Superior short-term learning effect of visual and sensory organisation ability when sensory information is unreliable in adolescent rhythmic gymnasts.

Rhythmic gymnasts specialise in dynamic balance under sensory conditions of numerous somatosensory, visual, and vestibular stimulations. This study investigated whether adolescent rhythmic gymnasts are superior to peers in Sensory Organisation test (SOT) performance, which quantifies the ability to maintain standing balance in six sensory conditions, and explored whether they plateaued faster during familiarisation with the SOT. Three and six sessions of SOTs were administered to 15 female rhythmic gymnasts (15.0 ± 1.8 years) and matched peers (15.1 ± 2.1 years), respectively. The gymnasts were superior to their peers in terms of fitness measures, and their performance was better in the SOT equilibrium score when visual information was unreliable. The SOT learning effects were shown in more challenging sensory conditions between Sessions 1 and 2 and were equivalent in both groups; however, over time, the gymnasts gained marginally significant better visual ability and relied less on visual sense when unreliable. In conclusion, adolescent rhythmic gymnasts have generally the same sensory organisation ability and learning rates as their peers. However, when visual information is unreliable, they have superior sensory organisation ability and learn faster to rely less on visual sense.

Bone Mineralization in Rhythmic Gymnasts Entering Puberty: Associations with Jumping Performance and Body Composition Variables.

This study examined bone mineral density (BMD) accrual in prepubertal rhythmic gymnasts entering puberty and their age-matched untrained control girls, and associations with baseline jumping performance and body composition over the 3-year period. Whole body (WB) and femoral neck (FN) BMD, WB fat mass (FM) and fat free mass (FFM), countermovement jump (CMJ) and rebound jumps for 15 s (RJ15s) were assessed in 25 rhythmic gymnasts and 25 untrained controls at baseline and after 3-year period. The changes over this period were calculated (Δ scores). Pubertal maturation over the 3-year period was slower in rhythmic gymnasts compared to untrained controls, while no difference in bone age development was seen. WB BMD increased similarly in both groups, while the increase in FN BMD was higher in rhythmic gymnasts compared with untrained controls. In rhythmic gymnasts, baseline FFM was the most significant predictor of ΔWB BMD explaining 19.2% of the variability, while baseline RJ15s was the most significant predictor of ΔFN BMD explaining 18.5% of the variability. In untrained controls, baseline FM explained 51.8 and 18.9% of the variability in ΔWB BMD and ΔFN BMD, respectively. In conclusion, mechanical loading of high-intensity athletic activity had beneficial effect on BMD accrual in rhythmic gymnasts and may have counterbalanced such negative factors on bone development as slower pubertal maturation and lower body FM. Baseline FFM and repeated jumps test performance were related to BMD accrual in rhythmic gymnasts, while baseline FM was related to BMD accrual in untrained controls.

Adipocytokine and ghrelin levels in relation to bone mineral density in prepubertal rhythmic gymnasts entering puberty: a 3-year follow-up study.

PURPOSE: To investigate changes in bone mineral density (BMD) in rhythmic gymnasts (RG) entering puberty and their age-matched untrained controls (UC) over the 36-month period, and associations with leptin, adiponectin and ghrelin over this period. METHODS: Whole body (WB), lumbar spine (LS) and femoral neck (FN) BMD, WB bone mineral content (BMC), and leptin, adiponectin and ghrelin were measured in 35 RG and 33 UC girls at baseline and at 12-month intervals over the next 3 years. The change over the 36 months was calculated (∆ score). RESULTS: The pubertal development over the next 36 months was slower in RG compard to UC, while there was no difference in bone age development between the groups. BMD at all sites was higher in RG in comparison with UC at every measurement point. ∆LS BMD and ∆FN BMD, but not ∆WB BMD and ∆WB BMC, were higher in RG compared with UC. None of the measured hormones at baseline or their ∆ scores correlated with ∆BMD and ∆BMC in RG. Baseline fat free mass correlated with ∆WB BMD and ∆WB BMC in RG, while baseline leptin was related to ∆WB BMC, ∆WB BMD and ∆LS BMD in UC. CONCLUSIONS: Measured baseline hormones and their ∆ scores did not correlate with increases in bone mineral values in RG entering puberty. Although the pubertal development in RG was slower than in UC, high-intensity training appeared to increase BMD growth and counterbalance negative effects of slow pubertal develpment, lower fat mass and leptin in RG.

Growth and body composition in Brazilian female rhythmic gymnastics athletes.

The aim was to analyse the physical growth and body composition of rhythmic gymnastics athletes relative to their level of somatic maturation. This was a cross-sectional study of 136 athletes on 23 teams from Brazil. Mass, standing height and sitting height were measured. Fat-free and fat masses, body fat percentages and ages of the predicted peak height velocity (PHV) were calculated. The z scores for mass were negative during all ages according to both WHO and Brazilian references, and that for standing height were also negative for all ages according to WHO reference but only until 12 years old according to Brazilian reference. The mean age of the predicted PHV was 12.1 years. The mean mass, standing and sitting heights, body fat percentage, fat-free mass and fat mass increased significantly until 4 to 5 years after the age of the PHV. Menarche was reached in only 26% of these athletes and mean age was 13.2 years. The mass was below the national reference standards, and the standing height was below only for the international reference, but they also had late recovery of mass and standing height during puberty. In conclusion, these athletes had a potential to gain mass and standing height several years after PHV, indicating late maturation.

Associations of Circulating Irisin and Fibroblast Growth Factor-21 Levels with Measures of Energy Homeostasis in Highly Trained Adolescent Rhythmic Gymnasts.

The aim of this investigation was to determine the associations of serum irisin and fibroblast growth factor-21 (FGF-21) with the measures of energy homeostasis, training stress and other energy homeostasis hormones in highly trained adolescent rhythmic gymnasts (RG). Thirty-three RG and 20 untrained controls (UC) aged 14−18 years participated in this study. Body composition, resting energy expenditure (REE), peak oxygen consumption, and different energy homeostasis hormones in serum, including irisin, FGF-21, leptin, and resistin, were measured. Irisin and FGF-21 were not significantly different (p > 0.05) between RG and UC groups. In RG, serum irisin was positively associated with REE (r = 0.40; p = 0.021) and leptin (r = 0.60; p = 0.013), while serum FGF-21 was related to body fat mass (r = 0.46; p = 0.007) and leptin (r = 0.45; p = 0.009). Irisin was related to FGF-21, independent of age, body fat, and lean masses (r = 0.36; p = 0.049) in RG. In conclusion, serum irisin concentration was associated with energy expenditure and serum FGF-21 level with energy availability measures in lean adolescent athletes, while no relationships of irisin and FGF-21 with energy status measures were observed in lean nonathletic adolescents.

Isokinetic leg muscle strength relationship to dynamic balance reflects gymnast-specific differences in adolescent females.

Balance, together with other motor qualities, plays an important role in the successful execution of specific gymnastic skills. However, it is also not clear whether different demands on dynamic balance and power produced by lower limb can be observed in sport-specific differences among gymnasts of various modalities. The question also is as to what extent isokinetic leg muscle strength contributes to anterior and posterior postural stability in gymnasts. Therefore, the aim of the study was i) to compare variables of dynamic balance and isokinetic leg muscle strength in rhythmic, artistic, and aerobic gymnasts, and ii) to investigate the relationship of reach distances in anterior, posteromedial, and posterolateral directions, as well as the composite score in the Y-balance test with an isokinetic muscle strength during knee extension and flexion at different velocities in female gymnasts of various disciplines. Altogether seven aerobic, five artistic, and six rhythmic gymnasts performed the Y-balance test and isokinetic leg muscle strength test at 60°/s, 180°/s, and 300°/s. Results showed significant between-group differences in the composite score in the Y-balance test of the dominant (F = 3.536, p = .041) and non-dominant symmetry (F = 4.804, p = .015). Similarly, average power produced during knee extension and knee flexion at 60°/s, 180°/s and 300°/s differed significantly among these groups (all at p˂0.05). In addition, there was a significant relationship between the composite score of the dominant limb symmetry and isokinetic dominant limb extension strength at 60°/s (r = .54), 180°/s (r = .87), and 300°/s (r = .84) in aerobic gymnasts. The composite score of the dominant limb symmetry was also associated with isokinetic dominant limb extension strength, albeit only at 60°/s in both artistic (r = .60) and rhythmic gymnasts (r = .55). Such between-group differences may be ascribed to their different demands on maintenance of balance under dynamic conditions and leg muscle power within their sport specializations. Taking into account significant association between the dominant limb symmetry and isokinetic dominant limb extension strength, it may be concluded that both muscle strength and fast speeds contribute to dynamic balance in adolescent gymnasts.

The Associations of Body Image Perception with Serum Resistin Levels in Highly Trained Adolescent Estonian Rhythmic Gymnasts.

Rhythmic gymnasts (RGs) are more likely to be dissatisfied with their body mass and shape compared to untrained controls (UCs). However, due to the lack of information, the aim of this study was to investigate the associations of body image perception (BIP) with body composition, daily energy consumption and different blood biochemical markers in adolescent RGs compared to UCs. Thirty-three highly trained RG girls and 20 UC girls aged 14-18 years participated in this cross-sectional study. Height, body mass, body composition, energy intake, resting energy expenditure, training volume and different blood biochemical markers were measured. The body attitude test (BAT) was used to evaluate the BIP of the participants. There were no differences in the total BAT scores between the groups. In RGs, the BAT score correlated positively with the serum resistin level (r = 0.35; p = 0.047). A stepwise multiple regression analysis showed that 40.8% of the variability in the BAT score was determined by resistin and BMI. The association of BIP with resistin values was observed only in RGs. In conclusion, our findings add to the increasing evidence that resistin may be a link between BIP and body composition, most likely through fat mass, in adolescent female RGs.

Body Composition, Dietary Intake and the Risk of Low Energy Availability in Elite-Level Competitive Rhythmic Gymnasts.

The aim of this study was to analyze dietary intake and body composition in a group of elite-level competitive rhythmic gymnasts from Spain. We undertook body composition and nutritional analysis of 30 elite gymnasts, divided into two groups by age: pre-teen (9-12 years) (n = 17) and teen (13-18 years) (n = 13). Measures of height, weight, and bioimpedance were used to calculate body mass index and percent body fat. Energy and nutrient intakes were assessed based on 7-day food records. The two groups had similar percentages of total body fat (pre-teen: 13.99 ± 3.83% vs. teen: 14.33 ± 5.57%; p > 0.05). The energy availability values for pre-teens were above the recommended values (>40 kcal/FFM/day) 69.38 ± 14.47 kcal/FFM/day, while those for the teens were much lower (34.7 ± 7.5 kcal/FFM/day). The distribution of the daily energy intake across the macronutrients indicates that both groups ingested less than the recommended level of carbohydrates and more than the recommended level of fat. Very low intakes of calcium and vitamin D among other micronutrients were also noted. The main finding is that teenage gymnasts do not consume as much energy as they need each day, which explains their weight and development. Moreover, they are at a high risk of developing low energy availability that could negatively impact their performance and future health.

Comparison of bone metabolism based on the different ages and competition levels of junior and high school female rhythmic gymnasts.

PURPOSE: This study was to clarify the effect of age and competition level by measuring bone metabolism markers and bone mineral density measurements of junior high school and high school female rhythmic gymnasts, who restrict their diets to maintain a low body weight, while routinely undertaking long hours of high-intensity exercise, comparing the gymnasts based on their elite/non-elite. METHODS: The study investigated 7 junior high school and 12 high school female rhythmic gymnasts. For comparison by competition level, the 7 junior high school gymnasts were separated into 3 gymnasts who competed at national level (junior high school elite), and 4 gymnasts who did not compete at that level (junior high school non-elite), and the 12 high school gymnasts were separated into 7 gymnasts who competed at national level (high school elite) and 5 gymnasts who did not compete at that level (high school non-elite). The measurement items were bone mineral density, bone metabolism markers (undercarboxylated osteocalcin (ucOC), osteocalcin (OC), bone-specific alkaline phosphatase (BAP), calcium (Ca), inorganic phosphorus (P), alkaline phosphatase (ALP), parathyroid hormone (PTH), type 1 collagen cross-linked N-telopeptide (NTx)). We also surveyed the gymnasts' height, weight and nutrition. RESULTS: In this study we found: 1) The high school gymnasts who competed at high-level rhythmic gymnastics had good results for bone metabolism markers and bone mineral density. 2) Elite high school gymnasts had restricted diets. 3) Nutritionally, their energy intake and carbohydrate intake was low, but their intake of protein, calcium, iron, vitamin D and vitamin K was good. CONCLUSION: The results found that the elite gymnastics showed a higher bone density than the non-elite group that suggests the possibility of inhibiting bone formation in the bone metabolism.

Body composition and inflammatory markers in pubertal girls: Comparison between athletes and non-athletic controls.

Various inflammation parameters are increased with childhood obesity, but few comparable data are found in lean growing athletes. This study aims to characterize differences in 12 simultaneously measured inflammatory parameters between pubertal rhythmic gymnasts (RG) and untrained controls (UC), and to examine the relationship between body composition and inflammatory markers. Sixty 10-12-year-old girls were divided into RG (n = 30) and UC (n = 30). Fat mass (FM) and fat free mass (FFM) were measured by dual-energy X-ray absorptiometry. Leptin and 12 inflammatory parameters (interleukin [IL]-2, IL-4, IL-6, IL-8, IL-10, vascular endothelial growth factor, interferon-gamma [IFN-γ], tumor necrosis factor-alpha, IL-1α, IL-1ß, monocyte chemotactic protein-1 and epidermal growth factor) were measured from fasting blood samples. No differences were seen in 12 inflammatory markers between studied groups. As expected, leptin (RG: 2.4 ± 1.1; UC: 7.6 ± 4.2 ng ml-1) and FM (RG: 7.3 ± 2.3; UC: 11.8 ± 5.1 kg) were lower (p < .05) in RG compared to UC. In the whole group of lean pubertal girls, 69.0% of the variability in body FM was determined by leptin, and 11.2% of the variability in body FFM was explained by IFN-γ. In conclusion, measured 12 inflammatory biomarkers were not different between RG and UC, despite lower leptin and FM in RG. In lean pubertal girls, IFN-γ was independently associated with FFM, and leptin with FM.

Habitual dietary protein intake affects body iron status in Japanese female college rhythmic gymnasts: a follow-up study.

BACKGROUND: Many rhythmic gymnasts stay lean by reducing their body weight (BW); however, this may result in iron deficiency (ID). Our previous cross-sectional study reported an association between ID incidence and protein intake in gymnasts during the pre-season. The present study aimed to examine the association between dietary protein intake and ID incidence in a 2-year follow-up study. METHODS: Elite Japanese female college rhythmic gymnasts [mean age ± standard deviation (SD): 18.4 ± 0.5 years] were recruited on a voluntary basis every August for 9 years. Anthropometric, dietary intake, and hematological parameters were measured at baseline and 2 years later. A total of 20 participants without ID at baseline were divided into either a lower (L, n = 11) or higher (H, n = 9) protein group based on median protein intake (1.3 g protein/kg BW). RESULTS: Participants consumed 1.08 ± 0.16 and 1.55 ± 0.14 g/kg BW of protein in the L and H groups, respectively. No significant changes in the intake of protein and other nutrients were observed between baseline and 2-year follow-up in both groups. ID was observed in a total of eight (72.8 %) participants in the L group and one (11.2 %) in the H group at follow-up. The incidence of ID was significantly lower in the H group than the L group (Fisher's exact test, odds ratio, 0.043; 95 % CI 0.004-0.552; p = 0.010). CONCLUSIONS: During the pre-season weight loss period, habitually higher protein intake may reduce ID incidence among elite college female rhythmic gymnasts.

Salivary adiponectin levels are associated with training intensity but not with bone mass or reproductive function in elite Rhythmic Gymnasts.

Elite Rhythmic Gymnasts (RGs) constitute a unique metabolic model and they are prone to developing Anorexia Athletica. The aim of the present study was to evaluate the effect of training intensity on salivary adiponectin levels and assess a possible role of salivary adiponectin levels as a predictive factor of reproductive dysfunction and bone mass acquisition in elite RGs. The study included 80 elite female RGs participating in the World Rhythmic Gymnastics Championship tournament held in Montpellier, France on September 2011. Anthropometric values were assessed, training data and menstrual pattern were recorded, bone mass was measured with Broadband ultrasound attenuation (dB/Mhz) and baseline salivary adiponectin levels were determined. The athletes were classified as intensely and very intensely trained, considering the mean training intensity (40.84h/week). Moreover, considering their reproductive status, they were divided into RG's with normal menstruation, primary amenorrhea and oligomenorrhea. All comparisons were adjusted to age, BMI and body fat percentage differences. Very intensely trained RGs showed higher salivary adiponectin levels (p=0.05). Moreover, salivary adiponectin levels showed significant correlation with training intensity (r=0.409, p=0.003). On the other hand, no association of salivary adiponectin levels was documented with either reproductive function or bone mass acquisition. The results of the present study suggest that, in elite RGs, salivary adiponectin levels are associated with the intensity of training, possibly reflecting the deterioration of energy balance rather than the training stress. On the other hand, a predictive role of salivary adiponectin levels in reproductive dysfunction or bone mass acquisition could not be supported.

Peripubertal female athletes in high-impact sports show improved bone mass acquisition and bone geometry.

OBJECTIVE: Intensive physical training may have a sport-dependent effect on bone mass acquisition. This cross-sectional study evaluated bone mass acquisition in girls practicing sports that put different mechanical loads on bone. MATERIALS/METHODS: Eighty girls from 10.7 to 18.0 years old (mean 13.83 ± 1.97) were recruited: 20 artistic gymnasts (AG; high-impact activity), 20 rhythmic gymnasts (RG; medium-impact activity), 20 swimmers (SW, no-impact activity), and 20 age-matched controls (CON; leisure physical activity <3h/wk). Areal bone mineral density (aBMD) was determined using DEXA. Hip structural analysis applied at the femur evaluated cross-sectional area (CSA, cm(2)), section modulus (Z, cm(3)), and buckling ratio. Bone turnover markers and OPG/RANKL levels were analyzed. RESULTS: AG had higher aBMD than SW and CON at all bone sites and higher values than RG in the lumbar spine and radius. RG had higher aBMD than SW and CON only in the femoral region. CSA and mean cortical thickness were significantly higher and the buckling ratio was significantly lower in both gymnast groups compared with SW and CON. In RG only, endocortical diameter and width were reduced, while Z was only increased in AG compared with SW and CON. Reduced bone remodeling was observed in RG compared with AG only when groups were subdivided according to menarcheal status. All groups showed similar OPG concentrations, while RANKL concentrations increased with age and were decreased in SW. CONCLUSION: High-impact activity clearly had a favorable effect on aBMD and bone geometry during the growth period, although the bone health benefits seem to be more marked after menarche.

The Status of Nutrient and Food Intakes and the Nutritional Knowledge in Adolescent Rhythmic Gymnasts

The objectives of this study were to investigate 1) the foods intake as well as nutrients intake, 2) the nutritional knowledge, and 3) the relations between the foods and nutrients intakes and nutritional knowledge in adolescent rhythmic gymnasts (RGs). The results are summarized as follows. Average daily intakes of energy, calcium, iron, vitamin A, vitamin B1, vitamin B2 and niacin were in 45 - 74% of the RDAs for Koreans. Average daily energy intake was only about 50% of energy expenditure by physical activities. Average daily intakes of each food group were generally lower, but intakes of breads and confectionaries, sugar and sweets, milks and dairy products, and instant foods were higher in the RGs compared to the nonathletic students of the same age from the National Health and Nutrition Suvey. The contribution of empty-calorie foods such as breads and confectionaries, beverage and instant foods to the major energy nutrients were high. Mean of total nutritional knowledge score of RGs was 28.4 of total score 50. In categorical score of nutritional knowledge, the RGs make a best score on food sources and they get the lowest marks for food exchange. Among the nutrients, intakes of crude fiber, animal Fe, Na, K, vitamin A, carotene, vitamin B1, niacin and vitamin C and, among the food groups, intakes of mushrooms, fruits and meats had relations with one of the total or categorical nutritional knowledge scores in the RGs. In conclusion, nutritional status of adolescent RGs was poor due to their unbalanced diet composed of empty-calorie foods, and their undesirable food intake pattern was supposed to be related to the low nutritional knowledge score of them. These results indicate that the RGs should be given more nutritional knowledge to improve their nutritional status and the exercise performance.