Establishment of hypertension risk nomograms based on physical fitness parameters for men and women: a cross-sectional study

Objective

This study aims to establish hypertension risk nomograms for Chinese male and female adults, respectively.

Method

A series of questionnaire surveys, physical assessments, and biochemical indicator tests were performed on 18,367 adult participants in China. The optimization of variable selection was conducted by running cyclic coordinate descent with 10-fold cross-validation through the least absolute shrinkage and selection operator (LASSO) regression. The nomograms were built by including the predictors selected through multivariable logistic regression. Calibration plots, receiver operating characteristic curves (ROC), decision curve analysis (DCA), clinical impact curves (CIC), and net reduction curve plots (NRC) were used to validate the models.

Results

Out of a total of 18 variables, 5 predictors-namely age, body mass index, waistline, hipline, and resting heart rate-were identified for the hypertension risk predictive model for men with an area under the ROC of 0.693 in the training set and 0.707 in the validation set. Seven predictors-namely age, body mass index, body weight, cardiovascular disease history, waistline, resting heart rate, and daily activity level-were identified for the hypertension risk predictive model for women with an area under the ROC of 0.720 in the training set and 0.748 in the validation set. The nomograms for both men and women were externally well-validated.

Conclusion

Gender differences may induce heterogeneity in hypertension risk prediction between men and women. Besides basic demographic and anthropometric parameters, information related to the functional status of the cardiovascular system and physical activity appears to be necessary.

The influence of running shoe with different carbon-fiber plate designs on internal foot mechanics: A pilot computational analysis

A carbon-fiber plate (CFP) embedded into running shoes is a commonly applied method to improve running economy, but little is known in regard the effects of CFP design features on internal foot mechanics. This study aimed to explore how systematic changes in CFP geometrical variations (i.e., thickness and location) can alter plantar pressure and strain under the forefoot as well as metatarsal stress state through computational simulations. A foot-shoe finite element (FE) model was built and different CFP features including three thicknesses (1 mm, 2 mm, and 3 mm) and three placements (high-loaded (just below the insole), mid-loaded (in between the midsole), and low-loaded (just above the outsole)) were further modulated within the shoe sole. Simulations were conducted at the impact peak instant during forefoot strike running. Compared with the no-CFP shoe, peak plantar pressure and compressive strain under the forefoot consistently decreased when the CFP thickness increased, and the low-loaded conditions were found more effective (peak pressure decreased up to 31.91% and compressive strain decreased up to 18.61%). In terms of metatarsal stress, CFP designs resulted in varied effects and were dependent on their locations. Specifically, high-loaded CFP led to relatively higher peak metatarsal stress without the reduction trend as thickness increased (peak stress increased up to 12.91%), while low-loaded conditions showed a gradual reduction in peak stress, decreasing by 0.74%. Therefore, a low-loaded thicker CFP should be considered to achieve the pressure-relief effects of running shoes without the expense of increased metatarsal stress.

Design and Validation of a New Tennis-Specific Reactive Agility Test-A Pilot Study

Agility is an important ability for tennis players, but there is an evident lack of studies focusing on the applicability of tennis-specific agility tests that capture a combination of the physical and cognitive agility performance. Therefore, the main aim of this study was to design and test measurement properties of the tennis-specific reactive agility test that would be feasible and practical for regular implementation. A total of 32 youth tennis players (21 males and 11 females; 10.85 ± 1.50 years) participated in this study. The measurement characteristics of the newly designed reactive agility tennis-specific (TS-RAN) test have been established by comparing it with two generic agility tests and with two tennis-specific pre-planned agility tests. The overall reliability of the new TS-RAN test can only be considered "moderate to good", as although the results of participants showed good internal consistency, the within-subject reliability of the test proved to be unsatisfactory, since the participants showed a lack of performance consistency. This is not unexpected considering the very young age of the participants who performed the test for the very first time. The new TS-RAN test was highly projected (0.91) on the same single latent dimension, with the variance predominately explained by the tennis-specific agility tests. The test's greatest strength is its high feasibility, since the test does not require any special set-up nor technical equipment, and that makes it practical for regular implementation in a practical setting. Further research studies are needed in order to confirm the test's potential to be widely accepted and used.

Table tennis match analysis: a review

In table tennis, many different approaches to scientific founded match analysis have been developed since the first ones in the 1960s. The aim of this paper is to give a review on some of the most acknowledged methods of match analysis in table tennis. The first chapter presents a historical overview of match analysis from all over the world. The second part reviews different approaches to match analysis in more detail, using the performance analysis classification of theoretical and practical performance analysis. The review includes the most actual theoretical performance analysis techniques in table tennis: performance indices, simulative approaches, momentum analysis, footwork analysis, and finally an approach which uses top expert knowledge for a comprehensive technical-tactical analysis. In the section of practical performance analysis, the paper presents two "best practice" examples describing performance analysis procedures of the two most successful countries of the last Olympics: China and Japan. The paper ends with a summary on the impact of the different approaches and gives an outlook on promising new developments.

Does a perceptuomotor skills assessment have added value to detect talent for table tennis in primary school children?

Talent detection intends to support lifelong sports participation, reduce dropouts and stimulate sports at the elite level. For this purpose it is important to reveal the specific profile which directs children to the sports that connect to their strengths and preferences. This study evaluated a perceptuomotor skills assessment as part of talent detection for table tennis, a sport in which perceptuomotor skills are considered essential to cope with the difficult technical aspects. Primary school children (n = 121) and gifted young table tennis players (n = 146) were assessed using the Dutch perceptuomotor skills assessment measuring "ball control" and "gross motor function". A discriminant function analysis confirmed the added value by identifying primary school children fitting the table tennis perceptuomotor profile of the young gifted table tennis players (28%). General linear model analyses for the assessment's individual test items showed that the table tennis players outperformed their primary school peers on all "ball control" items (P < 0.001). In conclusion, the assessment appears to be of added value for talent detection in table tennis at this young age. Longitudinal studies need to reveal the predictive value for sports participation and elite sports.

Differences in Movement Speed Before and After a Split-Step Between Professional and Junior Tennis Players

This study investigated tennis players’ speed before, during and after the split-step, deceleration before and acceleration after the split-step in four different stroke groups in three age categories. Seven male professional, eleven male and ten female junior tennis players were recorded with video cameras at official tournaments. Using the SAGIT system, we gathered data on 8,545 split-steps. Tennis players performed a split-step in 82.9% of cases. A tennis player’s speed, deceleration and acceleration were measured 0.2 s before and after the split-step. Differences between categories and stroke groups for each of the five variables were analyzed with a two-way ANOVA. The differences between the groups of players were generally much higher in the speed before, during and after the split-step than in the deceleration before and acceleration after the split-step. Most of these differences were observed between the various stroke groups. These results suggest that players use three types of movement while performing a split-step. In the first type, which is typical of serving and returning, the speed before, during and after the split-step is lower (0.55 to 1.2 m/s). The second type of movement is characteristic of baseline strokes where tennis players achieve higher speed than in the first type (0.7 to 1.66 m/s). The third type occurs in strokes where a tennis player is moving or already at the net (0.78 to 1.9 m/s). Movement in tennis is an area that requires constant development in terms of designing and upgrading movement patterns, increasing speed and practice in specific game situations.

Structural Analysis of Technical-Tactical Elements in Table Tennis and their Role in Different Playing Zones

For the purpose of determining the overall structure of technical-tactical elements in table tennis and evaluating their role in different playing zones around the table, a new measuring instrument (a questionnaire) was formulated that took advantage of the expert knowledge of top, world class table tennis coaches. The results of the hierarchical taxonomic (cluster) analysis showed that the overall structure of the technical-tactical elements forming the table tennis technique could be divided into three basic groups; a group of technical-tactical elements (A) used in the phase of preparing one’s own and disabling the opponent’s attack; a group of technical-tactical elements (B) used in the phase of attack and counterattack; and a group of technical-tactical elements (C) used in the phase of defense. The differences among the obtained groups of table tennis elements were determined by applying the Kruskal-Wallis test, while relations between the groups and their role in different playing zones around the table were analyzed by comparing the average values of the experts’ scores.

Relationship of Speed, Agility, Neuromuscular Power, and Selected Anthropometrical Variables and Performance Results of Male and Female Junior Tennis Players

The aim of the study was to analyses the relation between the selected speed, agility, and neuromuscular power test items. The sample of subjects consisted of 154 male and 152 female young tennis players. Using six motor and three anthropometrical tests we investigate differences between males and females and between two age categories. Finally, we analyzed the relation between motor and anthropometrical tests and a player's tennis performance. The correlation between the two agility test items and 5-m sprint is very large in male players, while only moderate with 20-m sprint in female category. Male tennis players have higher correlations between speed test items and neuromuscular test items. The speed test item (5-m sprint) has large correlation with a player's tennis performance. One-way analysis of variance results indicated that young male tennis players performed significantly better than females in all motor test items. Significant differences between genders have not been revealed only in the body mass index. Differences between the males aged 18& under and 16& under have been noted as significant in all test items, except the vertical jump, while differences between the females have been noted as significant in three anthropometrical tests, quarter jump, and the fan-drill test. Regression analyses have shown that the system of prediction variables explains a relatively small part of variance (46%--males and 40%--females). In both genders, it has been revealed that test items measuring speed significantly influence a player's tennis performance.

Anthropological analysis of taekwondo--new methodological approach

The aim of this research is to determine the order and importance of impacts of particular anthropological characteristics and technical and tactical competence on success in taekwondo according to opinions of top taekwondo instructors (experts). Partial objectives include analysis of metric characteristics of the measuring instrument, and determining differences between two disciplines (sparring and technical discipline of patterns) and two competition systems (WTF and ITF). In accordance with the aims, the research was conducted on a sample of respondents which consisted of 730 taekwondo instructors from 6 continents and from 69 countries (from which we selected 242 instructors), who are at different success levels in both taekwondo competition systems (styles) and two taekwondo disciplines. The respondents were divided into 3 qualitative subsamples (OST-USP-VRH) using the dependant variable of accomplished results of the instructor. In 6 languages, they electronically evaluated the impact in percentage value (%) of motor and functional skills (MOTFS), morphological characteristics (MORF), psychological profile of an athlete (PSIH), athletic intelligence (INTE) and technical and tactical competence - (TE-TA) on success in taekwondo. The analysis of metric characteristics of the constructed instrument showed a satisfactory degree of agreement (IHr) which is proportional to the level of respondent quality, i.e. it grows along with the increase in instructor quality in all analysed disciplines of both systems. Top instructors assigned the highest portion of impact on success to the motor and functional skills (MOTFS) variable: WTF-SPB=29.1, ITF-SPB=29.2, WTF-THN=35.0, ITF-THN=32.0). Statistically significant differences in opinions of instructors of different styles and disciplines were not recorded in any of the analysed variables. The only exception is the psychological profile of an athlete variable, which WTF instructors of sparring (AM=23.7%), on a significance level of p<0.01, evaluate as having a statistically significantly higher impact on success in tackwondo than WTF instructors of the technical discipline of patterns (15.4%).