Effects of Game Location, Quality of Opposition, and Starting Quarter Score in the Outcome of Elite Water Polo Quarters.

The notational analysis is used to investigate teams' performance in water polo, especially focused on the determinants of success. Recently, a new topic has emerged "the situational variables," which includes the game conditions that may influence the performance at a behavioral level. The aim of this study was to identify the interactive effects of starting quarter score (SQS) (i.e., score difference at the beginning of each quarter and at the final score) and game location (GL) (i.e., home and away teams) in relation to quality of opposition (i.e., positions of difference between opposing teams at the end-of-season rankings) in elite men's water polo games. Data comprised 528 games (n = 2,112 quarters) from the first Spanish water polo division. A linear regression analysis was applied to show the impact of SQS and GL in relation to quality of opposition (unbalanced and balanced) for quarter (all quarters, and second, third, and fourth quarters). Results showed that SQS has an important effect for all quarters (0.16) and for the second (0.14) and third (0.14) quarters in balanced games (whereas the fourth quarter has an unpredictable outcome), and for each quarter (all quarters: 0.33; second quarter: 0.55; third quarter: 0.44; fourth quarter: 0.26) in unbalanced games. In addition, GL effects emerged for balanced (0.31) and unbalanced (0.45) games for all quarters and specifically for the second quarter of the unbalanced games. Therefore, this study showed that the elite water polo game dynamics, indirectly providing a reference for coaches (i.e., effective tactical approach) and physical trainers (i.e., high performance intensities), plans to improve their players' performance.

Classifying young soccer players by training performances.

Players within the same age group may present different physical and physiological profiles. This study classified young soccer players according to their physical and physiological profiles obtained during the training sessions and compared classification by age and playing position criteria. 151 male elite Portuguese soccer players (under 15, under 17, and under 19 years old) participated. Time-motion and body acceleration and deceleration data were collected using GPS technology with heart rate monitored continuously across the selected training sessions. The data were grouped using two-step cluster analysis to classify athletes. A repeated-measures factorial ANOVA was performed to identify differences in the variables. Three clusters comprised 15.2%, 37.1%, and 47.7% of the total sample, respectively. Players of the same ages and playing experience had different performance profiles. Grouping players with similar physiological profiles during training sessions may allow coaches to balance oppositions and reduce the variability of the physiological outcomes.

Physiological responses and activity profiles of football small-sided games.

The aim of this study was to identify the acute physiological responses and activity profiles of football small-sided games (SSG) formats. Ten professional football players participated in 4 variations of SSG (2-, 3-, 4-, and 5-a-side) with an intermittent regime involving 3 × 6-minute bouts with 1 minute of passive planned rest in which the heart rate (HR), rating of perceived exertion (RPE), activity profile, and body load were recorded. The higher percentage of maximum HR values were found in 2- and 3-a-side formats (p ≤ 0.05). The lowest RPE value was found at the 5-a-side, and the highest was found at the 2-a-side (13.48 ± 2.67 and 17.01 ± 1.80, respectively, p ≤ 0.05). The distance covered in the 2-a-side format (598.97 ± 78.91 m) was smaller than in all other formats. The 2-a-side format presented the lowest number of sprints (0.71 ± 0.86) and the 3-a-side the highest (2.50 ± 1.65). Statistically significant differences were found across SSG in the total body load. The 4-a-side presented the highest and the 5-a-side the lowest values (95.18 ± 17.54 and 86.43 ± 14.47, respectively). The body load per minute declined each 2 minutes of play. Maintaining a constant area:player ratio, coaches can use lower number of players (2- and 3-a-side) to increase cardiovascular effects but use higher number of players (4- and 5-a-side) to increase variability and specificity according to the competition demands.

Attack and serve performances according to the match period and quality of opposition in elite volleyball matches.

The purpose of this study was to examine attack and serve performances in the beginning and end of the initial and final sets of volleyball matches according to the quality of opposition. Six hundred rallies from the Men's World Cup 2007 were selectively sampled from a total of 5,117 rallies observed using video match analysis. Rally-by-rally double moving averages of serve and attack efficacy were plotted by 4 different match periods (first 15 rallies of the initial set; first 15 rallies of the final set; last 15 rallies of the initial set; and last 15 rallies of the final set). Approximate entropy values were calculated to analyze the amount of data randomness. The results were examined according to the quality of opposition in 2 types of games: higher level (HIGH) including the first 4 ranked teams and lower level (LOW) composed of the last 5 ranked teams. The results suggested that volleyball matches presented different profiles depending on the match period. Considering the teams' level, a greater adaptation was found within the HIGH × HIGH matches according to the match period and a more strategic use of the serve and attack tactics taking into account the type of the set (initial or final set) and the period (beginning or end of the set). The findings emphasize the need for coaches and players to perceive the most important points at the end of the set and to manage their effort throughout the match attempting to reach this period in optimal condition. Therefore, it might be beneficial to coaches to stress the need to perform at the highest level, particularly at the end of the training drills that simulate competition scenarios.

Effects of the number of players and game type constraints on heart rate, rating of perceived exertion, and technical actions of small-sided soccer games.

The purpose of this study was to identify the variation of heart rate (HR), rating of perceived exertion (RPE), and technical actions between 2 soccer small-sided games (SSGs; 3 × 3 and 4 × 4) in 3 game type constraints (when playing only offense [OFF], playing only defense [DEF], and both situations [GAME]). Sixteen high-level young male players were analyzed (age 15.75 ± 0.45 years; height 172.4 ± 4.83 cm; body mass 64.5 ± 6.44 kg; HRmax199.1 ± 9.08 b·min(-1); and 8.06 ± 1.98 years of soccer practice). All tasks were performed in 4 periods of 4 minutes interspersed with 2 minutes of active recovery. The HR was measured continuously and then analyzed by the time spent into 4 training zones according to individual %HRmax (zone 1 <75%; zone 2 75-84.9%; zone 3 85-89.9%; and zone 4 ≥90%). Results identified that players were most frequently in zones 2 and 3. The 3 × 3 SSGs elicited higher HR and RPE and the most intense situation was GAME. Despite the known higher frequencies from technical actions in SSGs with fewer players, player effectiveness in 3 × 3 and 4 × 4 was identical. The use of GAME, OFF, and DEF game type constraints should be carefully planned. Using the 3 × 3 format seems more adequate when aiming for aerobic performance optimal effects; however, DEF situations should only be used to promote aerobic recovery effects. The inclusion of an additional player in SSGs had different interactions in game type constraints, and only GAME presented adequate intensity.

Changes in Locomotor Ratio During Basketball Game Quarters From Elite Under-18 Teams.

Quantifying game and training demands in basketball allows to determine player's readiness and optimizes preparation to perform and reduce injury risks. Available research is using tracking technology to perform general descriptions of the game activities at professional levels, but somehow, is not exploring the possibilities of gathering data from new variables that can contribute with complementary information for the coaching staffs. The aim of this study was to identify changes in locomotor ratio, at higher and lower speeds, during the game quarters from elite under-18 basketball teams. Ninety-four male players participated in the study (age: 17.4 ± 0.74 years; height: 199.0 ± 0.1 cm; body mass: 87.1 ± 13.1 kg) from different playing positions, Guards (n = 35), Forwards (n = 42), and Centers (n = 17). Data were gathered from an international tournament and players' movements were measured using a portable ultra-wide band position-tracking system (WIMU PRO®, Realtrack Systems, Almeria, Spain). The following variables were measured: (1) relative distance in different speed zones: walking (<6.0 km·h-1), jogging (6.0-12.0 km·h-1), running (12.1-18.0 km·h-1), high-intensity running (18.1-24.0 km·h-1), and sprinting (>24.1 km·h-1); and (2) player load, vector magnitude expressed as the square root of the sum of the squared instantaneous rates of change in acceleration in each of the three planes divided by 100. Afterward, these variables were used to calculate players' locomotor ratio (player load per meter covered) at higher (running, high-intensity running, and sprinting) and lower speeds (walking and jogging). Results from the locomotor ratio at both lower and higher speeds presented a significant effect for the quarter (F = 7.3, p < 0.001 and F = 7.1, p < 0.001, respectively) and player position (F = 3.1, p = 0.04, F = 9.2, p < 0.001, respectively). There was an increase in the locomotor ratio from game quarter (Q) Q1 to Q4 at lower speeds, but contrary trends at higher speeds, i.e., the values have decreased from Q1 to Q4. Also, forwards and centers of the best teams presented lower values at higher speeds. Altogether, the findings may be used by coaching staffs as a first baseline to elaborate normative behavior models from the players' performance and also to induce variability and adaptation in specific practice planning.

Data-Driven Visual Performance Analysis in Soccer: An Exploratory Prototype.

In soccer, understanding of collective tactical behavior has become an integral part in sports analysis at elite levels. Evolution of technology allows collection of increasingly larger and more specific data sets related to sport activities in cost-effective and accessible manner. All this information is minutely scrutinized by thousands of analysts around the globe in search of answers that can in the long-term help increase the performance of individuals or teams in their respective competitions. As the volume of data increases in size, so does the complexity of the problem and the need for suitable tools that leverage the cognitive load involved in the investigation. It is proven that visualization and computer-vision techniques, correctly applied to the context of a problem, help data analysts focus on the relevant information at each stage of the process, and generally lead to a better understanding of the facts that lie behind the data. In the current study, we presented a software prototype capable of assisting researchers and performance analysts in their duty of studying group collective behavior in soccer games and trainings. We used geospatial data acquired from a professional match to demonstrate its capabilities in two different case studies. Furthermore, we successfully proved the efficiency of the different visualization techniques implemented in the prototype and demonstrated how visual analysis can effectively improve some of the basic tasks employed by sports experts on their daily work, complementing more traditional approaches.

Mental Fatigue and Spatial References Impair Soccer Players' Physical and Tactical Performances.

This study examined the effects of mental fatigue and additional corridor and pitch sector lines on players' physical and tactical performances during soccer small-sided games. Twelve youth players performed four Gk+6vs6+Gk small-sided games. Prior to the game, one team performed a motor coordination task to induce mental fatigue, while the other one performed a control task. A repeated measures design allowed to compare players' performances across four conditions: (a) with mental fatigue against opponents without mental fatigue in a normal pitch (MEN), (b) with mental fatigue on a pitch with additional reference lines (#MEN); (c) without mental fatigue against mentally fatigued opponents on a normal pitch (CTR); and (d) without mental fatigue on a pitch with reference lines (#CTR). Player's physical performance was assessed by the distance covered per minute and the number of accelerations and decelerations (0.5-3.0 m/s2; > -3.0 m/s2). Positional data was used to determine individual (spatial exploration index, time synchronized in longitudinal and lateral directions) and team-related variables (length, width, speed of dispersion and contraction). Unclear effects were found for the physical activity measures in most of the conditions. There was a small decrease in time spent laterally synchronized and a moderate decrease in the contraction speed when MEN compared to the CTR. Also, there was a small decrease in the time spent longitudinally synchronized during the #MEN condition compared to MEN. The results showed that mental fatigue affects the ability to use environmental information and players' positioning, while the additional reference lines may have enhanced the use of less relevant information to guide their actions during the #MEN condition. Overall, coaches could manipulate the mental fatigue and reference lines to induce variability and adaptation in young soccer players' behavior.

Effects of pacing, status and unbalance in time motion variables, heart rate and tactical behaviour when playing 5-a-side football small-sided games.

OBJECTIVES: To compare time-motion variables, heart rate and players' tactical behaviour according to game pace (slow, normal or fast), status (winning and losing) and team unbalance (superiority and inferiority) in football 5-a-side small-sided games. To identify the most discriminating variables in classifying performances according to these constraints. DESIGN: Cross-sectional field study. METHODS: The data were gathered using global positioning systems (5 Hz) in 5-a-side small-sided games (7 × 5 min) played by twenty-four footballers. The tactical performance was measured using dynamical positioning variables, processed by non-linear signal processing techniques (approximate entropy). ANOVA models were used to compare between constraints and discriminant analyses to identify the variables that best discriminate between pacing and status × unbalance constraints. RESULTS: The fast paced games had the highest mean speed value, followed by normal and slow paced games (8.2 ± 0.6 km h(-1), 7.8 ± 0.5 km h(-1) and 6.2 ± 0.4 km h(-1), respectively). The stronger predictor variables of pacing were the randomness in distance to team centroid and the distances covered above 13 km h(-1). The results also changed according to game status and team unbalance. The strongest predictor variables were the distance covered below 6.9 km h(-1), distance and randomness to team centroid, with higher values when winning in superiority conditions. CONCLUSIONS: Practice task design manipulating game pace, status and team unbalance significantly influenced the emergent behavioural dynamics. Collective positioning variables were more accurate in discriminating these constraints and, therefore, need to be considered when planning and monitoring performance.

Time-motion and physiological profile of football training sessions performed by under-15, under-17 and under-19 elite Portuguese players.

PURPOSE: To provide the time-motion and physiological profile of regular training sessions (TS) performed during the competitive season by under-15 (U15), under-17 (U17), and under-19 (U19) elite-level Portuguese soccer players. METHODS: One hundred fifty-one elite players of U15 (age 14.0 ± 0.2 y, n = 56), U17 (age 15.8 ± 0.4 y, n = 66), and U19 (age 17.8 ± 0.6 y, n = 29) participated in the study during a 9-wk period. Time-motion and body-impact data were collected using GPS technology (15 Hz) across 38 randomly selected TS that resulted in a total of 612 samples. In addition, heart rate (HR) was continuously monitored (1 Hz) in the selected TS. RESULTS: The total distances covered (m) were higher in U17 (4648.3 ± 831.9), followed by U19 (4212.5 ± 935.4) and U15 (3964.5 ± 725.4) players (F = 45.84, P < .001). Total body impacts and relative impacts were lower in U15 (total: 490.8 ± 309.5, F = 7.3, P < .01), but no differences were identified between U17 (total: 584.0 ± 363.5) and U19 (total: 613.1 ± 329.4). U19 players had less high- and very-high-intensity activity (above 16 km/h; F = 11.8, P < .001) and moderate-intensity activity (10.0-15.9 km/h; F = 15.07, P < .001). HR values showed significant effects of zone (F = 575.7, P < .001) and interaction with age group (F = 9.7, P < .001), with pairwise differences between all zones (zone 1, <75%; zone 2, 75-84.9%; zone 3, 85-89.9%; zone 4, ≥90%). All players spent most of their time below 75% HRmax (U15, ~50%; U17, ~42%; U19, ~50%). CONCLUSION: Results showed high variability between TS, refraining from identifying meaningful trends when measuring performance, although different demands were identified according to age group. The U15 TS were less physiologically demanding, probably because of increased focus on small-sided games to develop basic tactical principles and technical skills. The focus on game-like situations imposed higher external and internal workloads on U17 and U19 players.