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Purpose: Different studies indicate that female players in team sports such as soccer tend to have a lower change-of-direction (COD) deficit (CODD) than their male counterparts and that players who performed better in linear and curved sprints tended to have a worse CODD, suggesting that maximum speed does not equate to a faster COD. This study assessed how performance variables related to speed and jumping influence the variability of %CODD among adult highly trained female soccer players. Methods: Fifty-two highly trained female soccer players (age 23.1 [3.25] y; height 163.6 [5.49] cm; weight 59.7 [5.71] kg) participated in this study and performed 180COD, 40-m sprint, countermovement jump, and standing broad jump tests. Results: Significant correlations were found between 180CODL, %CODDR, %CODDL, and between-limbs standing broad jump asymmetry (r =.28–.74). A very large correlation existed between %CODDR and %CODDL (r =.91). Regression analyses indicated a strong inverse relationship between the 10-m sprint time and %CODDR and %CODDL. No predictive models were found for 180COD in either limb. Differences in performance variables such as 180CODR, 180CODL, and asymmetry %CODD were significant between the high- and low-%CODD groups, with moderate to large effect sizes. Conclusion: The present study suggests that specific physical-performance variables, particularly acceleration and unilateral horizontal jumping, are vital to improving COD in highly trained female soccer players, highlighting the need for specific training interventions. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effects of unilateral flywheel training (FT), using a rotational conical pulley, including multidirectional movements with either preplanned or random unanticipated/unexpected executions on functional performance in football players. Methods: A total of 32 young male football players were randomly assigned to an FT program including preplanned unilateral multidirectional movements (PTG, n = 11), an FT executing the same unilateral movements through random (ie, right or left leg) unanticipated (ie, verbal or visual cue) or unexpected (ie, moment where the cue was provided) situations (UTG, n = 11), or a control group (n = 10) that followed their football training routine. FT consisted of 1 set × 5–12 repetitions of 4 exercises performed once a week for 10 weeks. Intermittent endurance performance, repeated unilateral and bilateral jumping ability, change-of-direction (COD) ability, linear sprint velocity, preplanned repeated-sprint ability (RSA), and uncertainty RSA (RSA-RANDOM) were assessed preintervention and postintervention. Results: Significant improvements were found in RSA-RANDOM performance (P <.05, effect size [ES] range: UTG [1.83–2.16], PTG [0.69–0.73]) and COD (P <.05, ES: UTG = 1.34, PTG = 0.98]) in both training groups. Furthermore, significant improvements were also found in intermittent endurance performance (P =.016, ES = 0.37) and sprinting (P =.006, ES = 0.45) in UTG. No changes in any variable were found in the control group. No significant between-groups differences (P >.05) were reported between UTG and PTG, while differences were observed to the control group in unilateral jumping ability, COD, and RSA-RANDOM for UTG, and in RSA-RANDOM for PTG. Conclusions: A 10-week unilateral FT improved RSA-RANDOM and COD ability in youth football players, so both preplanned and unexpected situations should be included on strength training. [ABSTRACT FROM AUTHOR]

Background: the purpose of this study was to analyze the reliability of a field-based fitness test battery in young trained football players, according to biological age. Methods: 197 young trained football players (12–19 years old) participated in the study. We measured anthropometric measurements (i.e., height, sitting height, length leg, and body mass), a bilateral vertical jumping test (CMJ), a progressive loading test of squats and hip thrust, acceleration and speed tests (10 m and 30 m sprint tests), a change-of-direction ability test (V–cut test), and a cardiorespiratory fitness test (30–15 intermittent fitness test). Statistical data are shown as the mean ± standard deviation by PHV group in tests and retests. Test reliability was assessed through the intraclass correlation coefficient (ICC), with an ICC above 0.9 being considered high. To evaluate accuracy and repeatability, standard error of measurement, coefficient of variation, and minimum detectable change at 90% were determined and Bland–Altman diagrams were used, establishing a statistical significance of p < 0.05. Results: All of the tests showed non-significant differences between the test and retest in the pooled sample (p > 0.05). Furthermore, all of them presented a trivial effect size (<0.2) and high intraclass correlation coefficients (>0.9), which indicates the high reproducibility of the tests, despite some of them presenting a significant difference between trials (i.e., the CMJ, 10 m sprint, V–cut, and squat tests). Low measurement errors were found for all tests (coefficient of variation [CV] = 4.39–9.39), except for the CMJ and the progressive loading test for squat and hip thrust exercises (CV = 12.2–21.11). Similar results were found irrespective of biological age group. Conclusions: All tests were reliable for the pooled sample as well as for the biological age groups. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to analyze the relationship between physical preparation, training sessions (TS) and friendly matches' (FM) demands, and playing status during European Championship (EC). Method: Twelve under-16 (U-16) basketball players performed physical (jumping, agility, aerobic fitness, and lower limb asymmetry index [ASI]) tests prior to attending the national team training camp. External training load was assessed using the WIMU PRO System put in place during TS (n = 19) and FM (n = 3), integrating the national team preparation. Perceptual response (RPE), muscle soreness (DOMS), and game-related statistics were also collected. Playing status during the U-16 EC (starters vs nonstarters) were taken into consideration to analyze the between-subjects differences across all variables. A stepwise discriminant analysis was computed to identify the construct that best differentiated the players' playing status (starters vs nonstarters) during the EC. Results: The starters were characterized by lower movement demands in both TS (ES: -0.02 to -1.26) and FM (ES: -0.03 to -1.94), however, outscored nonstarters in most FM-related statistics (ES: 0.10 to 3.62), with exception to blocks and rebounds. The number of high-intensity decelerations during FM (p [less than or equal to] 0.05), but also training DOMS, number of steals, efficiency, minutes during FM, and countermovement jump (CMJ) (p [less than or equal to] 0.01) substantially discriminated the playing status over the course of the EC. Conclusion: Game-related statistics obtained in FM seem to be a determinant aspect that increases the probability to be the starter during the EC.

Purpose: Change of direction while dribbling appears to be of interest for on-court performance in basketball. The study aim was to assess the validity and reliability of the V-cut dribbling test (VcutBk) in young basketball players. Methods: Ninety-two young basketball players from 8 to 21 years old (74% male) were classified in relation to peak height velocity (PHV) offset. To examine validity and test–retest reliability, VcutBk was performed in 2 identical sessions separated by 1 week. Participants also performed the V-cut test and linear sprint test with and without dribbling to analyze correlations between tests in different somatic maturity stages. Results: The relationships of the VcutBk with the other tests and skill-time-related deficits were interpreted from large (r >.51) to very large (r >.71). The comparisons between pre-PHV and post-PHV groups of basketball players showed significant and large effect in the VcutBk (d = 2.04; mean difference = 2.59; 95% CI, 1.86 to 3.32). Also, significant main effects when comparing PHV groups were reported in all skill-time-related deficits (P <.001, η p 2 =. 13 -.28 , moderate to large effect size). Test–retest reliability and signal-to-noise ratio analysis did not show substantial between-trials differences in VcutBk. Reliability scores showed high intraclass correlation coefficient (.95) and low coefficient of variation (0.23%). Conclusions: The VcutBk seems to be a valid and reliable test to assess change of direction while dribbling. VcutBk performance and skill-time-related deficits seem to be sensitive to somatic maturity. Basketball coaches should consider the VcutBk to assess young basketball players. [ABSTRACT FROM AUTHOR]

Gonzalo-Skok, O, and Bishop, C. Influence of maturation and determinants of repeated-sprint ability in youth basketball players. J Strength Cond Res 38(2): 325-333, 2024--The main aims of the current study were (a) to determine the main predictors of general and specific repeated-sprint ability (RSA) tests, (b) to analyze the relationships between RSA tests and independent measures of physical performance, (c) to examine whether between-age differences exist, and (d) to assess whether maturation affects those mentioned above in young basketball players. Thirty-five young (U-14 to U-16), highly trained basketball players performed a linear sprint test (5, 10, and 25 m), an incremental running test, and 2 repeated-sprint tests (general [RSG]: 6325 m; specific [RSS]: 635 + 5 m with a 45° change of direction and 20 seconds of passive recovery in both tests). Anthropometric variables were measured and used to calculate age at peak height velocity (APHV), which was used to determine maturation. The main determinants of RSA tests were aerobic performance and linear sprinting for RSS (R250.84) and adding the percentage of body fat for RSG (R250.94). Almost perfect relationships (r 5 0.93-0.99) were found between all RSA variables (i.e., the best [RSGb and RSSb] and mean time [RSGm and RSSm]). As age increased, performance in RSA was evident, as shown by improved best and mean scores. When APHV was controlled for, no significant differences were apparent in the comparison from U-14 and U-16 in 25 m, RSGb, and RSGm. By contrast, significant differences (p < 0.05) were still evident with APHV controlled between U-14 and U-16 in 5m, 10m, RSSb, and RSSm. In conclusion, maturation positively affects linear sprinting and linear RSA performance, whereas specific (multidirectional) RSA seems to be related to other factors. [ABSTRACT FROM AUTHOR]

The aims of this study were to determine the feasibility of the injury prevention program (IPP), to examine the reliability of perceptual response to an IPP and to analyze the acute effects of both external and internal demands of in-court training sessions in the IPP. Twelve young basketball players participated in a national team (NT) training camp (120 total individual samples). While players only completed five exclusive in-court training sessions, the IPP was always performed before such in-court practices in the rest of the sessions. The rating of perceived exertion (RPE) was determined at the completion of each IPP. Training load (TL) measures during in-court practices were collected using indoor tracking system, and individual heart rate monitors. Independent t -tests and analysis of variance were used to compare between-sessions TL measures and to test the main effect of RPE in TL. The mean RPE of all IPP sessions was 14.7 ± 0.86. Moreover, there was moderate reliability (ICC = 0.69) between IPP sessions for the RPE and an acceptable coefficient of variation (CV = 4.45%). Furthermore, after IPP, subjects significantly covered more distance per minute (total, ≤ 6 km/h and 6.1–12 km/h) and performed a higher number of body impacts per minute (total, very light and moderate do heavy). Also, the main effect of RPE during IPP sessions was significantly observed in distance covered per minute (total and 12.1–18 km/h) during in-court training sessions. This IPP could serve as a feasible and reliable strategy to implement during NT preparation. [ABSTRACT FROM AUTHOR]

This study aimed to analyse the relationship between the maturational state and contextual factors with future basketball career success in Under-16 (U16) Portuguese youth preparing for the U16 European Basketball Championships. Eighty-five Under-15 (U15) and U16 male basketball players (height: 189.7 ± 6.53 cm; body mass: 81.1 ± 9.96 kg; the age of peak height velocity: 13.3 ± 0.7 y) were selected by the Portuguese national coaching staff to participate in a national team training camp in 2016, 2017, and 2018 years. A binary logistic regression was employed to identify the influence of maturation, born quartile, demographic, geographic and economic characteristics, and sport career (i.e., drop out during first season and chance of playing professionally). Early maturing players were typically classified as inside players. Training experience and predicted adult height, and type of first club were able to predict players who dropped out during their first season at senior level (both p < 0.01). No variables were able to predict who played in a professional league during their first season at senior level. Practitioners should use these data to consider how national level basketball players are identified and developed, but also keep in mind of their specific contextual factors. [ABSTRACT FROM AUTHOR]

Purpose: To examine the effects of an 8-week combined strength and power training intervention on physical performance and interlimb asymmetries in adolescent female soccer players. Methods: Thirty-seven adolescent female soccer players (age 16.1 [1.1] y) were randomly assigned to a control group (n = 18) or experimental group (n = 19). The experimental group performed combined strength and power training twice a week, which consisted of strength and power exercises that trained the major muscles of the lower body and trunk musculature. Preintervention and postintervention tests included unilateral and bilateral horizontal and countermovement jump tests, a 40-m sprint test (10- and 30-m split times), a 10-m sprint with a 180° change-of-direction (COD) test, and a multiple-COD test (V-cut test). Asymmetries were also analyzed in the unilateral tests. Results: Significant group-by-time interaction of the improvement between pretest and posttest was observed for speed (effect size [ES]: −1.30 to −1.16) and COD tests (ES: −0.62 to −0.61) but not in jumping (ES: −0.09 to 0.28) and interlimb-asymmetry tests (ES: −0.13 to 0.57). Conclusions: The short-term in-season combined strength and power training program induced greater speed and COD performance improvements than soccer training alone in adolescent female soccer players. [ABSTRACT FROM AUTHOR]

The aims of this study were to (1) analyse time and movement variability in a football (soccer) agility task performed with or without ball, both in the following situations a) reacting to the movement of two players with a single exit gate (R1), b) reacting to the movement of one player with two possible exit gates (R2) and c) not reacting to a stimulus; and, (2) analyse the relationship between time and movement variability. Seventeen semi-professional female football players participated in the study. Acceleration was measured using an inertial measurement unit attached to each player through an elastic belt close to the sacrum. Entropy was calculated from the acceleration signal and time was extracted using a magnet-based timing system. Movement variability was reduced whereas time increased when adding the ball and/or the reaction, finding no differences between R1 and R2. A moderate negative correlation was found between time and movement variability (r = −0.56, p < 0.01). Our findings demonstrate that increasing the difficulty and/or the amount of information from the environment, decreased movement variability and increased the time. The measurement of movement variability in addition to time in an agility task can be used to determine the mastery level of players. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effects of performing different unilateral strength training interventions on unilateral and bilateral jumping performance and their related asymmetries in young soccer players. Methods: Forty-five young (U-17) male soccer players were randomly assigned to 3 eccentric overload training programs. The first group executed the same volume with both legs starting with the weaker leg (SVW, n = 15); the second group carried out double volume with the weaker leg and also starting with the weaker leg (DVW, n = 15); and the third group performed the same volume with both legs starting with the stronger leg (SVS, n = 15). Jumping-performance assessment included a single-leg horizontal jump test, a triple single-leg horizontal jump test, a bilateral countermovement jump (CMJ) test, and a unilateral CMJ lest. Asymmetries were also analyzed in the unilateral jumping tests. Results: CMJ was improved (effect size [ES]: 0.27-0.48) and CMJ asymmetry was possibly reduced (ES: 0.08-0.24) in all groups. Substantial improvements were found in triple hop (ES: 0.52-0.71) in SVW and DVW, and triple-hop asymmetry was substantially decreased (ES: 0.88) in DVW. Belween-groups analysis showed a substantially better performance in triple hop and horizontal hop with right leg in SVW and DVW compared with SVS. Conclusions: Unilateral strength training programs were shown to substantially improve bilateral jumping performance, while unilateral jumping was substantially enhanced in the groups that started the training session with the weaker leg. Finally, between-limbs asymmetries in the triple hop were mainly reduced through performing double volume with the weaker leg. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effects of resisted change-of-direction (COD) movements, using several relative loads, on soccer players' physical performance. Methods: Fifty-four male soccer players were randomly assigned to 1 of the following 3 groups, which differed only in the magnitude of the external load used during the COD training: COD training without external load (COD-0; n = 16), COD training with a 12.5% body-mass external load (COD-12.5; n = 19), and COD training with a 50% body-mass external load (COD-50; n= 19). Participants performed the specific COD training twice per week for 6 wk. Before and after the training period, a battery of tests was completed: countermovement jump, 30-m running sprint (time in 10 m [T10], 20 m [T20] and 30 m [T30]), L-run test, and V-cut test. Results: Within-group comparisons showed substantial improvements in countermovement jump and T10 (likely) in COD-0, whereas countermovement jump, T10, and T20 were substantially enhanced (possibly to likely) in COD-50. COD-12.5 induced substantial improvements in all analyzed variables (likely to most likely). Between-groups comparisons showed better effects on all analyzed variables for COD-12.5 than for COD-O (possibly to very likely), whereas COD-50 only showed possibly better effects than COD-O on T10. In addition, COD-12.5 induced a better effect on L-run and V-cut tests than COD-50 (possibly to likely). Conclusions: These results indicate that COD training, especially moderate load (12.5% body mass) resisted COD training, may have a positive effect on COD skills, running sprint performance, and jumping ability in young soccer players. [ABSTRACT FROM AUTHOR]

Purpose: To determine the discriminators as variables to select the under-16 national-team players and to examine the influence of biological age on physical/technical parameters among young basketball players. Methods: Thirty-four under-15 male basketball players performed several anthropometrical (height, wingspan, body mass, and fingers length) and physical (jumping, sprinting, throwing, flexibility, change-of-direction speed, and aerobic fitness) tests during the under-15 male national-team training camp. Maturity offset, lower-limb asymmetry index, and power outputs for jumping and sprinting were also computed. In addition, game performance was taken into consideration using game-related statistics (assists, turnovers, steals, rebounds, blocks, and points) of 5 games of during the previous regional tournament (April 2016). Cluster analysis was used to analyze the between-maturation status (prepubertal, pubertal, and postpubertal) differences in physical parameters. Results: The postpubertals showed a significantly better performance in power outputs (jumping and sprinting), throwing abilities, and blocks, whereas prepubertal perlormed significantly better in aerobic fitness and assists. Receiver-operating-characteristic curve confirmed maturational status (area under the curve [AUC] = 0.804; P < .05) and training experience (AUC = 0.789; P < .05) as the most important attributes in predicting under-16 national-team selection. Players with more than 5.5 years of training experience and less than 1.4 y to the age at peak height velocity were most likely to be selected. Conclusion: Maturational status seems to be a key variable that increases the probability of selection for the Portuguese under-16 national team. [ABSTRACT FROM AUTHOR]