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The objective was to assess and compare the tactical conduct of players aged U-8, U-10, and U-12 during full- and small-sided games, focusing on tactical modeling and interaction dynamics. Each age group comprised three teams (n = 180; 60 per category; 20 per team), engaging in a tournament where teams faced each other once in both formats − 18 matches; 3 per category in each format. Full-sided games (GK + 10 vs.10 + GK; 100 × 68 m) and small-sided games (U-8: GK + 4 vs. 4 + GK (36 × 20 m); U-10: GK + 7 vs. 7 + GK (52.5 × 34 m); U-12: GK + 10 vs. 10 + GK (68 × 45 m). Standard playing times (3 periods of 12 minutes (U-8s); 3 periods of 15 minutes (U-10s); and 3 periods of 20 minutes (U-12s), with a 5-minute break. Variables were examined using descriptive analysis (mean, standard deviation, and confidence interval), with paired t-tests and Wilcoxon tests employed for inter-format comparisons. Despite players benefiting from more time and space in full-sided games (increased ball receptions and overall ball involvement), results from small-sided games indicate three key advantages: 1) More goals (U-8s: z = –3.44, p = .050) and shots on target (U-8: z = –3.25, p = .001; U-10: z = –2.72, p = .007); 2) Game space management—ball circulation in larger amplitude (U-10: t = –4.20, p = .001; U-12: t = –4.35, p < .001); and with more transitions (U-10: t = –3.60, p = .002; U-12: t = –4.16, p = .001) and 3) Fast decision-making—larger ball velocity circulation (U-08: t = –3.54, p = .003; U-10: t = –5.13, p < .001; U-12: t = –5.80, p < .001). [ABSTRACT FROM AUTHOR]

Purpose: The extra-time (ET) period of soccer is competed during fixture congested schedules with often limited recovery time between matches. The aim of this study was to assess muscle damage recovery following 90- and 120-min (i.e., incorporation of ET) of simulated soccer match-play. Methods: Twelve semiprofessional soccer players completed 90 and 120-min treadmill-based soccer-specific exercise in a counterbalanced order. Creatine kinase (CK), creatinine, urea, aspartate aminotransferase, perceived muscle soreness, pain pressure threshold, reactive strength index, countermovement jump height, and isokinetic strength assessments of eccentric knee flexors at 60, 180 and 270 deg‧s−1 were taken at baseline and immediately-, 24, 48 and 72-hr post-exercise to assess recovery. Results: No significant between-trial interactions except for CK were found. Pairwise comparisons detected a 53% increase in CK at 24-hr (455 ± 29 μ∙L−1) following 120-min of simulated match-play vs. the corresponding post 90-min time-point (299 ± 29 μ∙L−1; p <.01). The 120-min trial caused a 58% higher CK response at 72-hr (244 ± 25 μ∙L−1) vs. post 90-min comparisons (154 ± 29 μ∙L−1; p =.02). No interaction effects were detected for any other recovery variables. Creatine kinase and perceived muscle soreness remained elevated up to 72-hr in both trials (p <.01). Conclusions: These data indicate that 120 min of simulated soccer match-play delays the time-course of CK recovery up to 72-hr post-match. However, 120 min of simulated soccer has no additional impact on functional recovery and perceived muscle soreness vs. 90 min. Recovery should be investigated following 90- and 120-min of actual match-play.Trial registration The study was pre-registered on the Open Science Framework (DOI: 10.17605/OSF.IO/VGU6T Date: 10/06/2019). [ABSTRACT FROM AUTHOR]

Reports of programmed cell death (PCD) across the taxonomic spectrum of photosynthetic unicellular organisms raise questions concerning its ecological and evolutionary roles. However, prior to ecological studies or evolutionary interpretations, it is essential to document phenotypic changes associated with PCD at the single-cell level, since death-related responses vary between taxa and within a single taxon depending on environmental stimuli. Here, we report responses to rapidly changing light, temperature and fluctuations in macronutrients in the model selenastracean green microalga Ankistrodesmus densus (Chlorophyta, Chlorophyceae, Sphaeropleales). We used stringent, but environmentally appropriate, conditions of prolonged darkness, nitrogen starvation (4 days), heat (1 h at 44°C) and cold shock (3 h at 2 ± 2°C). PCD phenotypes were examined by ultrastructural changes, phosphatidylserine (PS) externalization and DNA degradation. Flow cytometric Annexin V FITC analyses revealed that darkness and nitrogen-deprived cultures had significantly higher proportions of cells with PS externalization compared with controls (p < 0.05). Heat and cold treatments did not affect PS externalization (p = 0.44 and p = 0.99, respectively). Transmission electron microscopy (TEM) of light-deprived cells demonstrated, among other ultrastructural changes, marked cytoplasmic vacuolization suggesting a subtype of PCD known as vacuolar cell death. Nitrogen-starved cells had less vacuolization but presented more typical ultrastructural markers of PCD such as chromatin condensation and marginalization. In contrast, the more severe heat and cold shock treatments resulted in necrotic-like features. These findings suggest that prolonged darkness and nitrogen starvation induce PCD in a small (8.4 3.5 and 7.42 2.6%, respectively) but significant (p < 0.05) fraction of the A. densus population. Documenting these different death-related phenotypes depending on different environmental inducers is essential for interpreting ecological studies. Furthermore, our data support the hypothesis that autophagic/vacuolar cell death (VCD), which is central to organism homeostasis in plants (Streptophyta), occurs in Chlorophyta. VCD probably arose long before the evolution of multicellularity in plants. HIGHLIGHTS Darkness and nitrogen deprivation induce different programmed cell death markers in Ankistrodesmus densus; Plant vacuolar-like cell death occurs in Chlorophyta; There is crossover between the vacuolar and apoptosis-like death morphotypes. [ABSTRACT FROM AUTHOR]

This scoping review aimed to systematically map studies/tests for assessing the tactical domain of young soccer players. The study followed the PRISMA-ScR and Joanna Briggs Institute guidelines. The databases searched were Scopus, SPORTDiscus, SciELO, LILACS, and BDTD. The eligibility criteria were defined based on the elements of population, context, and concept, without restrictions on the period, language, and type of publication. Twenty-four papers were included, from 1997 to 2020, totalling 29 tests/instruments for the assessment of the tactical domain, with the majority of studies having an European sample. Twelve terms were used to nominate the tactical component, regardless of the assessment method and approach. Six tests met eight or nine criteria in the critical appraisal: TCTOF, TACSIS Spanish version, Semi-Structured Interview, TCTP-OE, GPET, and FUTSAT. Thus, it is concluded that studies and tests for the assessment of the tactical domain of young soccer players are recent and mainly European; there is no consensus about the adopted terminology; and few tests met the majority of the quality criteria. Therefore, we suggest: a) the construction/adaptation of tests with samples from other continents; b) the use of the proposed criteria; and c) that the terms tactical knowledge and tactical performance are adopted. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse variations of internal load across small-sided games (SSG) in professional soccer. Twenty players (mean ± SD; age 28.1 ± 4.6 yo, height 176.7 ± 4.9 cm, weight 72.0 ± 7.8 kg) performed 3v3, 4v4, and 6v6 formats with/without goalkeeper and touch limitations. Each condition was repeated over three sessions and heart rate (HR) measures including average HR (HRavg), Edwards' training impulse (Edwards' TRIMP) and time in red zone (>80% of maximal HR) were recorded. All measures had trivial-to-moderate typical error (TE) and trivial differences were observed within intervals. The HRavg showed less coefficient of variations (0.9% to 1.7%) compared to Edwards'TRIMP.min−1 and red zone.min−1 (2% to 9.7%). A reduction trend in TE was observed when touching limitations or using goalkeepers. Practitioners can use different SSG formats but if the aim is to have less noise at higher intensities, more controlled drills are recommended. [ABSTRACT FROM AUTHOR]

This study investigates the factors driving football players with identical training experience and genetics to have dramatically different career paths. We studied two paired cases from a pool of 32 talented U-20 players who were twice World Champions. The first paired case is a set of monozygotic twins that played football for exactly the same period of time yet only one of them was selected for the national team. The second paired case refers to an outstanding player who got injured and withdrew from his football career and the player who replaced him in the national team. Semi-structured interviews were conducted and then analyzed inductively. The results provide a description of opportunities (affordances) that could only be taken by those who were ready to act skillfully when such rare event occurred. To act on such affordances (or not) may dramatically change the outcome of a player's career. These results suggest that expert performance and high achievement emerge from circumstances resulting from the self-organization of several performer-environmental factors. Acting on such opportunities (affordances) implies being perceptually attuned to and ready for unpredictable events. This research builds on the ecological dynamics approach and provides a basis for further understanding of expertise and expert performance. [ABSTRACT FROM AUTHOR]

This systematic review with meta-analysis (SRMA) was conducted to assess the effects of high-intensity interval training (HIIT) programmes on men soccer players' aerobic fitness (maximal oxygen uptake and aerobic performance), repeated sprint ability (RSA), vertical jump height (VJH), and linear sprinting time (ST). An electronic search yielded 1,714 articles, 33 of which were included in the present study. Meta-analyses revealed significant benefits of HIIT compared to controls in maximal oxygen uptake (p = 0.018), AP (p = 0.041), and RSA (p = 0.049). No significant effects were found in terms of ST (p = 0.080). The meta-analyses of non-controlled studies revealed significant improvements after HIIT in maximal oxygen uptake (p = 0.001), AP (p = 0.007), RSA (p = 0.001), and ST (p < 0.001). However, no significant improvements in VHJ were found (p = 0.063). Furthermore, no significant differences were found in sub-group analysis (comparisons between HIIT types). In conclusion, HIIT is effective for improving maximal oxygen uptake, AP, and RSA regardless of the HIIT type. For VHJ and ST outcomes, it seems reasonable to complement the HIIT since it might not be enough to achieve significant changes. [ABSTRACT FROM AUTHOR]

The study explored the perception of rink-hockey head coaches in relation to the use of performance analysis as a tool to assist training and match preparation, observation and interventions. Seven experienced First Division Portuguese rink-hockey head coaches were included in the study. Semi-structured interviews were carried out and the data were analysed through inductive and deductive content analyses. Several themes emerged from the interviews including "preparation/observation" and "intervention". Rink-hockey head coaches prefer to analyse the opponents themselves to plan training, as well as to assist with tactical preparation and implement within-match strategies. They considered video analysis an important tool to analyse opponents' strengths and weaknesses, with particular focus on the opponent's goalkeeper. Seek to identify qualities and deficiencies in the opponents' team and individual players. Focus the analysis of opponents' teams on the five moments of the game. Training intervention involves the adaption of training exercises, whereby information is communicated during meetings. These data have implications both from a performance and a training practice perspective. Future research should focus on players and goalkeepers' perspectives. [ABSTRACT FROM AUTHOR]

This study aimed to compare the quantity and quality of tactical actions of high- and low-performing players in two small-sided and conditioned games: (1) standard 3v3 plus goalkeepers, featuring equality for both teams, and; (2) numerical superiority in the offensive phase with two joker players inside the playing field. Fifty-one Under-15 soccer players who performed 8,267 tactical actions were evaluated with the use of the System of Tactical Assessment in Soccer (FUT-SAT). Descriptive statistics, Kolmogorov-Smirnov, t-student, Wilcoxon and Cohen's kappa tests were applied (p < 0.05) using the SPSS, version 20.0. The high-performing players performed more actions inside the centre of play and low-performing players only increased actions outside the centre of play. Playing with jokers also made the high-performing players increase the total amount of offensive and defensive tactical actions whilst the low-performing players only performed more defensive tactical actions. It was concluded that high-performing players adapt better their positions and their movements on situational demands of the game, performing more offensive and defensive actions closer to the ball carrier. On the other hand, low-performing players performed more actions in spaces further from the centre of play, in both the offensive and defensive phase. [ABSTRACT FROM AUTHOR]

Decision-making in soccer is considered an important factor for soccer players achieve high-performance level. Studies in several sports indicated that tactical decision-making skills are necessary for skilful performance. We aimed to analyse whether soccer players with different levels of decision-making skills can be differentiated based on their engagement in various types and amounts of soccer activities during their development. The sample comprised 149 Brazilian youth male soccer players (M = 14.9, SD = 1.6 years). We examined the type and amount of soccer activities that contributed to distinguish players with different levels of offensive and defensive decision-making skills. Players' tactical decision-making skills were assessed with an objective video-based test (TacticUP® video test for soccer). We used a retrospective questionnaire to collect information about previous participation in different soccer developmental activities. The main activities that differentiated high/low skill groups in the macrostructure activities were: i) team practice; and in the microstructure: ii) collective tactics; and iii) "high decision-making opportunities". We concluded that previous soccer developmental activities discriminate youth soccer players with different levels of decision-making skills. The main activities that differentiated high/low groups were: 1) team practice; 2) collective tactics in team practice, and; 3) "high decision-making opportunities" in team practice. [ABSTRACT FROM AUTHOR]

The description of life-history traits is a prerequisite to understand the complex patterns of bird biodiversity. However, most of the highly diverse Neotropical avifauna still lack basic information on their reproductive behavior. Here, we describe the breeding biology of the Creamy-bellied Thrush (Turdus amaurochalinus) in a periurban area of southeast Brazil. We found 67 nests between early September and December in 2017 and 2018. Nests were 3.8 ± 1.9 m (mean ± SD) above ground, in native plants (43.3%), exotic plants (43.3%), and anthropogenic structures (13.4%). Clutch size was 2.9 ± 0.3 eggs, which were incubated exclusively by females during 75.6 ± 18.1% of the time. Both sexes reared the nestlings, but females performed more feeding trips and removed more fecal sacs than males. Incubation and nestling periods lasted, respectively, 13.0 ± 0.6 and 13.2 ± 1.5 days. Overall nesting success according to Mayfield method was 31.6%, and predation was the major cause of nest failure (52.8%). We concluded that this species had higher nest attentiveness, shorter nestling period, and higher nest survival compared to other Neotropical thrushes. The use of exotic plants and anthropogenic structures as nesting substrate may enhance the settlement of this migratory thrush in human-modified areas. [ABSTRACT FROM AUTHOR]

This study aimed to systematically review the association between cardiorespiratory fitness and telomere length (TL). Studies were identified from searches in Cochrane Central, PubMed, Scopus, Sportdiscus, and Web of Science databases through July 2019. Eligibility criteria included: cross-sectional, prospective, and experimental study design; outcomes included TL; results expressed the relationship between cardiorespiratory fitness and TL; studies published in English, Portuguese, or Spanish. A total of 20 articles met the inclusion criteria. Sixteen studies (80%) reported a significant relationship between cardiorespiratory fitness, or training load, and TL. Better cardiorespiratory fitness or a large cardiorespiratory training load are associated with an increase in TL. Although, TL was related to regular moderate-to-vigorous aerobic exercise and cardiorespiratory fitness in older healthy humans, it was not related to cardiorespiratory fitness among young subjects. There seems to be a positive and significant relationship between cardiorespiratory fitness and TL, mainly among middle age and older people, which emphasizes the importance of cardiorespiratory fitness for healthy ageing. Therefore, endurance exercise and better cardiorespiratory fitness may regulate the TL in middle age and older adults, slowing the cellular ageing process. [ABSTRACT FROM AUTHOR]

The purpose of this study was to analyse the performance of professional rink hockey goalkeepers and ascertain whether this is influenced by the opposition's offensive play. A sample of 40 matches, including 1713 shots on goal from the Portuguese First Division (2016/2017) was analysed using Chi-square and logistic regression analysis. The results suggest that goalkeepers are more effective in the first half versus the second half (odds ratio [OR] = 1.39; 95% CI: 1.06–1.82; p = 0.017) of matches. Goalkeeping performance was also lower in the direct free-hits (OR = 0.22; 95% CI: 0.13–0.38; p < 0.001) and penalties (OR = 0.12; 95% CI: 0.06–0.22; p < 0.001), when compared with indirect free-hits. The technique most used by rink hockey goalkeepers to save shots at goal is the "knee on the floor". Observations demonstrate that when attacks commence in the oppositions defensive area, teams are 55% more likely to score and shots at the upper zones of the goal have a higher probability of being successful. These findings could assist coaches and researchers in understanding current goalkeeping performance in relation to offensive patterns of play in rink hockey. [ABSTRACT FROM AUTHOR]

Adolescent characteristics of young adult soccer players (n = 35) were compared with those of youth teammates (n = 124) no longer involved in soccer. Former U-13 players active in soccer as young adults were slightly later in maturation and performed better in several functional and soccer skills than youth teammates. Former U-15 players active in soccer as young adults did not differ in maturity status from youth teammates but were chronologically older and performed better in agility and ball control. Young adult regional and national players in both age groups were rated significantly higher on the potential for success by their youth coaches, and national players were rated significantly higher than regional players. The results highlight the need for study of interactions among coaches, youth training and playing environments and the growth, maturity, functional, skill and behavioural characteristics of youth players, and how these interactions may influence persistence in soccer and later playing status. [ABSTRACT FROM AUTHOR]

The purpose of this paper was to analyse expert futsal coaches process of decision-making from preparation to competitive moments. Ten expert and professional coaches' (M = 46,9 ± 7,93 years old andM= 15,4 ± 7,22 years of coaching experience) from different countries were interviewed using asemi-structured interview (quantitative and qualitative) with two different goals: (1) evaluate the preparation for decision-making moment during the game; (2) classifying the importance of different game related points for decision-making during match moment. The data analysis was processed through combination of deductive and inductive methods through software QSR NVivo 11. The results revealed that coaches' share similar ideas when preparing their teams. Coaches focus first their attention on their own team identity and frame andsecond on opposition team behaviour and frame. It was also possible to identify clear coaching behavioural signs possible to be structured as cues and guiding lines for their decision-making process and actions before and during competitive moments. Such information can be important for the development of most appropriated coaching education curriculums according to game demands specificities. [ABSTRACT FROM AUTHOR]

This study compared the relative physical demands of official matches and sided games (medium and large) in professional soccer players by means of a global positioning system. Twenty-three professional male soccer players (24.632.84 years old; 180.946.49 cm; 77.196.46 kg; 52.995.01 VO2max) participated in the study. Total distance, running distance, sprinting distance, number of sprints, and acceleration sum were quantified per minute to compare the different games. Running distance in full match was greater than in 5vs5+GK (d = 2.303, moderate effect), 6vs6+GK (d = 1.719, moderate effect) and 9vs9+GK (d = 1.084, minimum effect) sided games. Greater values for sprinting distance were found in the full match compared to 5vs5+GK (d = 3.673, strong effect), 6vs6+GK (d = 2.606, moderate effect) and 9vs9+GK (d = 1.903, moderate effect) sided games. However, the load was greater in the 5vs5+GK game compared to the 6vs6+GK (d = 1.323, moderate effect) and 9vs9+GK (d = 1.030, minimum effect) games and the full match (d = 1.478, moderate effect). This study revealed that medium-sided games are not appropriate for simulating the sprinting conditions of official full matches. However, medium-sided games are more intense than full matches in that accelerations are made more often in medium-sided games. [ABSTRACT FROM AUTHOR]

The purpose of this paper was to systematically review and organise the literature on soccer SSGs, in order to ascertain the most frequently researched topics, characterise the methodologies employed, and systematise the evolution of the related research areas. A systematic review of Web of Science, Pubmed and SPORTDiscus databases was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. The following keywords were used: football and soccer, with each one associated with the terms: “small sided games”, SSG, “drill-based training”, “small sided”, “conditioned games” and “position games”. The search returned 394 records. After screening against set criteria, a total of 77 manuscripts were fully reviewed. The most common topics of analysis were (1) pitch area; (2) player number: (a) with/without a goalkeeper; (b) with floater(s) in/outside the pitch; (3) goal: (a) goal vs. scoring zone; (b) number of goals; (c) size of goals; (4) rules modification/task constraints (a) no. of ball touches; (b) offside rule; (c) others; (4) training regimen; (5) coach encouragement. This review provides valuable information on the complex relationship between technical, tactical and physiological interactions in SSGs and how the manipulation of these types of variables can improve the soccer training process. [ABSTRACT FROM AUTHOR]

Based on a socio-ecological framework for physical education (PE), this study explored and analysed the perspectives of physically active and inactive adolescent boys and girls with different socioeconomic status (SES), regarding the meanings that PE had on their physical activity (PA) lifestyles throughout childhood and adolescence. An interpretative and qualitative design was adopted and operationalised through an individual two-hours in-depth interview. Thematic analysis identified five main themes that distinguish active from inactive adolescents: ‘Early experiences of PE at primary school’; ‘PE experiences in middle and secondary school’; ‘Friendly, professional and pedagogue. That’s what I want from my PE teacher’; ‘Friends in PE and PA’; ‘Active lifestyles? Are schools and PE ready for making a difference …’. Regardless of the lifestyle, girls revealed more PE negative experiences, related to uninteresting and competitive activities, groups’ constitution and logistic factors. SES played a major role on their PA and PE experiences, with low SES adolescents having limited opportunities inclusively within the primary school PE context. This study provides evidence for the importance of promoting positive PE and PA experiences in early years. Based on adolescents’ voices, several recommendations are discussed that can be considered for improving PE professionals’ effectiveness in promoting active lifestyles. [ABSTRACT FROM AUTHOR]

The aim of this study was to quantify the type of offensive sequences that result in goals in elite futsal. Thirty competitive games in the Spanish Primera Division de Sala were analysed using computerised notation analysis for patterns of play that resulted in goals. More goals were scored in positional attack (42%) and from set pieces (27%) compared to other activities. The number of defence to offense “transitions” (n = 45) and the start of offensive plays due to the rules of the game (n = 45) were the most common type of sequences that resulted in goals compared to other patterns of play. The central offensive zonal areas were the most common for shots on goal, with 73% of all goals scored from these areas of the pitch compared to defensive and wide zones. The foot was the main part of the body involved in scoring (n = 114). T-pattern analysis of offensive sequences revealed regular patterns of play, which are common in goal scoring opportunities in futsal and are typical movement patterns in this sport. The data demonstrate common offensive sequences and movement patterns related to goals in elite futsal and this could provide important information for the development of physical and technical training drills that replicate important game situations. [ABSTRACT FROM PUBLISHER]

The main focus of this paper was to review the available literature on match analysis in adult male football. The most common research topics were identified, their methodologies described and the evolutionary tendencies of this research area systematised. A systematic review of Institute for Scientific Information (ISI)Web of Knowledgedatabase was performed according to PRISMA (Preferred Reporting Items for Systematic reviews and Meta-analyses) guidelines. The following keywords were used:footballandsoccer, each one associated with the terms:match analysis, performance analysis, notational analysis, game analysis, tactical analysisandpatterns of play. Of 2732 studies initially identified, only 53 were fully reviewed, and their outcome measures abstracted and analysed. Studies that fit all inclusion criteria were organised according to their research design as descriptive, comparative or predictive. Results showed that 10 studies focused predominantly on a description of technical, tactical and physical performance variables. From all comparative studies, the dependent variables more frequently used were “playing position” and “competitive level”. Even though the literature stresses the importance of developing predictive models of sports performance, only few studies (n= 8) have focused on modelling football performance. Situational variables like game location, quality of opposing teams, match status and match half have been progressively included as object of research, since they seem to work as effective covariables of football performance. Taking into account the limitations of the reviewed studies, future research should provide comprehensive operational definitions for the studied variables, use standardised categories and description of activities and participants, and consider integrating the situational and interactional contexts into the analysis of football performance. [ABSTRACT FROM AUTHOR]

The majority of phytoplankton pigment studies are from marine, estuarine and oceanic waters, and commonly use estimates of the ratio between marker pigments and chlorophyll a (chl a) for calculating the contribution of phytoplankton groups to total chl a. In this study, we examined pigment ratios obtained with CHEMTAX processing of field data from a range of tropical and temperate freshwater bodies with contrasting water transparency, depth of the mixed layer, and trophic state. The pigment ratios obtained from processing data from fresh waters corresponded quite well with existing values from pure cultures, and were compared with the marine marker pigment:chl a ratio calculated with CHEMTAX using identical procedures. In deep, stratifying lakes a large variation of some pigment ratios with depth was observed, as well as seasonal variation relating to changes in water column structure. There was considerable variation of average phytoplankton pigment ratios among the freshwater bodies studied. Pigment ratios were significantly correlated to indicators of nutrient availability, to depth of the euphotic zone, or to a proxy of light availability. The substantial variation in marker pigment:chl a ratio confirms that algorithms which account for natural variation of pigments in phytoplankton groups are required for accurate assessment of phytoplankton groups based on marker pigment concentration alone. [ABSTRACT FROM AUTHOR]

Purpose: Monitoring players’ training load allows practitioners to enhance physical performance while reducing injury risk. The aim of this study was to identify the key external load indicators in professional U19 soccer. Methods: Twenty-four-professional Italian young (U19) soccer players were monitored by using the rating of perceived exertion (CR-10 RPE scale) and a wearable inertial sensor during the competitive season. Three main components were detected by a Principal Component Analysis (PCA): i) volume metabolic related component, ii) intensity mechanical stimuli component, and iii) intensity metabolic/mechanical component. We hence computed two scores (i.e. Performance [PERF] and total workload [WORK]) permitting to investigate the weekly microcycle. Results: Correlation analysis showed that scores (i.e. PERF and WORK) are low correlated (r = -0.20) suggesting that they were independent. Autocorrelation analysis showed that a weekly microcycle is detectable in all the scores. Two-way ANOVA RM showed a statistical difference between match day (MD) and playing position for the three PCA components and PERF score. Conclusion: We proposed an innovative approach to assess both the players’ physical performance and training load by using a machine learning approach allowing reducing a large dataset in an objective way. This approach may help practitioners to prescribe the training in the microcycle based on the two scores. [ABSTRACT FROM AUTHOR]

An abstract is presented of the article "English Premier League, Spain's La Liga and Italia Serie A - What's Different?" by Hugo Sarmento, Antonino Pereira, Nuno Matos, Jorge Campaniano, Maria T. Anguera, and Jose Leitano.