The combined analysis of urine and blood metabolomics profiles provides an accurate prediction of the training and competitive status of Chinese professional swimmers.

Objective: The purpose of this study was to employ metabolomics for the analysis of urine metabolites in swimmers, with the aim of establishing models for assessing their athletic status and competitive potential. Furthermore, the study sought to compare the identification efficacy of multi-component (urine and blood) model versus single-component (urine or blood) models, in order to determine the optimal approach for evaluating training and competitive status. Methods: A total of 187 Chinese professional swimmers, comprising 103 elite and 84 sub-elite level athletes, were selected as subjects for this study. Urine samples were obtained from each participant and subjected to nuclear magnetic resonance (NMR) metabolomics analysis. Significant urine metabolites were screened through multivariable logistic regression analysis, and an identification model was established. Based on the previously established model of blood metabolites, this study compared the discriminative and predictive performance of three models: either urine or blood metabolites model and urine + blood metabolites model. Results: Among 39 urine metabolites, 10 were found to be significantly associated with the athletic status of swimmers (p < 0.05). Of these, levels of 2-KC, cis-aconitate, formate, and LAC were higher in elite swimmers compared to sub-elite athletes, while levels of 3-HIV, creatinine, 3-HIB, hippurate, pseudouridine, and trigonelline were lower in elite swimmers. Notably, 2-KC and 3-HIB exhibited the most substantial differences. An identification model was developed to estimate physical performance and athletic level of swimmers while adjusting for different covariates and including 2-KC and 3-HIB. The urine metabolites model showed an area under the curve (AUC) of 0.852 (95% CI: 0.793-0.912) for discrimination. Among the three identification models tested, the combination of urine and blood metabolites showed the highest performance than either urine or blood metabolites, with an AUC of 0.925 (95% CI: 0.888-0.963). Conclusion: The two urine metabolites, 2-KC and 3-HIV, can serve as significant urine metabolic markers to establish a discrimination model for identifying the athletic status and competitive potential of Chinese elite swimmers. Combining two screened urine metabolites with four metabolites reported exhibiting significant differences in blood resulted in improved predictive performance compared to using urine metabolites alone. These findings indicate that combining blood and urine metabolites has a greater potential for identifying and predicting the athletic status and competitive potential of Chinese professional swimmers.

Blood Metabolomics Analysis Identifies Differential Serum Metabolites in Elite and Sub-elite Swimmers.

Objective: Metabolites in body fluids, such as lactate, glucose, and creatinine, have been measured by conventional methods to evaluate physical function and performance or athletic status. The objectives of the current study were to explore the novel metabolite biomarkers in professional swimmers with different competition levels using nuclear magnetic resonance (NMR) metabolomics, and try to establish a model to identify the athletic status or predict the competitive potential. Methods: Serum samples were collected from 103 elite and 84 sub-elite level Chinese professional swimmers, and were profiled by NMR analysis. Results: Out of the thirty-six serum metabolites profiled, ten were associated with the athletic status of swimmers (with p < 0.05). When compared with sub-elite swimmers, elite swimmers had higher levels of high-density lipoprotein (HDL), unsaturated fatty acid, lactic acid, and methanol. Elite swimmers had lower levels of isoleucine, 3-hydroxybutyric acid, acetoacetate, glutamine, glycine, and α-glucose. A model with four metabolites, including HDL, glutamine, methanol, and α-glucose, was established to predict athletic status by adjusting with different covariates. The area under the curve (AUC) of the best model was 0.904 (95% CI: 0.862-0.947), with a sensitivity and specificity of 75.5 and 90.2%, respectively. Conclusion: We have identified ten metabolite biomarkers with differentially expressed levels between elite and sub-elite swimmers, the differences could result from genetic or sports level between the two cohorts. A model with four metabolites has successfully differentiated professional swimmers with different competitive levels.

Prediction and Identification of Power Performance Using Polygenic Models of Three Single-Nucleotide Polymorphisms in Chinese Elite Athletes.

Objective: The manuscript aims to explore the relationship between power performance and SNPs of Chinese elite athletes and to create polygenic models. Methods: One hundred three Chinese elite athletes were divided into the power group (n = 60) and endurance group (n = 43) by their sports event. Best standing long jump (SLJ) and standing vertical jump (SVJ) were collected. Twenty SNPs were genotyped by SNaPshot. Genotype distribution and allele frequency were compared between groups. Additional genotype data of 125 Chinese elite athletes were used to verify the screened SNPs. Predictive and identifying models were established by multivariate logistic regression analysis. Results: ACTN3 (rs1815739), ADRB3 (rs4994), CNTFR (rs2070802), and PPARGC1A (rs8192678) were significantly different in genotype distribution or allele frequency between groups (p < 0.05). The predictive model consisted of ACTN3 (rs1815739), ADRB3 (rs4994), and PPARGC1A (rs8192678), the area under curve (AUC) of which was 0.736. The identifying model consisted of body mass index (BMI), standing vertical jump (SVJ), ACTN3, ADRB3, and PPARGC1A, the area under curve (AUC) of which was 0.854. Based on the two models, nomograms were created to visualize the results. Conclusion: Two models can be used for talent identification in Chinese athletes, among which the predictive model can be used in adolescent athletes to predict development potential of power performance and the identifying one can be used in elite athletes to evaluate power athletic status. These can be applied quickly and visually by using nomograms. When the score is more than the 130 or 148 cutoff, it suggests that the athlete has a good development potential or a high level for power performance.

Sparsely Wiring Connectivity in the Upper Beta Band Characterizes the Brains of Top Swimming Athletes.

Human brains are extremely energy costly in neural connections and activities. However, it is unknown what is the difference in the brain connectivity between top athletes with long-term professional trainings and age-matched controls. Here we ask whether long-term training can lower brain-wiring cost while have better performance. Since elite swimming requires athletes to move their arms and legs at different tempos in time with high coordination skills, we selected an eye-hand-foot complex reaction (CR) task to examine the relations between the task performance and the brain connections and activities, as well as to explore the energy cost-efficiency of top athletes. Twenty-one master-level professional swimmers and 23 age-matched non-professional swimmers as controls were recruited to perform the CR task with concurrent 8-channel EEG recordings. Reaction time and accuracy of the CR task were recorded. Topological network analysis of various frequency bands was performed using the phase lag index (PLI) technique to avoid volume conduction effects. The wiring number of connections and mean frequency were calculated to reflect the wiring and activity cost, respectively. Results showed that professional athletes demonstrated better eye-hand-foot coordination than controls when performing the CR task, indexing by faster reaction time and higher accuracy. Comparing to controls, athletes' brain demonstrated significantly less connections and weaker correlations in upper beta frequency band between the frontal and parietal regions, while demonstrated stronger connectivity in the low theta frequency band between sites of F3 and Cz/C4. Additionally, athletes showed highly stable and low eye-blinking rates across different reaction performance, while controls had high blinking frequency with high variance. Elite athletes' brain may be characterized with energy efficient sparsely wiring connections in support of superior motor performance and better cognitive performance in the eye-hand-foot complex reaction task.

Hematological, Hormonal and Fitness Indices in Youth Swimmers: Gender-Related Comparisons.

This study objective was to evaluate gender differences in hematological, hormonal and fitness variables among youth swimmers and to explore relationships between erythrocyte indices and aerobic and anaerobic capacity. 137 girls and 171 boys participated in the study and were divided into three groups based on their training experience. Blood samples were obtained to determine red blood cell counts, hemoglobin concentration, hematocrit, and plasma erythropoietin and testosterone levels. VO2max was assessed using a submaximal cycle protocol. 76 girls and 102 boys also undertook a Wingate test to determine their peak anaerobic power. Boys had higher (p < 0.05) means than girls for all hematological variables except for erythropoietin and these variables demonstrated an increase with training in boys. The average VO2max in l∙min-1 and peak anaerobic power in watts were also higher in boys (2.91 ± 0.08 and 547 ± 28, respectively) than girls (2.25 ± 0.07 and 450 ± 26, respectively). Modest but significant (p < 0.05) correlations were found between VO2max and red blood cell counts (r = 0.252), hemoglobin concentration (r = 0.345), or hematocrit (r = 0.345) and between peak anaerobic power and red blood cell counts (r = 0.304), hemoglobin concentration (r = 0.319) or hematocrit (r = 0.351). This study revealed relatively lower yet age- and gender-appropriate hematological, hormonal and fitness indices in youth swimmers. The gender-related differences in erythrocyte indices seem unrelated to erythropoietin and may be explained by the higher testosterone levels seen in boys. Given their correlation to both aerobic and anaerobic capacity, erythrocyte indices may be used as part of talent identification for sports.

ACTN3 R577X Gene Variant Is Associated With Muscle-Related Phenotypes in Elite Chinese Sprint/Power Athletes.

Yang, R, Shen, X, Wang, Y, Voisin, S, Cai, G, Fu, Y, Xu, W, Eynon, N, Bishop, DJ, and Yan, X. ACTN3 R577X gene variant is associated with muscle-related phenotypes in elite Chinese sprint/power athletes. J Strength Cond Res 31(4): 1107-1115, 2017-The ACTN3 R577X polymorphism (rs1815739) has been shown to influence athletic performance. The aim of this study was to investigate the prevalence of this polymorphism in elite Chinese track and field athletes, and to explore its effects on athletes' level of competition and lower-extremity power. We compared the ACTN3 R577X genotypes and allele frequencies in 59 elite sprint/power athletes, 44 elite endurance athletes, and 50 healthy controls from Chinese Han origin. We then subcategorized the athletes into international level and national level and investigated the effects of ACTN3 genotype on lower-extremity power. Genotype distribution of the sprint/power athletes was significantly different from endurance athletes (p = 0.001) and controls (p < 0.001). The frequency of the RR genotype was significantly higher in international-level than that in the national-level sprint/power athletes (p = 0.004), with no international-level sprint/power athletes with XX genotype. The best standing long jump and standing vertical jump results of sprint/power athletes were better in the RR than those in the RX + XX genotypes (p = 0.004 and p = 0.001, respectively). In conclusion, the ACTN3 R577X polymorphism influences the level of competition and lower-extremity power of elite Chinese sprint/power athletes. Including relevant phenotypes such as muscle performance in future studies is important to further understand the effects of gene variants on elite athletic performance.

Automated determination of bone age in a modern chinese population.

Rationale and Objective. Large studies have previously been performed to set up a Chinese bone age reference, but it has been difficult to compare the maturation of Chinese children with populations elsewhere due to the potential variability between raters in different parts of the world. We re-analysed the radiographs from a large study of normal Chinese children using an automated bone age rating method to establish a Chinese bone age reference, and to compare the tempo of maturation in the Chinese with other populations. Materials and Methods. X-rays from 2883 boys and 3143 girls aged 2-20 years from five Chinese cities, taken in 2005, were evaluated using the BoneXpert automated method. Results. Chinese children reached full maturity at the same age as previously studied Asian children from Los Angeles, but 0.6 years earlier than Caucasian children in Los Angeles. The Greulich-Pyle bone age method was adapted to the Chinese population creating a new bone age scale BX-China05. The standard deviation between BX-China05 and chronologic age was 1.01 years in boys aged 8-14, and 1.08 years in girls aged 7-12. Conclusion. By eliminating rater variability, the automated method provides a reliable and efficient standard for bone age determination in China.

[Relationship of certain skeletal maturity indicators of hand and wrist with adolescent growth spurt].

OBJECTIVE: To investigate the relationship of certain skeletal maturity indicators of hand and wrist with adolescent growth spurt. METHODS: 14 757 normal urban children, 7373 boys and 7384 girls, aged 7 - 20, all of Han nationality, from Shanghai, Guangzhou, Wenzhou, Dalian, and Shijiazhuang underwent measurement of height and weight, and left wrist anterior-posterior radiography. The incremental curve was fitted graphically according to the differences between the means for height at series ages. The ages of attainment of eleven skeletal indicators were defined by regression analysis for middle phalange 3, radius, and adductor sesamoid of the first finger. RESULTS: The accelerative phase of adolescent growth spurt was accompanied by becoming square of middle phalange 3 and the appearance of adductor sesamoid of the first finger. Peak growth velocity (PGV) was reached at about the time of epiphysis capping in middle phalange 3 and ossification of the adductor sesamoid of first finger. Decelerated phase of growth was indicated by the beginning of epiphysis fusion in radius and full maturity in adductor sesamoid of first finger. When the epiphysis of middle phalange 3 and the half of epiphysis of radius were respectively fused with their diaphyses, the growth spurt was ended. CONCLUSION: Certain skeletal maturity indicators of hand and wrist can be used to indicate the period of adolescent growth that a child has reached.

[Reference values of differences between TW3-C RUS and TW3-C Carpal bone ages of children from five cities of China].

OBJECTIVE: The determination of skeletal maturity has an important role in pediatric clinical practice, especially in relation to endocrinological problems and growth disorders, and it is frequently useful in diagnosis and monitoring treatment. It has been suggested that the difference between radius, ulna and short bonse (RUS) and carpal may be of differential diagnostic significance. However, no data on comparison among bone ages of Chinese children are available. The differences between TW3-Chinese RUS (TW3-C RUS) and TW3-Chinese Carpal (TW3-C Carpal) bone age of Chinese children were observed in this study to provide references for skeletal development estimation. METHODS: Totally 9408 Han healthy children (5066 boys, 4302 girls) aged 1.5 - 13.5 years from 5 cities of China were enrolled in this study. The bone ages of the children were estimated by TW3-C RUS and TW3-C Carpal. The Z score curves of the differences between them were fitted by BCPE distribution and the goodness-of-fit of Box-Cox power exponential distribution (BCPE) models were assessed by Q-test and percents of cases of sample below the fitted percentile curves. RESULTS: The means of the differences between TW3-C RUS and TW3-C Carpal were -0.19 - 0.17 over the age 2.0 - 13.5 years in boys and -0.12 - 0.13 from age 1.5 - 11.5 years in girls. The standard deviations were respectively 0.47 - 1.01 years for boys and 0.49 - 0.82 years for girls. The degrees of freedom, with respect to the parameter curves from BCPE distribution, were selected and the percentile curves were fitted by BCPE. The differences between percents of cases below the fitted percentile curves and expected values were all under 0.66%, exception of difference for 90th percentile in girls. CONCLUSIONS: The differences between TW3-C RUS and TW3-C Carpal varied with age, the standard deviations increased gradually before 4.5 years of age in boys and 4 years of age in girls, and afterwards the variations decreased steadily until the TW3-C Carpal has reached full maturity. However, there was sex diversity in the extent of the variations. The differences between TW3-C RUS and TW3-C Carpal for boys were evidently greater than that for girls. The sex difference decreased progressively after 10 years. The proposed Z scores curves charts should provide reference for clinical practice.

Standards of TW3 skeletal maturity for Chinese children.

This study included 17 401 normal Han urban children aged 1-20 years from five cities in China in 2005. The skeletal maturity scores were assessed by the Tanner-Whitehouse 3 (TW3) method, and the smoothed centiles curves of scores (TW3-Chinese RUS and TW3-Chinese Carpal) were calculated using the LMS method. The skeletal maturity of the Chinese is approximately the same as Europeans in childhood, but the extent of TW3-RUS skeletal maturity advance in puberty and the ages of complete maturity of TW-Carpals are evidently more advanced in the Chinese.