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.

Gradient CNT/PVDF piezoelectric composite with enhanced force-electric coupling for soccer training

Real-time monitoring of ball–shoe interactions can provide essential information for high-quality instruction in personalized soccer training,yet existing monitoring systems struggle to reflect specific forces,loci,and durations of action.Here,we design a self-powered piezoelectric sensor constructed by the gradient carbon nanotube/polyvinylidene fluoride(CNT/PVDF)composite to monitor the interactions between the ball and the shoe.Two-dimensional Raman mapping demonstrates the gradient structure of CNT/PVDF prepared by programmable electrospinning combined with a hot pressing.Benefitting from the synergistic effect of local polarization caused by the enrichment of CNT and the reduced diffusion of silver patterns in gradient structure,the as-prepared composite exhibits enhanced force-electric coupling with an excellent sensitivity of 80 mV/N and durability over 15,000 cycles.On this basis,we conformally attach a 3×3 sensor array to a soccer shoe,enabling real-time acquisition of kick position and contact force,which could provide quantitative assessment and personalize guidance for the training of soccer players.This self-powered piezoelectric sensor network system offers a promising paradigm for wearable monitoring under strong impact forces.

Effect of acupuncture on heart rate variability during prolonged high-intensity training in soccer players

OBJECTIVE: To investigate the effects of acupuncture therapy compared with sham acupuncture on heart rate variability(HRV) in 24 elite soccer players during 4-week, high-intensity training sessions.METHODS: The subjects were randomly divided into two groups: acupuncture group(AG) and sham acupuncture group(SG). In addition, AG had been implemented two times/week to stimulate Zusanli(ST 36), Hegu(LI 4), Shenshu(BL 23), and Chize(LU5). While SG, had been applied to utilize a special "placebo-needle" technique on the same sites.What's more, the HRV parameters were calculated before and after interventions, respectively.RESULTS: First, stress index(SI) had a significantly increased in SG(P = 0.031) compare pre-test with post-test, however, no significantly difference in AG(P = 0.102). Secondly, standard deviation of N-N intervals(SNDD) have enormously significantly high-er in AG when comparing baseline with post therapy(P = 0.001), while, declined in SG(P = 0.827).Meanwhile, the root mean square of successive differences(RMSSD) were significant differences in AG(P = 0.023). What's more, when the high-frequency(HF) were significantly higher in AG(P = 0.047) after receiving the acupuncture therapy, the lowe-frequency(LF) power were decreased but no significant in AG and SG. Comparing with pre-experiment, the ratio of LF/HF was lower in AG, but higher in SG. Furthermore, it was significant difference when compare the post-experiment parameters of AG with SG(P = 0.015). And HF parameters have significance(P = 0.005) compare between two groups during the post-experiment.CONCLUSION: Based on evidence, acupuncture therapy on special acupoints could strengthen the parasympathetic nervous activity and modulates the balance between parasympathetic and sympathetic activity in soccer players while they engage in high-intensity training.