Small-Sided Games and Technical Skills in Soccer Training： Systematic Review and Implications for Sport and Physical Education Practitioners

High-level of technical skills and tactical behaviour are key factors for an optimal performance in soccer games. About the most used and innovative training methods, the small-sided games （SSGs） seem to be a worthy and valid methodology to train simultaneously many skills by reproducing several conditions of a real match. Accordingly, the aim of this study was to conduct a systematic review of the available literature to lead an improved understanding in the usefulness of SSGs for improving technical skills in soccer. To ensure a rigorous and reliable approach, the review was performed according to PRISMA （Preferred Reporting Items for Systematic review and Meta-analyses） guidelines. 1031 records were initially identified, but only 26 studies were further included in the review. Moreover, other two studies were added after a check of the bibliography of two major reviews. So, each of these studies was analysed according to the aforementioned guidelines and using inclusion criteria related to SSG and training in soccer. The current analysis provided several indications and recommendations for coaches and trainers of soccer teams in order to improve several technical skills by means of the use of SSGs. Furthermore, several evidences for using SSGs in school environment are also provided.

Anthropometric and Physical Performance Profiles of High School Age American Football Players: 11th and 12th Grade Japanese Athletes

Purpose To compare anthropometric and physical performance profiles of Japanese 11th and 12th grade American football players within each positional group.Methods Fifty-two 11th and 12th grade American football players from two Japanese high schools participated in the study during the summer pre-season period.They performed anthropometric(height and body mass)and physical(vertical jump,broad jump,40-yard dash,pro-agility shuttle 4-kg medicine ball chest throw,front throw,and back throw)testing.Vertical jump momentum and 10-yard sprint momentum were also calculated by multiplying the velocity and body mass.Athletes were divided into two groups by playing positions:skill players and linemen.Results Skill players in the 12th grade were better at medicine ball chest throw(d=0.73,P=0.04)and vertical jump momen-tum(d=0.75,P=0.03)than those in the 11th grade.However,there were no differences in any measurements(P>0.05)between linemen from the two grades.Conclusion The current study suggests that upper and lower body absolute power and momentum production can be improved for skill players even over 17 years old.On the other hand,body size and speed,attributes that did not change between 11th and 12th grades,seem to be essential talent identification criteria in the current environment.Further study is needed to monitor longitudinal performance improvements in implementing talent development programs by focusing on the quality of speed,agility and power development at the youth level.

Speed of Thought and Speed of Feet:Examining Perceptual-Cognitive Expertise and Physical Performance in an English Football Academy

The world's greatest professional football players are able to execute effective tactical decisions as well as fulfil various physical demands.However,the degree to which both are associated with greater potential in a football academy is unknown.Therefore,the aim of this study was to investigate decision-making skill and physical performance as contributing factors to coach potential rankings in an English football academy.Ninety-eight outfield academy players(Foundation Development Phase[FDP]under-9 to under-11 n=40;Youth Development Phase[YDP]under-12 to under-16 n=58)participated in the study.They engaged in 45 film-based simulations at two occlusion phases(e.g.,the visual display is cut-off at a precise time during an action),firstly"during"and secondly"post"execution,to examine decision-making skill.Participants also completed four fitness tests to examine physical performance.A classification of"higher-potentials"(top third)and"lower-potentials"(bottom third)were applied through coach rankings.Independent t-tests compared the decision-making and physical performance tests.Higher-potentials made significantly more accurate decisions within the"post"phase within the FDP(P<0.05)and the"during"phase within the YDP(P<0.05).Additionally,higher-potentials were significantly faster for the 0-30 m sprint in both the FDP and YDP(P<0.05),with higher-potentials within the YDP also significantly faster in the 0-10 m sprint(P<0.05)and jumped significantly higher in the countermovement jump(P<0.05).These findings indicated that greater football potential may be associated with superior perceptual-cognitive expertise and quicker sprint ability in both academy age phases,with a greater discriminatory function within the older cohort.

Genetic Testing in Professional Football:Perspectives of Key Stakeholders

Purpose Genetic research in football is currently in it’s infancy but is growing rapidly.However,the practical application of genetic testing in football and the views concerning its use are unknown.Thus,the purpose of this study was to assess the current practical application of genetic testing in professional football and provide an insight into the perspectives of key stakeholders(i.e.,coaches,practitioners,players).Methods In total,122 participants completed an online anonymous survey.This consisted of 21 multiple choice and Likert scale questions,with the option of providing an explanation for each response.Results Findings revealed genetic testing is rarely utilised by key stakeholders(10%)or their respective organisations(14%).However,three quarters(75%)had the opinion that genetic testing will have great utility in the future.The majority(72%)believed genetic testing should be used for athlete development and injury risk,whilst 35%believed that genetic testing should be utilised for talent identification purposes.However,most key stakeholders viewed their own(89%)and their col-leagues’(79%)knowledge related to genetic testing as insufficient;mainly due to ineffective current communication methods(91%).Most believed educational workshops are required(71%),whilst nearly all(91%)were interested in developing their expertise on the utility of genetic testing.Conclusion Genetic testing is rarely used within professional football,although key stakeholders anticipate that it will be utilised more in the future.As such,educational support may prove valuable in improving key stakeholder knowledge and the practical application of genetic testing in professional football.

Association Between rs1815739 Polymorphism of ACTN3 Gene and Athletic Ability in Chinese Sprinters

Purpose The aim of this study was to investigate the prevalence of the ACTN3 rs1815739 polymorphism and to study its association with athletes'level of competition and lower-extremity power.Method Time-of-flight mass spectrometry(TOFMS)and polymerase chain reaction-restriction fragment length polymor-phism(PCR-RFLP)techniques were employed to identify the ACTN3 rs1815739 genotypes and allele frequencies in 108 elite sprinters and 206 untrained controls.Questionnaires were then used to assess subjects'100 m sprint,standing jump(SJ)and standing triple jump(STJ)personal best record.Results(1)The RR,RX and XX genotype distribution of the ACTN3 rs1815739 polymorphism is 42.6%,49.1%,8.3%,respectively.R and X alleles frequency is 67.1%and 32.9%,respectively,which comply with Hardy Weinberg equilibrium(HWE)through Chi-square(x2)tests(x2=0.661;df=2;P=0.718).(2)Significant differences were found in R allele fre-quency between the elite sprinter group and controls.(3)The athletes'100 m sprint,SJ,and STJ personal best records were better in those with RR and RX than XX genotype.A significant association was observed between the R alleles and 100 m sprint,SJ,and STJ results of male and female athletes.Conclusion The present results indicate that ACTN3 rs1815739 polymorphism has a significant association with speed and lower-extremity power in sprint/power athletes.