Impact of match-related contextual variables on weekly training load in a professional soccer team: a full season study

Does accumulated physical load in different time windows affect hamstring injuries in elite football players?

BACKGROUND

This study aims to investigate how accumulated training load over different time windows (7, 14, and 28 days) influences the incidence of hamstring injuries in elite football players.

METHODS

A descriptive and longitudinal study was developed in 343 players in three teams (2nd Team, U-19 team, and U-18 team) from the academy of an elite football club in Spanish La Liga that also competed in the Union of European Football Associations Champions League during four seasons, from 2017/18 to 2020/21. External load variables (total distance, high-speed running, accelerations, etc.) for training and competition have been studied considering the volume variables during three different time windows along the different seasons (7 days, 14 days, and 28 days).

RESULTS

Results did not show differences in the shortest time windows (7- and 14-week periods), showing that strength and conditioning coaches should analyse longer periods of time and compare them to previous periods with the same length in order to improve workload management and reduce injury risk.

CONCLUSIONS

It is important consider the accumulated load (chronic) in periods of 28 days to avoid an increase that generates a hamstring injury. The control of the training load in blocks of 28-day time windows seems essential to minimize the injury rate in football players.

An analysis of transition-resulted goal scoring patterns in football leagues: a comparison of the first 5 rounds and the last 5 rounds prior midway of the season

OBJECTIVE

This study investigated the concept of 'game style' in football, focusing on a team's distinctive approach characterized by tactics, formations, and strategies. The objective is to compare goal-scoring patterns related to "non-offensive transition," "set pieces," "offensive transition," and "positive outcomes" across different league groups.

METHODOLOGY

The sample comprises 702 football games, categorized into three league groups: Top Leagues, Marginal Leagues, and Emerging Leagues. A total of 2140 goals were analyzed, classifying them into four types: "No Transitions", "Set Pieces", "Offensive Transitions (direct), and "Positive Outcomes" of offensive transitions. The study aims to identify relevant differences between two distinct competitive periods, namely "Rounds 1 to 5" and "Rounds Last 5."

RESULTS

The analysis reveals no significant differences in scoring methods between "Rounds 1 to 5" and "Rounds Last 5" across all variables in the analyzed league groups, except for goals conceded by "No Transition" in the Emerging Leagues. Additionally, results indicate that goals resulting from direct offensive transitions and positive outcomes substantially impact the Top Leagues, constituting 54% of the total scoring.

CONCLUSION

The study emphasizes the importance of establishing and maintaining consolidated game patterns, as demonstrated by the consistent scoring patterns across different league groups. While most leagues show no variations in scoring methods between early and late rounds, attention to goals conceded by "No Transition" in Emerging Leagues is warranted. The prominence of direct offensive transitions and positive outcomes in Top Leagues highlights the relevance of these strategies in the scoring process, emphasizing the need for teams to focus on developing and implementing effective game patterns.

Effects of Contextual Variables on Match Load in a Professional Soccer Team Attending to the Different Season Periods

This study aimed to analyze the effects of contextual variables (i.e., match location and match outcome) and season periods on match load (i.e., internal and external load) in professional Brazilian soccer players. Thirty-six professional players from the same soccer team participated in this study. The season was split into four phases: matches 1-16 (i.e., Phase 1 = P1); matches 17-32 (i.e., Phase 2 = P2); matches 33-48, (i.e., Phase 3 = P3); matches 49-65 (i.e., Phase 4 = P4). Considering match outcome, when the team wins, Cognitive load, Emotional load, and Affective load were significantly higher in away vs. home matches (p < 0.05). Considering season phases, in P3, Mental Fatigue was significantly higher in drawing than in losing matches (p < 0.05). Additionally, considering the match outcome, when the team lost, Total Distance (TD)/min and TD > 19 km·h-1/min were significantly lower in P1 than P2 (p < 0.001), P3 (p < 0.001), and P4 (p < 0.001). These results suggest to strength and conditioning coaches the need to consider the outcome and location of the previous game when planning the week, as well as the phase of the season they are in to reduce fatigue and injury risk.

Internal and external load during on-field training drills with an aim of improving the physical performance of players in professional soccer: a retrospective observational study

Extensive research has led to evidence-based methodological recommendations for appropriate prescription and implementation of different training drills to improve the physical performance of professional soccer players, while also pointing out limitations of drills. Less is known about the current methods used in an ecological context and the extent to which evidence-based considerations are applied. Knowledge of current practices might also enable to identify pitfalls in successful implementation and/or deficiencies in the communication of scientific knowledge. Thus, the aim of this study was to quantify and compare the load that players experience in an ecological context during drills that are frequently used, and in which there is an intention to improve the players' physical capacities. Therefore, a retrospective observational cohort study was conducted over a 14-month period, analyzing 9 load measures during training drills of 39 players of a team competing in the highest Swiss league. The load experienced by players was statistically significant different between the assessed drill categories for each load measure (all p < .001). This indicates different drills provide different stimuli. HIIT drills proved to be a more powerful tool of getting players to cover distances at high-speed and to spend time at an intensity ≥90% HRmax compared to sided games. The sprint distance of players was very low in all sided games and in most cases also in HIIT drills, in the latter the players also hardly performed any deceleration. In small goal-oriented sided games, players covered a greater distance per minute when outside floaters were present. Particularly regarding an improvement of the players' aerobic capacity, the present data emphasize the relevance for coaches to ensure an appropriate exposure. In general, the importance of individual load management in professional soccer is highlighted.

Quantification of training load across two competitive seasons in elite senior and youth male soccer players from an English Premiership club

This study aimed to compare the daily training load (TL) in first-team and U-18 soccer players from an English Premiership club. 36 first-team (age 23.2 ± 5.9 years, weight 75.2 ± 8.1 kg, height 1.83 ± 0.06 m), and 22 U-18 players (age 17.5 ± 1.1 years, weight 71.1 ± 8.2 kg, height 1.78 ± 0.08 m) participated. GPS metrics were measured during all pitch training sessions throughout the 2020-21 and 2021-22 seasons. Linear mixed-effect model analyses revealed that, irrespective of training day, U-18 players covered greater total and explosive distance than first-team players, and performed a higher number of accelerations and decelerations, whereas first-team players covered greater sprint distance. Irrespective of the team, all examined variables were greater at match-day (MD)-3, while the number of accelerations and decelerations were higher at MD-4. Significant team-by-training day interactions revealed that U-18 players covered greater total and high-intensity distances than first-team players at MD-4, MD-2, and MD-1, whereas first-team players covered greater total and high-intensity distances at MD-3. Sprint distance was greater for first-team players at MD-3 and MD-4, while explosive distance was greater for U-18 players at MD-2. Also, U-18 players performed a higher number of accelerations than first-team players at MD-3 and MD-2, and a higher number of decelerations at MD-4. The present results provide novel information on TL patterns in English Premiership soccer and contribute to understanding how training methods to physically develop players are implemented in different countries and leagues.

Advancing and critical appraisal of an integrative load monitoring approach in microcycles in professional soccer

Despite load monitoring being considered an integral part of targeted performance management, including injury and illness prevention, there is currently no consensus of an effective monitoring system in professional soccer. Thus, the aims were to apply an integrative load monitoring approach, previously established in rink-hockey, in professional soccer; extend this approach with further data (Short Recovery and Stress Scale); assess this (extended) approach, thereby further evaluating the relationship between the used external load (EL) measures (total distance, distance above 55% and 70% of individual maximal speed, number of accelerations and decelerations > 4 m/s2, total loading) and the internal load (IL) measure session rate of perceived exertion training load (sRPE-TL) as well as between the used EL measures and sRPE. This retrospective observational cohort study analyzed data from a Swiss team collected over a 14 week-period during the 2021/22 season. Based on our findings, the integrative approach tested proved to be an applicable load monitoring tool in professional soccer, placing players on a fitness-fatigue continuum throughout the different microcycle sessions without using tests, thus providing relevant information to individually tailor training programs. sRPE-TL (ρ [95% CI] = .55 [.51 to .59] to .87 [.85 to .88]; all p < .001) better reflected the EL experienced by players than sRPE (ρ [95% CI] = .45 [.40 to .50] to .71 [.69 to .75]; all p < .001) supporting the definition of sRPE-TL as a measure of IL. However, for even stronger relevance of the tested tool, further research is warranted, especially to ascertain its sensitivity and determine an optimal selection of EL and IL measures. In sum, the present data clearly demonstrate the importance of load management taking place at an individual level, even within team structures, thereby analyzing a set of both EL and IL measures.

Training and match load ratios in professional soccer-should we use player- or position-specific match reference values?

Careful load management is needed to optimize the physical capacity, a key performance component, of soccer players. The training load of soccer players is often expressed as a percentage of match load. However, no study has yet evaluated how training match load ratios are affected by using either a player-specific or position-specific reference for match load. Therefore, this study aimed to compare training match load ratios of professional soccer players per day of a microcycle with match load being player-specific and position-specific, respectively. Additionally, the load that players typically experience per day of a microcycle and its variation should be analyzed. Therefore, a retrospective observational cohort study was conducted over a 14-month period, analyzing 11 external load measures during sessions of 20 players belonging to a team competing in the highest Swiss league. Within a microcycle, typical full matches presented a unique load for players, and they experienced higher training loads on days with a greater temporal distance to a match. Load variation proved to be highly associated with the day in a microcycle and the load measure. Substantial differences in typical load were evident in (i) trainings between players, (ii) matches both between players and positions, and (iii) training match load ratios when using player-specific or position-specific match references. The importance of individual load management in professional soccer was reaffirmed. When consulting training match load ratios for that purpose, one should be aware of the aim, select appropriate reference values depending on it, and interpret the ratios accurately to finally draw adequate conclusions.

Quantifying training load and intensity in elite male ice hockey according to game-related contextual variables

We aimed to quantify training load (TL) and intensity during practice sessions according to game-related contextual variables (game outcome, opponent standard, game location) in an elite male ice hockey team. Practice data were collected using a wearable 200-Hz accelerometer, heart rate (HR) recording, and session-rating of perceived exertion (s-RPE) throughout 23 sessions (n = 306 files). The reference team performed a greater number of accelerations, decelerations, spent longer time > 85% maximum HR (t85%HRmax) and reported greater s-RPE after losing a game compared to a win (r = 0.13-0.19). Moreover, a lower number of accelerations, decelerations, t85%HRmax and s-RPE (r = 0.15-0.45) were found before playing against a top-ranked opponent. In contrast, more accelerations, decelerations, longer t85%HRmax and greater s-RPE were observed after playing against a top-ranked team opponent (r = 0.15-0.41). The players performed more accelerations/min, spent more t85%HRmax and reported greater s-RPE before playing an away game (r = 0.13-0.22). Weekly TL seems to slightly increase after losing a game, when preparing a game against a weaker opponent, after playing against a stronger opponent, and when preparing an away game. On the other hand, training intensity seems not to be affected by game-related contextual variables. Thus, ice hockey practitioners involved with TL monitoring should consider the interplay of the numerous variables that influence the volume of prescribed training and the actual training responses in each individual player.

Analysis of team success based on match technical and running performance in a professional soccer league

Background

The aims of this study were to (1) determine the match technical and running performance required by different teams based on their final ranking position in a professional soccer league; and (2) analyze the correlation between teams’ success at the end of the season and variables related to match technical and running performance.

Methods

These performance data were collected during a total of 612 matches in the German Bundesliga. The final ranking position and the total of points obtained by each team at the end of the season were registered for the analysis of the correlation between team success and performance.

Results

The main findings were that there was a significant interaction (p < 0.05) between the ranking position, and both match technical and running performance. However, goals scored, saved shots on goal by the goalkeeper, assists, allowed shots on goal, goals conceded, ball possession ratio and successful passes from open play were the variables with the strongest correlation (r > 0.7; p ≤ 0.01) with the total of points obtained at the end of the season.

Conclusions

Strength and conditioning coaches may consider these results to develop adequate training strategies, which may not only optimize performance but also reduce the injury risk.