Physical Performance Indicators Research Articles

Effectiveness of use of sports and healthy swimming eguipment in increase of physical fitness of girls 17-21 years old

In the course of the study, the peculiarities of physical fitness and changes in indicators of physical performance of young women aged 17-21 under the influence of systematic sports and recreational swimming were studied. The purpose of our study was to assess the effectiveness of using sports and recreational swimming to improve the physical fitness of young women aged 17-21. 38 young women who attend the ZFP groups and health swimming groups of the "Akvarena" pool in Kharkiv took part in the study. The studied women were divided into control (CG, n = 20) and experimental (EG, n = 18) groups. Specialized classes in groups of general physical training and classes in recreational swimming groups were held for nine months, 2-3 times a week, the duration of one class was 45 minutes. The following methods were used during data collection: analysis of literary sources; test method; pedagogical experiment; pedagogical observation; method of mathematical processing of research data. The work presents materials that show that the use of sports and health swimming facilities contributed to the significant optimization of the main indicators of physical fitness of young women who attend sports and health swimming classes (speed, strength, agility, speed and strength abilities), the growth of their aerobic capabilities and level general physical capacity. After the formative experiment, all the indicators used in the study in the women of the experimental group, who were engaged in recreational swimming, were reliable and better than in the young women of the control group, who practiced according to the traditional program for the ZFP groups on land. The obtained results provide grounds for the use of recreational swimming to increase the effectiveness of the process of physical education of young people and young women in particular.

The effects of nicotine withdrawal on exercise-related physical ability and sports performance in nicotine addicts: a systematic review and meta-analysis.

Previous research has established that nicotine withdrawal can ameliorate cardiovascular and pulmonary function in smokers. Nevertheless, the impact on physical fitness and athletic performance remains under-investigated. To evaluating the impacts of nicotine withdrawal on both exercise performance and exercise-associated physical capabilities in nicotine-dependent individuals. A comprehensive systematic review and meta-analysis. The data was compiled from databases such as PubMed, Scopus, Web of Science, Cochrane Central, and EBSCO. The selection criteria required studies to elucidate the effects of nicotine withdrawal on exercise performance or exercise-related physical abilities. Moreover, the selected studies needed to provide discernible experimental results. The random effects model was employed in data analysis, utilizing the standardized mean difference (SMD) and the 95% confidence intervals (95% CIs) to estimate participants' exercise performance and physical abilities, referencing the Mean ±SD during baseline and withdrawal states. Out of the selected studies, 10 trials were included, encompassing 13,538 participants aged 18 to 65 years. The findings suggest that nicotine withdrawal could potentially enhance sports performance (SMD = 0.45, 95% CI: 0.03 to 0.88; I^2 = 83%), particularly in terms of aerobic capacity. Short-term nicotine withdrawal (spanning 12 to 24 hours) might lead to a decline in participants' physical abilities in certain aspects like reaction time and sustained attention (SMD = -0.83, 95% CI: -1.91 to 0.25; I^2 = 79%), whereas long-term withdrawal (lasting 48 hours or more) demonstrated an opposing trend (SMD = 0.25, 95% CI: 0.12 to 0.39; I^2 = 81%). Overall, the results show that long-term nicotine withdrawal exhibited some positive impacts on sports performance and exercise-related physical ability, with the withdrawal duration being an indicator of subsequent physical performance. Mid- to long-term (≥3 months) nicotine withdrawal significantly improved the exercisers' exercise-related physical ability and sports performance. Conversely, short-term (≤24 hours) nicotine withdrawal considerably hampered exercisers' performance and physical cognition. It is suggested that exercises avoid abrupt nicotine cessation prior to competitions, as long-term nicotine withdrawal has been shown to significantly enhance exercise-related physiological capacities and athletic performance. By referring to existing literatures we also found that athletes with existing nicotine addiction may could consume nicotine 15-30 minutes before competition to enhance athletic performance and physical function.PROSPERO registration number CRD42023411381.

Biological maturity vs. relative age: Independent impact on physical performance in male and female youth handball players.

Maturity status and relative age are two of the determining factors in talent development. The aim of the study was to analyze the influence of biological maturity status and relative age on physical performance in young male and female handball players. The sample included 48 males (14.11 ± 1.17 years) and 41 females (14.25 ± 1.64 years) players from one Spanish professional handball academy. Anthropometric data (height, sitting height, body mass and self-reported biological parent heights) and physical performance data (CMJ, DJ, 20 m speed, T-test and throwing velocity) were collected. Biological maturity status was determined as the percentage of predicted adult height, while relative age was estimated in birth quartiles based on biennial age grouping (Q1-Q8). The results showed a positive correlation between maturity status and CMJ in male players (p < 0.01). Differences in CMJ performance according to maturity status were identified (p < 0.05), with higher jump heights being recorded especially in early maturing boys (p < 0.01) and first lines and wings (p < 0.05). The variance in CMJ test scores could be explained by the maturity status by 42.90% in U-15 (p < 0.05) and 72.60% in U-16 male players (p < 0.001). By contrast, no differences were found in girls (p > 0.05). Moreover, no relationships were found between relative age and indices of physical performance (p > 0.05). Overall, maturity status had greater impacts on the tests of physical performance than relative age. Stakeholders should monitor the maturity status of young handball players to avoid physical performance biases that do not allow them to develop their sporting potential.

VO2MAX, 6-minute walk, and muscle strength each correlate with frailty in US veterans.

Frailty often manifests as an increased vulnerability to adverse outcomes, and detecting frailty is useful for informed healthcare decisions. Veterans are at higher risk for developing frailty and at younger ages. The goal of this study was to investigate approaches in Veterans that can better inform the physiologic underpinnings of frailty, including maximal oxygen uptake (VO2max), 6-min walk, muscle strength, and inflammatory biomarkers. Participants (N = 42) were recruited from the Buffalo VA Medical Center. Inclusion criteria: ages 60-85, male or female, any race, and not having significant comorbidities or cognitive impairment. Outcome measures included: the Fried frailty phenotype, the short physical performance battery (SPPB), quality of life (QOL) using the Q-LES-Q-SF, and the following physiologic assessments: VO2max assessment on an upright stationary bicycle, 6-min walk, and arm and leg strength. Additionally, inflammatory biomarkers (C-reactive protein, IL-6, IL-10, interferon-γ, and TNF-α) were measured using ELLA single and multiplex ELISA. Participants: 70.3 ± 7.4years of age: 34 males and 8 females, BMI = 30.7 ± 5.4kg/m2, 26 white and 16 African American. A total of 18 (42.8%) were non-frail, 20 (47.6%) were pre-frail, and 4 (9.5%) were frail. VO2max negatively correlated with Fried frailty scores (r = -0.40, p = 0.03, N = 30), and positively correlated with SPPB scores (r = 0.50, p = 0.005), and QOL (r = 0.40, p = 0.03). The 6-min walk test also significantly correlated with VO2max (r = 0.57, p = 0.001, N = 42) and SPPB (r = 0.55, p = 0.0006), but did not quite reach a significant association with frailty (r = -0.28, p = 0.07). Arm strength negatively correlated with frailty (r = -0.47, p = 0.02, N = 26), but not other parameters. Inflammatory profiles did not differ between non-frail and pre-frail/frail participants. Objectively measured cardiorespiratory fitness was associated with important functional outcomes including physical performance, QOL, and frailty in this group of older Veterans. Furthermore, the 6-min walk test correlated with VO2max and SPPB, but more validation is necessary to confirm sensitivity for frailty. Arm strength may also be an important indicator of frailty, however the relationship to other indicators of physical performance is unclear.

Clinically relevant differences in spinal mobility related to daytime performance in patients with axial spondyloarthritis

ObjectivePatients with axial spondyloarthritis (axSpA) suffer from clinical symptoms like morning stiffness and back pain. Mobility of patients with axSpA is often impaired. The aim of this study is to...

Non-linear trends using the generalized additive models in physical and technical performances of the Chinese Super League players.

This study aimed to investigate the non-linear evolution of position-specific physical and technical performance indicators across different tactical formations in the Chinese Super League (CSL) from the 2015 to the 2021 seasons. Match data were collected from 800 games played in six common formations (3-5-2, 4-3-3, 4-2-3-1, 4-4-2, 3-4-3, and 4-1-4-1). Players were classified into five positions: central defenders (CD; match observations = 2,219), fullbacks (FB; match observations = 2,060), central midfielders (CM; match observations = 2,786), wide midfielders (WM; match observations = 1,587), and forwards (FW; match observations = 1,680). Generalized additive models (GAMs) were constructed to analyze the nonlinear evolution trends in position-specific physical and technical performance across seasons and formations. The results showed that the total distance covered by CDs in the 3-5-2 formation showed a non-linear upward trend from the 2015 to 2021 seasons (R2 = 0.3, p = 0.006); FBs in the 3-4-3, 4-1-4-1, and 3-5-2 formations exhibited non-linear upward trends in number of sprints and sprint distance from the 2015 to 2021 seasons (R2 = 0.189-0.448; P < 0.03, respectively); the high-speed running of FWs in the 4-2-3-1 formation displayed a non-linear decline trend from the 2015 to 2021 seasons (R2 = 0.477; P < 0.001); CMs in the 4-2-3-1 formation demonstrated a non-linear increasing trend in the ball retention percentage (R2 = 0.369; p = 0.001); WMs in the 4-4-2 formation showed a non-linear decreasing trend in ball retention percentage and passes from the 2015 to 2021 seasons (R2 = 0.259-0.29; P = 0.006, respectively). These findings revealed non-linear evolutionary trends in physical and technical performances across positions and formations, providing an in-depth understanding of the changing match demands placed on players during matches. This enables the optimization of training and tactics by developing targeted strategies tailored to meet the specific requirements of different formations and playing positions.

Maximum strength and power as determinants of on-ice sprint performance in elite U16 to adult ice hockey players.

In ice hockey, speed strength is one of the major physical key performance indicators, which is significantly influenced by maximum strength. The objective of this study was to evaluate the age-dependent relationship of off-ice maximum strength and vertical jump performance with on-ice linear sprint performance, considering age and performance level. Ninety-one male youth and adult professional ice hockey players (age: 19.3 ± 5.49 years) were recruited and divided into four age groups: under 16, 18, 21 years old and professional elite players (Pro) (i.e., > 21 years). They were tested in maximal isometric strength, squat jump (loaded and unloaded), countermovement jump and on-ice sprint performance (15 m and 30 m linear sprint; 15 m flying linear sprint). Statistical analysis revealed that on-ice sprint performance correlated with isometric strength performance (r = |0.34|-|0.63|) and with off-ice jump performance (r = |0.61|-|0.77|) without an influence of age group or performance level. However, performance differed between age groups and performance level, the largest differences being found between the youngest age group (U16) and the Pro group (g = 0.966-3.281). The present study shows that maximum strength influences on-ice sprint performances in ice hockey players, as well as performance differences between age groups and professional players. Strength and jumping performance should therefore be included in regular performance testing in ice hockey. Since performance differences are observed for almost all strength and speed-strength performances of the youth teams to the Pros, training of these variables is strongly recommended to improve in the transition phase from junior to elite level.

Impact of daily physical therapy over 2 weeks on spinal mobility including objective electronic measurements and function in patients with axial spondyloarthritis.

Patients with axial spondyloarthritis (axSpA) are often compromised by impaired function and mobility. The standardized 2-week inpatient program 'multimodal rheumatologic complex treatment' (MRCT) was designed for patients with axSpA. The Epionics SPINE (ES) is an objective tool validated to assess mobility. To investigate the impact of MRCT on physical function and mobility including range of motion (RoM) and kinematics (RoK). Single-center interventional, observational trial. Patients with axSpA presenting with high disease activity and impaired physical function were consecutively recruited to undergo MRCT. Assessments performed before (V1) and after (V2) the intervention included Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis functional index (BASFI), Bath Ankylosing Spondylitis Metrology Index (BASMI), the ankylosing spondylitis physical performance index (ASPI), the Short Physical Performance Battery (SPPB), and ES measurements. At baseline, the 80 patients included had: BASDAI 5.5 ± 1.5, BASFI 5.6 ± 2.0, BASMI 4.2 ± 1.8, SPPB 13.8 ± 1.8, and ASPI 37.3 ± 18.1 s. Clinically relevant improvements between V1 versus V2 were noted for BASFI, BASMI, and all other assessments (p < 0.001), and also for ES measures of RoK (all p < 0.003) and RoM (all p < 0.04), while a positive trend was seen for flexion and extension (RoM). There was no significant effect of changes in medication (all p > 0.05). The 2-weeks MRCT was associated with definite improvements of function and mobility. Importantly, the effect of this extensive physical activity was confirmed by using the ES as an objective tool to assess spinal mobility. The ES demonstrated for the first time that the RoK of spinal mobility can significantly improve related to an exercise intervention. Ethical Committee: Ruhr-Universität (reference-number: 19-6735-BR).

Reserve capabilities of the cardiorespiratory system in athletes of certain sports under conditions of intense muscular activity

This study provides data on the peculiarities of adaptation of the cardiorespiratory system to muscle load in athletes engaged in certain types of martial arts (judo, Thai boxing, MMA, and jiu-jitsu). Changes in physiological indicators such as weight, height, vital capacity, glossopharyngeal inhalation (GI), blood pressure, heart rate, physical performance, endurance according to the physical work capacity test at a heart rate of 170 beats per minute (PWC 170) and membrane patch colorimetry (MPC) tests, and heart rate variability are shown, with the calculation of the main indices of the humoral-vegetative balance. The results showed that the vital capacity of the lungs and tidal volume in athletes were 6-8% lower than the required values and corresponded to the “average level” of the functional capabilities of the respiratory system. Calculations of the Skibinsky, Robinson, and Shapovalova indices showed a functional insufficiency in the adaptation of the cardiorespiratory system to physical activity. Against the background of the development of muscle strength functions, indicators of physical performance and endurance of athletes (PWC 170 and maximum oxygen consumption (MOC) tests) turned out to be “below average” levels in absolute and relative values. To identify hidden functional disorders of the cardiovascular system, variability studies were conducted on heart rate (HRV), the results of which showed that 60% of athletes (in all groups), regardless of the type of sport, had a good level of functional capability of the cardiovascular system. The remaining athletes revealed a low level of adaptation mechanisms and functional state of the cardiorespiratory systems, the reason for which was insufficient training of the body of endurance athletes. Research has shown that athletes who have not previously engaged in special training for endurance and increased performance need to develop cardiorespiratory capabilities that ensure the activity of metabolic processes and replenish energy reserves for successful sports activities.

Genetic and Physiological Predictors of Bioenergetic Adaptation Skeletal Muscles in Athletes of Cyclic Sports

When performing maximum loads, an important criterion for assessing prospects is the achievement of the best result with the least metabolic changes in the body of athletes, which indicates the possibility of further increasing physical performance. The study of the mechanisms of energy supply and the reaction of body systems when testing performance under special conditions is one of the important conditions for the development of additional biochemical criteria for assessing the prospects of athletes. Purpose: To study genetic and physiological predictors of bioenergetic adaptation of skeletal muscles in athletes of cyclic sports. Methods: 76 athletes of cyclic sports (speed skating, running disciplines in track-and-field) of European origin who lived in the Southern Urals region took part in the study. The average age of the study participants was 22.1 ± 2.5 y.o. Experience in sports was at least 5 years. We used the Step One Real-Time PCR System (Applied Biosystems, USA) device for real-time polymerase chain reaction. The study of bio-energetic indicators of athletes' physical performance was carried out using the bicycle ergometry method (test with maximum load). Biochemical studies were carried out using a Lactate Scout Plus lactometer. Results: Significant differences were found in the ΔLa (%) indicator: in athletes with a dominant homozygous genotype R/R, lactate clearance during a 10-minute rest after performing a bicycle ergometer load is statistically significantly higher than in athletes with a recessive homozygous genotype X/X (20.14±12.74%, versus 11.11±3.12%; p&lt;0.05). The major allele C (R) was associated with moderate and high lactate clearance (OR = 2.25 [95% CI: 0.99 – 5.11] and OR = 2.24 [95% CI: 0.91 – 5.51], respectively). At the same time, a statistically significant association was identified between the minor allele T(X) and the homozygous genotype TT (XX) with low lactate clearance (OR = 12.14 [95% CI: 1.30 – 13.55]). High values of lactate clearance indicate the utilization of lactate from peripheral blood and more efficient recovery processes in carriers of the major allele C (R). Conclusions: lactate clearance during a 10-minute rest period after a bicycle ergometer test with maximum load and DNA profiling of the ACTN3 gene rs1815739 can be recommended as significant physiological and genetic predictors of bioenergetic adaptation of skeletal muscles in cyclical sports athletes of Caucasian origin in the Southern Urals.

Ramadan Fasting and Short-Term Maximal Physical Performance: Searching for Optimal Timing of the Last Meal "Suhoor" in Female Pre-University Handball Players.

Aiming to identify the ideal suhoor timing for maintaining optimal physical performance and health indicators during Ramadan intermittent fasting, the present study compares the effects of early vs. late Suhoor on short-term high-intensity physical exercise while controlling the body mass index (BMI) oral temperature (OT), dietary intake, and sleep patterns. In a randomized design, 19 female pre-university handball players (age: 16.8 ± 0.4 y; height: 1.70 ± 0.9 m; and body mass: 61.5 ± 6.9 kg) underwent two test sessions (at 08:00 a.m. and 05:00 p.m.) at four different conditions: ten days prior to Ramadan (R - 10), the final ten days of Ramadan (R) including both Early Suhoor R(ES) and Late Suhoor R(LS) conditions, and the ten days immediately following Ramadan (R + 10). A recovery period of at least 48 h has been set between successive test sessions at each period. Outcome measures included the Countermovement Jumps Test (CMJ), Modified Agility t-Test (MATT), Repeated Sprint Ability (RSA), and Rating of Perceived Exertion (RPE). The Pittsburgh Sleep Quality Index (PSQI), OT, BMI, and daily diary intake were assessed across the three periods. The total scores of PSQI decreased significantly during R and R + 10 compared to R - 10. When performed in the afternoon, CMJ, MATT, and RSA performance decreased significantly at R(ES) and R(LS) conditions compared to R - 10. However, these performances decreased only after R(ES) when performed in the morning. Furthermore, performances were lower during R(ES) compared to R(LS) in the afternoon for all tests and the morning for MATT and RSA tests. These findings support prior research showing a deterioration of physical performance during Ramadan fasting and indicate a more pronounced impact following early Suhoor condition. Therefore, consuming a late suhoor, closer to pre-dawn time, could be suggested as an effective strategy to minimize physical performance decline during short-term high-intensity exercise.

Distribution of Bioelectrical Impedance Vector Analysis and Phase Angle in Korean Elderly and Sarcopenia.

This study aimed to verify whether bioelectrical impedance vector analysis (BIVA) can support the clinical evaluation of sarcopenia in elderly individuals and evaluate the relationships between phase angle (PhA), physical performance, and muscle mass. The sample comprised 134 free-living elderly individuals of both sexes aged 69-91 years. Anthropometric parameters, grip strength, dual-energy X-ray absorptiometry findings, bioimpedance analysis results, and physical performance were also measured. The impedance vector distributions were evaluated in elderly individuals using BIVA. BIVA revealed significant differences between the sarcopenia and non-sarcopenia groups (both sexes). The sarcopenia group had a significantly lower PhA than the non-sarcopenia group in both sexes (p < 0.05). PhA was significantly correlated with age, appendicular skeletal muscle (ASM), handgrip strength (HGS), and muscle quality in both sexes and significantly correlated with ASM/Height2 and physical performance in males. BIVA can be used as a field assessment method in elderly Koreans with sarcopenia. PhA is a good indicator of muscle strength, muscle quality, and physical performance in males. These methods can help diagnose sarcopenia in elderly individuals with reduced mobility.

Effect of galectin-3 on synovial inflammation in knee osteoarthritis via stimulating phosphatidylinositol-3-kinase/Akt pathway

Galectin-3 (Gal-3), a glycan-binding protein responsible for inflammation, has been reportedly implicated in inflammatory arthritis. This study aimed to determine clinical and pathological effects of Gal-3 on inflammation in knee osteoarthritis (OA). Gal-3 mRNA and protein levels in synoviocytes, synovium, synovial fluid, and plasma of knee OA patients were determined using real-time polymerase chain reaction, immunohistochemistry, and enzyme-linked immunosorbent assay. Signaling mechanism underlying inflammatory effect of Gal-3 was further elucidated in human knee OA synoviocytes. Clinical study uncovered significant increases in plasma and synovial fluid Gal-3 levels in knee OA patients, particularly those with advanced-stage. In knee OA patients, plasma Gal-3 was significantly associated with radiographic severity and indicators of body composition, physical performance, and knee pain and disability. In the inflamed synovium of knee OA patients, further analysis depicted a marked up-regulation of Gal-3 mRNA expression, consistent with immunohistochemical analysis showing localization of Gal-3 protein in the lining and sublining layers of the inflamed synovium. An in vitro study unveiled that aberrant Gal-3 mRNA expression was regulated by tumor necrosis factor (TNF)-α in knee OA synoviocytes. Gal-3 significantly enhanced production of NO and IL-6, up-regulated mRNA expressions of IL-6, NF-κB, and MMP-13, and down-regulated mRNA expressions of ACAN and SOX-9 via stimulating Akt phosphorylation in knee OA synoviocytes. Gal-3 exerted an inflammatory action, which might emerge as a possible mediator of synovitis and cartilage degeneration in knee OA.

Influence of participation in a health fitness program on the indicators of physical condition in adolescent underweight girls

The article presents the results of the study of the influence of participation in a health fitness program on the indicators of physical development, physical fitness and work capacity, physical activity in 12-13-year-old underweight girls. The objective of the study was to assess the impact of engagement in a health fitness program on the indicators of physical condition of adolescent underweight girls. To address the objective and tasks of the research, the following methods were used: analysis of special scientific and methodological literature and documentary materials, matching and comparison, anthropometric, physiological, and pedagogical methods, and mathematical statistics methods. Results. To determine the impact of participation in the health fitness program on the indicators of physical condition, a transformative pedagogical experiment was conducted, which lasted for 9 months. As performance criteria, indicators of physical condition were used, which, according to the results of previous studies, had a close correlation with the general level of physical condition, namely: physical activity (moderate level), physiometric indicators of physical development (grip strength of right and left hand), physical performance (Ruffier's test), indicators of physical fitness (tilting the trunk forward from a sitting position, 30 m run, 4 x 9 m shuttle run, raising the trunk in a sitting position). According to the results of the study, a probable improvement of the investigated indicators was found. The obtained results prove the effectiveness of the developed training program and demonstrate the expediency of its implementation for correcting indicators of girls’ physical condition. Conclusions. The evaluation of the effectiveness of the developed health fitness program showed that there were statistically significant changes in the indicators of physical fitness and physical performance of 12-13-year-old underweight girls, as well as in their somatometric and physiometric indicators of physical development and physical activity.

Design of a perceptron model-based physical fitness index monitoring system for sports training

Abstract The purpose of designing a sports training fitness index monitoring system is to grasp better the physical performance data of athletes in the training process to ensure training safety. In this paper, the principle of multilayer perceptron is explained based on the perceptron model, the optimal loss function of multilayer perceptron is solved by using the activation function and forward propagation algorithm, the sensor data collection module is constructed, and the physical fitness index monitoring system for sports training is built by this method. To verify the feasibility of the detection system in this paper, experimental analysis was conducted from three aspects: the distribution of physical fitness index monitoring information density, physical fitness index data and monitoring data accuracy. The index monitoring density distribution was between 0.11 and 2.09 from the monitoring information density. Regarding physical performance indicators, the average values of maximum oxygen uptake, heart rate, relative energy metabolism level, and exercise intensity were 41.02, 121.58, and 11.84, respectively. From the accuracy of indicator monitoring data, the accuracy of the system in this paper was 93.63%, which was 21.57 and 11.03 percentage points higher than that of GAN and MCNN algorithms, respectively. The physical fitness index monitoring system constructed based on the perceptron model can effectively realize the monitoring of physical fitness indexes, help trainers master the training rhythm, and improve the safety of sports training.

The Establishment of the Cut-off Value of Weight-for-Height for Preschool Children in China and an Empirical Study on the Influence of Overweight and Obesity on Physical Performance.

We aimed to establish the cut-off value of weight-for-height for preschool children in China, and to explore the influence of overweight and obesity on the physical performance of preschool children. Data from 31 provinces in China monitored in 2010 and 2014, the standard deviation unit curves of WFH were established by using GAMLSS (generalized additive model for location, scale, and shape) method preschool children in China, and then the cut-off values of normal weight, overweight and obesity were divided. The research group tested 5 physical performance indicators of 5154 preschool children from April 2018 to June 2019 in Beijing and Zhejiang in China. We then compared physical performance differences between the normal-weight group and the overweight-obesity group. A smooth and effective standard deviation unit curve of WFH was established. The overweight and obesity of Chinese preschool children were at a high level. Being overweight and obese reduced preschool children's relative strength, speed, sensitivity, coordination, and balance ability, but did not reduce preschool children's flexibility. In general, the physical performance of preschool children in the normal weight group was better than that in the overweight and obesity group. It is suggested to use the WFH criteria in this study to evaluate overweight and obesity in Chinese preschool children, and strengthen physical activity and take in energy substances properly of preschool children, to control the spread of overweight and obesity, to improve physical performance level.

Jumping Rope Improves the Physical Fitness of Preadolescents Aged 10-12 Years: A Meta-Analysis.

To systematically review the effects of jumping rope on physical fitness among 10 to 12-year-old preadolescents, and to provide evidence-based support for its use in school physical education curriculum work. The PubMed, Web of Science, SPORTDiscus, ScienceDirect, and CNKI databases were searched for randomized controlled trials that assessed jumping rope and physical fitness among preadolescents aged 10-12 years. Meta-analyses were used to calculate the standardized mean difference (SMD) values and 95% confidence intervals (CI), and subgroup analyses were conducted on intervention duration, frequency and period. A total of 1048 subjects from 15 studies were included. Compared to regular physical education courses, jumping rope did not show a significant advantage in terms of body morphology. In terms of physical function, boys showed greater improvements in vital capacity, and girls showed greater improvements in resting HR. In terms of physical performance, boys showed greater improvements in speed, upper-body strength, lower-body strength, muscular endurance and agility, while girls showed greater improvements in coordination and balance. Boys experienced a minimal improvement in flexibility, while girls did not show a significant difference. Combining the results of the subgroup analyses, the optimal session time, frequency and intervention length of jumping rope for significantly improving the physical fitness of preadolescents were >40 min, 2 times/week and 8-12 weeks, respectively. In conclusion, jumping rope provides small to large benefits over regular physical education for both boys and girls aged 10-12 years in terms of physical function and physical performance indicators other than flexibility, while showing no significant advantage in terms of body morphology. Based on the available research, it is recommended that children aged 10-12 years participate in jump rope sessions for at least 40 minutes once or twice a week for 8-12 weeks to better develop physical fitness.

Research and Application of Contactless Measurement of Transformer Winding Tilt Angle Based on Machine Vision

In the process of producing winding coils for power transformers, it is necessary to detect the tilt angle of the winding, which is one of the important parameters that affects the physical performance indicators of the transformer. The current detection method is manual measurement using a contact angle ruler, which is not only time-consuming but also has large errors. To solve this problem, this paper adopts a contactless measurement method based on machine vision technology. Firstly, this method uses a camera to take pictures of the winding image and performs a 0° correction and preprocessing on the image, using the OTSU method for binarization. An image self-segmentation and splicing method is proposed to obtain a single-wire image and perform skeleton extraction. Secondly, this paper compares three angle detection methods: the improved interval rotation projection method, quadratic iterative least squares method, and Hough transform method and through experimental analysis, compares their accuracy and operating speed. The experimental results show that the Hough transform method has the fastest operating speed and can complete detection in an average of only 0.1 s, while the interval rotation projection method has the highest accuracy, with a maximum error of less than 0.15°. Finally, this paper designs and implements visualization detection software, which can replace manual detection work and has a high accuracy and operating speed.

Apelin as a Potential Regulator of Peak Athletic Performance

Apelin, as a cardiokine/myokine, is emerging as an important regulator of cardiac and skeletal muscle homeostasis. Loss of apelin signaling results in premature cardiac aging and sarcopenia. However, the contribution of apelin to peak athletic performance remains largely elusive. In this paper, we assessed the impact of maximal cardiorespiratory exercise testing on the plasma apelin levels of 58 male professional soccer players. Circulating apelin-13 and apelin-36, on average, increased transiently after a single bout of treadmill exercise; however, apelin responses (Δapelin = peak - baseline values) showed a striking interindividual variability. Baseline apelin-13 levels were inversely correlated with those of Δapelin-13 and Δapelin-36. Δapelin-13 showed a positive correlation with the maximal metabolic equivalent, relative maximal O2 consumption, and peak circulatory power, whereas such an association in the case of Δapelin-36 could not be detected. In conclusion, we observed a pronounced individual-to-individual variation in exercise-induced changes in the plasma levels of apelin-13 and apelin-36. Since changes in plasma apelin-13 levels correlated with the indicators of physical performance, whole-body oxygen consumption and pumping capability of the heart, apelin, as a novel exerkine, may be a determinant of peak athletic performance.

Vitamin D Supplementation in Adults with Spinal Cord Injury: A Systematic Review

Background: The current systematic review was conducted to investigate the effects of vitamin D supplementation on vitamin D levels, bone health, and physical performance indices in adults with spinal cord injury (SCI).&#x0D; Methods: The PubMed, Scopus, Web of Science, and Embase databases were searched for studies published up to June 2020, with no language limits. To determine the risk of bias, the Academy of Nutrition and Dietetics Quality criteria checklist was used.&#x0D; Results: Eight studies that met all of the inclusion criteria were identified. All of the eligible studies had a high level of heterogeneity regarding outcome measures, study design, and the dose of vitamin D. The majority of the trials showed beneficial effects of vitamin D supplementation on serum vitamin D levels and other outcome measures in patients with SCI. Three randomized controlled trials revealed a low risk of bias, whilst other studies were rated as the either neutral or negative risk of bias.&#x0D; Conclusion: This review suggests that vitamin D supplementation could improve vitamin D levels, bone health, and physical performance indices in individuals with SCI. However, due to the high level of heterogeneity, the results should be interpreted with caution. Further studies on this population should be performed to have sufficient power and a robust design to give definitive conclusions.