20-m Sprint Test Research Articles

Effects of Different Intensities of Weighted Vest Warming up Session on Physical Performances of Power Sports Athletes

Optimum physical performance is vital component for athletes to excellent in their sports. Weighted vest warming up is one of the ways to manipulate intensities of warming. The purpose of this was to investigate the effect of different intensities weighted vest warming up session on physical performances. Twenty participants from power sports athletes was did all weighted vest warming up protocol (a) wore weighted vest 6% of body mass,(W6),(b) wore weighted vest 12% of body mass (W12) (c) with body weight only or 0% of additional weight in intensities of warming up session (W0). All participants undergo cross over design and evaluated using vertical jump test, standing broad jump test, seated medicine ball toss test and 20m sprint test after finish each warming up sessions. 1-way, repeated-measures analysis of variance on the test result showed significant different of the effect different intensities of weighted vest warming up session on all physical performances test. In conclusion, usage of 6% and 12 % from body weight of additional weight on weighted vest warming up session can promote to improving physical performances.

The effects of maturation on jumping ability and sprint adaptations to plyometric training in youth soccer players

ABSTRACTThe aim of this study was to investigate the effects of maturation on power and sprint performance adaptations following 6 weeks of plyometric training in youth soccer players during pre-season. Sixty male soccer players were categorized into 3 maturity groups (Pre, Mid and Post peak height velocity [PHV]) and then randomly assigned to plyometric group and control group. Vertical jump, standing long jump, and 20-m sprint (with and without ball) tests were collected before- and after-intervention. After the intervention, the Pre, Mid and Post-PHV groups showed significant (P ≤ 0.05) and small to moderate effect size (ES) improvement in vertical jump (ES = 0.48; 0.57; 0.73), peak power output (E = 0.60; 0.64; 0.76), standing long jump (ES = 0.62; 0.65; 0.7), 20-m sprint (ES = −0.58; −0.66), and 20-m sprint with ball (ES = −0.44; −0.8; −0.55) performances. The Post-PHV soccer players indicated greater gains than Pre-PHV in vertical jump and sprint performance after training (P ≤ 0.05). Short-term plyometric training had positive effects on sprinting and jumping-power which are important determinants of match-winning actions in soccer. These results indicate that a sixty foot contact, twice per week program, seems effective in improving power and sprint performance in youth soccer players.

Effects of Core Strength Training Using Stable Versus Unstable Surfaces on Lower Body Quality in 8th Grade Male and Female Students in a Junior High School in Bandung

Objective: To investigate the effects of core strength training performed on stable (CSTS) compared to unstable surfaces (CSTU) on physical fitness in school-aged boys and girls. Methods: In this study, 72 (36 males, 36 females) untrained healthy subjects (mean age: 14±1 years, age range: 13–15 years) were randomly assigned to a CSTS group for stable surface (n = 36; 18 males and 18 females) or a CSTU group for unstable surface (n = 36; 18 males and 18 females). Core strength training performed on stable as compared to unstable surfaces were assessed on pre- and post-tests. Training period lasted 6 weeks (2 sessions/week). The components of physical fitness were assessed using standing long jump test, stand-and-reach test, 20-m sprint test, jumping sideway test, and y balance test. Results: This study showed significant results in increased components of physical fitness in both CSTS and CSTU groups (p 0.05). Conclusion: Core strength training performed on unstable and stable surfaces increases all components of physical fitness in youths. Core strength training performed on unstable surface can better improve the physical fitness compared to the stable surface. There were differences of physical fitness between gender in both groups except for stand-and-reach test. Keywords: Resistance training, physical fitness, gender DOI: 10.15850/ijihs.v6n1.1050

Physical Fitness Evaluation of School Children in Southern Italy: A Cross Sectional Evaluation

The aim of this work was to evaluate the fitness levels of different physical components in schoolchildren in southern Italy and identify age-related effects of physical performance. One hundred and fifty-four schoolchildren with ages ranging between 6 and 10 years (age 8.1 ± 1.45 years; 33.70 ± 10.25 kg; 131.50 ± 13.60 cm) were recruited for the investigation. Each scholar underwent a fitness-test battery composed of five elements. A Hand-Grip Strength Test to assess the strength of the hand muscles, a Standing Broad Jump Test to assess lower body explosive strength, a Sit-Up Test to exhaustion to evaluate abdominal muscular endurance, a 4 × 10-m Shuttle Run Test to assess agility, and a 20-m sprint test to assess speed. Cross-sectional analysis revealed that boys perform better than girls and that age affects performance. Lower limb measures show a significant increase after 8 years of age, whereas upper limb measures show a significant increase at 7 and 10 years of age. No age-related differences were found in muscular endurance measures. It is possible to consider age-related performance measures to program exercise interventions that follow the growth characteristics of schoolchildren.

THE EFFECT OF SIX WEEKS SPRINT TRAINING ON SERUM ANTIOXIDANT LEVELS IN SOCCER PLAYERS

The aim of this study was to determine the effect of six week sprint training applied to soccer players on antioxidant levels. Eighteen football players participated voluntarily and six-weekly sprint training was applied. Soccer players were given a 20-m sprint test to determine antioxidant levels before training, and blood samples were taken before and after the test and this were repeated after six weeks. The effects of the training to the antioxidant systems were searched by the estimated the levels of SOD, CAT and MDA on the taken blood samples before and after the sprint training. The statistically significant results were obtained for serum CAT (2,89±0,85 and 8,42±0,81 U/ml) and MDA (16,39±2,66 and 29,10±2,62 mmol/L) (p<0,05) values before and after the sprint test of the athletes at the end of the 6-week sprint training, but there was no statistically significant result despite the difference in SOD (1,74±0,13and 2,49±0,13 U/ml) value. On the other hand statistically significant results were found in serum SOD (1.67±0.36 and 0,88±0,20 U/ml) and CAT (0.15±0.01and 5,25±0,47 U/ml) (p<0,05) values before and after sprint test of athletes, but there was no statistically significant result even though there was a difference in MDA (4.83±0.99 and 3,68±0,77 mmol/L) value. Consequently, making training can cause development on antioxidant defense, and it can affect the antioxidant production. Article visualizations:

Physical Condition Differences between Semi-Professional and Amateur Soccer Players

The purpose of the study was to examine and compare the physical fitness of Greek soccer players participating in teams of different divisions before the beginning of the preparation period. Eighteen semi-professional soccer players and nineteen amateur soccer players participated. All the tests performed on field (30m sprint, Illinois agility test, counter movement jump, squat jump, YoYo IR test and sit and reach test). The measurements performed before the beginning of the preparation period. Semi-professionals presented significantly faster values in 30m sprint and agility test compared to amateur by 7.6% and 8.2% respectively (p<0.001 for both). Semi-professionals jump higher in SJ and CMJ compared to amateurs by 27% and 16.4% respectively (p<0.001 and p<0.05). Amateurs had 20.6% worst performance at sit and reach test (p<0.01). Also, the VO2max for amateurs were 26.5% lower than semi-professionals (p<0.001). Semi-professionals performed better on all physical condition tests. These findings can be attributed to more specific training of semiprofessionals. Amateur soccer players and their trainers give less attention to physical condition and use their time to play and for technical and tactical exercises.

Effects of Plyometric Training on Components of Physical Fitness in Prepuberal Male Soccer Athletes: The Role of Surface Instability.

Negra, Y, Chaabene, H, Sammoud, S, Bouguezzi, R, Mkaouer, B, Hachana, Y, and Granacher, U. Effects of plyometric training on components of physical fitness in prepuberal male soccer athletes: the role of surface instability. J Strength Cond Res 31(12): 3295-3304, 2017-Previous studies contrasted the effects of plyometric training (PT) conducted on stable vs. unstable surfaces on components of physical fitness in child and adolescent soccer players. Depending on the training modality (stable vs. unstable), specific performance improvements were found for jump (stable PT) and balance performances (unstable PT). In an attempt to combine the effects of both training modalities, this study examined the effects of PT on stable surfaces compared with combined PT on stable and unstable surfaces on components of physical fitness in prepuberal male soccer athletes. Thirty-three boys were randomly assigned to either a PT on stable surfaces (PTS; n = 17; age = 12.1 ± 0.5 years; height = 151.6 ± 5.7 cm; body mass = 39.2 ± 6.5 kg; and maturity offset = -2.3 ± 0.5 years) or a combined PT on stable and unstable surfaces (PTC; n = 16; age = 12.2 ± 0.6 years; height = 154.6 ± 8.1 cm; body mass = 38.7 ± 5.0 kg; and maturity offset = -2.2 ± 0.6 years). Both intervention groups conducted 4 soccer-specific training sessions per week combined with either 2 PTS or PTC sessions. Before and after 8 weeks of training, proxies of muscle power (e.g., countermovement jump [CMJ], standing long jump [SLJ]), muscle strength (e.g., reactive strength index [RSI]), speed (e.g., 20-m sprint test), agility (e.g., modified Illinois change of direction test [MICODT]), static balance (e.g., stable stork balance test [SSBT]), and dynamic balance (unstable stork balance test [USBT]) were tested. An analysis of covariance model was used to test between-group differences (PTS vs. PTC) at posttest using baseline outcomes as covariates. No significant between-group differences at posttest were observed for CMJ (p > 0.05, d = 0.41), SLJ (p > 0.05, d = 0.36), RSI (p > 0.05, d = 0.57), 20-m sprint test (p > 0.05, d = 0.06), MICODT (p > 0.05, d = 0.23), and SSBT (p > 0.05, d = 0.20). However, statistically significant between-group differences at posttest were noted for the USBT (p < 0.01, d = 1.49) in favor of the PTC group. For most physical fitness tests (except RSI), significant pre-to-post improvements were observed for both groups (p < 0.01, d = 0.55-3.96). Eight weeks of PTS or PTC resulted in similar performance improvements in components of physical fitness except for dynamic balance. From a performance-enhancing perspective, PTC is recommended for pediatric strength and conditioning coaches because it produced comparable training effects as PTS on proxies of muscle power, muscle strength, speed, agility, static balance, and additional effects on dynamic balance.

A MONITORING STUDY ON CHANGES IN PHYSICAL PARAMETERS TO YOUNG PLAYERS THROUGHOUT 5 MONTHS OF TRAINING IN FOOTBALL TEAMS IN SHKODRA, ALBANIA

The best performance of soccer practitioners is certainly a consequence of regular football training, which also seems to bring acceleration to physical growth (Navarro F, 2000). The aim of this study was to give evidence on changes in physical parameters to young players throughout 5 months of training in football teams in Shkodra. Selection of the sample measurements were made in 2 teams of the city of Shkodra. In these measurements participated 78 boys players in the first and second phase of the measurements for a period of 5 months. The participant undertook anthropometrics parameters evaluation and performed three speed test (10m and 30m sprint test, speed and agility 10x5m). The necessary measurements for testing were: for the maximum capacity of the Vo2max oxygen (Andersen test) and strength tests. The difference between the first and second test (T2- T1) results of 10 m, presents the following values: mean of improvement 0.26 s (standard deviation 0.26 s and average error 0.04 s (p = 0.00)). Meanwhile, the difference between the results of the first and second tests of 30m velocity (improvement) is the following: average 0.18 s (standard deviation 0.37 s and average error 0.06 s (p = 0.00)). The difference between the results of the first and the second aerobic capacity tests is the following: average 26.6 m (standard deviation 126.28 m and average error of 51.55 m (p = 0.63)). The difference between the results of the first and second tests of the lower leg limbs presents the following values: mean -0.06 times (standard deviation 0.20 times and standard error of 0.03 times average (p = 0.05)). The results of the study showed the impact of training load at different stages of the training cycle for linear running speed, changes in speed, strength, and aerobic capacity to new football players in Shkodra. These results can serve as a basis for comparisons with colleagues in similar research studies. We have noticed that the speed performance and the ability to quickly change the direction of the players have improved throughout the observation period. For aerobic capacity, we did not notice a major improvement during the pre-season training period, while at the end of the season, sustainability increased slightly. We conclude that the training process in the youth plays an important role in the development of young players and positively influences the development of individual athletic performance components. Article visualizations:

THE ROLE AND ASSOCIATION OF BODY HEIGHT AND WEIGHT OF THE PERFORMANCE OF MOTOR ABILITIES IN SOCCER PLAYERS

The youth ability to perform high-speed running actions such as sprints to win possession of the ball or to pass defending players is believed to be critical to the outcome of soccer matches (Bradley et al., 2009). As such, sprint ability has been reported to be a physical prerequisite for professional soccer players (Cometti et al., 2001; Gissiset al., 2006). The goal of this study was to evaluate the role and association of body weight and height in the performance of motor abilities in youth soccer players. Methods: The subjects of this study were 64 youth soccer players with an average weight 47.5 kg (+/- 7.3 kg) and height 157.3 cm (+/- 7.4cm). Anthropometrics were measured as body height and weight in youth. The subject underwent to perform a speed test (10m and 30m sprint test, 10x5m speed agility test) and standing long jump to evaluate explosive power to lower limbs. Analysis of correlation was performed to find out if there was the association. Result: The results show that; body weight were correlated with motor abilities as follows; body weight with 10m sprint test (r= -0.054; sig= 0.671), body weight with 30m sprint test (r= -0.049; sig= 0.724), body weight with 10x5m agility test (r= -0.025; sig= 0.871), body weight with standing long jump test (r= 0.193; sig= 0.163). While body height were correlated with motor abilities as follows; body height with 10m sprint test (r= -0.051; sig= 0.6), body height with 30m sprint test (r= -0.054; sig= 0.671), body height with 10x5m agility test (r= -0.018; sig= 0.909), body height with standing long jump test (r= 0.215; sig= 0.119). Conclusion: There was a negative but no significant correlation between body weight and body height with motor abilities with regard to speed and agility. There was no significant correlation between body weight and height with explosive power of lower limbs. This results even though found no significance correlation but negative correlation, suggest that coaches should be careful with anthropometrics variables of their players in designing athletic program with regard to speed and agility. Article visualizations:

The Influence of Physical Qualities on Activity Profiles of Female Australian Football Match Play.

The transition of female Australian football (AF) players from amateur to semielite competitions has the potential for athletes to be underprepared for match play. To gain an understanding of the match demands of female football, the aims of this study were to highlight the physical qualities that discriminate selected and nonselected female AF players, investigate activity profiles of female AF players, and gain an understanding of the influence of physical qualities on performance in female AF Methods: Twenty-two female AF state academy players (mean [SD]: age = 23.2 [4.5] y) and 27 nonselected players (mean [SD]: age = 23.4 [4.9] y) completed a Yo-Yo intermittent recovery test level 1, countermovement jump, and 30-m sprint tests were completed prior to the competitive season. During 14 matches, players wore global positioning system units to describe the running demands of match play. Selected players were faster over 30m (ES = 0.57; P = .04) and covered greater distances on the Yo-Yo IR1 (ES = 1.09; P < .001). Selected midfielders spent greater time on the field and covered greater total distances (ES = 0.73-0.85; P < .01). Players faster over 5m (r = -.612) and 30m (r = -.807) and who performed better on the Yo-Yo IR1 (r = .489) covered greater high-speed distances during match play. An emphasis should be placed on the development of physical fitness in this playing group to ensure optimal preparation for the national competition.

Repeated-Sprint Sequences During Female Soccer Matches Using Fixed and Individual Speed Thresholds

Nakamura, FY, Pereira, LA, Loturco, I, Rosseti, M, Moura, FA, and Bradley, PS. Repeated-sprint sequences during female soccer matches using fixed and individual speed thresholds. J Strength Cond Res 31(7): 1802-1810, 2017-The main objective of this study was to characterize the occurrence of single sprint and repeated-sprint sequences (RSS) during elite female soccer matches, using fixed (20 km·h) and individually based speed thresholds (>90% of the mean speed from a 20-m sprint test). Eleven elite female soccer players from the same team participated in the study. All players performed a 20-m linear sprint test, and were assessed in up to 10 official matches using Global Positioning System technology. Magnitude-based inferences were used to test for meaningful differences. Results revealed that irrespective of adopting fixed or individual speed thresholds, female players produced only a few RSS during matches (2.3 ± 2.4 sequences using the fixed threshold and 3.3 ± 3.0 sequences using the individually based threshold), with most sequences composing of just 2 sprints. Additionally, central defenders performed fewer sprints (10.2 ± 4.1) than other positions (fullbacks: 28.1 ± 5.5; midfielders: 21.9 ± 10.5; forwards: 31.9 ± 11.1; with the differences being likely to almost certainly associated with effect sizes ranging from 1.65 to 2.72), and sprinting ability declined in the second half. The data do not support the notion that RSS occurs frequently during soccer matches in female players, irrespective of using fixed or individual speed thresholds to define sprint occurrence. However, repeated-sprint ability development cannot be ruled out from soccer training programs because of its association with match-related performance.

Maximal Sprinting Speed of Elite Soccer Players During Training and Matches.

The aim of the present study was to compare (a) the maximal sprinting speed (MSS) attained by soccer players during matches (MSSmatch) according to their level of play (professional first French division vs. elite amateur fourth French division) and the playing positions and (b) the MSS attained by professional soccer players during 14 different types of small-sided games (SSG, MSSSSG) and match-play. All players monitored through the study performed a 40-m sprint test to assess individual MSS (MSStest) and compare it to the training and match activity, with the calculation of the percentage of MSStest (%MSStest) reached. No differences were found according to the level of play; however, positional wide players achieved a higher MSSmatch, %MSStest, and MSSSSG than central players (both defenders and midfielders) during matches and SSG. MSSmatch were higher than all MSSSSG, and MSSSSG were positively correlated with the area of the pitch (0.45, p < 0.001), its length (0.53, p < 0.001), and the number of players involved (0.38, p < 0.001). The closer SSG was to match situation in terms of rules, the higher the MSSSSG. Wide players reached higher MSS in match and SSG than central players, confirming the relevance of using SSG close to match situation to specifically prepare elite players to the maximal running speed demand of the match.

Physical Fitness and Body Composition in 8-10-Year-Old Danish Children Are Associated With Sports Club Participation.

Larsen, MN, Nielsen, CM, Ørntoft, CØ, Randers, M, Manniche, V, Hansen, L, Hansen, PR, Bangsbo, J, and Krustrup, P. Physical fitness and body composition in 8–10-year-old Danish children are associated with sports club participation. J Strength Cond Res 31(12): 3425–3434, 2017—We investigated whether physical fitness and body composition in 8–10-year-old Danish children are associated with sports club participation. The study included 423 schoolchildren, comprising 209 girls and 214 boys, of whom 67 and 74%, respectively, were active in sports clubs. Yo-Yo intermittent recovery level 1 for children (YYIR1C), balance, jump and coordination tests, together with dual-energy X-ray absorptiometry, were used to determine exercise capacity and body composition. Children active in sports clubs had better (p < 0.05) YYIR1C (33%, 767 ± 26 vs. 575 ± 29 m), 20-m sprint (3%, 4.33 ± 0.03 vs. 4.48 ± 0.04 seconds), coordination (6%, 68 ± 1 vs. 72 ± 1 second), and balance test performances (9%, 19.3 ± 0.5 vs. 21.2 ± 0.7 falls·min−1) and lower fat mass index (16%, 3.8 ± 0.1 vs. 4.5 ± 0.2 kg[fat]·m−2) than children not active in sports clubs. Ball game players had better (p < 0.05) YYIR1C (38%, 925 ± 39 vs. 671 ± 28 m), 20-m sprint (4%, 4.25 ± 0.03 vs. 4.42 ± 0.04 seconds), and coordination test performances (5%, 65 ± 1 vs. 69 ± 1 second), along with higher (p < 0.05) lean body mass (5%, 24.00 ± 0.22 vs. 22.83 ± 0.25 kg) and whole-body BMD (2%, 0.90 ± < 0.01 vs. 0.88 ± <0.01 g·cm−2) compared with children active in other sports. The study showed that 8‒10-year-old Danish children engaged in sports-club activity, especially ball game players, have better exercise capacity and superior body composition compared with children not active in sports clubs.

Lunar Phases Effects On Short-term, Explosive Physical Performance Among Young Trained Athletes

Beliefs in lunar effect on human physiology and behavior started back in ancient times. Outcomes recently revealed that (i) aggressive behavior increased around full moon (FM), and (ii) a physical fitness index increased in sedentary students at new moon (NM) and FM compared to other moon phases. This has been attributed to the alteration of cardiovascular parameters (i.e., heart rate (HR) and blood pressure (BP) which were affected by the gravitational pull of the moon. However, there was no attention on the effect of lunar cycle (moon illumination and Gravitational pull) on physical performance in athletes. PURPOSE: to evaluate whether short-term explosive performance can be influenced by the different phases of lunar cycle. METHODS: Methods: Fourteen young male taekwondo athletes (Age: 16.9±0.7years, Height: 159.7±50.6 cm, Body Mass: 62.85±7.84 kg, Body Fat: 10.9±4.7) performed: squat jump (SJ), countermovement jump (CMJ), and 10-m sprint tests to assess explosive physical performance during the different phases of the lunar cycle (NM, FQ (First Quarter), FM, and LQ (Last Quarter). The testing sessions at the different moon phases were performed in a counterbalanced order. Tests’ order was kept the same (SJ, CMJ, then 10-m sprint) and all sessions were performed at evening times (6:00 to 8:00 p.m.) on the first day of each concerned lunar phase. Each parameter was measured over two consecutive lunar months in the calendar (April and May 2016). Astronomical data (lunar phases) were acquired from the United States Naval Observatory astronomical applications department data services (http://aa.usno.navy.mil/data/). RESULTS: ANOVA showed that there was no significant lunar cycle effect for all explosive tests measures F(3, 93)=1.834; p>0.05; ηp2=0.124. CONCLUSIONS: Moon phases did not affect evening explosive performances (mainly phosphagens’ pathway based efforts) among young trained athletes. Therefore, it seems that moon phase/illumination do not have an effect on short term physical performance in young trained adolescents. Future studies may evaluate whether High Intensity (predominance of the “glycolytic pathway” in addition to the “phosphagen’s pathway”) and Endurance (predominance of “oxidative phosphorylation”), performances would be affected by lunar cycle in athletes.

Evaulation of Some Physiological and Biomotor Features of Young Tennis Players

Aim: The aim of this study is to determine some physiological and biomotor properties of 9-13 years old tennis players, and detect the effect of gender on performance. Material and Methods: 19 voluntary male tennis players, (average age: 11.21±1.08 year, average height: 1.52±0.11 cm, average weight: 44.76±7.87 kg, average sport background: 3.15±1.11 year ),17 voluntary female tennis players, (average age: 11.05±1.51 year, average height: 1.48±0.08 cm, average weight: 35.84±5.75 kg, sport background: 2.7±0.91 year ) who exercise at a tennis club in Ankara participated in this study. The subjects’ anthropometric measurements were taken. Then, 5 m sprint test, 10 m sprint test, flexibility test, push up test, sit up test, long jump test, medicine ball throw test, stability test were performed on the mentioned subjects. After calculating the descriptive statistics of the voluntaries, the data collected from performance tests were evaluated with Levene test and it showed normal distribution. T test was used to identify which groups had significant differences. Results: In the applied test, it has been observed that except the 10-m sprint test; there were not any significant (p<0.05) differences. Conclusion: we could state that there is no difference between gender and all parameters of 9-13 years old tennis players and the similar training models can be applied to the players regardless of their gender.

The influence of genetic polymorphisms on performance and cardiac and hemodynamic parameters among Brazilian soccer players.

This study investigated whether ACTN3 R577X, AMPD1 C34T, I/D ACE, and M235T AGT polymorphisms can affect performance tests such as jumping, sprinting, and endurance in 220 young male athletes from professional minor league soccer team from São Paulo Futebol Clube, Brazil. I/D ACE and M235T AGT polymorphisms were also analyzed according to cardiac and hemodynamic parameters. Athletes were grouped or not by age. DNA from saliva and Taqman assays were used for genotyping 220 athletes and the results were associated with performance tests. Ventricle mass, ventricle end-diastolic diameter, end-diastolic volume, and ejection fraction were assessed by echocardiogram. Arterial pressure, heart rate, and oximetry were assessed by a cardioscope. The main results of this study were that athletes who carried RR/RX (ACTN3) and DD (ACE) genotypes presented better performance during jump and sprint tests. On the other hand, athletes with ID/II genotype presented better results during endurance test, while AGT genotypes did not seem to favor the athletes during the evaluated physical tests. CC genotype (AMPD1) only favored the athletes during 10-m sprint test. Although there are environmental interactions influencing performance, the present results suggest that RR/RX ACTN3 and ACE DD genotypes may benefit athletes in activities that require strength and speed, while II ACE genotype may benefit athletes in endurance activities. This information could help coaches to plan the training session to improve the athletes' performance.

Associations between Change of Direction, Balance, Speed, and Muscle Power in Prepubescent Soccer Players

Relationships between change of direction (CoD), balance, speed, and power are less extensively studied in youth but provide important information for training. The aim of this study was to determine associations between CoD, balance, speed, and leg power in prepubescent soccer players. Thirty young male soccer players (9.26 ± 0.76 years; Peak-Height-Velocity: -3.42 ± 0.47 years) were assessed for CoD (shuttle run), Y-balance, speed (10-30-m sprint), and muscle power (unilateral, bilateral countermovement jumps [CMJ], unilateral, bilateral standing long jumps [SLJ], and triple hop test). Positive correlations were observed between the shuttle run, and 10-m (r=0.46) and 30-m sprint time (r= 0.47). Negative correlations were found between the shuttle run and SLJ (r=-0.44), bilateral CMJ (r= -0.42), and composite Y-balance (r=−0.49). Linear stepwise regression analysis revealed that 25% of the adjusted variance in the shuttle run test was explained by the Y-balance test (F=9.28; p<0.005). When the 10-m sprint test was added, explained variance amounted to 47% (F=11.87; p<0.001). Medium-sized associations were illustrated between speed, dynamic balance, and CoD in prepubescent soccer players. A greater emphasis on balance and sprint training might be an advantage for youth with less developed neuromuscular capabilities to improve CoD abilities.

Reference values for running sprint field tests in preschool children: A population-based study

The purpose of this study was to determine reference values in the 20m sprint test for Spanish preschool children and to examine the influence of age, sex and anthropometrics characteristics in sprint performance. A cross-sectional study was used. A total of 3076 children, aged 3 to 6 years, participated in this study (1539 girls and 1537 boys). To measure running speed, the 20m sprint test was used. In the analysis of reliability, using test–retest with 89 children (48% boys), the following descriptive results were obtained (mean, SD): at pretest=5.72±0.98s, at retest=5.71±0.87s (p=0.819), and an intraclass correlation coefficient=0.929 (95% confidence interval 0.891–0.954). Boys are faster than girls at 3 to 5 years old, but no significant differences were found at 6 years old. In relation to age, the sprint time was shorter as kids got older. This study provides reference values for running speed assessment through a 20m sprint test carried out on a large sample of Spanish preschoolers.

Effects of High-Velocity Resistance Training on Athletic Performance in Prepuberal Male Soccer Athletes.

Negra, Y, Chaabene, H, Hammami, M, Hachana, Y, and Granacher, U. Effects of high-velocity resistance training on athletic performance in prepuberal male soccer athletes. J Strength Cond Res 30(12): 3290-3297, 2016-The aim of this study was to assess the effectiveness of a 12-week in-season low-to-moderate load high-velocity resistance training (HVRT) in addition to soccer training as compared with soccer training only on proxies of athletic performance in prepubertal soccer players. Twenty-four male soccer players performed 2 different protocols: (a) regular soccer training with 5 sessions per week (n = 11; age = 12.7 ± 0.3 years) and (b) regular soccer training with 3 sessions per week and HVRT with 2 sessions per week (n = 13; age = 12.8 ± 0.2 years). The outcome measures included tests for the assessment of muscle strength (e.g., 1 repetition maximum [1RM] half-squat tests), jump ability (e.g., countermovement jump, squat jump [SJ], standing long jump [SLJ], and multiple 5-bound tests [MB5s]), linear speed (e.g., 5-, 10-, 20-, and 30-m sprint tests), and change of direction (e.g., T-test and Illinois change of direction test). Results revealed significant group × test interactions for the SJ test (p ≤ 0.05, d = 0.59) and the SLJ test (p < 0.01, d = 0.83). Post hoc tests illustrated significant pre-post changes in the HVRT group (SJ: [INCREMENT]22%, p < 0.001, d = 1.26; SLJ: [INCREMENT]15%, p < 0.001, d = 1.30) but not in the control group. In addition, tendencies toward significant interaction effects were found for the 1RM half-squat (p = 0.08, d = 0.54) and the 10-m sprint test (p = 0.06, d = 0.57). Significant pre-post changes were found for both parameters in the HVRT group only (1RM: [INCREMENT]25%, p < 0.001, d = 1.23; 10-m sprint: [INCREMENT]7%, p < 0.0001, d = 1.47). In summary, in-season low-to-moderate load HVRT conducted in combination with regular soccer training is a safe and feasible intervention that has positive effects on maximal strength, vertical and horizontal jump and sprint performance as compared with soccer training only.

Change of Direction Deficit: A More Isolated Measure of Change of Direction Performance Than Total 505 Time

Nimphius, S, Callaghan, SJ, Spiteri, T, and Lockie, RG. Change of direction deficit: A more isolated measure of change of direction performance than total 505 time. J Strength Cond Res 30 (11): 3024-3032, 2016-Most change of direction (COD) tests use total time to evaluate COD performance. This makes it difficult to identify COD ability because the majority of time is a function of linear running. The COD deficit has been proposed as a practical measure to isolate COD ability independent of sprint speed. This study evaluated relationships between sprint time, 505 time, and COD deficit, and whether the COD deficit identified a different and more isolated measure of COD ability compared with 505 time. Seventeen cricketers performed the 505 for both left and right sides and 30-m sprint tests (with 10-m split time). The COD deficit for both sides was calculated as the difference between average 505 and 10-m time. Correlations were calculated between all variables (p ≤ 0.05). To compare 505 time and COD deficit, z-scores were calculated; the difference in these scores was evaluated for each subject. The COD deficit correlated to 505 (r = 0.74-0.81) but not sprint time (r = -0.11 to 0.10). In contrast, 505 time did correlate with sprint time (r = 0.52-0.70). Five of 17 subjects were classified differently for COD ability when comparing standardized scores for 505 time vs. COD deficit. Most subjects (88-94%) had a meaningful difference between 505 time and COD deficit. Using 505 time to determine COD ability may result in a large amount of replication to linear speed assessments. The COD deficit may be a practical tool to better isolate and identify an athlete's ability to change direction.