Comparative Analysis of Load Profile between Small-Sided Games and Official Matches in Youth Soccer Players

Effect of Rule Modifications on Kinematic Parameters Using Maturity Stage as a Moderating Variable in U-10 Football Players

The aim of the present study was to analyse the effects of regulatory modifications in competitive situations on cinematic variables, considering maturity stage as a moderating factor, in youth football players. A quasi-experimental study was conducted in which 45 players with a mean age of 9.47 ± 0.54 participated. The independent variable analysed was the modification of rules (playing time, scoring, and specific rules). The dependent variables analysed were cinematic variables. These variables were recorded with WimuTM. The maturity stage was considered a moderating factor in this effect. The main results indicate that the modified competition reduced the total distance covered, maximum acceleration speed, and distance covered in acceleration and deceleration in different speed zones. In addition, the maturity stage was found to moderate the effect of the intervention on the total distance covered, distance covered by accelerating in zone 3, and distance covered by decelerating in zone 3. Thus, the proposed modification appeared to reduce the physical demand for competition. Furthermore, it reduced the differences between players with early maturational development and those with late maturational development.

Association between match-related physical activity profiles and playing positions in different tasks: A data driven approach

Assessing the intensity characteristics of specific soccer drills (matches, small-side game, and match-based exercises) could help practitioners to plan training sessions by providing the optimal stimulus for every player. In this paper, we propose a data analytics framework to assess the neuromuscular or metabolic characteristics of a soccer-specific exercise in relation with the expected match intensity. GPS data describing the physical tasks' external intensity during an entire season of twenty-eight semi-professional soccer players competing at the fourth Italian division were used in this study. A supervised machine-learning approach was tested in order to detect difference in playing positions in different sport-specific drills. Moreover, a non-supervised machine-learning model was used to profile the match neuromuscular and metabolic characteristics. Players' playing positions during matches and match-based exercises are characterised by specific metabolic and neuromuscular characteristics related to tactical demands, while in the small-side game these differences are not detected. Additionally, our framework permits to evaluate if the match performance request is mirrored during training drills. Practitioners could evaluate the type of stimulus performed by a player in a specific training drill in order to assess if they reflect the matches characteristics of their specific playing position.

Identifying the ideal weekly training load for in-game performance in an elite Brazilian soccer team

Introduction: The purpose of this study was to investigate the ideal training load to be applied during periods of fixture congestion to ensure an adequate dose-response effect for performance maintenance. Methods: Match performance data and corresponding pre-match training load sessions (both N = 498 match performance cases and training-block session cases) were collected (with the catapult system, VECTOR7) from 36 male professional soccer players (23.5 ± 5.2 years; 178 ± 4 cm; 75.5 ± 6.0 kg) belonging to the Brazilian First Division team during the 2022 season. The following data were collected in match and training sessions: jump, acceleration, deceleration, and change of direction (COD); running distance producing metabolic power at different intensities (>20, >20-35, >35-45, >45-55, and >55 W kg-1), total distance (m), relative distance (m/min), running distance at different speeds (>20, >25, and >30 km/h), number of sprints (running >25 km/h), and maximum speed (km/h). Mixed linear model (MLM), decision tree regression (DTR), and cluster K means model (SPSS v.26) approach were performed to identify the most critical variables (and their respective load) in the training sessions that could explain the athlete's match performance. Results: MLM and DTR regression show that training load significantly affects game performance in a specific way. According to the present data, an interference phenomenon can occur when a high load of two different skills (running in a straight line vs COD, deceleration, and jumping) is applied in the same training block of the week. The cluster approach, followed by a chi-squared test, identified significant associations between training load and athlete match performance in a dose-dependent manner. Discussion: The high load values described here have a beneficial effect on match performance, despite the interference between stimuli discussed above. We present a positive training load from a congested season from the Brazilian First Division team. The study suggests that an interference effect occurs when high physical training loads are applied to different specific physical skills throughout the season.

Optimization of training for professional rugby union players: investigating the impact of different small-sided games models on GPS-derived performance metrics

Introduction: Professional rugby union players can improve their performance by engaging in small-sided games (SSGs), which simulate the movement patterns of the game. This study collected metrics related to running performance and mechanical workload and their relative values from both forward and back positions, aiming to explore the impact of different SSGs factors on athlete workload, as well as the workload difference between official games (OGs) and SSGs. Methods: The monitored GPS data were collected from SSGs with different player numbers and pitch sizes (five sessions), SSG rules (5 weeks, four sessions per week), and OGs conducted throughout the year. Additionally, the study compared changes in players' sprinting performance before and after two SSG sessions. Results: Backs had greater workload than forwards. Less space and number of players SSG (4 vs. 4, 660 m2) was conducive to facilitating training for players in acceleration and deceleration. Conversely, larger spaces were associated with improved running performance. However, the introduction of a floater had no significant impact on performance improvement. Additionally, the 7 vs. 4 model (seven players engaged with four opponents) resulted in the greatest workload during medium-hard accelerations (F = 52.76-88.23, p < 0.001, ηp 2 = 0.19-0.28). Japan touch model allowed for more high-speed running training (F = 47.93-243.55, p < 0.001, ηp 2 = 1.52). The workload performed by SSGs can almost cover that of OGs (F = 23.36-454.21, p < 0.05, ηp 2 = 0.03-0.57). In the context of ηp 2, values around 0.01, 0.06 and 0.14 indicate small, medium and large effects respectively. Discussion: However, given the significantly higher workload of SSGs and the slight decrease in sprinting performance, further research is required to examine the training patterns of SSGs. This study provided insight into the impact of player numbers, pitch size, and rules on rugby-specific SSGs. Coaches should optimize SSG setups for enhanced training outcomes, ensuring the long-term development of physical capacity, technical and tactical skills.

Comparison of external load indicators between official matches and sport-specific training in semi-professional soccer players: focus on intensity and strength

BACKGROUND

The aim of this study was to investigate any differences in external load indicators (ELi) between official matches (OM) and sport-specific tasks in semi-professional soccer players.

METHODS

Among 28 semi-professional soccer players, 1932 observations (age: 25±6 years, height: 183±6 cm, weight: 75.2±7 kg; FC Palermo, Palermo, Italy) were collected through GPS devices (Qstarz BT-Q1000EX, 10 Hz; Qstarz International Co., Ltd., Taipei, Taiwan) and the related software (LaGalaColli V: 8.6.4.3; Spinitalia Srl, Rome, Italy) during the season 2019-2020. Participants were monitored during OM, friendly matches (FM), small sided games (SSG), and match-based exercises (MBE), considering the percentage of intense accelerations (%int. acc.), percentage of intense decelerations (%int. dec.), and passive recovery time /min (PrT/m) as Eli.

RESULTS

We detected the highest mean value for PrT/m in OM and the lowest in MBE and SSG (18.36±4.38 and 13.4±5.26 and 13.4±4.29 (s/min), respectively). The lowest mean values of %int. acc. and %int. dec. were found in OM and the highest in SSG (8.64±1.52 vs. 13.02±3.14 and 9.25±1.56 vs. 15.68±3.14, for %int. acc. and %int. dec., respectively). Significant differences between the four tasks for all the ELi considered (P<0.001). The post-hoc pairwise comparisons revealed significant differences for all the ELi between all tasks (P<0.001) except for the %int. acc. between MBE vs. FM (P=0.003). No significant difference was found in PrT/m between MBE vs. FM and SSG vs. FM.

CONCLUSIONS

ELi are in accordance with the performance model by achieving better values in training than OM, suggesting the fundamental role of GPS for monitoring external load in soccer.

External load profile during different sport-specific activities in semi-professional soccer players

BACKGROUND

Global Positioning System (GPS) devices are widely used in soccer for monitoring external load (EL) indicators with the aim of maximizing sports performance.The aim of this study was to investigate the EL indicators differences in players of different playing positions (i.e., central backs, external strikers, fullbacks, midfielders, strikers, wide midfielder) between and within different sport-specific tasks and official matches.

METHODS

1932 observations from 28 semi-professional soccer players (age: 25 ± 6 years, height: 183 ± 6 cm, weight: 75.2 ± 7 kg) were collected through GPS devices (Qstarz BT-Q1000EX, 10 Hz) during the season 2019-2020. Participants were monitored during Official Match (OM), Friendly Matches (FM), Small Sided Games (SSG), and Match-Based Exercises (MBE). Metabolic (i.e., metabolic power, percentage of metabolic power > 35w, number of intense actions per minute, distance per minute, passive recovery time per minute) and neuromuscular indicators (i.e., percentage of intense accelerations, percentage of intense decelerations, change of direction per min > 30°) were recorded during each task.

RESULTS

Statistically significant differences were detected in EL indicators between playing positions within each task and between tasks. In particular, results from the two-way ANOVA tests showed significant interaction, but with small effect size, in all the EL indicators between playing positions for each task and within tasks. Moreover, statistical differences, but with small effect size, between playing positions were detected in each task and for each EL indicator. Finally, the strongest statistical differences (with large effect size) were detected between tasks for each EL indicator. Details of the Tukey post-hoc analysis reporting the pairwise comparisons within and between tasks with playing positions are also provided.

CONCLUSION

In semi-professional soccer players, different metabolic and neuromuscular performance were detected in different playing position between and within different tasks and official matches. Coaches should consider the different physical responses related to different physical tasks and playing position to design the most appropriate training program.

Quantifying Exposure and Intra-Individual Reliability of High-Speed and Sprint Running During Sided-Games Training in Soccer Players: A Systematic Review and Meta-analysis

BACKGROUND

Sided games (i.e., small sided, medium sided, large sided) involve tactical, technical, physical, and psychological elements and are commonly implemented in soccer training. Although soccer sided-games research is plentiful, a meta-analytical synthesis of external load exposure during sided games is lacking.

OBJECTIVE

The objective of this systematic review and meta-analysis was to: (1) synthesize the evidence on high-speed and sprint running exposure induced by sided games in adult soccer players, (2) establish pooled estimates and intra-individual reliability for high-speed and sprint running exposure, and (3) explore the moderating effects of game format and playing constraints.

METHODS

A literature search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. Four databases (PubMed/MEDLINE, Scopus, SPORTDiscus, Web of Science Core Collection) were systematically searched up to 25 January, 2022. Eligibility criteria were adult soccer players (population); training programs incorporating sided games (intervention); game manipulations including number of players, pitch dimension, and game orientation (comparator); and high-speed, very high-speed, and sprint relative (m[Formula: see text]min^-1) running distances and associated intra-individual reliability (outcome). Eligible study risk of bias was evaluated using RoBANS. Pooled estimates for high-speed and sprint running exposure, and their intra-individual reliability, along with the moderating effect of tracking device running velocity thresholds, pitch dimension (i.e., area per player), and game orientation (i.e. score or possession), were determined via a multi-level mixed-effects meta-analysis. Estimate uncertainty is presented as 95% compatibility intervals (CIs) with the likely range of relative distances in similar future studies determined via 95% prediction intervals.

RESULTS

A total of 104 and 7 studies met our eligibility criteria for the main and reliability analyses, respectively. The range of relative distances covered across small-sided games, medium-sided games, and large-sided games was 14.8 m[Formula: see text]min^-1 (95% CI 12.3-17.4) to 17.2 m[Formula: see text]min^-1 (95% CI 13.5-20.8) for high-speed running, 2.7 m[Formula: see text]min^-1 (95% CI 1.8-3.5) to 3.6 m[Formula: see text]min^-1 (95% CI 2.3-4.8) for very high-speed running, and 0.2 m[Formula: see text]min^-1 (95% CI 0.1-0.4) to 0.7 m[Formula: see text]min^-1 (95% CI 0.5-0.9) for sprinting. Across different game formats, 95% prediction intervals showed future exposure for high-speed, very high-speed running, and sprinting to be 0-46.5 m[Formula: see text]min^-1, 0-14.2 m[Formula: see text]min^-1, and 0-2.6 m[Formula: see text]min^-1, respectively. High-speed, very high-speed running, and sprinting showed poor reliability with a pooled coefficient of variation of 22.8% with distances being moderated by device speed thresholds, pitch dimension, and game orientation.

CONCLUSIONS

This review is the first to provide a detailed synthesis of exposure and intra-individual reliability of high-speed and sprint running during soccer sided games. Our estimates, along with the moderating influence of common programming variables such as velocity thresholds, area per player, and game orientation should be considered for informed planning of small-sided games, medium-sided games, and large-sided games soccer training.

CLINICAL TRIAL REGISTRATION

Open Science Framework available through https://osf.io/a4xr2/ .

Physiological and locomotor demands during small-sided games are related to match demands and physical fitness? A study conducted on youth soccer players

Aim

The purpose of the study was: (i) to analyze the relationships of physiological and locomotor demands between small-sided games (3v3 and 5v5) and official matches (11v11); (ii) to analyze the relationships between small-sided games demands and the physical fitness of youth soccer players.

Methods

The observational study lasted three weeks. In the first week participants performed the 5v5 (50 × 31 and 40 × 25 m) repeatedly over four days. In the third week they repeatedly performed the 3v3 (39 × 24 and 32 × 19 m) over four consecutive days. Twenty youth soccer players (age: 16.8 ± 0.41) were tested twice for their final velocity at 30–15 Intermittent Fitness test (VIFT), peak speed attained at 30-m sprint test (peak speed), and anaerobic speed reserve (ASR). The heart rate responses and locomotor demands were monitored in the SSGs (3v3 and 5v5) and matches (11v11) occurring once a week. The Polar Team Pro was used as the instrument to monitor heart rate and locomotor demands. Three official matches were also monitored during the period.

Results

Results revealed no significant correlations (p > 0.05) between small-sided games and match physiological or locomotor demands. However, VIFT and ASR were significantly correlated with distance covered at 5v5 (r = 0.483; p = 0.031; and r = − 0.474; p = 0.035, respectively), average speed (r = 0.474; p = 0.035; and r = − 0.453; p = 0.045, respectively), while VIFT was also significantly correlated with distance covered at Z2 intensity (r = 0.510; p = 0.022).

Conclusions

The results suggest that the physiological and locomotor demands occurring in small-sided games are significantly different from those occurring in official matches. Thus, physiological and locomotor similarities between small-sided games and official matches are scarce. Considering the second purpose of this study, the results suggest that VIFT and ASR are important physical fitness parameters to modulate the amount of distance covered by the players in 5v5, the average pace, and also the distance covered at high intensities.

MONITORIZACIÓN DE UN MICROCICLO COMPETITIVO EN BALONCESTO FEMENINO PROFESIONAL MEDIANTE DISPOSITIVOS INERCIALES

La implementación de estrategias efectivas de control de carga en el entrenamiento es primordial para mejorar el rendimiento. El objetivo fue caracterizar las demandas soportadas durante un microciclo competitivo de un equipo profesional de baloncesto femenino y su interacción con la competición. Diez jugadoras se equiparon con un dispositivo inercial y una banda de frecuencia cardíaca. Se analizó la carga soportada por las jugadoras durante el entrenamiento y la competición mediante variables de Carga Externa: (i) Distancia recorrida, (ii) Distancia recorrida a alta intensidad, (iii) Playerload, (iv) Saltos, (v) Aceleraciones y Deceleraciones, y (vi) Velocidad máxima y media; y variables de Carga Interna: (i) Frecuencia cardíaca media y máxima, (ii) Zonas de % Frecuencia Cardíaca Máxima. Se analizaron diferencias entre el entrenamiento y la competición mediante un análisis ANOVA, observando que la competición fue la condición más exigente en todas las variables estudiadas a excepción de los saltos por minuto.

External Workload Compared Between Competitive and Non-Competitive Matches for Professional Male Soccer Players

The purpose of this study was to compare the external load in competitive (official) and non-competitive matches (friendly, training and modified-sided games) in professional soccer players. Time-motion data for 10 elite male soccer players (age = 20.1 ± 2.1 years; body height = 178.8 ± 5.9; body mass = 71.4 ± 7.3; % body fat = 11.0 ± 1.1 and VO_2max = 55.96 ± 3.3) from a professional Spanish first division team were recorded during official (n = 12), friendly (n = 7) and training (n = 6) matches and a 5 vs. 5 + goalkeepers modified-sided game (n = 3). GPS devices were used to monitor players’ external loads: total distance covered, distance covered at different speeds (<13.9 km·h^-1, >14, >18, >21 and >25 km·h^-1), peak speed (km·h^-1), and the number of accelerations and decelerations (1.5–2.5 m·s^-2, 2.5–4 m·s^-2 and 4–8 m·s^-2). One-way analysis of variance of the magnitude-based inference was used to determine differences between matches. Data indicated that official matches scored statistically higher peak speeds (ES = 1.40–2.20). In modified-sided games more total distance was covered at <13.9 km·h^-1 and >14 km·h^-1 than in regular matches (ES = 0.72–2.21), but lower distances were covered at >21 km·h^-1 and >25 km·h^-1 than in official and friendly matches (ES = 0.51–2.53) and at >25 km·h^-1 than in training matches (ES = 0.92). Likewise, the modified-side games showed a greater number of accelerations and decelerations than other types of matches (ES = 1.46–2.51). This work shows that friendly and training matches, in conjunction with modified-side games, are suitable tools to prepare soccer players for official matches.

Differences in External and Internal Load in Elite Youth Soccer Players within Different Match Timing Zones

The aim of this study was to determine and analyze the differences between the players’ internal (IL) and external load (EL) in different time zones (T1: 0–45 min, T2: 45–70 min, T3: 0–70 min, T4: 70–90 min, T5: 45–90 min, and T6: 0–90 min) in elite youth soccer matches (U17–19 age category). The monitored group comprised elite youth soccer players (n = 66; age = 17.5 ± 1.2 years; body height = 178.5 ± 8.7 cm; body mass = 70.4 ± 6.3 kg). Multivariate analysis of variances was used to compare the following variables: relative total distance covered (TDCrel), distance covered in different speed zones (Z1–Z6), high-metabolic load distance (HMLD), maximum running speed (Smax), number of acceleration (ACC) and deceleration (DCC) entries in different speed zones (Z1, Z2, Z3), and maximum heart rate (HRmax). Results revealed significant differences (p < 0.05) in the first 70 min (T3) compared to the last 20 min of the match (T4) in the following: TDCrel was higher, up to 6.6% (123.09 ± 9.48 vs. 115.03 ± 9.42 m.min−1); distance in Z5 (22.4%, 6.08 ± 1.82 vs. 4.72 ± 1.72 m.min−1); Z4 (18.6%, 20.15 ± 4.82 vs. 16.40 ± 3.48 m.min−1); Z3 (10.4%, 53.06 ± 47.52 m.min−1); and HMLD (16.1%, 34.86 ± 5.67 vs. 29.26 ± 5.11 m.min−1). We also found higher running performance in the first half (T1) than in the second half (T5) in the following parameters: TDCrel, Z5, Z4, ACCZ1, ACCZ2, and DCCZ1. With progressive time (in T4) we found a significant decrease in physical running performance, probably due to fatigue, which can lead to potential injury or losing in a match. The results of this study may provide helpful information in developing training strategies for coaches and in the set-up of plan for potential substitution of exhausted players mainly for the last 20 min of a match (T4). The present results are expressed as a relative value and should be compared with other study results with irregular timing zones.

Acceleration and deceleration demands during training sessions in football: a systematic review

PURPOSE

The aim of this review is to summarize the current scientific knowledge about acceleration and deceleration demands during football training.

METHODS

A systematic search of three electronic databases (PubMed, SPORTDiscus, Web of Science) was performed to identify peer-reviewed relevant English-language articles, following PRISMA guidelines.

RESULTS

All acceleration and deceleration data were analyzed and organized into four categories: i) training drills variables (i.e. manipulated drills variables such as number of players in small-sided games), ii) training exercises (i.e. different drills such small games or circuit training), iii) players' positions (i.e. demands for each playing position) and iv) training schedule (i.e. training sessions presented as microcycles, season sections or full season). Full-text articles of 42 studies were included in the final analysis. Players' level included: amateur, youth, semi-professional, professional and elite players. All playing positions were considered, including goalkeepers. Six different global position systems brands were used, with the majority measuring data at 10 Hz. Different thresholds and intensities were used in several papers. Lower acceleration and deceleration intensities occurred more often than higher intensities in all four categories.

CONCLUSION

Different exercises elicit different demands and small-sided games presented higher acceleration and deceleration demands than circuit training and other running based drills. Furthermore, manipulating drills variables, as reducing or increasing number of players in small-sided games increase or decrease demands, respectively. Additionally, wide playing positions, such as fullbacks, are generally exposed to higher acceleration and deceleration demands. From a planning point of view, acceleration and deceleration demands decrease as match day approaches.

Applying Different Strategies of Task Constraint Manipulation in Small-Sided and Conditioned Games: How Do They Impact Physical and Tactical Demands?

This study aimed to investigate how different strategies of task constraint manipulation impact physical and tactical demands in small-sided and conditioned games (SSCG). Ten recreational U-17 soccer players participated in this study (16.89 ± 0.11 years). We used different strategies of task manipulation to design two 4 vs. 4 SSCG: Structural SSCG and Functional SSCG. In Structural SSCG, pitch format and goal sizes were manipulated, while in Functional SSCG, players were allowed to kick the ball twice and at least 5 passes to shoot at the opponent’s goal. Players participated in four Structural and Functional SSCG, of five minutes duration with a two-minute interval in between. Players’ physical performance and tactical behavior were assessed using the WIMU PROTM inertial device. Structural SSCG stimulated players to cover more distance in sprinting (p = 0.003) and high-speed running (p < 0.001). Regarding tactical behavior, Structural SSCG stimulated players to explore game space better (p < 0.001). Moreover, Functional SSCG stimulated players to be closer to the ball, decreasing the effective playing space (p = 0.008). We conclude that these strategies of task constraint manipulation impact physical and tactical demands of the game.

Inter- and intra-microcycle external load analysis in female professional soccer players: A playing position approach

This study analyzes the inter- and intra-differences in external load across the microcycle in professional female soccer players. External load during four consecutive microcycles (i.e., M1, M2, M3, and M4) and training sessions (i.e., MD-4, MD-3, MD-2, and MD-1) and a match day (i.e., MD) were registered in seventeen female professional soccer players (age: 26.3 ± 4.6 years; height: 166.3 ± 6.1 cm; body mass: 59.8 ± 6.8 kg; and body mass index: 21.6 ± 1.7 kg·m^-2) who belonged to the same team in Spanish first division. A 10-Hz GPS that integrated a 100-Hz triaxial accelerometer was used to register external load. The results showed lower decelerations in M2 compared to M1 and M3 (p < 0.05), lower high-intensity distance (>16.0 km·h^-1) in M3 vs. M2, and greater relative sprint distance (>21.0 km·min^-1) in M4 vs. M1 and M3 (p < 0.05). MD-3 registered the highest load for all variables (p < 0.05). Forwards (FWs) performed (p < 0.05) significantly more sprints (meters and number > 21.0 km·h^-1) than central midfielders (CMs) and central defenders (CDs) in MD-2 and MD. Both, fitness and conditioning staff should pay special attention to the external loads for each playing position in training sessions to optimize the training process.

Analysis of Intensities Using Inertial Motion Devices in Female Soccer: Do You Train like You Compete?

Intensity research in female soccer is limited. This study aimed to investigate whether female professional soccer players train with external and internal intensities similar to those recorded in real competition. The specific players' position, the game situation and training task type were analyzed in a total of 18 female players (26.25 ± 3.89 years). The empirical, descriptive and associative study was structured into two parts. Part 1: characterizing the training sessions (n = 13) and official matches (n = 3) using the Integral Analysis System of Training Tasks. The association between sports planning variables was evaluated using adjusted standardized residuals from contingency tables, Chi-Square and Fisher tests, as well as the Phi and Cramer's V coefficients. The main findings show that the coach and/or physical trainer predominantly planned training sessions using small-sided games, which integrate physical fitness and tactical-technical behaviors of the game and imply a medium-high subjective external intensity (20.63 ± 5.79 points). The subjective external intensity of the matches was very high (30.00 ± 0.00 points). Part 2: quantifying the external and internal intensity through the inertial motion devices and heart rate monitors. Differences in the intensities according to the type of session (training session and match), specific position of the players, game situation and type of the training task were assessed through different statistical tests. By specific position (Kruskal-Wallis H and one-factor ANOVA tests), defenders performed fewer accelerations/min and decelerations/min, while they recorded higher heart rates in training sessions and official matches. In contrast, the wingbacks performed higher accelerations/min and decelerations/min in training sessions and official matches. The wingers had the lowest heart rate in official matches. Regarding the game situation (Kruskal-Wallis H test) measured during training sessions, the unopposed tasks recorded higher accelerations/min and decelerations/min, while the small-sided games and full games recorded higher values in the rest of the intensities (both subjective and objective). With regard to the type of training task (Kruskal-Wallis H test), the simple application exercises recorded higher accelerations/min and decelerations/min. Distance in meters/min was greater in the complex application exercises. High-intensity activity/min and player load/min were higher in the simple specific game. In addition, modified sport and real game recorded higher subjective external intensity*min, sprints/min and heart rate. Furthermore, training sessions differed statistically (Mann-Whitney U test) from official matches in terms of subjective intensity and the objective external and internal intensity variables weighted by minutes. For all these reasons, female players do not train (training sessions) as they compete (official matches). The use of inertial motion devices has made it possible to quantify intensities during training sessions and real competition in soccer.

Integrating video tracking and GPS to quantify accelerations and decelerations in elite soccer

The aim of this study was to analyze the degree of agreement comparing number and distance covered in different acceleration and deceleration sections registered by a video tracking system (MEDIACOACH) and a GPS device (WIMU PRO) during official competition. Data from a Spanish professional club were registered over the course of a season. First, the descriptive statistics presented more bursts of accelerations and decelerations in WIMU PRO than in MEDIACOACH, whereas the distances covered recorded by both systems were similar. Second, negative relationships were found (i.e., negative bias) comparing WIMU PRO to MEDIACOACH in the number of accelerations and decelerations between 0/1 m/s² and ½ m/s² (p < 0.05), and in the distances covered in accelerations and decelerations (p < 0.05) between 0/1 m/s² and in accelerations and decelerations registered between 2/3 m/s² and more than 3 m/s². Moreover, the differences in means (i.e., standardized mean bias) across the two devices were trivial (> 0.19) and small (0.2-0.59) for most variables. The standardized typical errors in the estimate (TEE) were moderate (0.3-0.59) and small to moderate (0.1-0.29 to 0.3-0.59), respectively. Also, the Intra class Correlation Coefficients (ICCs) for agreement and consistency between systems showed good and excellent values (> 0.90). The magnitude of change in means (%) between systems, defined as the percentage change between the numbers or values, was below 14% and 7% for number and distances covered, respectively. All scores in the smallest worthwhile change were lower than 9% and in the coefficients of variation were lower than 95% and 15%, respectively. Thus, both systems demonstrated an acceptable degree of agreement and could be useful in analyzing players' acceleration demands in professional soccer. However, caution is required when interpreting the results and a comparison with a gold standard is required in order to validate both systems.

Training Load in Different Age Category Soccer Players and Relationship to Different Pitch Size Small-Sided Games

This study sought to evaluate the training load in different age category soccer players associated with distinct pitch size small-sided games (SSGs). Twenty-four soccer players (eight in each age category: U-12, U-15, and U-23) performed three consecutive 4 vs. 4 ball possession SSGs (SSG1: 16 × 24 m; SSG2: 20 × 30 m; and SSG3: 24 × 36 m) all with 3 min duration and 3 min rest. Subjects carried ultra-wideband-based position-tracking system devices (WIMU PRO, RealTrack System). Total distance covered increased from SSG1 to SSG3 in all age categories and predominantly in running speeds below 12 km·h⁻¹. Moreover, distance covered in 12–18 km·h⁻¹ running speed was different in all performed SSGs and age categories. Residual or null values were observed at 18–21 km·h⁻¹ or above running speed, namely in U-12, the only age category where metabolic power and high metabolic load distance differences occurred throughout the performed SSGs. Edwards’ TRIMP differences between age categories was only observed in SSG2 (U-12 < U-15). The design of SSGs must consider that the training load of the players differs according to their age category and metabolic assessment should be considered in parallel to external load evaluation in SSGs. Wearable technology represents a fundamental support in soccer.

Assessment of Body Composition, Lower Limbs Power, and Anaerobic Power of Senior Soccer Players in Portugal: Differences According to the Competitive Level

BACKGROUND

During a soccer game, the most diversified stimuli occur all the time, the physical condition level plays a determinant role, and there may be variations according to the competitive level. In this sense, the present study aimed to verify differences in body composition, lower limbs power, and anaerobic power, comparing senior soccer players of different competitive levels.

METHODS

Participants were 81 players belonging to six soccer teams, aged between 18 and 35 years, with a mean age of 23.14 ± 4.23 years, who were divided into three distinct competitive levels: Elite, Sub-Elite and Non-Elite. The players performed bioimpedance evaluations on a tetrapolarInbody270 scale (body composition), the Countermovement Jump (CMJ) through the ChronoJump (lower limbs power), and Running Anaerobic Sprint Test (RAST) (anaerobic power).

RESULTS

Based on the competitive level analysis, we verified that the players present body composition values similar to each other regardless of the competitive level in which they play. Concerning the performance evaluations, we verified that the elite players present higher values of highest jump (p = 0.012; d = 0.76, moderate; and p = 0.022; d = 0.71, moderate) and maximum force produced (p = 0.05; d = 0.64, moderate; and p = 0.002; d = 1.00, moderate), together with higher values of anaerobic power (p < 0.001; d = 2.43, very large; and p < 0.001; d = 2.22, very large), compared to the others.

CONCLUSIONS

We can thus conclude that there is a homogeneity regarding the body composition of soccer players, regardless of their competitive level; in turn, elite players show better performance indicators in all variables.

Effects of Small-Sided Game Interventions on the Technical Execution and Tactical Behaviors of Young and Youth Team Sports Players: A Systematic Review and Meta-Analysis

Background: Small-sided games (SSGs) are an adjusted form of official games that are often used in training scenarios to introduce a specific tactical issue to team sports players. Besides the acute effects of SSGs on players' performance, it is expectable that the consistent use of these drill-based games induces adaptations in the technical execution and tactical behaviors of youth team sports players.

Objective: This systematic review with meta-analysis was conducted to assess the effects of SSG programs on the technical execution and tactical behaviors of young and youth team sports players.

Data Sources: The data sources utilized were PubMed, Scopus, SPORTDiscus, and Web of Science.

Study Eligibility Criteria: (i) Young and youth team sports players (i.e., < 18 years old) of any sex or skill level, without injury, illness, or other clinical conditions; (ii) SSGs-based programs not restricted to the duration and a minimum of one weekly training session; (iii) passive or active control groups; (iv) pre-post interventions values of technical execution and/or tactical behavior; (v) randomized and non-randomized controlled trials; and (vi) peer-reviewed original full-text studies written in English, Portuguese and/or Spanish.

Results: The database search initially yielded 803 titles. From those, six articles were eligible for the systematic review and meta-analysis. None of the included studies presented tactical behavior outcomes. The results showed a small effect of SSGs on technical execution (ES = 0.59; 95% CI = 0.29 to 0.89; p < 0.001; I² = 0.0%; Egger's test p = 0.590) when compared to controls. Sub-group analysis of the training factor revealed similar (p = 0.433) moderate (ES = 0.68, four study groups) and small (ES = 0.44, three study groups) improvements in technical execution after >17 and <17 SSG training sessions, respectively.

Conclusions: This systematic review and meta-analysis revealed a significant beneficial effect of using SSG training programs for enhancing technical execution in young and youth players. The benefits were similar despite the various numbers of training sessions applied. Further studies should add tactical behaviors as one of the outcomes for controlling the effects of SSG training programs.

Performance Parameters in Competitive Alpine Skiing Disciplines of Slalom, Giant Slalom and Super-Giant Slalom

The objective of this study was to describe the kinematic patterns and impacts in male and female skiers in the super-giant slalom, giant slalom and slalom disciplines of an international alpine skiing competition using a portable Global Navigation Satellite Systems (GNSS) technology device. Fifteen skiers (males, n = 9, females, n = 6) volunteered to participate in this study. Data acquisition was carried out using a wireless inertial measurement device (WIMUTM PRO: hybrid location system GNSS at 18 Hz with a precision locator UltraWideband UWD (<10 cm) and 3D accelerometers 1000 Hz) where distances covered in different speed and acceleration thresholds and impacts above 5g were recorded in each of the disciplines. Male and female alpine skiers showed different physical parameters and impacts even though they competed in the same courses in the disciplines of slalom, giant slalom and super-giant slalom (total impacts: p < 0.001; impacts > 7 g: p = 0.013; impacts 6.1–7 g: p = 0.002; impacts 5.1–6 g: p = 0.006). In male skiers, the distances traveled at different speed thresholds have a direct relation to the ranking of skiers, but this ideal threshold decreased as the technicality of the discipline increased. In the case of female skiers, although no relation was seen with the speed thresholds, greater distances covered at medium accelerations improved skiing performance. The external load in alpine skiing varied based on sex and discipline. This information could be essential to develop sex-specific and discipline-specific training programs in alpine skiing.

Comparative external workload analysis based on the new functional classification in cerebral palsy football 7-a-side. A full-season study

The evolution of functional classification (FT) is important for promoting competitive balance. Technological advances allow the objective monitoring of competitive demands that is required to manage and individualize workloads. Therefore, this study aimed to characterize external workload in all matches from the 2018/2019 season of the CPF7 Spanish National League and to compare demands based on the new FT (FT1, FT2 yFT3) in time-motion (locomotion and speed changes) and accelerometer-based workload (impacts). Statistical analysis was composed of one-way ANOVA with Bonferroni post-hoc and omega partial squared effect size. Differences were found among all FT in total distance, running, high-intensity, sprinting, very high accelerations and decelerations (FT3> FT2> FT1; p < .01; ω_p²= 0.29-to-0.43); and with respect to the highest functional limitation (FT3 = FT2> FT1) in maximum sprinting, moderate-high accelerations and decelerations, total impacts and at very-low intensity (ω_p²= 0.13-to-0.29). In conclusion, FT3 players presented a physical advantage with respect to FT2-FT1 players in competition, especially in high-intensity actions that are crucial in team-sports performance. The present results facilitate designing specific training workloads according to FT, players' disability and competition demands, being the first approach to characterize match demands with inertial devices based on the new FT.

Effects of football versus aerobic exercise training on muscle architecture in healthy men adults: a study protocol of a two-armed randomized controlled trial

BACKGROUND

Sports and exercise training can attenuate age-related declines in physical function. As people age, they suffer a progressive deterioration of overall muscle structure and function, such as muscle diameter, strength, mass, and power. Therefore, supporting older adults-aged 50 years and above-to continue being physically active is a very important factor. Several forms of exercise (strength, agility, endurance, balance, and flexibility) are recommended. In this regard, football has been repeatedly shown to be an integrative approach to promote measures of strength, endurance, and agility. However, there has been no previous randomized controlled trial that comparatively investigates the effects of football training versus traditional aerobic exercise training on muscle architecture and patella tendon properties in healthy community dwellers. The study protocol is designed to examine whether football differentially affects muscle thickness, muscle length, fascicle length, pennation angle, patella tendon length, and thickness compared to a workload matched traditional aerobic exercise training regimen.

METHODS

The study sample consists of 60 untrained but healthy men (50-60 years old), who will be randomly assigned (strata: age, activate) to two groups: football group (n = 30) and aerobic group (n = 30). The intervention will take place within 12 consecutive weeks, two times a week for 60 min each session. The football group will perform recreational football training as a large-sided game, whereas the aerobic group undergoes a running exercise. Both groups have the same external workload ranging between moderate and high exercise intensity. The outcome measure will be collected before and after the intervention period.

DISCUSSION

Findings of this study will provide insight into the effects of 24 sessions of both football and aerobic training program on the selected groups of men adults, including detecting their effects on the thigh muscle architecture.

TRIAL REGISTRATION

DRKS-German Clinical Trials Register, DRKS00020536 . Registered on 30 January 2020.

Match and Training High Intensity Activity-Demands Profile During a Competitive Mesocycle in Youth Elite Soccer Players

The monitoring of the high intensity activity-demands profile during official matches (OMs) and training sessions (TSs) provides a deeper understanding of the relationship between training and competition loads as well as players’ fitness characteristics. The aims of this study were to: 1) describe the training and match high intensity activity-demands profile in U-19 soccer players; 2) compare the profile depending on the type of session (OM or TS) throughout match-weeks; and 3) differentiate between profiles depending on the match location (home or away). Twenty-five U-19 Spanish soccer players were monitored during TSs and OMs for a one-month competitive period using a WIMU PRO^TM wearable inertial device. The variables of the study were: high speed running distance (HSRD), total sprints (SPs), maximum speed (MS) and player load (PL). OMs required higher demands than TSs in HSRD (460.99 ± 206.18 vs. 315.45 ± 180.12 m; p < 0.01; d = 0.75), SPs (10.86 ± 6.64 vs. 7.23 ± 4.82; p < 0.01; d = 0.69), MS (29.99 ± 2.54 vs. 28.50 ± 2.4 km/h; p < 0.01; d = 0.59) and PL (103.08 ± 24.15 vs. 83.18 ± 17.96 a.u.; p < 0.01; d = 0.94). The interaction between the type of session and mean week’s demands presented differences with medium effect size in MS (p < 0.01; ω_p² = 0.06) and small effect size in HSRD (p = 0.04; ω_p² = 0.03), and SP (p = 0.05; ω_p² = 0.03), but there were no differences in PL (p = 0.18; ω_p² = 0). Finally, no differences were found in the match location comparison (p > 0.33; d = 0.22–0.33). Therefore, the profiles presented could be useful for future scientific purposes and serve as valid information for coaches trying to optimize performance.

Effect of Playing Position, Match Half, and Match Day on the Trunk Inclination, G-Forces, and Locomotor Efficiency Experienced by Elite Soccer Players in Match Play

The rapid growth of wearable sensors has allowed the analysis of trunk kinematics during the match, which is necessary for having a better understanding of the postural demands of soccer players. However, some contextual variables may have an impact on the physical demands of the players. This study aimed to analyze the effect of three contextual variables (playing position, match half, and match day) on the sagittal trunk inclination, G-forces, and locomotor efficiency experienced by soccer players in match play. Then, wearable sensors were used to collect the trunk kinematics during 13 matches. Firstly, positional differences were found on the trunk inclination (p = 0.01) and the G-forces experienced by the players (p < 0.001). For example, the greatest and lowest trunk inclination was found for FW (~34.01°) and FB (~28.85°) while the greatest and lowest G-forces were found for WMF (1.16 G) and CD (1.12 G), respectively. However, there were no positional differences in the locomotor efficiency (p = 0.10). Secondly, the match half had a significant effect on the trunk inclination (p = 0.01) and the G-forces experienced by the players (p < 0.001) with significantly lower values observed during the second half. No differences between halves were found on the locomotor efficiency for any playing position (p = 0.41). Finally, no significant effect of match day on any variable was observed. This investigation is one of the first steps towards enhancing the understanding of trunk kinematics from elite soccer players. The positional differences found on the trunk inclination and G-forces imply that the development of position-specific training drills considering the postural demands is necessary to prepare the players not only for the physical demands but also for successful performance in the field of regard. The resistance to fatigue needs to be trained given the differences between halves.

Accelerometry as a method for external workload monitoring in invasion team sports. A systematic review

Accelerometry is a recent method used to quantify workload in team sports. A rapidly increasing number of studies supports the practical implementation of accelerometry monitoring to regulate and optimize training schemes. Therefore, the purposes of this study were: (1) to reflect the current state of knowledge about accelerometry as a method of workload monitoring in invasion team sports according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, and (2) to conclude recommendations for application and scientific investigations. The Web of Science, PubMed and Scopus databases were searched for relevant published studies according to the following keywords: "accelerometry" or "accelerometer" or "microtechnology" or "inertial devices", and "load" or "workload", and "sport". Of the 1383 studies initially identified, 118 were selected for a full review. The main results indicate that the most frequent findings were (i) devices' body location: scapulae; (b) devices brand: Catapult Sports; (iii) variables: PlayerLoadTM and its variations; (iv) sports: rugby, Australian football, soccer and basketball; (v) sex: male; (vi) competition level: professional and elite; and (vii) context: separate training or competition. A great number of variables and devices from various companies make the comparability between findings difficult; unification is required. Although the most common location is at scapulae because of its optimal signal reception for time-motion analysis, new methods for multi-location skills and locomotion assessment without losing tracking accuracy should be developed.

Worst case scenario match analysis and contextual variables in professional soccer players: a longitudinal study

This study aimed to describe the worst-case scenarios (WCS) of professional soccer players by playing position in different durations and analyse WCS considering different contextual variables (match half, match location and match outcome). A longitudinal study was conducted in a professional soccer team. Data were collected from different WCS durations in the total distance (TD), high-speed running distance (HSRD), and sprinting distance (SPD). A mixed analysis of variance was performed to compare different WCS durations between playing positions and contextual variables, making pairwise comparisons by Bonferroni post hoc test. Positional differences were found for TD (p < 0.01, ω_p² = 0.02), HSRD (p < 0.01, ω_p² = 0.01) and SPD (p < 0.01, ω_p² = 0.02). There was a significant interaction when comparing WCS by match half in TD (F = 6.1, p < 0.01, ω_p² = 0.07) but no significant differences in HSRD (p = 0.403, ω_p² = 0) or SPD (p = 0.376, ω_p² = 0). A significant interaction was identified when comparing WCS by match location in TD (F = 51.5, p < 0.01, ω_p² = 0.14), HSRD (F = 19.15, p < 0.01, ω_p² = 0.05) and SPD (F = 8.95, p < 0.01, ω_p² = 0.01) as well as WCS by match outcome in TD (F = 36.4, p < 0.01, ω_p² = 0.08), HSRD (F = 13.6, p < 0.01, ω_p² = 0.04) and SPD (F = 7.4, p < 0.01, ω_p² = 0.02). Positional differences exist in TD, HSRD, and SPD in match-play WCS, and contextual variables such as match half, match location and match outcome have a significant impact on the WCS of professional soccer players.

Quantification of external load of elite rink hockey players in official matches

BACKGROUND

The demands of elite rink hockey competition are unknown to coaches, although nowadays the explosion of tracking technology makes it possible to fill this research gap. The aims of this study were twofold: firstly, to describe the external load demands involved in a rink hockey match and secondly, to ascertain whether there were differences between exterior (EX) and interior or forward (IN) player positions.

METHODS

A retrospective observational study was conducted between 2017 and 2018 competitive season. Eight professional players (6 EX and 2 IN) participated voluntarily in the study during 9 official matches. Data logging was performed with a local positioning system and the variables studied were distance covered (DT), distance covered above 18 km/h (HSS), player load (PL), number of high-intensity accelerations (ACC) and number of high-intensity decelerations (DEC).

RESULTS

The average values per player were 4646±1135 m of DT for EX and 4919±1374 for IN, 897±252 m of HSS for EX and 981±313 for IN (mean ±SD); 173±69 and 167.5±57.5 ACC for EX and IN, respectively, and 164±56 and 152.5±42 DEC for EX and IN, respectively (median±IQR); and there were no significant differences (P>0.05), between positions.

CONCLUSIONS

The findings of this study allow us to ascertain the external load in matches and that EX and IN did not present different physical demands. With this information, coaches can adjust training loads more accurately.

Influence of Contextual Variables in the Changes of Direction and Centripetal Force Generated during an Elite-Level Soccer Team Season

The study of the contextual variables that affect soccer performance is important to be able to reproduce the competition context during the training sessions. Therefore, the aim of the present study was to evaluate the effect of match outcome as related to goal difference (large win, >2 goals, LW; narrow win, 1–2 goals, NW; drawing, D; narrow loss, 1–2 goals, NL; or large loss, >2 goals, LL), match location (home, H; away, A; neutral, N), type of competition (international, INT; national, NAT; friendly, F), phase of the season (summer preseason, SPS; in-season 1, IS1; winter preseason, WPS; in-season 2), and the field surface (natural grass, NG; artificial turf, TF) on the change of direction (COD) and centripetal force (CentF) generated during official games. Thirty male elite-level soccer players (age: 26.57 ± 5.56 years) were assessed while using WIMU PRO^TM inertial devices (RealTrack Systems, Almeria, Spain) in 38 matches during the 2017–2018 season, selecting for analysis the number of COD at different intensities and the CentF, depending on the turn direction. Statistical analyses comprised a one-way ANOVA with the Bonferroni post-hoc and t-test for independent samples. The main results showed that the match outcome (ω_p² = 0.01–0.04; NW = D = NL > LL), match location (ω_p² = 0.01–0.06; A = N > H), type of competition (ω_p² = 0.01–0.02; INT > NAT > F), and period of the season (ω_p² = 0.01–0.02; SPS = IS1 = WPS > IS2) all exert some influence. No effect was found for the playing surface. Therefore, match outcome, match location, type of competition, and period of the season influence the demands of centripetal force and changes of direction. These aspects should be considered in the design of training sessions and microcycle workload planning during the season to improve competitive success.

Quantification of Internal and External Load in School Football According to Gender and Teaching Methodology

The design of teaching tasks determines the physical and physiological demands that students are exposed to in physical education classes. The purpose of this study is to quantify and compare, according to gender and teaching methodology, the external (eTL) and internal (iTL) load resulting from the application of two programs that follow different teaching methodologies, i.e., a Tactical Games Approach (TGA) and Direct Instruction (DI), to teach school football. The Ratings of Perceived Exertion (RPEs) recorded in the assessments were also studied. A total of 41 students in the fifth year of primary education from a state school from Spain participated in the study (23 boys and 18 girls), aged from 10 to 11 (M ± SD, 10.63 ± 0.49 years) and divided into two class groups. All the sessions were monitored with inertial devices that made it possible to record physical activity and convert the information into kinematic parameters. The results indicated that the students who followed the TGA method recorded higher iTL values (heart rate) and spent more time performing high-intensity activities. Boys recorded higher eTL, iTL, and RPE values than girls. There was an evolution in the RPE between the assessments, with both groups presenting a more efficient RPE in the posttest. The TGA method favors student physical fitness and health, thus, this method is recommended when planning physical education sessions.

Analysis of playing position and match statusrelated differences in external load demands on amateur handball: a case study

Abstract Currently, the load quantification during training and competition in all sports is important to injury prevention, design specific training sessions, and player performance enhancement. The present study aimed to describe the external load profile of amateur-level handball players and to compare the playing position and match outcome-related differences in an official 2nd Regional Division male official match. 19 handball players were monitored by WIMU PROTM electronic performance and tracking systems (EPTS) with ultrawide-band (UWB) indoor location technology. Statistical analysis was composed of a t-student independent sample test and one-way ANOVA with Bonferroni posthoc. In amateur handball, most demands are composed of aerobic intensity displacements (<12 km/h, 76% playing time) and low-intensity impacts (<5G). Differences were found between playing positions where wingers obtained the greatest values in high-intensity actions, centers in the volume of demands, and defensive specialist players in impacts. Besides, the winning teams performed greater high-intensity demands both in displacements and speed changes. In conclusion, the present results realized the first approximation to handball amateur demands, considering the playing role and match status-related demands to design specific training plans.

Positional Differences in Peak- and Accumulated- Training Load Relative to Match Load in Elite Football

Quantification of training and match load is an important method to personalize the training stimulus' prescription to players according to their match demands. The present study used time-motion analysis and triaxial-accelerometer to quantify and compare: a) The most demanding passages of play in training sessions and matches (5-min peaks); b) and the accumulated load of typical microcycles and official matches, by playing position. Players performance data in 15 official home matches and 11 in-season microcycles were collected for analysis. Players were divided into four different playing positions: Centre-backs, wing-backs, centre midfielders, and centre forwards. The results show that match demands were overperformed for acceleration counts (acc_counts) (131%-166%) and deceleration counts (dec_counts) (108%-134%), by all positions. However, relative to match values, training values for sprint distance (sprint_dist) and high-intensity run distance (HIR_dist) were considerably lower (36%-61% and 57%-71%) than for accelerations and decelerations. The most pronounced difference on the 5-min peaks was observed in sprints (sprint_peak), with wing-backs achieving during the microcycle only 64% of the sprint_peak in matches, while centre backs, centre midfielders, and centre forwards levelled and overperformed the match values (107%, 100%, and 107%, respectively). Differences observed across playing positions in matches and microcycles underline the lack of position specificity of common training drills/sessions adopted by coaches in elite football.

Accelerometry-Based External Load Indicators in Sport: Too Many Options, Same Practical Outcome?

With the development of new microsensor technology to assess load in sports, some indicators of external load through accelerometry-based data have been created by sport technology companies. Thus, the study aim was to analyze the agreement between different accelerometry-based external load indicators (ABELIs) available in sport science. A U-16 male soccer team was assessed during three official matches, divided by periods, to obtain 3-D accelerometry data (x, y and z axes). An average of 1,420,000 data points was analyzed per axis per player. The ABELIs were calculated using this information, and the agreement between them was explored. The following ABELIs were considered after a literature review: AcelT, Player Load_RT, PlayerLoad^TM, Impulse Load, Player Load_RE and Total Load. In order to compare ABELIs, two analyses were performed using: (1) absolute data; and (2) normalized and centered data (Z-scores). In absolute and centered data, very large to nearly perfect correlations (1st period: r > 0.803, p > 0.01; 2nd period: r > 0.919; p > 0.01) were found. Instead, very large differences were found in absolute values (bias = -579,226.6 to 285,931.1; t = -224.66 to 213.91, p < 0.01), and no differences in scaled and centered values (bias = 0; t = 1; p = 1). In conclusion, considering the different output (magnitude and units) among ABELIs, the standardization of a universal index to calculate accelerometer load is needed in order to make possible between-study comparison.

Comparative Study of Two Intervention Programmes for Teaching Soccer to School-Age Students

The objective of this study was to design and analyse the differences and/or similarities of two homogeneous intervention programmes (didactic units) based on two different teaching methods, Direct Instruction (DI) and Tactical Games Approach (TGA), for teaching school-age soccer. The sample was composed of 58 tasks, 29 for each intervention programme. The pedagogical and external Training Load (eTL) variables recorded in the Integral System for Training Tasks Analysis (SIATE) were studied. The two intervention programmes were compared using Chi-Square, Mann-Whitney U and the Adjusted Standardized Residuals statistical tests. Likewise, the strength of association of the variables under study was calculated using Cramer’s Phi and Cramer’s V coefficients. Both intervention programmes had the same number of tasks (n = 29), sessions (n = 12), game phases (x²= 0.000; p = 1.000), specific contents (x² = 5.311; p = 0.968) and didactic objectives, as well as different levels of eTL (U = 145.000; p = 0.000; d = 1.357); which are necessary requirements to be considered similar. The differences and/or similarities between both intervention programmes will offer teachers guidelines to develop different didactic units using the specific DI and TGA methodologies.