The dancer as a performing athlete: physiological considerations.

The physical demands placed on dancers from current choreography and performance schedules make their physiology and fitness just as important as skill development. However, even at the height of their professional careers, dancers' aerobic power, muscular strength, muscular balance, bone and joint integrity are the 'Achilles heels' of the dance-only selection and training system. This partly reflects the unfounded view, shared by sections of the dance world, that any exercise training that is not directly related to dance would diminish dancers' aesthetic appearances. Given that performing dance itself elicits only limited stimuli for positive fitness adaptations, it is not surprising that professional dancers often demonstrate values similar to those obtained from healthy sedentary individuals of comparable age in key fitness-related parameters. In contrast, recent data on male and female dancers revealed that supplementary exercise training can lead to improvements of such fitness parameters and reduce incidents of dance injuries, without interfering with key artistic and aesthetic requirements. It seems, however, that strict selection and training regimens have succeeded in transforming dance to an activity practised by individuals who have selectively developed different flexibility characteristics compared with athletes. Bodyweight targets are normally met by low energy intakes, with female dance students and professional ballerinas reported to consume below 70% and 80% of the recommended daily allowance of energy intake, respectively, while the female athlete 'triad' of disordered eating, amenorrhoea and osteoporosis is now well recognised and is seen just as commonly in dancers.An awareness of these factors will assist dancers and their teachers to improve training techniques, to employ effective injury prevention strategies and to determine better physical conditioning. However, any change in the traditional training regimes must be approached cautiously to ensure that the aesthetic content of the dance is not affected by new training techniques. Since physiological aspects of performing dance have been viewed primarily in the context of ballet, further scientific research on all forms of dance is required

Prevalence and risk factors of dance injury during COVID-19: a cross-sectional study from university students in China

© (2021) The Authors. Published by Frontiers Media. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3389/fpsyg.2021.759413Objectives: Although COVID-19 has transformed dancers’ training environment worldwide, little is known on how this has affected injury prevalence, causes and risk factors. Methods: An online investigation was conducted (September to November 2020) involving Chinese full-time dance students, which covered two 6-month periods just before and during the first COVID-19 lockdown. Results: 2086 students (19 ±2.4yrs) responded. Injury prevalence before lockdown dropped from 39.6% to 16.5% during lockdown (p<0.01). A significant increase in injury severity during lockdown was noted with a 4.1% increase in moderate to severe injuries (p<0.05). During the lockdown, injuries of the lower back, feet and shoulders decreased significantly (p<0.01), but the knees, ankles and groin/hip-joint injuries remained the same. Recurrence of old injury and fatigue remained as the top 2 perceived causes of injury between the two periods with unsuitable floor (p<0.01), cold environment (p<0.05) and set/props (p<0.05) increasing. Students’ fatigue degree decreased (p<0.01) and sleep hours increased (p<0.01) during lockdown. Binary logistic regression analysis indicated that dance injury was associated with fatigue, hours of sleep, and action taken if they suspected an injury during lockdown (p<0.05), but was only related to time set aside for cool-down and age before lockdown (p<0.05). Conclusion: Although the injury prevalence dropped significantly during the first COVID-19 lockdown in Chinese dance students, the main dance injury characteristics remained the same. Decreased fatigue and longer sleep hours could explain the aforementioned drop in injury prevalence during the lockdown.This work was supported by the China Scholarship Council for their financial contribution (D.Y

Obesity in chronic inflammation using rheumatoid arthritis as a model : definition, significance, and effects of physical activity & lifestyle

Background: Inflammation is the natural reaction of the body to an antigen. In some conditions, this reaction continues even after the elimination of the antigen, entering a chronic stage; it targets normal cells of the body and causes extensive damage. Rheumatoid arthritis (RA) is such a condition. It associates with significant metabolic alterations that lead to changes in body composition and especially body fat (BF) increases. In the general population, increased body fat (i.e. obesity) associates with a number of health disorders such as systemic low grade inflammation and a significantly increased risk for cardiovascular disease (CVD). Both effects of obesity could have detrimental effects in RA. Increased inflammation could worsen disease activity while obesity could further increase the already high CVD risk in RA. However, obesity in RA has attracted minimal scientific attention. Aims: The present project aimed to: 1) assess whether the existing measures of adiposity are able to identify the changes in body composition of RA patients, 2) if necessary develop RA-specific measures of adiposity, 3) investigate the association of obesity with disease characteristics and CVD profile of the patients, 4) and identify factors that might affect body weight and composition in these patients. Methods: A total of 1167 volunteers were assessed. Of them 43 suffered from osteoarthritis and 82 were healthy controls. These, together with 516 RA patients were used in the first study. Their body mass index (BMI), BF, and disease characteristics were assessed. In the second, third, fourth and fifth studies a separate set of 400 RA patients was assessed. In addition to the above assessments, their cardiovascular profile and more detailed disease characteristics were obtained. For the final study, 126 RA patients were assessed for all the above and also data on their physical activity levels and their diet were collected. Results: Assessments of adiposity for the general population are not valid for RA patients. Thus, we proposed RA-specific measures of adiposity. These are able to better identify RA patients with increased BF. We were also able to find associations between obesity and disease activity. Both underweight and obese RA patients had more active disease compared to normal-weight patients. Obese patients had significantly worse CVD profile compared to normal-weight. The newly devised measures of adiposity were able to identify those at increased risk. However, not all obese individuals were unhealthy and not all normal-weight healthy. Among our patients we were able to identify subtypes of obesity with distinct phenotypic characteristics that warrant special attention. Finally, we were able to identify factors that influence body weight and composition. Cigarette smoking protected against obesity while its cessation associated with increased adiposity. Physical activity was also found to be protective against obesity while diet or inflammation of the disease failed to produce any significant results. Conclusions: Obesity is a significant threat to the health of RA patients. The measures of adiposity developed herein should be used to identify obese RA patients. Physical activity seems like the sole mode for effective weight management in this population. Health and exercise professionals should actively encourage their patients to exercise as much as they can. This study has created more questions than it answered; further research in the association of obesity and inflammation, as well as in ways to treat it, is essential.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

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

Fit to Dance Survey: elements of lifestyle and injury incidence in Chinese dancers

This is an accepted manuscript of an article published by Science & Medicine, Inc in Medical Problems of Performing Artists on March 2020, available online: https://doi.org/10.21091/mppa.2020.1002 The accepted version of the publication may differ from the final published version.The Fit to Dance survey has been conducted a number of times using primarily Western participants and has provided foundation data for other studies. The purpose of the current study was to replicate the Fit to Dance 2 survey focusing on features of health and injuries in pre-professional and professional Chinese dancers of different genres. Results revealed that respondents (n=1040) were from Chinese Folk dance (44.4%), Chinese Classical Dance (25.6%), ballet (10.2%) and contemporary dance (9.8%). Compared to the Fit to Dance 2 survey, alcohol consumption (29% vs 82%; p<0.01) and smoking (13% vs 21%; p<0.05) were significantly less in Chinese dancers, but a higher percentage reported using weight reducing eating plans (57% vs 23%; p<0.01) or having psychological issues with food (27% vs 24%; p<0.05). Reported injuries in a 12-month period prior to data collection were significantly lower in the current survey (49% vs 80%; p<0.01). The type of injury (muscle and joint/ligament) and perceived cause of injury (fatigue, overwork and reoccurrence of an old injury) were the same in both the current and previous survey. Mean injury rate for the studied 12-month period ranged from 4.9 injuries per dancer (contemporary) to 3.4 injuries per dancer (Chinese Folk dance) which is comparable to previously reported data on western dance populations. This survey has provided the first comprehensive data on the health and injury incidence of Chinese dancers

Validation of the Polar RS800CX for assessing heart rate variability during rest, moderate cycling and post-exercise recovery

Background: Heart rate variability (HRV) is an autonomic nervous system marker that provides reliable information for both disease prevention and diagnosis; it is also used in sport settings. We examined the validity of the Polar RS800CX heart rate monitor during rest, moderate cycling, and recovery in considering the total of 24 HRV indices. Method: A total of 32 healthy males (age=24.78±6.87 years, body mass index=24.48±3.13 kg/m 2 ) completed a session comprised by three 20-minute time periods of resting, cycling at 60% of maximal heart rate, and recovery using a Polar RS800CX and an electrocardiogram (ECG) monitors. The HRV indices included time-domain, frequency-domain, Poincaré plot and recurrence plot. Bland–Altman plot analysis was used to estimate agreement between Polar RS800CX and ECG. Results: We detected significant associations (r>0.75, p<0.05) in all HRV indices, while five out of 24 HRV indices displayed significant mean differences (p<0.05) between Polar RS800CX and ECG during the resting period. However, for the exercise and recovery periods, we found significant mean differences (p<0.05) in 16/24 and 22/24 HRV indices between the two monitors, respectively. Conclusion: It is concluded that Polar RS800CX is a valid tool for monitoring HRV in individuals at resting conditions, but it displays inconsistency when used during exercise at 60% of maximal heart rate and recovery periods.Published versio

Stretch Intensity vs. Inflammation: A Dose-dependent Association?

The intensity of stretching is rarely reported in scientific literature. In this study, we examined the effects of stretching intensities at 30%, 60%, and 90% of maximum range of movement (mROM) on the inflammatory response of the right hamstring muscle. Methods: A randomised within-subject trial was conducted with 11 healthy recreationally active males over a three week period. Participants were strapped into an isokinetic dynamometer in the supine position, with the right knee fastened in a knee immobilizer. After randomising the ROM percentages, the hamstring muscle was moved to one of the three chosen ROM percentages for that week and held there for 5 x 60 seconds followed by a 10 second rest between repetitions. A 5ml blood sample was collected pre-, immediately post, and at 24 hours post intervention for high sensitivity C-reactive protein (hsCRP) assessments. Results: Significant increases in hsCRP levels were observed between 30% mROM and 90% mROM (p=0.004) and 60% mROM and 90% mROM (p=0.034), but not between 30% and 60% (p>0.05). Conclusions: Muscle stretching at submaximal levels does not elicit a significant systemic inflammatory responses

Associations between balance ability and dance performance using field balance tests

Purpose: Although balance is a key element of dance, it remains to be confirmed which balance components are associated with dance performance. The aim of this study was to assess the associations between different balance field tests and dance performance in an in-house measure in ballet, contemporary and jazz genres. Methods: 83 female undergraduate dance students (20±1.5 years; 163.04±6.59 cm; 60.97±10.76 kg) were subjected to the Star Excursion Balance Test (SEBT), the Airplane test, a dance-specific pirouette test, the modified Romberg test, and the BioSway Balance System (Biodex, USA). The results from these balance tests were compared to the participants’ technique and repertoire performance scores in ballet, contemporary, and jazz genres. Results: Ballet scores were best predicted by SEBT 90˚ and Romberg for technique (r = 0.4, p = 0.001, SEE ±2.49) and Romberg, SEBT 90˚, and SEBT 225˚ for repertoire (r = 0.51, p = 0.001, SEE±1.99). Contemporary data indicated SEBT 90˚ and Romberg for technique (r = 0.37, p = 0.001, SEE±2.67) and SEBT 225˚ for repertoire (r = 0.27, p = 0.015, SEE±2.29). Jazz indicated SEBT 90˚, Romberg, SEBT 315˚, and SEBT 225˚ for technique (r = 0.51, p = 0.001, SEE±2.28) and SEBT 225˚ and Romberg for repertoire (r = 0.41, p = 0.001, SEE±2.29). Conclusion: The present study suggests that balance ability has a limited influence on dance performance, with existing field balance tests demonstrating low to moderate associations with dance technique and repertoire