Ballet dancers cardiorespiratory, oxidative and muscle damage responses to classes and rehearsals

Systematic review of methods used to measure training load in dance

Dance is a popular physical activity. Increased dance training has been associated with an increased risk of injury. Given the established association between training load (TL) and injury in sport, knowledge of how TL is currently being measured in dance is critical. The objective of this study is to summarise published literature examining TL monitoring in dance settings. Six prominent databases (CINAHL, EMBASE, Medline, ProQuest, Scopus, SportDiscus) were searched and nine dance-specific journals were handsearched up to May 2022. Selected studies met inclusion criteria, where original TL data were collected from at least one dancer in a class, rehearsal and/or performance. Studies were excluded if TL was not captured in a dance class, rehearsal or performance. Two reviewers independently assessed each record for inclusion at title, abstract and full-text screening stages. Study quality was assessed using Joanna Briggs Institute Critical Appraisal Tool checklists for each study design. The 199 included studies reported on female dancers (61%), ballet genre (55%) and the professional level (31%). Dance hours were the most common tool used to measure TL (90%), followed by heart rate (20%), and portable metabolic systems (9%). The most common metric for each tool was mean weekly hours (n=381; median=9.5 hours, range=0.2-48.7 hours), mean heart rate (n=143) and mean oxygen consumption (n=93). Further research on TL is needed in dance, including a consensus on what tools and metrics are best suited for TL monitoring in dance.

Dietary Iron and the Elite Dancer

Dancers are an athlete population at high risk of developing iron deficiency (ID). The aesthetic nature of the discipline means dancers potentially utilise dietary restriction to meet physique goals. In combination with high training demands, this means dancers are susceptible to problems related to low energy availability (LEA), which impacts nutrient intake. In the presence of LEA, ID is common because of a reduced mineral content within the low energy diet. Left untreated, ID becomes an issue that results in fatigue, reduced aerobic work capacity, and ultimately, iron deficient anaemia (IDA). Such progression can be detrimental to a dancer’s capacity given the physically demanding nature of training, rehearsal, and performances. Previous literature has focused on the manifestation and treatment of ID primarily in the context of endurance athletes; however, a dance-specific context addressing the interplay between dance training and performance, LEA and ID is essential for practitioners working in this space. By consolidating findings from identified studies of dancers and other relevant athlete groups, this review explores causal factors of ID and potential treatment strategies for dancers to optimise absorption from an oral iron supplementation regime to adequately support health and performance.

Fit to Teach?-Cardiorespiratory Capacity, Vitamin D3, and Ferritin in Physical Education Teachers With Specialization in Dance

ABSTRACT

Schmidt, M, Ohlendorf, D, Groneberg, DA, and Wanke, EM. Fit to teach?-Cardiorespiratory capacity, vitamin D3, and ferritin in physical education teachers with specialization in dance. J Strength Cond Res 35(4): 1156-1164, 2021-Numerous studies have shown that good cardiorespiratory capacity is of great importance for a healthy and long-term professional career as a dancer. Although the cardiorespiratory demands during teaching can reach into the submaximal intensity range, current data on the objective physical fitness of this occupational group are still missing. The aim of this pilot project was to determine selected cardiorespiratory parameters. In addition, measurements of the vitamin D3 (25(OH)D3) and iron balance as well as a subjective assessment of dance teachers' (DTs) fitness were performed. Twenty-one DTs (f: n = 18, m: n = 3) aged 48.2 ± 9.3 years were examined for cardiorespiratory performance within the framework of maximum bicycle spiroergometry. In addition, the self-perception of DTs' fitness was examined as well as the serum vit D3 levels and ferritin concentration in the blood. The cardiorespiratory fitness of DTs can be assessed as average (maximal oxygen consumption, V̇o2max = 29.5 ± 7.1 ml·k-1·min-1; physical working capacity, PWCmax = 165.0 ± 44.4). The DTs seemed to underestimate or overestimate their own capacity. Laboratory diagnostics showed that the 25(OH)D3 levels (21.8 ± 8.5 ng·ml-1) and serum ferritin values (102.4 ± 35.0 g·dl-1) were not optimal for almost the entire sample. In view of the physical occupational requirements, an increase in aerobic cardiorespiratory fitness by endurance-oriented basic training for DTs seems advisable. In addition, the substitution of vit D3 is worth being discussed.

Choreography-Specific Cross-Training and Conditioning Programs

Because of increased choreographic demands, early specialization, multi-genre dancers, and high incidence of career-ending injuries, there is a need for enhanced training methodologies to address the unique needs of today's professional dancer. It is imperative for company directors, instructors, choreographers, and dance medicine practitioners to consider implementing the most specific conditioning and training programs to prepare their dancers to meet or exceed expectations without resultant injury. Quantifying effectiveness of choreography-specific training programs is an area for further research. The implementation of scientific principles can and should be used to enhance dancers' health, performance, athleticism, and artistry.

Training session intensity affects plasma redox status in amateur rhythmic gymnasts

PURPOSE

The aim of this study was to examine systemic responses of oxidant/antioxidant status following 2 training sessions of different intensity in amateur rhythmic gymnasts.

METHODS

Before the experimental training, 10 female gymnasts performed a gradually increased exercise test to assess maximal heart rate, maximal oxygen consumption, and anaerobic threshold. They executed 2 intermittent training sessions separated by 48 h of recovery (48 h-post R): the first was performed at low-moderate intensity (LMI) and the second at high intensity (HI). Blood samples were collected immediately pre- and post-training and 48 h-post R. Hydroperoxide level (OxL) and total antioxidant capacity (TAC) were photometrically measured.

RESULTS

OxL was significantly higher in post-training and 48 h-post R following HI than the same conditions after an LMI session (HI vs. LMI post-training: 381.10 ± 46.17 (mean ± SD) vs. 344.18 ± 27.94 Units Carratelli (U.CARR); 48 h-post R: 412.21 ± 26.61 vs. 373.80 ± 36.08 U.CARR). There was no change in TAC between the 2 training sessions investigated. In LMI training, OxL significantly decreased in post-training and increased to reach the baseline at 48 h-post R, whereas TAC increased only at 48 h-post R. In HI training, OxL significantly increased to reach a high oxidative stress 48 h-post R, whereas TAC was lower in post-training than pre-training.

CONCLUSION

The pattern of OxL and TAC levels implies different regulation mechanisms by HI and LMI training sessions. High oxidative stress induced by an HI protocol might be associated with both insufficient TAC and recovery time at 48 h necessary to restore redox balance.

Association between Physical Exercise and Biomarkers of Oxidative Stress among Middle-Aged and Elderly Community Residents with Essential Hypertension in China

This study aimed to investigate the role of different types and frequencies of physical exercise in biomarkers of oxidative stress among middle-aged and elderly community residents with essential hypertension in China. A community-based cross-sectional survey was undertaken in 7 subdistricts. Individuals, 45-79 years old, with essential hypertension (n = 402) and without cardiovascular disease (n = 1047) were included. Superoxide dismutase (SOD) activities and plasma levels of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) were determined. Multilevel linear regression was used to estimate the associations between various types of physical exercise and oxidative stress biomarker levels. Participants engaged in high frequency walking/square dancing or taiji/yoga demonstrated decreased systolic blood pressure in both groups; however, diastolic blood pressure decreased only among individuals with hypertension participating in walking/square dancing. In individuals with hypertension, MDA levels decreased in those participating in walking/square dancing, SOD activity increased in those participating in walking/square dancing, and 4-HNE levels decreased in those involved in taiji/yoga. In individuals without cardiovascular disease, MDA levels decreased in those involved in walking/square dancing or taiji/yoga, SOD activity increased in those performing walking/square dancing, and 4-HNE levels decreased in those involved in taiji/yoga. Oxidative stress marker levels also improved in those involved in walking/square dancing or taiji/yoga groups as the exercise frequency increased. Thus, frequent participation in walking/square dancing or taiji/yoga effectively decreases hypertension-related oxidative stress biomarker levels.

Cardiorespiratory responses of a dance session designed for older women: A cross sectional study

BACKGROUND

Dancing has been increasingly used as a type of exercise intervention to improve cardiovascular fitness of older people. However, it is unclear which may be the exercise intensity of the dance sessions.

OBJECTIVE

To describe cardiorespiratory responses of a dance session for older women, and to identify intensity zones in relation to peak oxygen consumption (VO₂peak), first and second ventilatory thresholds (VT1 and VT2).

METHODS

Ten women (66 ± 5 yrs., BMI 27 ± 4) were examined on three occasions: Familiarization, maximum effort and dance sessions. Incremental treadmill test: 5 km/h, 2% slope each min, until maximum effort. Dance class (60 min): warm-up (20 min), across-the-floor (10 min), choreography (15 min), show (10 min) and cool-down (5 min). Ventilatory parameters were measured continuously (breath-by-breath).

RESULTS

VO₂ (mL·kg^-1·min^-1): Maximum effort: VO₂peak (23.3 ± 4.3), VT1 (17.2 ± 3.5) and VT2 (20.9 ± 3.4). Dancing: warm-up (12.8 ± 2.4, ~55%VO₂peak), across-the-floor (14.2 ± 2.4 ~62%VO₂peak), choreography (14.6 ± 3.2 ~63%VO₂peak) and show (16.1 ± 3.3, ~69% VO₂peak). Show was similar to VT1.

CONCLUSIONS

Cardiorespiratory demands of a dance class for older women are at low aerobic intensity. Show was similar to VT1, indicating that a dance class may be modulated to improve aerobic fitness, at least at initial stages of training.

Assessment of DNA damage in a group of professional dancers during a 10-month dancing season

Despite the numerous health benefits of physical activity, some studies 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 general population was also assessed as a control. 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 antioxidant system in dancers. Results of the present biomonitoring study indicate the need for more effective measures to protect ballet dancers from potentially occupational health risks related to regular intensive physical exercise.

The Effects of 17 Weeks of Ballet Training on the Autonomic Modulation, Hormonal and General Biochemical Profile of Female Adolescents

This study aimed to examine the alterations in physiological and biochemical markers, after 17 weeks of ballet training in high level ballet dancers. Twenty four female ballet dancers from 12 to 15 years old took part in the study. The study followed 17 weeks of ballet training and analyzed changes in body composition, the autonomic nervous system and biochemical variables before and after (post) training. The internal training load was obtained using the session rating of perceived exertion (session-RPE) method, calculated as the mean weekly session-RPE, monotony and strain. After 17 weeks of training there were significant increases in body mass, height, lean body mass, total protein, urea, hemoglobin concentration, testosterone and thyroxine. During this period, decreases in relative body fat, uric acid, red blood cells, C-reactive protein, and ferritin were also found. After the training period, the autonomic modulation demonstrated significant positive alterations, such as increases in parasympathetic related indices. Based on the results obtained we concluded that ballet training led to improvements in body composition and autonomic modulation. In general hematological and biochemical variables demonstrated that the training did not have adverse effects on the health state of the adolescents.

Amino acid supplementation and impact on immune function in the context of exercise

Moderate and chronic bouts of exercise may lead to positive metabolic, molecular, and morphological adaptations, improving health. Although exercise training stimulates the production of reactive oxygen species (ROS), their overall intracellular concentration may not reach damaging levels due to enhancement of antioxidant responses. However, inadequate exercise training (i.e., single bout of high-intensity or excessive exercise) may result in oxidative stress, muscle fatigue and muscle injury. Moreover, during the recovery period, impaired immunity has been reported, for example; excessive-inflammation and compensatory immunosuppression. Nutritional supplements, sometimes referred to as immuno-nutrients, may be required to reduce immunosuppression and excessive inflammation. Herein, we discuss the action and the possible targets of key immuno-nutrients such as L-glutamine, L-arginine, branched chain amino acids (BCAA) and whey protein.