The efficacy of different vitamin D supplementation delivery methods on serum 25(OH)D: A randomised double-blind placebo trial.

BACKGROUND: The use of vitamin D supplementation has increased due to greater recognition of widespread deficiency. AIMS: There has been little research on the effectiveness of different delivery methods and therefore the aim of was to test the efficacy of different delivery methods on serum 25(OH)D. METHODS: Using a randomised repeated measures double-blind placebo design (registered under ClinicalTrials.gov Identifier no. NCT03463642), changes in serum 25(OH)D over a 4-week period using a capillary spot method were monitored. 62 female participants blindly chose a number related to a supplementation delivery method: pill placebo, pill, oral liquid, oral liquid placebo, Skin oil application (SOA) placebo, SOA plus vitamin D3 suspension, or SOA plus vitamin D3 suspension with essential oil enhancer; active vitamin D supplements contained 100,000IU. Participants took their allocated supplements over a 24-hr period with serum 25(OH)D retested 4 weeks later. Liquid chromatography-tandem mass spectrometry method was applied to dried blood spot samples by an independent laboratory. RESULTS: ANCOVA reported a significant difference between the groups (F1,6 = 146.68; p < 0.001, eta2 = 0.51). Separate analysis within the delivery methods (pill, SOA, oral liquid) indicated significant differences between the active and placebo supplementation groups (p < 0.01). Post hoc analysis of absolute changes indicated vit D pill and SOA + vit D + essential oil had significant increases (p < 0.05) in serum 25(OH)D compared to all other interventions with no significant difference between them. CONCLUSIONS: In human participants vitamin D oral pill has the greatest effect on serum 25(OH)D levels. Skin oil application delivery of vitamin D using a penetrator enhancer has also been shown to be an effective method of delivery.

Genetic variation in Wnt/ß-catenin and ER signalling pathways in female and male elite dancers and its associations with low bone mineral density: a cross-section and longitudinal study.

The association of genetic polymorphisms with low bone mineral density in elite athletes have not been considered previously. The present study found that bone mass phenotypes in elite and pre-elite dancers are related to genetic variants at the Wnt/ß-catenin and ER pathways. INTRODUCTION: Some athletes (e.g. gymnasts, dancers, swimmers) are at increased risk for low bone mineral density (BMD) which, if untreated, can lead to osteoporosis. To investigate the association of genetic polymorphisms in the oestrogen receptor (ER) and the Wnt/ß-catenin signalling pathways with low BMD in elite and pre-elite dancers (impact sport athletes). METHODS: The study included three phases: (1) 151 elite and pre-elite dancers were screened for the presence of low BMD and traditional osteoporosis risk factors (low body weight, menstrual disturbances, low energy availability); (2) a genetic association study was conducted in 151 elite and pre-elite dancers and age- and sex- controls; (3) serum sclerostin was measured in 101 pre-elite dancers and age- and sex-matched controls within a 3-year period. RESULTS: Eighty dancers revealed low BMD: 56.3% had at least one traditional osteoporosis risk factor, whereas 28.6% did not display any risk factor (37.2% revealed traditional osteoporosis risk factors, but had normal BMD). Body weight, menstrual disturbances and energy availability did not fully predict bone mass acquisition. Instead, genetic polymorphisms in the ER and Wnt/ß-catenin pathways were found to be risk factors for low BMD in elite dancers. Sclerostin was significantly increased in dancers compared to controls during the 3-year follow-up (p < 0.05). CONCLUSIONS: Elite and pre-elite dancers demonstrate high prevalence of low BMD, which is likely related to genetic variants at the Wnt/ß-catenin and ER pathways and not to factors usually associated with BMD in athletes (body weight, menstrual disturbances, energy deficiency).

Leg-Length in Relation to Selected Ballet Performance Indicators.

It is unclear whether the modern ballet body stereotype of long limbs is advantageous in dance performance. Therefore, we investigated the relationship between leg-length and selected dance movements representative of power, dexterity, and range of motion in ballet dancers at different competence levels. METHODS: The total of 10 recreational, 24 vocational, and 10 professional ballerinas volunteered. They were subjected to: a) lower limb-length measurements, b) power tests (vertical jump-sautés and unilateral countermovement jump-temps levé), c) dexterity tests (tendus and double battement frappes), and d) flexibility tests (lateral active and passive-développé à la seconde). RESULTS: For power, regression analyses revealed negative leg-length relationships in recreational dancers (p<0.05) and positive leg-length relationships in vocational dancers (p<0.05). We also found negative relationships between leg-length and dexterity in the vocational group (p=0.01). No significant predictions of leg-length on power, dexterity, and range of motion were found in professional dancers. Multiple comparisons revealed significant differences between groups only for dexterity (p<0.01) and range of motion (p<0.01). CONCLUSION: Based on selected movements representative of power, dexterity, and range of motion, the present exploratory data indicate that lower limb length is not a determinative criterion for ballet success. Further studies should investigate whether body stereotypes, such as long limbs, are linked to dance injuries.

Bone mineral density in vocational and professional ballet dancers.

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. INTRODUCTION: The aims of this study were to (a) assess bone mineral density (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. METHODS: The total of 152 VBD (13 ± 2.3 years; 112 girls, 40 boys) and 96 controls (14 ± 2.1 years; 56 girls, 40 boys) and 184 PBD (28 ± 8.5 years; 129 females, 55 males) and 160 controls (27 ± 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. RESULTS: VBD revealed lower unadjusted BMD at all anatomical sites compared to controls (p < 0.001); following adjustments for Tanner stage and gynaecological 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. CONCLUSIONS: Both females and males VBD have lower BMD at impact and non-impact sites compared to control, 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.

Anthropometry and somatotypes of competitive DanceSport participants: a comparison of three different styles.

Anthropometry in dance and aesthetic sports has been shown to play an important role in selection and performance criteria. The aim of the present study was to examine variations in somatotype and anthropometry in three different competitive dance styles: DanceSport Standard, Latin American and Ten Dance. Anthropometry and somatotype data were collected from thirty couples competing in Standard (n=24 individuals), Latin American (n=14) and Ten Dance (n=22) styles. A single tester (ISAK Level 1) carried out all anthropometric measurements using the Heath-Carter protocol and somatotypes were calculated using the Heath-Carter's decimal equations. Results indicated that the mean somatotype for the male dancers was 2.4-3.9-3.2, whilst for females it was 2.7-2.7-3.5. Factorial analysis reported Standard dancers scored significantly higher for ectomorphy, sitting height and arm span than Latin dancers (p<0.05). Correlation analysis with the Standard dancer's International Ranking highlighted moderate positive correlation with mesomorphy (r=0.434, p<0.05) and negative correlation with ectomorphy (r=-0.546, p<0.001). The findings of this study show that somatotypes differ among DanceSport participants by dance style. Compared with other aesthetic sports, male and female dancers were less mesomorphic and more ectomorphic. Standard dancers tend to be more ectomorphic with greater height, longer arm span and greater sitting height compared with Latin American dancers. Although Standard dancers were ectomorphic, those dancers who had higher mesomorphic ranking had higher places in the dancers' international ranking.

Time motion and video analysis of classical ballet and contemporary dance performance.

Video analysis has become a useful tool in the preparation for sport performance and its use has highlighted the different physiological demands of seemingly similar sports and playing positions. The aim of the current study was to examine the performance differences between classical ballet and contemporary dance. In total 93 dance performances (48 ballet and 45 contemporary) were analysed for exercise intensity, changes in direction and specific discrete skills (e. g., jumps, lifts). Results revealed significant differences between the 2 dance forms for exercise intensity (p<0.001), changes in direction (p<0.001) and discrete skills (p<0.05) with gender differences noted in the latter (p<0.05). Ballet was characterised by longer periods at rest (38 s x min(-1)) and high to very high exercise intensities (9 s x min(-1)), whilst contemporary dance featured more continuous moderate exercise intensities (27 s x min(-1)). These differences have implications on the energy systems utilised during performance with ballet potentially stressing the anaerobic system more than contemporary dance. The observed high rates in the discrete skills in ballet (5 jumps x min(-1); 2 lifts x min(-1)) can cause local muscular damage, particularly in relatively weaker individuals. In conclusion, classical ballet and contemporary dance performances are as significantly different in the underlying physical demands placed on their performers as the artistic aspects of the choreography.

Hypermobility and dance: a review.

Joint hypermobility is defined as an excessive range of motion. Although the dance profession has often promoted hypermobility for aesthetic reasons, there is a belief amongst health professionals that potential risks associated with the condition may have been overlooked. The aims of this review were to examine the epidemiology of joint hypermobility in dancers; the effects on fatigue and bone health; the injury profile of hypermobile dancers; and the use of the Beighton score as a diagnostic tool. Depending on the criteria used, epidemiological studies suggest that hypermobility among dancers can be as high as 44%, especially in students. As hypermobility has been linked to fatigue in the general population, the hypermobile dancer should be careful given the association between fatigue and aetiology of injury in dance. Similarly, in light of research encouraging dancers to become fitter, this recommendation may not be appropriate for hypermobile dancers. In addition, the Beighton score used in most dance related studies may not be an appropriate measure of hypermobility in these populations. More research is necessary into this area to ascertain the reasons for the attrition rate from student to soloist/principal level and whether it is linked to dance health and injury issues.

Vibration training improves balance in unstable ankles.

Functional ankle instability (FAI) is a common condition following ankle injury characterised by increased risk of injury. Ankle sprains are a common acute form of injury suffered in dancing and loss of balance can affect not only risk of injury risk but also performance aesthetics. Whole body vibration training (WBVT) is a new rehabilitation method that has been linked with improving balance and muscle function. 38 female dancers with self reported unilateral FAI were randomly assigned in 2 groups: WBVT and control. Absolute centre of mass (COM) distribution during single leg stance, SEBT normalised research distances and Peroneus longus mean power frequency (f(med)) where measured pre and post 6-week intervention. There was a significant improvement in COM distribution over the 6 weeks from 1.05 ± 0.57 to 0.33 ± 0.42 cm² (P<0.05), and 4 of the 8 planes of direction in the SEBT Ant, Antlat, Med and Antmed from 77.5 ± 7.1 to 84.1 ± 5.8% (P<0.05) compared to control groups during the course of the 6 week training intervention. There was no evidence of improvement in peroneus longus (f(med)) over time (P=0.915) in either group. WBVT improved static balance and SEBT scores amongst dancers exhibiting ankle instability but did not affect peroneus longus muscle fatigue.

Effect of leg length on ROM, VJ and leg dexterity in dance.

We investigated the associations between leg length and specific ballet movements in different skill groups. Volunteers were from an undergraduate dance programme (n=18), a pre-professional school (n=43) and from an elite classical ballet company (n=45). Individual data were collected for anthropometry, vertical jump, leg dexterity, and leg active and passive ROM. ANCOVA identified both main effects as significant with regard to vertical jump (gender P<0.001 and skill P=0.017); leg length was also identified as a significant covariate (P=0.023). Analysis of leg dexterity identified no significant effects with gender, skill or leg length. Active and passive range of motion noted gender (P=0.001) and skill (P<0.001) differences. Leg length was found to be negatively associated with both active and passive ROM (P=0.002). In conclusion, the present data highlight the diverse and conflicting effects of leg length on fundamental ballet skills. The longer legs that benefit vertical jump have a negative influence on range of motion and leg dexterity except for highly skilled dancers, who through skill, seem to have overcome the effects of some of these dichotomies.

Scaling concept II rowing ergometer performance for differences in body mass to better reflect rowing in water.

We investigated whether the concept II indoor rowing ergometer accurately reflects rowing on water. Forty-nine junior elite male rowers from a Great Britain training camp completed a 2000 m concept II model C indoor rowing ergometer test and a water-based 2000 m single-scull rowing test. Rowing speed in water (3.66 m/s) was significantly slower than laboratory-based rowing performance (4.96 m/s). The relationship between the two rowing performances was found to be R2=28.9% (r=0.538). We identified that body mass (m) made a positive contribution to concept II rowing ergometer performance (r=0.68, P<0.001) but only a small, non-significant contribution to single-scull water rowing performance (r=0.039, P=0.79). The contribution that m made to single-scull rowing in addition to ergometer rowing speed (using allometric modeling) was found to be negative (P<0.001), confirming that m has a significant drag effect on water rowing speed. The optimal allometric model to predict single-scull rowing speed was the ratio (ergometer speed xm(-0.23))1.87 that increased R2 from 28.2% to 59.2%. Simply by dividing the concept II rowing ergometer speed by body mass (m0.23), the resulting "power-to-weight" ratio (ergometer speed xm(-0.23)) improves the ability of the concept II rowing performance to reflect rowing on water.

Fitness in contemporary dance: a systematic review.

It has been suggested that dancers are less fit compared to other athletes. However, the majority of studies make their arguments based on data deriving mainly from ballet. Therefore, the aim of the current review was to investigate: a) aerobic and anaerobic fitness, muscular strength and body composition characteristics in contemporary dancers of different levels, and b) whether supplementary exercise interventions, in addition to normal dance training, further improves contemporary dance performance. Three databases (Medline, Cochrane and the Cumulative Index to Nursing & Allied Health research database) were searched to identify publications regarding the main fitness components of contemporary professional and student dancers. At a professional level, it appears that contemporary dancers demonstrate higher maximal oxygen uptake and higher scores in muscular endurance than ballet dancers. However, contemporary dance students are equally fit compared to their ballet counterparts and their body composition is also very similar. Only two studies have investigated the effects of supplementary exercise training on aspects of dance performance. Further research is needed in order to confirm preliminary data, which suggest that the implementation of additional fitness training is beneficial for contemporary dance students to achieve a better performance outcome.