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The aim of this study was to determine the effect of acute caffeine supplementation on anaerobic performance in professional female basketball players. A double-blind, placebo-controlled, experimental design was used in a randomized counterbalanced manner. In separate sessions, 10 professional basketball players ingested caffeine (3 mg/kg body mass) or a placebo (dextrose: 3 mg/kg body mass) 60 min before completing countermovement jumps (CMJ) with and without arm swing, a squat jump (SJ), the Lane Agility Drill, 20-m sprints (with 5-m and 10-m split times recorded) with and without dribbling a ball, and a suicide run. Participants provided ratings of perceived exertion (RPE) and ratings of perceived performance 30 min following testing. Data analyses included the use of effect size (ES) and significance. Caffeine supplementation produced small nonsignificant (p > 0.05) increases in CMJ without arm swing (ES = 0.30), CMJ with arm swing (ES = 0.29), SJ (ES = 0.33), and the lane agility drill (ES = –0.27). Caffeine supplementation produced small to moderate significant improvements in 10-m (ES = –0.63; p = 0.05) and 20-m (ES = –0.41; p = 0.04) sprint times without dribbling. Caffeine supplementation promoted a moderate significant reduction in RPE during the test battery (ES = –1.18; p = 0.04) and a small nonsignificant improvement in perceived performance (ES = 0.23; p = 0.53). Acute caffeine supplementation may produce small to moderate improvements in key performance attributes required for basketball while reducing RPE.

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Stojanović, E, Aksović, N, Stojiljković, N, Stanković, R, Scanlan, AT, and Milanović, Z. Reliability, usefulness, and factorial validity of change-of-direction speed tests in adolescent basketball players. J Strength Cond Res XX(X): 000-000, 2018-The purposes of this study were to (1) determine the reliability, usefulness, and factorial validity of change-of-direction speed (CODS) tests in adolescent basketball players and (2) evaluate positional differences in test performances. Elite, adolescent male basketball players (n = 53; 17.3 ± 1.0 years) completed 6 CODS tests: "Lane Arrow Closeout," "Lane Agility Drill," "Reactive Shuttle Test," "Run-Shuffle-Run," "Compass Drill," and "Modified 505 Test." Players completed 3 trials of each test. All tests demonstrated acceptable reliability (intraclass correlation coefficient: 0.50-0.88; coefficient of variation: 5.1-7.9%). The typical error (TE) calculated for each test was above the smallest worthwhile change, rating the usefulness of all tests as marginal. The principal component factor analysis in all tests resulted in the extraction of one significant component that explained 74% of the total variance across tests. Positional comparisons showed that backcourt (guards) players performed better (small to moderate differences) in all CODS tests compared with frontcourt (forwards and centers) players. All tests were deemed reliable and valid in adolescent basketball players. The "Lane Agility Drill" and "Run-Shuffle-Run" tests seem the most appropriate to quantify changes in CODS possessing the lowest TE, whereas the "Lane Arrow Closeout" and "Lane Agility Drill" tests are the most sensitive in detecting positional differences.

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A method for optimization of Fixed Polarity ReedMuller expressions (FPRM) using the dual polarity property has been presented in [7]. In [2], this method has been extended to optimization of Kronecker expressions by introducing the notion of extended dual polarity property. In this paper, we propose a generalization of this method to optimization of Fixed polarity Galois field (GF) expressions for quaternary functions. The proposed method exploits a simple relationship between fixed polarity GF expressions for dual polarities.

This study compared the effects of acute caffeine supplementation (3 mg/kg) administered in the morning and evening on performance-related variables in basketball players. Eleven, nationallevel, adolescent male basketball players underwent field-based fitness testing on four occasions: morning (10:00) with caffeine ingestion (AM CAFF ), morning (10:00) with placebo ingestion (AM PLAC ), evening (21:00) with caffeine ingestion (PM CAFF ), and evening (21:00) with placebo ingestion (PM PLAC ). Fitness testing included of a countermovement jump without arm swing (CMJ), CMJ with arm swing (CMJAS), squat jump (SJ), Lane Agility Drill (LAD), 20-m linear sprint, and Suicide Run with (SRD) and without dribbling (SR). Data were analysed using twoway repeated measures analyses of variance and paired t-tests, with effect sizes (ES) also determined for all pairwise comparisons. Follow-up t-test comparisons revealed that AM CAFF produced small-moderate, significant (p<0.001), improvements in CMJ (ES = 0.51), CMJAS (ES = 0.40), SJ (ES = 0.51), and SR (ES = −0.45) compared to AM PLAC. AM CAFF also produced a moderate, significantly (p<0.001) faster LAD (ES = −0.61) compared to PM CAFF . PM PLAC demonstrated smallmoderate, significant (p<0.05) improvements in CMJ (ES = 0.43), CMJAS (ES = 0.48), and 20-m sprint (ES = −0.63) compared to AM PLAC . In contrast, AM PLAC resulted in large, significantly (p<0.001), faster SRD (ES = −1.46) and SR (ES = −1.59) compared to PM PLAC . Given the ergogenic effects of caffeine during basketball-specific fitness tests appear to be influenced by time of ingestion, basketball practitioners should consider administering caffeine only to players in the morning to improve vertical jump, sprinting, and change-of-direction performance, with no beneficial effects observed with caffeine ingestion in the evening. Highlights:. The effect of caffeine supplementation on basketball-specific performance related variables were mediated by ingestion time in elite, adolescent basketball players. . AMCAFF produced small-moderate improvements in vertical jump, change-of-direction, 20-m linear sprint, and repeated-sprint performance compared to AMPLAC while PMCAFF produced trivial differences in each performance-related variable compared to PMPLAC. . Comparisons between ingestion times in the placebo condition revealed vertical jump height and 20-m sprint speed were impaired in the morning compared to the evening, but these time-dependent differences were eliminated when caffeine was consumed in the morning. . Basketball practitioners should consider administering caffeine only to players in the morning to improve vertical jump, sprinting, and change-of-direction performance, with no beneficial effects observed with caffeine ingestion in the evening.

The purpose of this study was to determine the changes in physical performance after a 6-week skill-based conditioning training program in male competitive volleyball players. Sixteen male volleyball players (mean ± SD: age 22.3 ± 3.7 years, body height 190.7 ± 4.2 cm, and body mass 78.4 ± 4.5 kg) participated in this study. The players were tested for sprinting (5- and 10-m sprint), agility, and jumping performance (the vertical-jump test, the spike-jump test, and the standing broad jump [SBJ]). Compared with pretraining, there was a significant improvement in the 5- and 10-m speed. There were no significant differences between pretraining and posttraining for lower-body muscular power (vertical-jump height, spike-jump height, and SBJ) and agility. Based on our results, it could be concluded that a preseason skill-based conditioning program does not offer a sufficient stimulus for volleyball players. Therefore, a general conditioning and hypertrophy training along with specific volleyball conditioning is necessary in the preseason period for the development of the lower-body strength, agility and speed performance in volleyball players.