.3 years; 112 girls, 40 boys) and 96 controls (14 [+ or -] 2.1 years; 56 girls, 40 boys) and 184 PBD (28 [+ or -] 8.5 years; 129 females, 55 males) and 160 controls (27 [+ or -] 9.5 years; 110 female, 50 males) were assessed at the lumbar spine (LS), femoral neck (FN), forearm, and total body by dual-energy x-ray absorptiometry. Maturation and menarche were assessed via questionnaires. VBD revealed lower unadjusted BMD at all anatomical sites compared to controls (p < 0.001); following adjustments for Tanner stage and gynecological age, female VBD showed similar BMD values at impact sites. However, no factors were found to explain the lower adjusted BMD values in VBD (female and male) at the forearm (non-impact site) nor for the lower adjusted BMD values in male VBD at the FN. Compared to controls, female PBD showed higher unadjusted and adjusted BMD for potential associated factors at the FN impact site; (p < 0.001) and lower adjusted at the forearm (p < 0.001). Male PBD did not reveal lower BMD than controls at any site. It is concluded that both females and males VBD have lower BMD at impact and non-impact sites compared to controls, whereas this is only the case at non-impact site in female PBD. Maturation seems to explain the lower BMD at impact sites in female VBD.

Esteves F, Texeira E, Amorim T, Costa C, Pereira C, Fraga S, De Andrade VM, Texeira JP, Costa S. Assessment of DNA damage in a group of professional dancers during a 10-month dancing season. J Toxicol Environ Health, Part A. 2017;60(13-15):797-804.

Despite the numerous health benefits of physical activity, some studies have reported that increased intensity and duration may induce oxidative stress in several cellular components including DNA. The aim of this study was to assess the level of basal DNA damage as well as oxidative DNA damage in a group of professional dancers before and after a 10-month dancing season. A group of individuals from the general population was also assessed as controls. The alkaline version of the comet assay was the method selected to measure both basal DNA damage and oxidative stress, since this method quantifies both endpoints. In order to measure oxidative stress, the comet assay was coupled with a lesion-specific endonuclease (formamidopyrimidine glycosylase) to detect oxidized purines. The levels of oxidative DNA damage in dancers were significantly increased after the dancing season. Pre-season levels of oxidative DNA damage were lower in dancers than those obtained from the general population, suggesting an adaptation of the antioxidant system in dancers. Results of the present biomonitoring study indicate the need for more effective measures to protect ballet dancers from potential occupational health risks related to regular intensive physical exercise.

Berg T. Ballet as somatic practice: a case study exploring the integration of somatic practices in ballet pedagogy. J Dance Educ. 2017 Oct-Dec;17(4):147-57.

This case study explores one teacher's integration of Alexander Technique and the work of neuromuscular retrainer Irene Dowd in ballet pedagogy to establish a somatic approach to teaching, learning, and performing ballet technique. It highlights the teacher's unique teaching method called IMAGE TECH for dancers (ITD) and offers evidence to support ITD as a somatic approach to ballet pedagogy. The personal perspectives of the teacher and students in this ethnographic study support my observations that ITD integrates principles of somatic practices in ballet pedagogy. Additionally, these data illustrate the pedagogical innovation involved in the teacher's communication with her ballet students, which moves away from traditional authoritarian teaching practices. With ITD concepts communicated in such a way that the students feel confident to adapt the material individually, internal authority becomes established and ballet students can claim autonomy in their training and future careers.

Nishimura A, Nakazora S, Ito N, Fukuda A, Kato K, Sudo A. Endoscopic all-inside repair of the flexor hallucis longus tendon in posterior ankle impingement patients. Arthrosc Tech. 2017 Oct 9;6(5):e1829-e1835.

Longitudinal flexor hallucis longus (FHL) tendon tears are sometimes complicated by posterior ankle impingement syndrome (PAIS), especially in ballet dancers. In recent years, PAIS has been treated endoscopically, but it is difficult to suture FHL tendon tears endoscopically. In this report, we describe how to suture the FHL tendon endoscopically with the Meniscal Viper Repair system (Arthrex, Naples, FL). Without our endoscopic technique, when a patient is found to have a longitudinal tear of the FHL under endoscopy, we must choose to either neglect the tear or convert to an open repair. Open tendon suture techniques have reportedly had relatively good results but require a longer skin incision than endoscopic surgery for PAIS. Compared to the open repair, the advantages of our technique include earlier recovery, less pain, a lower rate of soft tissue complications, and improved healing through better preservation of the blood supply. This technique is an attractive and useful option because it is an easy and safe method for longitudinal FHL tendon tears.

Grochowska-Niedworok E, Kardas M, Fatyga E, Piorkowska-Staniek K, Muc-Wierzgon M, Kokot T. Study of top ballet school students revealed large deficiencies in their body weight and body fat. Acta Paediatr. 2018 Jun;107(6):1077-82.

This study assessed the nutritional status and physical activity levels of 150 female students aged 10 to 18 from three top Polish ballet schools. We analyzed the girls' body composition, physical activity level (PAL), and PAL coefficient. The ballet students also completed a questionnaire. The results revealed large deficiencies in the body weight and body fat of the young ballerinas. The mean body mass index (BMI) for the group was 16.8 kg/[m.sup.2]. Polish centile charts showed that 18% of the girls had BMIs below the norm and 54% had a lower than average body fat content, with a mean of 15.6%. The body fat content was lowest (13.8%) in the 13- to 15-year age group. On average, girls aged 10 to 12 had 15.7% body fat, while girls aged 16 to 18 had 18.4%. The mean values for the anthropometric measurements were higher in older girls. The majority (72%) of the respondents reported high physical activity levels, defined as more than 15 hours of exercise per week. It is concluded that special attention should be paid to low BMIs and body fat in young ballet school dancers aged 10 to 15 years.

Imura A, Iino Y. Regulation of hip joint kinetics for increasing angular momentum during the initiation of a pirouette en dehors in classical ballet. Hum Mov Sci. 2018 May 12;60:18-31.

This study examined how dancers regulate the hip joint kinetics to coordinate the upper and lower body angular momenta with the increased rotation of pirouette en dehors (pirouette) during the preparation. During the preparation of the pirouette, the upper body rotates greatly about the vertical axis; however, the lower extremity remains relatively stationary. Therefore, there must be specific control at the hip to coordinate the upper and lower body angular momenta in turns of increased rotation. Kinematics and kinetics of single to quadruple pirouettes performed by eight ballet dancers were analyzed using a motion capture system and force plates. Peak angular momentum of the upper body around the vertical axis increased from the single to the quadruple pirouettes. The vertical components of hip abductor torque of the anterior lower limb and hip adductor and flexor torques of the posterior lower limb contributed to generating the clockwise moment acting on the upper body around the vertical axis, which was reduced by the vertical components of the hip internal and external rotator torques. Thigh flexion angles of the posterior and anterior lower limbs, respectively, at the peak adductor and abductor torques at the corresponding hip joints changed with the number of revolutions and changed the percent contribution of the relevant hip joint torques about the vertical axis. The results suggest that dancers need to regulate hip joint torques along with thigh angles in the pirouettes depending on the number of revolutions.

To ensure that they are not overlooked in our selection process, we encourage authors to e-mail their recent articles for consideration to: ruthsol@ucsc.edu.

https://doi.org/10.12678/1089-313X.22.3.174

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Author:Solomon, Ruth; Solomon, John
Publication:Journal of Dance Medicine & Science
Date:Jul 1, 2018
Words:1508
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