On block bootstrapping areal data

Inference for random processes depends on the estimation of the long-run variance of a statistic. Commonly used approaches in time series analysis for estimating the long-run variance include bootstrap approaches and the class of heteroskedasticity and autocorrelation consistent covariance estimators. These approaches have been generalized to deal with point processes and continuou

Small Sided Games in Young Soccer Players

The purpose of this study was to compare the percentage of maximum heart rate (%HRmax), blood lactate (La-), and rating of perceived exertion (RPE, CR-10) responses across different formats of small-sided games (SSG) in elite young soccer players. Fourteen players (average age 16.7 +/- 0.6 years; height 177.6 +/- 4.1 cm; body mass 66.3 +/- 4.7 kg; average training age 6.7 +/- 1.6 years; percentage of body fat 8.4 +/- 2.6%) volunteered to perform the YoYo intermittent recovery test (level 1) and eight bouts of soccer drills including 2-a-side, 3-a-side, and 4-a-side games without goalkeepers in random order at two-day intervals. Heart rates were monitored throughout the SSGs, whereas the RPE and venous blood lactate were determined at the end of the last bout of each SSG. The differences in La-, %HRmax, and RPE either across the different SSGs or between the bouts were identified using 3 x 8 (games x exercise bouts) two-way analysis of variance with repeated measures. Significant differences were found in terms of La-, RPE, and %HRmax among the different types of SSG (p 0.05). 3-a-side and 4-a-side games elicited significantly higher responses than 2-a-side games in terms of %HRmax (p 0.05), whereas 4-a-side games resulted in significantly lower La- and RPE responses compared to 2-a-side and 3-a-side games. The results of this study show that physiological responses differ according to the numbers of players involved in small-sided games. Therefore, it can be concluded that 3-a-side and 4-a-side games could be more effective in improving high intensity aerobic performance than 2-a-side games, which in turn are more appropriate for developing anaerobic performance

in taekwondo practitioners

BACKGROUND: The purpose of this study was to compare the acute effects of different stretching types on sprint performance in taekwondo practitioners

EVIDENCE OF THE RELATIVE AGE EFFECT IN YOUTH SOCCER PLAYERS FROM TURKEY

The main purpose of this study was to ascertain whether the relative age effect (RAE) exists in development teams of soccer clubs across different professional leagues in Turkey. The players were allocated to one of six age subgroups (U14, U15, U16, U17, U19, U21) and league level was also considered as a factor; data on 8600 players in 408 professional teams were analyzed. Birth data and registration dates were collected by accessing the Turkish Football Federation's official website. The results showed that the RAE is strong and significant for each lower league and per age category (p0.05). An independent samples t-test on U21 soccer players' TE means also yielded no significant difference (p>0.05). In conclusion, amongst soccer players in development teams of professional clubs in Turkey, players born in the later months of the year are less likely to be selected than those born in the earlier months. It is also concluded that there is no association between TE and a player's league level

COMPARISON OF THE PHYSIOLOGICAL RESPONSES AND TIME-MOTION

Koklu, Y, Sert, O, Alemdaroglu, U, and Arslan, Y. Comparison of the physiological responses and time-motion characteristics of young soccer players in small-sided games: The effect of goalkeeper. J Strength Cond Res 29(4): 964-971, 2015-The purpose of this study was to investigate the effect of "with goalkeeper" (SSG(with)) and "without goalkeeper" (SSG(without)) conditions on players' physiological responses and timemotion characteristics in small-sided games. Sixteen young soccer players (age: 16.5 +/- 1.5 years; height: 175.5 +/- 5.2 cm; body mass: 63.0 +/- 6.9 kg; training experience: 6.3 +/- 1.3 years) participated in 2 different 2-a-side, 3-a-side, and 4-a-side games: SSG(with) and SSG(without). The players underwent anthropometric measurements (height and body mass) followed by the Yo-Yo intermittent recovery test (level 1). Then they played 2-a-side, 3-a-side, and 4-a-side SSG(with) and SSG(without) soccer-specific SSGs in random order at 2-day intervals. Heart rate (HR) responses and distance covered in different speed zones (walking [WLK, 0-6.9 km.h(-1)], low-intensity running [LIR, 7.0-12.9 km.h(-1)], moderate-intensity running [MIR, 13.0-17.9 km.h(-1)], and high-intensity running [HIR, >18 km.h(-1)]) were measured during the SSGs, whereas the rating of perceived exertion (RPE) and blood lactate (La2) were determined at the end of the last bout of each SSG. During the SSG(without) players showed higher % HR, La-, and RPE (p <= 0.05), greater distance covered in LIR, MIR, HIR, and total distance (p <= 0.05) compared with the SSG(with) during the 2-a-side, 3-a-side, and 4-a-side games. The results of this study suggest that both SSG(with) and SSG(without) could be used for the physiological adaptations required for soccerspecific aerobic endurance. However, if coaches want both higher physiological responses and greater distance covered in the intensity running zone from their teams, SSG(without) should be organized. In addition, this study also suggests that smaller format games (i.e., 2-a-side) may promote some anaerobic adaptations for youth soccer players

comparative study

OBJECTIVE: To compare the order effect of a combination of plyometric and resistance training sessions on isokinetic leg strength and vertical jump performance in undergraduate students over the course of a 6-week training program

Soccer Players

The purpose of this study was to compare the incremental running tests performed by young soccer players on a treadmill (Tr) and in the field (FTcod: 100 m change of direction and FTcir: 100 m circle). Nineteen players (average age 17.4 +/- 1.1 years; body height 172.0 +/- 5.7 cm; body mass 68.9 +/- 6.7 kg) volunteered to perform incremental Tr , FTcod and FTcir running tests. In all three tests, players ran for 3 min at 8, 10, 12 and 14 km.h(-1) and were given a 1 min rest interval between subsequent stages. Blood lactate concentrations (La-) were measured at 1 min rest intervals and the heart rate (HR) responses of players were recorded during the tests. After a 5 min recovery period, the second part of the test started; players ran at 15 km.h(-1) with velocity increments of 1 km.h(-1) every 1 min until exhaustion. This part was performed to determine maximum HR, maximum La- and the players' final velocities. The results showed that players had significantly lower La- (F = 6.93, p = 0.07, eta(2) = 0.46, 95%CI(TR-FTcir) -1.91/-0.34, 95%CI(TR-FTcod)= -1.59/-0.05) and HR (F = 9.08, p = 0.02, eta(2) = 0.53, 95%CI(TR-FTcir) = -6.98/-1.68, 95%CI(TR-FTcod)= -7.19/1.08) responses in the Tr test than in the FTcir and FTcod tests at 14 km.h(-1). It was also found that players completed the Tr test (F = 58.22, p = 0.00, eta(2) = 0.87) at higher final running velocities than the FTcir (95%CI(TR-FTcir) = 1.67/2.78) and FTcod (95%CI(TR-FTcod)= 1.69/2.85) tests. In conclusion, when coaches or sports scientists plan to train at higher running velocities or according to the final velocity in the test, it is advisable to carry out testing in the circumstances under which training will be carried out (in the field or on a treadmill).C1 [Koklu, Yusuf; Alemdaroglu, Utku; Demirhan, Ramazan; Arslan, Yunus] Pamukkale Univ, Fac Sport Sci, KINIKLI Kampusu, Denizli, Turkey

activities

Aim. The aim of this study was to investigate the effects of the length of recovery durations between bouts in 4x4min 3-a-side small-sided games (SSG) on time-motion analysis, technical actions and physiological responses of players.Methods. Twelve young soccer players participated in 4 different 3-a-side games in which the recovery durations between bouts were different (R1: 1 min, R2: 2 min, R3: 3 min, and R4: 4 min). Heart rate (HR), total distance covered in different speed zones, and technical performance were monitored during all SSGs, whereas the rating of perceived exertion (RPE, CR-10) and venous blood lactate were determined at the end of the last bout of each SSG.Results. Results showed that SSGs-R1 induced higher %HR-reserve and lower successful passes (vs. R3 and R4 conditions, P18 km.h(-1)), performed more tackles (vs. R1 condition, P<0.05) and had more ball contacts (vs. R1 and R2 conditions, P<0.05).Conclusion. According to these results, it is thought that R1 and R2 are suitable for inducing higher physiological responses, while R3 and R4 are more appropriate for training aim to improve technical skills in 4x4min 3-a-side SSGs among young soccer players. These findings provide evidence for coaches to justify the selection of recovery duration between bouts in 3-a-side SSGs among young soccer players

for measuring movement demands of team sports

Aim. The aim of this study was to determine the accuracy and reliability of SPI ProX global positioning system (GPS) devices for measuring movement at various speeds and movement patterns as evident in team sport demands.Methods. Eleven amateur soccer players performed a 40 m straight sprint test (with 10-20-30 m split times), a zigzag test, 30 m walking, jogging and moderate intensity runs.Results. Results indicated that the SPI ProX GPS measurements showed acceptable accuracy for all movement patterns for distance (Coefficient Of variation [CV]=0.14 % to 3.73%; 95% ratio limits of agreement [95% ratio LOA]=0.97 x / divided by 1.09 to 1.00 x / divided by 1.05) and speed (CV=4.22% to 9.52%; 95 %LOA=-0.17 +/- 1.70 km h(-1) to 2.30 +/- 1.17 km h(-1)) compared with the measured distance and speed determined from timing gates, respectively. Furthermore, acceptable reliability of SPI ProX GPS measures for distance (CV=0.34 % to 3.81%; 95 %LOA=-0.09 +/- 0.23 m to -0.34-12.31 m) and speed (CV=3.19% to 6.95%; 95 %LOA=-0.05 +/- 3.90 km h(-1) to 0.42 +/- 3.68 km h(-1)) were also evident.Conclusion. Whilst SPI ProX GPS devices were within acceptable ranges of reliability, they remained significantly different to criterion measures of team sport movement demands