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The expression of circulating microRNAs appears to be a promising indicator of physical strength. The objective of this study was to determine whether there is an association between the expression level of four selected microRNAs and body composition over time among young female volleyball players. Blood samples and body composition measurements were taken from 7 females who are Polish volleyball players before and after 5 matches played out between the years 2017 and 2018. The blood spots were used to assess the expression of four microRNAs: miR-320, miR-182, miR-223, and miR-486. Fat mass, PFB% and BMI were positively correlated with expression level (exp.l) of miR-182. The miR-320 the exp.l was positively correlated with muscle mass and TBW. There were inverse correlations between miR-486 exp.l and PBF%, as well as between miR-486 exp.l and body mass, muscle mass, TBW, FFM, and BMR. Conversely, there were positive correlations between miR-486 exp.l and body mass and fat mass. The miR-182 may be positively correlated with fat tissue, miR-320 was positively correlated with muscle mass, and miR-486 was negatively correlated with fat mass. Overall, our study shows that the expression of miR-182, miR-320, and miR-486 is associated with body composition. The results of our study also suggest that exercise may decrease the level of miR-486. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of a 4-week specific high-intensity interval training (HIIT) program performed between the anaerobic threshold (ANT) and the psychomotor fatigue threshold (PFT) on physiological parameters in 14 professional soccer players at the under-17 level. The first and second stages of the research protocol included a treadmill running exercise with increasing load and six 3-min four-versus-four games of soccer with a 3-min break between games. Players then participated in a training microcycle involving three specific HIIT exercises twice per week for 4 weeks, after which they repeated stages one and two, followed by an assessment of changes. The measurement of lactate (LA) determined ANT, whereas the choice reaction time (CRT) indicated PFT among other selected physiological parameters. The repeated-measure analysis of variance (ANOVA) compared mean values for the examined variables using Bonferroni post hoc test. It demonstrated significantly increased maximal oxygen consumption (VO2 max) from 45.9 ± 3.0 to 48.7 ± 2.6at the ANT and from 49.1 ± 3.4 to 52.0 ± 3.6 on the PFT after 4 weeks of training. A significant increase in the running speed (RS) at both thresholds and heart rate (HR) at the ANT (p ≤ 0.05) was also recorded. Moreover, the players exceeded their intensity of effort during ANTwhile playing four-versus-four soccermatches, but they did not reach intensity during PFT. In conclusion, the findings of the study demonstrated that both thresholds shifted toward higher loads and the proposed specific HIIT effectively increased the exercise capacity of soccer players. [ABSTRACT FROM AUTHOR]

Study aim: The elastic potential energy accumulated in the musculotendinous units during the countermovement phase of a jump adds up to the energy supplied by the contracting muscles used in the take-off phase. Consequently, the total mechanical energy used during the jump may reach higher values. Stiffness represents a quantitative measure of a body’s elastic properties. Therefore, the aim of this study was to establish the relationship between leg stiffness and the countermovement jump height.

Background: Stroboscopic training is based on an exercise with intermittent visual stimuli that force a greater demand on the visuomotor processing for improving performance under normal vision. While the stroboscopic effect is used as an effective tool to improve information processing in general perceptual-cognitive tasks, there is still a lack of research focused on identifying training protocols for sport-specific settings. Therefore, we aimed at assessing the effects of in-situ stroboscopic training on visual, visuomotor and reactive agility in young volleyball players. Methods: Fifty young volleyball athletes (26 males and 24 females; mean age, 16.5 ± 0.6 years) participated in this study and were each divided randomly into an experimental group and a control group, who then both performed identical volleyball-specific tasks, with the experimental group under stroboscopic influence. The participants were evaluated three times using laboratory based tests for simple and complex reaction speed, sensory sensitivity and saccade dynamics; before the after the 6-week-long training (short-term effect) and 4 weeks later (long-term effect). In addition, a field test investigated the effects of the training on reactive agility. Results: A significant TIME vs GROUP effect was observed for (1) simple motor time (p = 0.020, ηp² = 0.08), with improvement in the stroboscopic group in the post-test and retention test (p = 0.003, d = 0.42 and p = 0.027, d = 0.35, respectively); (2) complex reaction speed (p < 0.001, ηp² = 0.22), with a large post-test effect in the stroboscopic group (p < 0.001, d = 0.87) and a small effect in the non-stroboscopic group (p = 0.010, d = 0.31); (3) saccade dynamics (p = 0.011, ηp² = 0.09), with post- hoc tests in the stroboscopic group not reaching significance (p = 0.083, d = 0.54); and (4) reactive agility (p = 0.039, ηp² = 0.07), with a post-test improvement in the stroboscopic group (p = 0.017, d = 0.49). Neither sensory sensitivity nor simple reaction time was statistically significantly affected as a result of the training (p > 0.05). A significant TIME vs GENDER effect was observed for saccadic dynamics (p = 0.003, ηp² = 0.226) and reactive agility (p = 0.004, ηp² = 0.213), with stronger performance gains in the females. Conclusions: There was a larger effectiveness from the 6-week volleyball-specific training in the stroboscopic group compared to the non-stroboscopic group. The stroboscopic training resulted in significant improvements on most measures (three of five) of visual and visuomotor function with more marked enhancement in visuomotor than in sensory processing. Also, the stroboscopic intervention improved reactive agility, with more pronounced performance gains for short-term compared to the long-term changes. Gender differences in response to the stroboscopic training are inconclusive, therefore our findings do not offer a clear consensus. [ABSTRACT FROM AUTHOR]

This study aimed to assess the capacity for repeated maximal effort (RME) of soccer players in the thermo-natural conditions (NC) and in simulated conditions for the 2022 FIFA World Cup in Qatar (QSC). Twenty-four semi-professional soccer players participated in the study. The exercise test consisted of ten 6-second maximal efforts on a cycloergometer. A 90-second passive rest interval was used. The test was performed in a Weiss Technik WK-26 climate test chamber in two different conditions: 1) thermo-neutral conditions (NC—20.5°C; 58.7% humidity); and 2) simulated conditions for the 2022 World Cup in Qatar (QSC—28.5 ± 1.92°C; 58.7 ± 8.64% humidity). Power-related, physiological, psychomotor, blood, and electrolyte variables were recorded. Results showed that (1) players achieved higher peak power (max 1607,46 ± 192,70 [W] - 3rd rep), needed less time to peak power (min 0,95 ± 0,27 [s] - 3rd rep), and had a higher fatigue slope (max 218,67 ± 59,64 [W/sek] - 7th rep) in QSC than in NC (in each repetition of study protocol); (2) between the 1st repetition and subsequent repetitions a number of significants in among physiological, blood-related, and electrolyte variables were noted, but their direction was similar in both simulated conditions (e.g. V'O2/kg 37,59 ± 3,96 vs 37,95 ± 3,17 [ml/min/kg] - 3rd rep, LAC 13,16 ± 2,61 vs 14,18 ± 3,13 [mg/dl] - 10th rep or K 4,54 ± 0,29 vs 4,79 ± 0,36 [mmol/l] - 2nd rep when compare QCS and NC respectively); (3) an 8°C of temperature difference between the climatic conditions did not significantly affect the soccer players' physical and physiological responses in RME. The study results can be used in the design of training programs aimed to increase players' physiological adaptations by simulating soccer-specific conditions of play in terms of anaerobic capacity, in particular, repetitive maximal efforts. These findings will be useful during the upcoming 2022 World Cup in Qatar and in locations where high ambient temperatures are customary. [ABSTRACT FROM AUTHOR]

Physical education curricula in Polish schools should include more tasks to increase physical activity. The Tabata Training Program can help regulate body weight and induce changes in body fat and physical fitness. This study aimed to determine the effects of a 10-week PE curriculum supplemented by a Tabata Training Program on health-related fitness in 16-year-old secondary school students. The study examined 187 students (66 boys and 121 girls) assigned to either a Tabata Training Program intervention or control group. The intervention lasted 14 minutes during one physical education lesson per week. Pre- and postintervention, anthropometric measurements were taken, and each participant performed physical fitness tests to evaluate muscular strength, flexibility, speed/agility, and cardiovascular efficiency. Boys of the intervention group significantly reduced body fat (by 1.77%, p<.05) and increased cardiovascular efficiency (the physical efficiency index was higher by 3.61 points, p<.05). Girls increased cardiovascular efficiency only (the physical efficiency index increased by 5 points, p<.001). However, slight changes in motor parameters were observed in all the participants. The Tabata Training Program demonstrated partial effectiveness but should be individualized and sex differences should be considered. [ABSTRACT FROM AUTHOR]

The aim of the present exploratory study was to assess the changes in urinary oxytocin (OT) concentration during the period between five days before, and on the day of match, among rugby and handball players. Nine male rugby players with a mean age of 27.62 years (SD = 4.21) and 18 male handball players with a mean age of 17.03 years (SD = 0.57) participated. Urinary oxytocin level was measured by ELISA immunoassay as a ratio to the concentration of creatinine [mg/ml] measured through colorimetric detection. The relative level of OT to creatinine (OT/CRE) significantly differed between the type of player (rugby or handball) but not between times of measurements. Significant differences were only between OT/CRE level in a day of match in rugby players and in 5 days before match in handball players (p<0.05). There was no change in oxytocin levels during the time periods between five days before and on the day of a match, in either of the two kinds of players. The change in oxytocin might be traceable during the match but not before a match and this perhaps depends on a more subtle context of competition, but not on the assumption of competition. Further studies are needed based on more homogenous group with higher number of matches. [ABSTRACT FROM AUTHOR]

Limited evidence is available providing specific details about the perceptual-cognitive and motor factors that contribute to reactive agility (RA) and variations between genders in young athletes. The aim of the study was to investigate perceptual-cognitive and motor determinants of RA in competitive youth volleyball players. A total of 135 volleyball players (61 males, 74 females) aged 16–18 years were included in this study. The independent variables were as follows: explosive strength, maximal frequency of movements, simple and complex reaction time, selective attention, sensory sensitivity, and saccadic dynamics. Multiple linear regression analyses showed that explosive strength (ß = - 0.494; p < 0.001) and complex reaction time (ß = 0.225; p = 0.054) accounted for 23% of the variance in RA performance in male players. The best exploratory model for RA contributed 34.5% of the variance in RA for female players with significant determinants of explosive strength (ß = -0.387; p < 0.001), sensory sensitivity (ß = -0.326; p = 0.001) and selective attention (ß = 0.229; p = 0.020). Male athletes obtained better results in RA, in all motor tests (effect size of 0.88 to 2.58) and in five variables of perceptual-cognitive skills (effect size of 0.35 to 0.98). Motor and perceptual-cognitive components significantly contributed to performance in RA in competitive youth volleyball players. Gender differentiates between players' RA performance, motor properties and saccadic dynamics to a large extent, while the remaining analyzed perceptual-cognitive components vary between female and male players to a small and moderate extent. [ABSTRACT FROM AUTHOR]

Human females demonstrate higher religiosity than men in populations. Digit ratio (2D:4D), being a putative indicator of prenatal testosterone, is associated in varying degrees with characters that show sexual dimorphism. A small number of studies have indicated that religiosity may be associated with the biological basis of sex differences in humans. The objective of the present study was to ascertain whether 2D:4D in religiously oriented seminary students is different from individuals in other occupations. The study followed a cross-sectional design. Male participants of the study included 13 seminary students, 18 military chaplains and 91 control students from study courses relating to civil occupations. Lengths of second (2D) and fourth (4D) digits and their ratio (2D:4D) for each hand, height and weight were the variables and 2D:4D was the outcome measure. The results demonstrated that the seminary students had significantly higher 2D:4D than both the military chaplains and civil students. The military chaplains had the lowest 2D:4D. The study also revealed that the choice of religious occupation, and for that matter, religiosity, could be linked with the prenatal hormonal environment, particularly lower intrauterine testosterone compared to oestrogen. [ABSTRACT FROM AUTHOR]

The aims of this study were (1) to determine the match running performance required by different teams based on their final ranking position and (2) to analyze the association between match running performance variables and team success at the end of the season. A total of 1,224 match observations from professional soccer teams competing during two consecutive seasons in the German Bundesliga were analyzed. In addition, the final league ranking position and the total of points obtained by each team at the end of the season were registered for the analysis of the association between team success and match running performance. The main findings were that high ranked teams covered the greatest total distance with ball possession, sprinting distance with ball possession, and completed the greatest number of sprinting actions with ball possession and maximal velocity. Moreover, total distance covered with possession of the ball and maximal velocity were the most important variables to predict the total of points obtained at the end of the season. Specifically, the relative contribution of total distance covered with ball possession to the total of points obtained was greater than maximal velocity. Training programs for professional soccer players should be focused on improving the sprint capacity and running with possession of the ball (e.g., transitional tasks and small-sided games). Moreover, this has implications for injury prevention, physical, psychological, and technical-tactical training since today's soccer requires players to engage in repeated high-intensity actions, reach maximum speeds above 9 m/s, and develop technical-tactical coordination when running with the ball. [ABSTRACT FROM AUTHOR]

BACKGROUND: Carrying a properly weighted schoolbag is an important factor in preventing the occurrence of muscular skeletal disorder in early school age children. OBJECTIVE: The purpose of this cross- sectional observational study was to examine the schoolbag weight and to determine the percentage of children were carrying overloaded schoolbag. METHODS: The study group included pupils from five primary public schools in Wrocław, Poland. Anthropometrical measurements such body weight (BW) and height were conducted on 650 children (51.1% of boys). Children's age, gender, Cole's Index was juxtaposed with schoolbag weight. The mean age of the examined students was 8.7±0.8 years (range 7 to 10 years). RESULTS: The mean schoolbags weight was 3.7±0.92 kg, which represented 13.0±3.8% of pupils' BW. The percentage of pupils carry the schoolbags weighing more than 10% of their BW was 77.9%. More than a quarter of Polish children carry school backpack above 15% of their BW. The majority (96.8%) had schoolbags which may be carried on both shoulders. A significant negative correlation was observed between relative schoolbag weight and Cole's Index (rho = –0.44, p < 0.05). CONCLUSIONS: The problem of overloaded schoolbags among elementary school children was frequent. Pupils ought to be educated in the proper packing of their school backpacks. Additionally, parents and teachers should pay attention regarding the contents carried by children in their respective schoolbags. [ABSTRACT FROM AUTHOR]

Success in volleyball largely depends on motor abilities, particularly on maximum strength, power, jumping, and speed performance. However, a small number of studies assess the relationship between motor abilities and the effectiveness of volleyball technical skills. Therefore, the aim of the study was to assess the impact of the strength of the upper and lower limbs on the efficiency of serve reception during a 2 vs. 2 game, as well as to evaluate the results of motor measurements in the context of determining the usefulness of current testing procedures. The study involved a carefully chosen group of 12 girls aged 12–13 years (body height: 176.5 ± 4.2 cm, body mass: 58.6 ± 5.1 kg, and training experience: 43 ± 15 months) selected for the Lower Silesian Regional Volleyball Team. The following tests were conducted: handgrip strength with a hand dynamometer, bent-arm hang, 2 kg medicine ball throw, shoulder joint internal rotators (IR) peak torque, standing long jump, spike jump, and countermovement jump. The measurements of the shoulder joint IR peak torque were performed under isometric (at 10°, 35°, and 65° rotation angles) and isokinetic (at 60°/s, 180°/s, and 300°/s) conditions. The efficiency of serve reception was evaluated during a 2 vs. 2 games by using Data Volley statistical software. The strongest positive relationships were observed between the serve reception efficiency and the peak torque and power of the shoulder joint IR, the medicine ball throw distance, and handgrip strength. Jumping variables showed no associations with efficient of serve reception. Consequently, we suggest adding protocols to volleyball training that include strength exercises aimed at developing the IR muscle group. The isokinetic upper limb test should be introduced as a valid tool in selection process. Coaches who do not have access to modern research equipment should use the medicine ball throw test to evaluate strength abilities as an alternative assessment of the serve reception efficiency. [ABSTRACT FROM AUTHOR]

Greater hand grip strength enables players to start their movement by pushing away from the floor using the upper limbs with high vertical pressure exerted on the hands ([25]) and taking a convenient position to play the ball. [16] reported that shorter time during 5 m locomotion in a seated position was associated with greater distance of passing the ball with both hands in front of the chest in sitting volleyball players. Hand grip strength increased over a period of ten months in sitting volleyball players with a significant degree of disability and did not change in players with a moderate degree of disability and in healthy players ([6]). [6] noted that sitting volleyball players with a considerable degree of disability had the highest hand grip strength, which may suggest the involvement of dysfunction compensation in the lower extremities due to high adaptability of strength abilities. [Extracted from the article]

This study aimed to investigate the relationship between the climatic conditions predicted for the 2022 FIFA World Cup in Qatar and the capacity for repeated maximum effort (RSA), of soccer players. Twenty-four semi-professional soccer players participated in the study. The exercise test consisted of ten 6-second maximal efforts on a cycloergometer. A 90-second passive rest interval was used. Mechanical parameters were recorded in each repetition, and biochemical parameters at rest and even repetitions. The test was performed in a Weiss Technik WK-26 climate chamber under two different conditions: (1) thermoneutral (TNC - 20.5 °C; 58.7% humidity); (2) predicted for the 2022 World Cup in Qatar (QSC - 28.5 ± 1.92 °C; 58.7 ± 8.64% humidity). Significantly higher mean maximum power values were recorded in the second repetition under QSC conditions (1731,8 ± 214,4 W) (p = 0.025). A significantly longer time to reach maximum power was also recorded under TNC conditions compared to QSC conditions in repetition 2 (1,32 ± 0,33 s), (1,05 ± 0,29 s) (p = 0.016) and 6 (1,41 ± 0,48 s), (1,17 ± 0,25) (p = 0.036). There was a significantly higher rate of power loss, between repetition 2 (p = 0.023) and 4 (p = 0.043) under QSC conditions, compared to TNC. Considering the biochemical parameters, a significantly higher pO2 concentration was registered under QSC conditions in the 10th repetition (p = 0.006). The ambient temperature during exercise should be taken into account to determine the anaerobic exercise capacity of the athletes. At higher temperatures, there is a greater capacity for maximal effort, in terms of maximal power achieved, but with a greater decrease in performance. [ABSTRACT FROM AUTHOR]

Assessing the physical ability of players to perform change of direction and the cognitive and motor abilities revealed in reactive agility (RA) is necessary to understand the physical requirements and capabilities of professional players in handball and basketball. The main aim of this study was to determine the differences between professional female basketball and handball players in terms of anthropometric features, change of direction speed (CODS), and the RA task. Moreover, the relationships among anthropometric features, agility, and parameters of perception were determined. Two scenarios of the Five-Time Shuttle Run to Gates test (planned and unplanned) were used to evaluate the CODS and RA. The response time (RT) was also measured in the unplanned scenario. Additionally, the index of reactivity (REAC-INDEX) was specified as the difference between the RA test result and the measurement of CODS. There was a significant difference found in terms of body height, with basketball players being taller than handball players (p = 0.032). Professional female handball players achieved better results than professional female basketball players with regard to RA tasks (p = 0.01) and CODS (p = 0.041). Significant simple correlations between each anthropometric feature (body height, body mass) and values for CODS and RA were observed (r = 0.49–0.53). Applying partial correlation allowed for the assessment of actual relationships among CODS, RA, RT, and REAC-INDEX, without a confounding variable. Detaching the anthropometric parameters from the rest of the relationships resulted in maintenance or changes in r -values and an increased significance in the relationships between each pair: RA vs. RT, RA vs. REAC-INDEX, and RT vs. REAC-INDEX. The strongest associations were related to RT vs. REAC-INDEX (r = 0.97 at detaching body height or body mass, p < 0.001) and CODS vs. RA (r = 0.66 at detaching body height and r = −0.67 at detaching body mass, p < 0.001). It is recommended to use partial correlations in subsequent studies, as simple correlations are not reliable and may not reveal the apparent relationships between the variables. In addition, when determining the CODS and RA, it is suggested to take anthropometric and perception variables into account, such as reaction time or REAC-INDEX. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine how the four best teams in the 2018 Football Men's World Cup rotate by squad and how this impact the physical activity of the teams in consecutive rounds. The study sample consisted of the 31 players of the 4 best teams, who played in every tournament match, except for the third game of the group stage. The analysis included 186 observations and was carried out on the most exploited players (MEP) excluding goalkeepers, who played at least 450 mins (5 full matches) in the tournament. The analysis was conducted using data collected by an advanced motion analysis system known as STATS®. The selected physical activity parameters analyzed included: total distance covered (m/min), distance covered at various intensity ranges (m/min), top speed (km/h), and number of sprints performed. It was found that all four teams in the third match of the group stage have performed the largest number of rotations with most exploited players and introduced the highest number of rested players (7.75 ± 2.06). A significant increase was observed between the second and fourth match in the 0–7 km/h distance covered (37.99 ± 3.19–39.23 ± 3.35 m/min) and the top speed (28.12 ± 2.22–29.21 ± 2.64 km/h)— p < 0.05. Furthermore, MEPs in the knockout stage, used pacing strategies by increasing the amount of low-intensity running to maintain high intensity during the game. From a practical point of view, this investigation shows that squad rotation can be a valuable support to a pacing strategy by players. [ABSTRACT FROM AUTHOR]

The study aimed to identify the effects of situational (match location, match outcome and strength of team/opponent team) and environmental (ambient temperature, relative humidity, WBGT, ground and weather condition) factors on the physical and technical activity of elite football on individual playing positions. Physical and technical activity were collected from 779 football players competing in the German Bundesliga during 5 domestic seasons, from 2014/2015 to 2018/2019, totalling 1530 matches. The data on players' physical and technical activity was taken from the IMPIRE AG system. Based on the available data, 11 variables were selected to quantify the match activity profiles of players. The results showed that situational variables had major effects on the technical performance (especially number of passes performed) but minor effects on physical performance. In turn, among the analysed environmental factors, temperature is the most sensitive, which affects the Total Distance and Sprint Efforts of players in all five positions. This investigation demonstrated that, given that passing is a key technical activity in modern football, players and training staff should be particularly aware that passing maybe affected by situational variables. Professional players are able to react and adapt to various environmental conditions, modifying physical activity depending on the needs in German Bundesliga. These results could help coaches and analysts to better understand the influences of situational and environmental variables on individual playing positions during the evaluation of players' physical and technical performance. [ABSTRACT FROM AUTHOR]

Despite the general agreement that the interdisciplinary model of physical education (PE), based on the incorporation of core academic subjects into the PE curriculum, stimulates the holistic development of students, there is still a lack of methods for its implementation. Therefore, Eduball was created, i.e., a method that uses educational balls with printed letters, numbers, and other signs. Numerous studies have shown that children participating in activities with Eduballs can develop their physical fitness while simultaneously improving their academic performance, particularly in math and language, including some writing skills. However, little is known about the effects of Eduball on children's graphomotor skills, which are key for the academic performance of students throughout the entire schooling process. Here, we investigate whether 6-month participation in PE with Eduball stimulates graphomotor skills in primary school students, such as drawing prehandwriting letter patterns on unlined or lined paper and rewriting text on unlined or lined paper. Our results show that the Eduball class (N = 28) significantly improved these skills compared to the control class (N = 26) participating in traditional PE. For example, students from the experimental group wrote with a lower pen pressure and better stability of the line, in contrast to those from the control group. Therefore, this study demonstrates that the Eduball method successfully supports teachers in developing graphomotor skills in children. More broadly, our findings make clear once again that there is the need to integrate physical and cognitive development in education, which can be achieved by using an interdisciplinary model of PE. [ABSTRACT FROM AUTHOR]

Background. The optimal body mass index (BMI) and fat mass index (FMI) values for a positive change or the lowest risk of no positive change after high-intensity interval training (HIIT) using the Tabata protocol remain unclear. This study is aimed at establishing these optimal BMI and FMI values for the lowest risk of failure of aerobic performance in adolescents. Methods. A 10-week HIIT programme was introduced into the physical education of 73 students. BMI was calculated using height and weight. Bioelectrical impedance analysis measured body fat, and the InBody apparatus generated the FMI. Based on BMI and FMI, the participants were divided into four groups. Pre- and post-HIIT intervention analyses were carried out using the Harvard step test, which was used to determine the physical efficiency index (PEI). Results. The Youden index confirmed that the risk of no positive effects in PEI was the lowest for the second BMI interval (19.01-22.00 kg/m2) and FMI Q 2 − 3 (7.96-8.91 kg/m2). The optimal BMI value for the lowest risk of no change in PEI was 20.60 kg/m2, and the optimal FMI value was 8.84 kg/m2. Conclusion. A comparison of the two indices shows that FMI had stronger effects on PEI than BMI. In addition, the model obtained for FMI had higher accuracy. Identifying at-risk individuals, those in need of improving health-related fitness (H-RF), and those with a low risk of poor H-RF allows for efficient planning of individual intervention services and training programmes. [ABSTRACT FROM AUTHOR]

The purpose of this study was to ascertain the effect of playing three consecutive matches with extra time (ET) on the physical performance of selected Croatian players in their subsequent match, the final of the 2018 Men's World Cup in Russia. The case study consisted of 4 players on the Croatian national team (16 observations) who had played in all three matches up to 120 min. The consecutive full time matches (90 minutes) and extra time (30 minutes) were compared. The analysis was conducted using data collected by an advanced motion analysis system known as STATS and from interviews with the strength and conditioning coach of the Croatian national team. The recorded variables used were: total distance covered [m], distances covered [m] at intensity ranges of 20-25 km/h and above 25 km/h, and number of sprints performed. All the studied parameters systematically increased in each match up to 90 minutes of play, reached their maximum values in the semi-final and then decreased in the final match. Compared to the first extra time period, in the third extra time period the players covered twice as much distance with an intensity of 20-25 km/h and above 25 km/h, and recorded twice as many sprints. This investigation shows that players in central positions on the pitch are able to maintain or even increase high and very high intensity activity in three consecutive matches with extra time. These data complement the developing body of literature relating to the influence of accumulation of match play with extra time periods on high level players. [ABSTRACT FROM AUTHOR]

An increasing number of studies are evidencing relationships between physical activity (PA) and the mathematical performance of early school students. This is not surprising due to the fact that children grow in all areas simultaneously and their motor and intellectual developments determine each other. Nevertheless, such an approach of combining mathematics education with physical exercises, in addition through play, which is the basis of children's activity and the preferred way of spending time, is still rare at schools. In response to this problem, "Eduball" has been created, which is an educational ball with printed letters, numbers, and other signs used for team mini-games. Surprisingly, despite the studies on general usefulness of Eduball in preschool and early-school education and the effects of physical exercise classes carried out using these balls, still little is known about their impact on mathematical development. Here, we investigate the relationships between the use of Eduball and the acquisition of mathematical knowledge and skills by children. We used a quantitative approach in the form of an experiment in natural settings in which 7-year-old students (first grade) took part (N = 25). For the purposes of this experiment, we created scenarios of physical exercise classes integrated with mathematical contents that used Eduball. Mathematical knowledge and skills were assessed by one of the commonly used tests. The results were compared with the data from the control group of traditional physical education classes (N = 22). As assumed, after a 1-year experiment, students from both groups improved their results, but we found a greater progress in terms of mathematical knowledge and skills in the experimental class compared to the control one. Eduball particularly affected competences related to such mathematical categories as: sets and their elements, multiplication and division, geometric shapes and measuring length, and measuring volume and mass. In sum, our results show that physical exercise classes that used Eduball stimulate the acquisition of mathematical competences by students and, consequently, confirm that there is a strong relation of physical and mathematical development. Therefore, there is a need to review children's educational models, as well as primary school curricula, to combine physical and cognitive activities. [ABSTRACT FROM AUTHOR]

Previous studies in team sports have not reported evidence regarding the relative age effect (RAE) in relation to the talent identification (TI) process in volleyball, which is organized and controlled by a national federation. Volleyball is a non-contact team sport in which a player's physique does not directly affect other players in the game but is considered one of the most critical factors in the TI process. The aims of the present study were (1) to determine the differences in the quarterly distribution of age between Polish youth volleyball players from the Olympic Hopes Tournament (OHT) and the general population, (2) to investigate the quarterly differences in anthropometric characteristics and motor test results in OHT participants, and (3) to identify the criteria that determine selection for the National Volleyball Development Program (NVDP). The present study identified the RAE in young male (n = 2,528) and female (n = 2,441) Polish volleyball players between 14 and 15 years of age who competed in the elite OHT in 2004–2015. The study included anthropometric characteristics, motor test results, and selection for the NVDP. The multivariate analysis of covariance demonstrated no significant main effect for birth quarter or calendar age in any of the OHT female players or in male players selected for the NVDP. In the group of non-selected NVDP male players, the analysis demonstrated significant differences by birth quarter as a covariate for body height (F = 0.01, p < 0.001), spike reach (F = 7.33, p < 0.05), and block jump (F = 0.02, p < 0.001). Significant differences by calendar age as a covariate were observed for body mass (F = 0.53, p < 0.01), spike jump (F = 2.64, p < 0.05), block jump (F = 0.4, p < 0.01), and zigzag agility test results (F = 0.01, p < 0.01). The results showed a significant overrepresentation of early-born participants in the OHT and NVDP subsamples. The classification model demonstrated that a combination of four characteristics optimally discriminated between players selected for the NVDP and those who were not selected. This combination of variables correctly classified 77.7% of the female players and 71.8% of the male players in terms of their selection for the NVDP. The results of this study show that jumping ability and body height are crucial in the TI and selection process in youth volleyball. [ABSTRACT FROM AUTHOR]

Currently, there are several computational methods for stiffness during a hopping task, but they do not necessarily yield the same values. Therefore, it is essential that the simplicity of the equipment used does not affect the measurement validity. The aim of this study is to compare the stiffness values during a hopping task recorded in a laboratory environment and those acquired using the Myotest accelerometer. The measurements were performed on a group of 30 untrained female students (age: 23.0 ± 1.7 years, body height: 1.72 ± 0.07 m , and body mass: 64.8 ± 10.0 kg). According to the manual for the Myotest accelerometric system, each study participant performed three sets of 5 hops. Vertical stiffness was determined based on two measurement methods, one using the Myotest accelerometer and the other using Kistler force plates. The mean value (±SD) of vertical stiffness was 19.0 ± 9.3 kN / m in the countermovement phase and 15.1 ± 5.9 kN / m in the take-off phase. Furthermore, the stiffness determined using the Myotest was 30.7 ± 13.3 kN / m. However, significant relationships between the vertical stiffness in the countermovement phase and the Myotest stiffness (r = 0.79) and between the vertical stiffness in the take-off phase and the Myotest stiffness (r = 0.89) were found. The relationships between the vertical stiffness (in the countermovement and take-off phases) and the stiffness estimated using the Myotest allow us to conclude that despite the significantly overestimated stiffness value, the Myotest accelerometer can still be used for determination of the stiffness trends, e.g., following training. The overestimated stiffness values can result both from inaccuracy in the determination of ground contact time and flight time by the Myotest accelerometer and from the use of an equation that assumes that the movement of the center of mass has a harmonic profile. [ABSTRACT FROM AUTHOR]

Long-distance running and, in particular, running marathons has become an increasingly popular activity among the elderly. The aim of the study was to examine the effects of a marathon effort on the psychomotor performance and catecholamine concentration in runners over 50 years of age. The participants were male runners (n = 28) who completed the 32nd Wrocław Marathon in Poland. The runners' psychomotor performance was assessed on the basis of their choice reaction times (CRT), heart rate (HR) and running speed measurements. In addition, the adrenaline (A) and noradrenaline (NA) as well as lactate (LA) levels and anaerobic threshold (AT) were measured. The runners' CRT after crossing the finish line was significantly longer by 50 ms (p < 0.05) in response to each emitted audiovisual stimulus, as compared with baseline. The mean running speed was reduced by 1 km/h between the first speed measurement (5th km of the run) and the last (42.195 km) (p < 0.05). The observed three-fold increase in adrenaline and noradrenaline levels indicates an intense activity of the sympathetic–adrenergic system. The cognitive function levels in the studied marathon runners returned to baseline after 30 min of recovery, and the function of the sympathetic–adrenergic system by seven days after completing the marathon race. [ABSTRACT FROM AUTHOR]

The study was undertaken to investigate the relationships between linear speed, change of direction, and explosive power in the lower limbs of young soccer players. We aimed to determine the variables associated with effective change-of-direction speeds (time) based on the 30-m ZigZag (cutting maneuver) under 60° (CODS1), and 30 m sprint divided into forward-backward-forward movement (CODS2). Sixty young soccer players (age: 17.4 ± 0.7 years, height: 1.76 ± 0.06 m, weight: 68.1 ± 8.9 kg) from soccer sport clubs were included. The participants performed 30-m change-of-direction sprints and 30-m backward and forward sprints. For the maximum speed evaluation, a straight-line 30-m sprint test was performed. Counter-movement jumps and standing broad jumps were used to assess jumping ability. Pearson's linear correlation and a multiple stepwise linear regression model were used to adjust for variations related to the influence of functional speed and explosive power variables, which were analyzed based on the CODS1 and CODS2 data. Our results showed that 30-m CODS2 and standing broad jumps were associated with CODS1. The variation for the 30-m change-of-direction maneuvers under 60° could be explained by the results of 30-m forward-backward-forward change-of-direction. The standing broad jump explained 10% variation for the performances in change-of-direction sprint decrements and 9% variation for the 5-m change-of-direction with the best times, whereas straight-line sprinting was related to forward-backward-forward change-of-direction. The 10-m sprint explained 50% variation of the performances in the first 10-m forward running in the CODS2 and 12% variation for 10-m backward-forward change-of-direction. The 30-m sprint explained 36% variation for 30-m forward-backward-forward change-of-direction. The 30-m sprint and overall body mass also explained 58% variation for 10-m forward-backward change-of-direction. For coaching purposes, we report that forward-backward-forward and cutting maneuver change-of-direction movements are independent and highly useful skills. This information can help to provide better training prescriptions. [ABSTRACT FROM AUTHOR]

The relative age effect (RAE) is related to discrimination against youth athletes born in the last quarter of the calendar year. The current study presents research on the RAE in elite youth soccer players in Poland. Players in the Central Junior League (CLJ) finals represent 0.59% of the 25,756 players under 20 years old (U20). This study analyzed the post-game protocols of the CLJ knockout stage from the 2013/2014 and 2014/2015 seasons as well as the U17-U21 teams during 2015, including only players who played on the field for at least one minute (n = 395). The results revealed the existence of RAE in the examined groups (CLJ 2013/2014, χ23 = 15.441, p < 0.01, CLJ 2014/2015, χ23 = 20.891, p < 0.001 U17-U21, χ23 = 25.110, p < 0.001). In addition, the results differed by monthly birth distribution in the Polish population (PP) between 1995 and 1999. This study is the first to examine the RAE in youth soccer in Poland. The occurrence of the RAE with regard to the most promising youth and national team players suggests that a similar effect exists among younger age categories. To reduce the RAE related to identifying soccer talent, tools should be implemented to optimize the player-selection process, such as those that consider the biological development of a player. [ABSTRACT FROM AUTHOR]

The study aimed to examine the performance frequency of selected technical activities by soccer teams playing in the UEFA EURO 2016 in relation to match outcome and match status. Thirty-six matches of the group stage were analysed. The data were retrieved using an OPTA Sportsdata Company system. The notated technical activities: shots, passes, were expressed as frequency of performance (playing time/number of activities); while ball possession was expressed in percentage terms. There was a large effect size in frequency of shots on target (η2 = 0.201), of shots from inside the penalty area (η2 = 0.163) in relation to match outcome. A medium effect size was then found in frequency of passes (η2 = 0.102), short passes (η2 = 0.060) and ball possession (η2 = 0.113) in relation to match status. A team’s playing effectiveness requires a concurrent scrutiny of players’ technical activities in relation to match outcome and match status. Key technical activities affecting a successful match outcome are frequencies of different types of shots. However, when the team is playing to change an unfavourable score (losing and drawing in match status), the most important are frequencies of different types of passes and higher percent of ball possession. [ABSTRACT FROM AUTHOR]

The monitoring of players' work-rate profiles during competition is now feasible through computer-aided motion analysis. The aim of the present study was to examine how various playing positions and match outcomes (i.e. won, drawn, lost) affect the total distance, and the distances covered at different intensities, by soccer players in Germany's Bundesliga. Match performance data were collected for 556 soccer players competing in the Bundesliga during the 2014/15, 2015/16 and 2016/17 domestic seasons. A total of 13 039 individual match observations were made of outfield players (goalkeepers excluded). The analysis was carried out using an IMPIRE AG motion analysis system, with records of all players' movements in all the 918 matches. The recorded variables included total distance covered [km] and distance covered at intensities in the ranges below 11 km/h, 11-14 km/h, 14-17 km/h, 17-21 km/h, 21-24 km/h, and above 24 km/h. In won matches, as opposed to drawn and lost matches, the wide midfielders and forwards ran a significantly longer distance, primarily covered at intensities of 21-23.99 and above 24 km/h (p ≤ 0.05). The analysis of full-backs, central defenders and central midfielders in won matches - as opposed to drawn and lost matches - in turn reveals that players ran a significantly shorter distance, most likely to be covered at intensities of 17-20.99 and 21-23.99 km/h (p ≤ 0.05). The results of the present study emphasise the importance of match outcome and playing positions during the assessment of physical aspects of soccer performance. [ABSTRACT FROM AUTHOR]

The mastery of maximal and high-intensity physical activities is key for successful performance in football. The aim of this study was to compare respective sprinting skills of Polish and South African soccer players by conducting straight and zig-zag sprint tests. The study sample comprised a total of 40 college level soccer players, 20 from Poland and 20 from South Africa. The sprint tests included a 30m-straight sprint test and a 30m-Zig-zag sprint test. ANOVA, followed by Fisher's LSD as a post-hoc test, were used for statistical analysis. The study found that the Polish players were significantly faster by a margin of 0.117 seconds (p≤0.001) than their South African counterparts, and developed a significantly higher running speed with a corresponding margin of 0.198m/s (p≤0.001) after 30 metres. In the 30m-Zig-zag sprint test, the Polish players also exhibited a significantly higher level of speed skills than the South African players, with a difference in a running time of 0.939 seconds (p≤0.001) and in a running speed of 0.307m/s (p≤0.001) that represented greater differences than those found in the 30m straight sprint test. [ABSTRACT FROM AUTHOR]

Background The aim of the study was to determine fundamental movement skills of elementary school first-graders and to seek whether fundamental movement skills correlate with the pupils' age and gender. Material/Methods The study involved students in the first grade of elementary school in Krosno. The study was conducted at the beginning of the 2015/2016 school year. A total of 98 pupils (43 girls and 55 boys) aged six and seven were tested, using the Test of Gross Motor Development-2nd Edition. Results The study showed that the results of fundamental movement skills depend on the children's age and gender. Older girls achieved better results in locomotor and object control skills than six-year-old girls. The analysis revealed that boys achieved better scores than girls in the object control skills subtest. Conclusions The findings of this study demonstrated that the results can serve as an argument in the debate on the validity of reducing the school age in Poland. Understanding the importance of fundamental movement skills and awareness of irregularities in motor skills may help to prevent children's later school problems. [ABSTRACT FROM AUTHOR]

As drowning is a serious threat to life, aquatic education is a necessity. The aim of this study was to carry out a quantitative analysis of students' expressions of interest to participate in swimming activities compared to interests in other forms of physical activity. A total of 1328 girls and boys aged 16-18 years participated in the research. Subjects were at three different levels in nine high schools in a city in Poland. When completing a standardised questionnaire, respondents indicated and ranked five activities in which they were most interested. Relationships between interests, gender and age were analysed. Swimming evoked the most interest in adolescents, which was higher in girls than in boys and more permanent and stable throughout the monitored period. Despite the lack of swimming pools in the schools and the institutional mentoring, adolescents declared interest in swimming in almost each of the examined schools. Motives accompanying these interests are spontaneous in nature. Their skills and behaviours (safety) reveal negligence of the educational system. Adolescents' interest in aquatic education can be used to shape attitudes towards physical culture and implement the utilitarian goals of education. [ABSTRACT FROM AUTHOR]

Jumping and proprioception are important abilities in many sports. The efficiency of the proprioceptive system is indirectly related to jumps performed at specified heights. Therefore, this study recorded the ability of young athletes who play team sports to jump to a specific height compared with their maximum ability. A total of 154 male (age: 14.8 ± 0.9 years, body height: 181.8 ± 8.9 cm, body weight: 69.8 ± 11.8 kg, training experience: 3.8 ± 1.7 years) and 151 female (age: 14.1 ± 0.8 years, body height: 170.5 ± 6.5 cm, body weight: 60.3 ± 9.4 kg, training experience: 3.7 ± 1.4 years) team games players were recruited for this study. Each participant performed 2 counter-movement jumps with arm swing to 25, 50, 75, and 100% of the maximum height. Measurements were performed using a force plate. Jump height and its accuracy with respect to a specified height were calculated. The results revealed no significant differences in jump height and its accuracy to the specified heights between the groups (stratified by age, sex, and sport). Individuals with a higher jumping accuracy also exhibited greater maximum jump heights. Jumps to 25% of the maximum height were approximately 2 times higher than the target height. The decreased jump accuracy to a specific height when attempting to jump to lower heights should be reduced with training, particularly among athletes who play team sports. These findings provide useful information regarding the proprioceptive system for team sport coaches and may shape guidelines for training routines by working with submaximal loads. [ABSTRACT FROM AUTHOR]

The aim of the present study was to analyze motor activities of soccer players in seven consecutive rounds of matches of the 2014 World Cup in Brazil and to compare the performance of the world champions, the German national team with other participating teams. The study sample comprised 905 observations of 340 soccer players, who played full-time matches in all seven rounds of the tournament. The study was conducted using data collected from the Castrol Performance Index, a kinematic game analysis system that records movements of players with semi-automatic cameras. The following variables were analyzed: total distance covered, the percentage of total distance covered at high intensity, the number of sprints, frequency of sprints and peak running speed. A statistically significant increase (p ≤ 0.01) was noted in total distance covered, the percentage of distance covered at high intensity and total number of sprints, between the quarter-finals and semi-finals of the World Cup tournament in Brazil. The German national team covered a significantly longer total distance (p ≤ 0.05) and had a greater percentage of distance covered at high intensity (p ≤ 0.001) than players from other teams. The obtained results point to the necessity of development of players' aerobic endurance and speed-endurance abilities while preparing for top-level soccer tournaments. Winning a soccer championship requires players to run longer mean total distances and longer distances at high intensity during a single match. [ABSTRACT FROM AUTHOR]

Effectiveness when playing in team games depends on speed-strength (jumping) abilities. The manifestations of these abilities are usually measured using tests based on vertical jumps and sprinting. This raises the question as to whether relationships exist between variables that describe the vertical jump and running time. The aim of this study was to evaluate the relationships between jumping variables, namely the height of the countermovement jump (CMJ) with arm swing and relative peak muscle power and time of the 30m-sprint (in a straight line and with direction changes) in a group of 187 young athletes who practised team sports. Measurements used a force plate and Fusion Smart Speed System. Strong significant relationships were found between the variables of the CMJ and sprint time along individual sections of the straight line and direction changes of running. However, these relationships differed between subgroups in terms of age, sporting discipline and gender. The height of the CMJ with arm swing is likely to represent a universal variable that could be used to predict the level of motor abilities among young athletes. [ABSTRACT FROM AUTHOR]

An important role in handball and basketball is played by ability to accelerate and ability to repeat multiple sprints. The aim of the study was to assess level of ability in multi-directional sprinting and running time over the first 5 m of the 30 m sprint in 93 basketball and handball players (46 boys and 47 girls) aged 14 to 15 years. The attempts were also made to find the relationships between the time of a 5-m run to evaluate initial acceleration phase and multi-directional sprinting evaluated using Five-Time Shuttle Run To Gates Test. Statistical analysis revealed no important differences in times of 5-m runs and times of multi-directional sprinting between groups with different ages, genders, and sports specialties. Furthermore, no significant correlations were found based on Spearman's rank correlation coefficient between times of 5-m run and multi-directional sprinting in the most of subgroups studied. [ABSTRACT FROM AUTHOR]

The basic drill of plyometric training aimed at improving lower limb power and jump height is a drop jump. This exercise can be performed using different techniques, which substantially affects jump variables. Therefore, the aim of this study was to compare the values of the reactive strength index (RSI) for countermovement drop jumps (CDJs) and bounce drop jumps (BDJs). The study was carried out in a group of 8 male youth basketball players. The tests were conducted using the AMTI BP600900 force plate to measure ground reaction forces and the Noraxon MyoMotion system to record kinematic data. Each player performed two CDJs and two BDJs from the height of 15, 30, 45 and 60 cm. The RSI was calculated as a ratio of jump height and contact time. Moreover, the RSI was determined for the amortization and take-off phases separately. Significant differences (p < 0.05) between RSI values for CDJs and BDJs were recorded for jumps from 30, 45 and 60 cm. Differences in RSI values for jumps from 15 cm were not significant. Furthermore, CDJ height values were significantly higher (p < 0.05) than the values recorded for BDJs. Times of contact, amortization and take-off during BDJs were significantly shorter (p < 0.05) than the respective values obtained for CDJs. Therefore, the use of the RSI to monitor plyometric training should be based on the drop jump technique that is commonly performed by basketball players. [ABSTRACT FROM AUTHOR]

The ability to reach a high running velocity over a short distance is essential to a high playing performance in team games. The aim of this study was to determine the relationship between running time over a 10-meter section of a 30-meter sprint along a straight line and changes in the angle and angular velocity that were observed in the ankle, knee, and hip joints. The possible presence may help to optimize motion efficiency during acceleration sprint phase. Eighteen girls involved in team sports were examined in the study. The Fusion Smart Speed System was employed for running time measurements. The kinematic data were recorded using the Noraxon MyoMotion system. Statistically significant relationships were found between running time over a 10-meter section and the kinematic variables of hip and ankle joints. An excessively large flexion in hip joints might have an unfavorable effect on running time during the acceleration phase. Furthermore, in order to minimize running time during the acceleration phase, stride should be maintained along a line (a straight line) rather than from side to side. It is also necessary to ensure an adequate range of motion in the hip and ankle joints with respect to the sagittal axis. [ABSTRACT FROM AUTHOR]

Background. The aim of the study was to identify the interests in physical activity of students attending senior high schools and the organization of physical education in the new core curriculum. The research material consists of the results of students' physical activity from nine randomly selected senior high schools in Wrocław. Material and methods. In addition, in those randomly selected schools, the professional qualifications of 32 physical education teachers, sports infrastructure and the method of physical education implementation were diagnosed. Results. The study revealed significant differences in the interest of senior high school students. The differences in physical activity forms among students involved gender, age and school they attended and the seasons in which the survey was held. Students showed the greatest interests in swimming, team sports and downhill skiing. The most popular among the girls were swimming, dancing, skating and roller skating, whereas among the boys were team sports, swimming, martial arts and downhill skiing. The study which diagnosed the professional qualifications of PE teachers showed that all of them graduated from a University School of Physical Education, and most of them have been working for over 21 years. Half of the diagnosed qualified teachers have a professional degree. Half of the teachers have more than trainer's or instructor's qualifications in one discipline Among the teachers, most people have a trainer's or instructor's license to conduct classes in basketball, volleyball, swimming, soccer and downhill skiing. Conclusions. The study on the diagnosis of the ways of implementing PE classes showed that five senior high schools implemented a traditional classroom- lesson system, and in four schools - a mixed system (classes in the classroomlesson system, and activities to be chosen by a student).The study has shown that in more than half of the diagnosed senior high schools in Wroclaw some new opportunities for the organization of physical education are introduced. [ABSTRACT FROM AUTHOR]

Introduction. Team sports require comprehensive motor preparation of players. In addition to strength and endurance skills, increasing attention is being given to the development of players' speed skills. Aim of Study. The aim of the study was to evaluate reaction time and 30-metre, straight line sprint time in players selected for the Lower Silesian Regional Teams in Poland in 2013 and 2014. Material and Methods. The study involved 369 players aged 13-15 years (187 girls and 182 boys), members of football, handball, volleyball and basketball Regional Teams of Lower Silesia. Out of this group, 51 players participated in the study in 2013, and then repeated it in 2014. The study used Smart Jump and Smart Speed Systems to measure players' reaction and sprint times, which were measured at 5, 10, 15, 20, 25 and 30-metre intervals. Results. Mean reaction time to light stimuli observed in boys in 2013 and 2014 was 0.509 ± 0.141 and 0.467 ± 0.264 seconds, respectively. In girls, the mean reaction time was 0.553 ± 0.122 and 0.566 ± 0.0271 seconds in 2013 and 2014, respectively. Mean sprint time in 2013 for boys who were not selected for the Regional Teams the following year was 5.338 ± 0.285 seconds, while those who were selected reached 5.416 ± 0.321 seconds. Girls who did not qualify for the Regional Teams in 2014 achieved the time of 5.764 ± 0.305 seconds. The female players who repeated the study reached the mean time of 5.805 ± 0.28 seconds. Boys who joined the Regional Teams in 2014 had a 30-metre sprint time of 5.533 ± 0.359 s. Boys who were repeating the study achieved the time of 5.322 ± 0.295 s. Girls who were selected for the Regional Teams in 2014 reached 5.796 ± 0.348 s, while girls who were repeating the study - 5.839 ± 0.342 s. Conclusions. The players' reaction times may suggest that this ability was not a criterion for selecting male and female players for the Regional Teams of Lower Silesia. Male handball players were shown to posses the greatest speed potential. [ABSTRACT FROM AUTHOR]

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Amputee soccer is one of the types of soccer designed for the disabled, especially those who have undergone amputations, as well as those with extremity dysfunction. The objective of the study was to find the relationship between hand grip strength and sprint time in amputee soccer players. Thirteen field amputee soccer players participated in the study. A SAEHAN hydraulic hand dynamometer manufactured by Jamar was used for hand grip strength measurements. The sprint running test was conducted over a distance of 30 m. The Fusion Smart Speed System was employed for running time measurements. No statistically significant relationships were found between hand grip strength of the left or right hand, and sprint times over 1, 5, 10, 15, 20, 25 and 30 m. Analysis of the running velocity curve of the subjects showed an interesting profile characterized by a 15 meter-long acceleration phase and a significant velocity increase over a distance of 20 - 25 m. The study suggests that there is no relationship between hand grip strength and sprint effectiveness in amputee soccer players. The specificity of locomotion with the use of elbow crutches among elite Polish amputee soccer players probably accounts for the profile of the sprint velocity curve. Extension of the acceleration phase in the sprint run and a velocity increase in the subsequent part of the run were observed. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine relationships between results of soccer-specific skill tests and game-related soccer skills in young players aged 12 and 15 years. The participants were 60 male soccer players aged 11.87-14.76 years divided into two groups: lower secondary school candidates (12y) aged 11.87 ± 0.23 years (n = 30), and upper secondary school candidates (15y) aged 14.76 ± 0.42 years (n = 30). Soccer-specific skills were assessed using two outdoor tests in competitive match conditions: Dribble Test and Turning Test. The assessment of the game-related skills was carried out by five expert judges during a 5 vs 5 small-sided game. The evaluation criteria had been set by a panel of experts. The reliability of game-related skills assessments procedures was calculated using intra class correlation (ICC), standard error of the mean (SEM), coefficient of variation (CV). Spearman's rank correlation coefficients were used to determine the relationships between results of assessments of game-related skill and soccerspecific skill tests. Relationships between soccer-specific skills and game-related skills in 15-year-old players (-0.325 to -0.452) are less pronounced than in 12-year-old players (-0.496 to -0.667). It seems to be unjustified to use soccer-specific skill tests for prediction of young soccer players' potential. The results of these tests can depend on numerous biological differences in the development of adolescent players. In conclusion, evaluation of players by judges should be part in talent identification models in youth soccer. [ABSTRACT FROM AUTHOR]