Different Number Of Players Research Articles

Physiological Response of the Performance of Young Football Players During Small-Sided Games

Summary The main aim of the present study was to examine the cardiovascular response, time-motion characteristics, game performance and rated of perceived exertion (RPE) during small-sided games (SSGs) with different number of players. The research group consisted of elite youth male soccer players (n = 18) (aged 16.5 ±0.71 years, maximum heart rate (HRmax) 196.42 ±5.31 beats.min−1) from the FC DAC 1904 Dunajská Streda U17 soccer club. Cardiovascular response measurements included heart rate (HR) expressed in minimum, mean and maximum values and time spent in different intensity zones. Total distance covered, high intensity running and the number of accelerations and decelerations were captured by GPS. Individual game performance and the number of technical-tactical actions were recorded during every SSGs. After the game time we collected the ratings of perceived exertion scores from each player. Results showed that SSG with small number of players (3 vs. 3) triggered the highest HR response with mean value 168.00 ±8.48 beats.min−1, players spent the most time in maximal intensity zone 0:09:06 minutes, of SSG duration. This format of SSG was the mostintense for the players´ cardiovascular system, but we can’t find statistically significant differences between the HR values in SSGs. External load was the most demanding in SSG1 too, like in internal load. The highest scores in individual game performance were recorded in SSG2. In RPE scores SSG1 was the most difficult from the players point of view. In conclusion, the present research demonstrates the effectiveness of SSG1 in training sessions. Therefore, the coaching staff has the possibility to choose between SSGs during training sessions according to their physical, technical, tactical and psychological objectives.

Area per player in small-sided games to replicate the external load and estimated physiological match demands in elite soccer players.

The current study determined the area-per-player during small- or large-sided games with or without goalkeeper that replicates the relative (m·min-1) total distance, high-intensity running distance, sprint distance and metabolic power covered during official matches. Time-motion analysis was performed on twenty-five elite soccer-players during 26 home-matches. A total of 2565 individual samples for SSGs using different pitch sizes and different number of players were collected and classified as SSGs with (SSG-G) or without goalkeeper (SSG-P). A between-position comparison was also performed. The area-per-player needed to replicate the official match demands was largely higher in SSG-G vs SSG-P for total distance [187±53 vs 115±35 m2, effect size (ES): 1.60 95%CI 0.94/2.21], high-intensity running distance [262±72 vs 166±39 m2, ES: 1.66(0.99/2.27)] and metabolic power [177±42 vs 94±40, ES: 1.99(1.31/2.67)], but similar for sprint distance [(316±75 vs 295±99 m2, ES: 0.24(-0.32/0.79)] with direction of larger area-per-player for sprint distance > high-intensity running > total distance ≌ metabolic power for both SSG-G and SSG-P. In SSG-G, forwards required higher area-per-player than central-defenders [ES: 2.96(1.07/4.35)], wide-midfielders [ES: 2.45(0.64/3.78)] and wide-defenders [ES: 3.45(1.13/4.99)]. Central-midfielders required higher area-per-player than central-defenders [ES: 1.69(0.20/2.90)] and wide-midfielders [ES: 1.35(-0.13/2.57)]. In SSG-P, central defenders need lower area-per-player (ES: -6.01/-0.92) to overall replicate the match demands compared to all other positions. The current results may be used to gain knowledge of the SSGs relative to the match demands. This imply manipulating SSGs using higher or lower ApP, the presence of the goalkeeper or design specific rules to increase or decrease the position-specific demands with respect to the desired external load outcomes.

Intensity of Soccer Players’ Training Load in Small-Sided Games with Different Number of Players

Summary The main aim of this research was to compare differences in heart rate values (HR) of soccer players during small-sided games (SSGs) with different number of players. We assumed that the number of “neutral” player or players in small-sided games will significantly affect the intensity of SSGs and in this case the heart rate values of participating players. The experimental group consisted of older junior players from the FC DAC 1904 Dunajská Streda soccer club (n = 9). The heart rate values were evaluated on the basis of collected data, which we obtained using Polar sport testers and special software Polar Team2. In order to find out the statistical significance of the difference in heart rate was used the One-Way ANOVA and the Bonferroni post hoc test. The level of statistical significance we set at 5 %. We found out that with increasing number of “neutral” players’ the intensity of small-sided games gradually decreased. During SSG1 (3 vs. 3), we recorded the highest achieved average heart rate values of the monitored players, in average 171.33 ± 9.39 beats.min-1. This form of the SSGs was the most intense, but not statistically significant. Our recommendation is to employ SSGs in the systematic training process with different number of players, because we can adequately prepare the players for the match load itself. Attention need to be paid for the playing position requirements.

Combined Effect of Number of Players and Dribbling on Game-Based-Drill Demands in Basketball.

To examine the physiological, physical, and technical demands of game-based drills (GBDs) with regular dribble (RD) or no dribble (ND) involving a different number of players (3 vs 3, 4 vs 4, and 5 vs 5). Ten regional-level male basketball players performed 6 full-court GBD formats (each consisting of 3 bouts of 4 min and 2 min rest) on multiple occasions. The physiological and perceptual responses were measured through heart rate and rating of perceived exertion. Video-based time-motion analysis was performed to assess the GBD physical demands. The frequencies of occurrence and the duration were calculated for high-intensity, moderate-intensity, low-intensity, and recovery activities. Technical demands were assessed with a notional-analysis technique. A 2-way repeated-measures analysis of variance was used to assess statistical differences between GBD formats. A greater perceptual response (rating of perceived exertion) was recorded during 3 versus 3 than 5 versus 5 formats (P = .005). Significant interactions were observed for the number of recovery (P = .021), low-intensity activity (P = .007), and all movements (P = .001) completed. Greater time was spent performing low-intensity and high-intensity activities during RD than ND format. Greater technical demands were observed for several variables during 3 versus 3 than 4 versus 4 or 5 versus 5. A greater number of turnovers (P = .027), total (P ≤ .001), and correct passes (P ≤ .001) were recorded during ND than RD format. The number of players predominantly affected the perceptual response to GBD, while both the number of players and rule modification (RD vs ND) affected activities performed during GBD. Reducing the number of players increases the GBD technical elements, while ND format promotes a greater number of turnovers and passes.

Extracellular Nanovesicles Secreted by Human Osteosarcoma Cells Promote Angiogenesis

Angiogenesis involves a number of different players among which extracellular nanovesicles (EVs) have recently been proposed as an efficient cargo of pro-angiogenic mediators. Angiogenesis plays a key role in osteosarcoma (OS) development and progression. Acidity is a hallmark of malignancy in a variety of cancers, including sarcomas, as a result of an increased energetic metabolism. The aim of this study was to investigate the role of EVs derived from osteosarcoma cells on angiogenesis and whether extracellular acidity, generated by tumor metabolism, could influence EVs activity. For this purpose, we purified and characterized EVs from OS cells maintained at either acidic or neutral pH. The ability of EVs to induce angiogenesis was assessed in vitro by endothelial cell tube formation and in vivo using chicken chorioallantoic membrane. Our findings demonstrated that EVs derived from osteosarcoma cells maintained either in acidic or neutral conditions induced angiogenesis. The results showed that miRNA and protein content of EVs cargo are correlated with pro-angiogenic activity and this activity is increased by the acidity of tumor microenvironment. This study provides evidence that EVs released by human osteosarcoma cells act as carriers of active angiogenic stimuli that are able to promote endothelial cell functions relevant to angiogenesis.

A Match-Derived Relative Pitch Area Facilitates the Tactical Representativeness of Small-Sided Games for the Official Soccer Match.

Olthof, SBH, Frencken, WGP, and Lemmink, KAPM. A match-derived relative pitch area facilitates the tactical representativeness of small-sided games for the official soccer match. J Strength Cond Res 33(2): 523–530, 2019—Small-sided games (SSGs) are a promising training format in soccer to replicate (situations of) the official match across all age groups. Typically, SSGs are played on a smaller relative pitch area (RPA; i.e., <150 m2) than the match (320 m2 RPA), which results in different tactical demands. To create a more precise replication of tactical match demands in SSGs with less than 11 players per team, a match-derived RPA (320 m2) may be considered because this affords a similar playing area per player. In addition, subgroup analysis is necessary to deal with the different number of players in match and SSGs. Therefore, this study aims to investigate tactical demands of matches and various SSGs—with a different number of players and played on 320 m2 RPA—in talented youth soccer players. Twelve elite soccer teams in 4 age categories (under-13, under-15, under-17, and under-19) played official matches and 4 vs. 4 + goalkeepers (GKs), 6 vs. 6 + GKs, and 8 vs. 8 + GKs. Positional data were collected to calculate tactical variables (interpersonal distances, length, width, and surface areas) for all players and for 2- and 4-player subgroups. Corresponding tactical variability (coefficients of variation expressed as percentages) was determined for all players. Results demonstrated that in each age category, with an increase in number of players, team distances increased and tactical variability decreased. Subgroup analyses revealed similar team distances in matches and SSGs with the exception of larger interpersonal distances in 4 vs. 4 + GKs than the match in under-13, under-15, and under-17. Match-derived RPA in SSGs facilitates the tactical representativeness for the match. Soccer coaches can use such SSGs for an optimal tactical match preparation.

Perspectivas para o ensino do sistema defensivo 3:3 no handebol diante de desigualdades numéricas

Em uma partida de handebol pode haver vários momentos de desigualdade numérica. O objetivo deste trabalho foi de apresentar algumas possibilidades para o ensino do sistema defensivo 3:3 em situações de superioridade e inferioridade numérica deste, que considerem a complexidade e dinâmica do handebol. Nesse sentido, a proposta baseia-se basicamente em duas vertentes: jogos conceituais e método situacional. Com as perspectivas apresentadas durante esse ensaio, procuramos chamar a atenção dos treinadores sobre o ensino do sistema defensivo 3:3 e, ainda, apresentar diferentes estratégias para o seu ensino, aplicáveis a diferentes categorias.

Number of Players and Relative Pitch Area per Player: Comparing Their Influence on Heart Rate and Physical Demands in Under-12 and Under-13 Football Players.

The aim of the present study is to analyse the influence of different large-sided games (LSGs) on the physical and physiological variables in under-12s (U12) and -13s (U13) soccer players. The effects of the combination of different number of players per team, 7, 9, and 11 (P7, P9, and P11, respectively) with three relative pitch areas, 100, 200, and 300 m2 (A100, A200, and A300, respectively), were analysed in this study. The variables analysed were: 1) global indicator such as total distance (TD); work:rest ratio (W:R); player-load (PL) and maximal speed (Vmax); 2) heart rate (HR) mean and time spent in different intensity zones of HR (<75%, 75–84%, 84–90% and >90%), and; 3) five absolute (<8, 8–13, 13–16 and >16 Km h-1) and three relative speed categories (<40%, 40–60% and >60% Vmax). The results support the theory that a change in format (player number and pitch dimensions) affects no similarly in the two players categories. Although it can seem that U13 players are more demanded in this kind of LSG, when the work load is assessed from a relative point of view, great pitch dimensions and/or high number of player per team are involved in the training task to the U12 players. The results of this study could alert to the coaches to avoid some types of LSGs for the U12 players such as: P11 played in A100, A200 or A300, P9 played in A200 or A300 and P7 played in A300 due to that U13>U12 in several physical and physiological variables (W:R, time spent in 84–90%HRmax, distance in 8–13 and 13–16 Km h-1 and time spent in 40–60%Vmax). These results may help youth soccer coaches to plan the progressive introduction of LSGs so that task demands are adapted to the physiological and physical development of participants.

Effect of different number of players and training regimes on physiological and technical demands of ball-drills in basketball

This study aimed to analyse the effects of two factors (number of players and training regimes) on players’ physiological and technical demands in basketball ball-drills. Twenty-one young basketball players performed four different ball-drills (two levels for each factor). The number of players involved was 2vs2 and 4vs4, while ball-drill regimes were continuous and intermittent. Physiological demand was assessed using the percentage of maximal heart rate (%HRmax), Edwards’ training load and rating of perceived exertion (RPE). Furthermore, the following technical actions were collected: dribbles, steals, rebounds, turnovers, passes (total, correct, wrong and % of correct pass) and shots (total, scored, missed and % of made shot). A 2 × 2 (number of players × regime) two-way ANOVA with repeated measures was applied for physiological parameters and technical actions. The 2vs2 condition showed higher %HRmax (P < 0.001), Edwards’ training load (P < 0.001), RPE (P < 0.001), number of dribbles (P < 0.001), rebounds (P < 0.001), passes [total (P = 0.005) and correct (P = 0.005)] and shots [total (P < 0.001) scored (P < 0.001) and missed (P < 0.001)] than 4vs4. Moreover, the continuous regime revealed higher %HRmax (P < 0.001), Edwards’ training load (P < 0.001), RPE (P = 0.006) and dribbles (P < 0.001) than the intermittent regime. This study showed that both number of players and regime are useful variables able to modify basketball ball-drills workload.

Influence of the number of players and the relative pitch area per player on heart rate and physical demands in youth soccer.

The aim of this study was to analyze the influence of different large-sided games on the physical and physiological variables in under-13 soccer players. The effects on heart rate (HR) and physical demands of different number of players (NP) (7, 9, and 11) together with the relative pitch area (RPA) (100, 200, and 300 m) during two 12-minute repetitions were analyzed in this study. The variables analyzed were mean, maximum and different intensity zones of HR; total distance (TD); work:rest ratio (W:R); player load (PL); 5 absolute and 3 relative speed categories. The results support the hypothesis that a change in pitch dimensions affects locomotor activity more than the NP does but also refute the hypothesis that the change in the NP has a greater effect on HR. To be more specific, an increase in the RPA per player (300/200/100 m2) was associated with higher values of the following variables: TD (2,250-2,314/2,003-2,148/1,766-1,845 m), W:R (0.5-0.6/0.4-0.5/0.3 arbitrary unit [AU]), PL (271-306/246-285/229-267 AU), %HRmean (85-88/85-89/81-83%), %HRmax (95-100/97-100/95-98%), and affected the percentage of time spent in both absolute (above 8 km·h(-1)) and relative speed (above 40% Vmax) categories (p ≤ 0.05, effect size: 0.31-0.85). These results may help youth soccer coaches to plan the progressive introduction of large-sided games so that task demands are adapted to the physiological and physical development of participants.

Heart Rate Responses during Small-Sided Soccer Games

The purpose of the present study was to examine the heart rate responses during small-sided games with different number of players. Sixteen professional soccer players were evaluated for body fat (%) using the skin fold thickness at three sites, VO2 max and running velocity at the lactate threshold using an incremental treadmill protocol. %HRmax was measured during four-, five-, six-, seven-, and eight-a side soccer games. The four-a-side game showed significantly (p<0.05) higher %HRmax in comparison to the other small-sided games. On the other hand, the %HRmax of the eight-a-side game was significantly lower (p<0.05) than three-, four-, five-, six-, and seven-a-side game. The intensity of small-sided games decreases as the number of players increase. The monitoring of heart rate during small-sided games combined with laboratory VO2 max tests is a possible way to define target training intensity zones.

Offit Paul: Autism’s False Prophets: Bad Science, Risky Medicine, and the Search for a Cure

In Autism’s False Prophets, Paul Offit, M.D., Maurice R. Hilleman Professor of Vaccinology, Professor of Pediatrics at The University of Pennsylvania, and co-inventor of a rotavirus vaccine, makes an important contribution to popular debates about the etiology and treatment of autism spectrum disorders. The book is arguably the most detailed and thorough history available of the current anti-vaccine movement and the increasingly widespread popular belief that vaccines and/or ingredients in vaccines are related both to autism and the changing prevalence of autism. Offit provides a sustained scientific attack against the misinformation disseminated by the media and a small but vocal group of anti-vaccine advocates. He pays special attention to the therapies and therapists (autism’s ‘‘false prophets’’) that emerged out of the current anti-vaccine movement. And by situating the autism debate in the larger context of the complex interactions between science, society, and politics, Offit identifies a set of problems that will resonate with nearly all medical scientists, whatever their field of expertise. Offit argues that false information, unscientific hypotheses, and inaccurate and simplistic media coverage on autism and vaccines are hurting the public health. In order to correct the misinformation, he focuses on the most common public fallacy about autism today: that the measles mumps rubella vaccine (MMR) and/or the mercury containing preservative, thimerosal, which was in many vaccines (but not in the MMR) until late 2001, cause autism. Public fears about MMR and thimerosal led to a decline in vaccination rates and an increase in preventable illness. For example, in 1995, 92% of British 2-year-olds were vaccinated against measles, and there were 112 recorded cases of the disease in the UK. A decade later, only 81% of 2-year-olds had received the vaccine and there were 958 cases. According to the World Health Organization, in 2005, 242,000 people died of measles worldwide, but because of the previous success of vaccine programs, most Europeans and Americans have never seen a case of measles and do not understand its dangers. Measles is on the rise in the US, as evidenced by scores of cases in Iowa in 2004, Indiana in 2005, and Massachusetts in 2006. So far in 2008, the US is having the worst outbreak of measles in years. The MMR fears first developed in 1995 when a doctor in England, Andrew Wakefield, published a paper in The Lancet claiming that a number of children had developed autism within a month after receiving the MMR. Although it is well known that the onset of autism is typically insidious, thus making it difficult to identify a moment when an autistic child’s disorder begins, many found Wakefield’s thesis plausible. It seemed to make little difference to the media and the wider public when it was revealed that Wakefield had serious conflicts of interest he had failed to disclose, that the majority of the co-authors retracted their support for the paper’s conclusions, and that The Lancet issued a partial retraction of the paper. Nor did it seem to make a difference when ten subsequent studies refuted the hypothesis that the MMR vaccine is linked to autism. The thimerosal story is less straightforward and must be attributed to a number of different players, such as Neal Halsey (a well respected vaccine expert), US government agencies responsible for overseeing immunization policy, politicians with a personal relationship to autism, such as Dan Burton (R-IN), two single-minded journalists named David Kirby and Dan Olmsted, small interest groups, such as SafeMinds (with which Kirby has been involved) and R. R. Grinker (&) The George Washington University, Washington, DC, USA e-mail: rgrink@gwu.edu