Accumulative weekly load in a professional football team: with special reference to match playing time and game position

A Narrative Review of the Velocity and Acceleration Profile in Football: The Influence of Playing Position

To enhance athletic performance and reduce the risk of injury, load quantification has allowed for a better understanding of the individual characteristics of the physical demands on soccer players during training or competition. In this regard, it appears crucial to summarize scientific evidence to provide useful information and future directions related to the speed and acceleration profiles of male soccer players. This review aims to evaluate the findings reflected in the available literature on both profiles in football, synthesizing and discussing data from scientific articles, while providing insights into quantification methods, employed thresholds, tracking systems, terminology, playing position, and microcycle day. Therefore, it is hoped that this narrative review can support objective decision-making in practice for coaches, sports scientists, and medical teams regarding individualized load management and the appropriate selection of metrics, to explore current trends in soccer player profiles.

Is Match Playing Time a Potential Tool for Managing Load in Women's Handball?

ABSTRACT

García-Sánchez, C, Navarro, RM, Nieto-Acevedo, R, and de la Rubia, A. Is match playing time a potential tool for managing load in women's handball? J Strength Cond Res 38(12): e769-e775, 2024-The aim of this study was to explore the external load experienced by female handball players according to the time played in official matches (≥40, <40, and ≤20 minutes) and in relation to playing positions (backs, pivots, and wings). Twenty-two female players from the Spanish second Division were monitored across 13 matches. Total distance covered, high-speed running distance (HSR), accelerations, decelerations, and PlayerLoad were collected in absolute and relative values using a local positioning system (WIMU PRO, Realtrack Systems SL, Almería, Spain). One-way ANOVA with partial eta-squared and Cohen's d were used to determine the differences between playing time groups and between playing positions. This study revealed that players with more match playing time had a higher absolute values in all external load variables ( p < 0.001; very large effects), except in HSR where only wings showed higher values according to the time played ( p < 0.001; very large effects). However, these differences between playing time groups disappear when the external load values were normalized according to the effective playing time ( p > 0.05). In relation to playing positions, wings covered more HSR/minutes than the other playing positions regardless of the playing time ( p < 0.05; large effects). In addition, backs performed more ACC/minutes than wings in the high playing time group and more than pivots in the low playing time group ( p < 0.05, moderate effects). In addition, backs performed more DEC/minutes than wings in the low playing time group ( p < 0.05, moderate effects). Therefore, handball coaches should consider the playing time as an effective tool to optimize the weekly load distribution.

Weekly external load distribution in football teams of different competitive levels

This study aimed to compare the microcycle load distribution between teams from different competitive levels. A total of 22 microcycles from one team of each competitive level (first division, 1st DIV, n = 32 players; second division, 2nd DIV, n = 23 players; third division, 3rd DIV, n = 23 players) were monitored using GPS (10 Hz, Catapult). During the match, a higher number of high accelerations (i.e., > 3 m/s, per min) were found in the 3rd DIV team compared to the 1st and 2nd DIV teams. On match day (MD) +1&+2, the 1st DIV team covered more total (per min, p < 0.001) and high-speed running distance (HSR per min, p < 0.001 and p = 0.042, respectively) than both the 2nd and 3rd DIV teams. The 2nd DIV team showed lower values in most distance-related variables (total distance covered per min, p < 0.001; running distance per min, p < 0.001; HSR per min, p < 0.001; and sprinting distance per min, p < 0.001) for both MD-4 and MD-3 compared to the 1st and 3rd DIV teams. In contrast, it showed higher sprinting distance per min (p < 0.001) on MD-2. In general, the 3rd DIV team showed higher values in the number of high accelerations (per min, p < 0.001) across all sessions. These results suggest that distance-related variables may be a priority when planning microcycles for the 1st DIV team, while accelerations are relevant for the 3rd DIV team. A higher emphasis on external load during MD-2 by the 2nd DIV team may explain the lower external loads across the microcycle.

Summarizing physical performance in professional soccer: development of a new composite index

The aims of this study were to create a composite index to measure the overall players' physical performance in professional soccer matches and analyze the effect of individual playing time and positional differences on this composite index. A total of 830 official matches from LaLiga men's first division and Spanish Copa del Rey were analyzed, which resulted in 24,980 match observations collected from 1138 male players (forwards, n = 286; midfielders, n = 441; defenders, n = 411). The physical performance variables, which represent the locomotor demands, were collected using electronic performance tracking systems. A Partial Least-Squares Structural Equation Model (PLS-SEM) was used to measure performance. The PLS-SEM output had three significant latent components, which explained 95% of the initial variability, that were related to the acceleration-specific performance (component 1), high-intensity running-related variables (component 2), and medium intensity actions variables (component 3). Also, a linear regression analysis was used to explore relationships between playing activity time (hours-X axis) and the composite index (10-point scale-Y axis), in which a strong and positive correlation was observed between individual playing time and the composite index (r = 0.76; p < 0.001; R2 = 0.58). Also, significant positive correlations were observed in forwards (r = 0.85; p < 0.001; R2 = 0.74), midfielders (r = 0.80; p < 0.001; R2 = 0.64), and defenders (r = 0.67; p < 0.001; R2 = 0.45). However, significant differences between playing positions with a small effect size (p < 0.05; eta-squared = 0.01) were found. From a practical perspective, this study may serve as a reference for sports performance practitioners to create a composite index that measures the overall players' physical performance. The instructions to create this index are available in the manuscript.

Effect of the role, playing position and the body characteristics on physical performance in female soccer players

The aims of this study were to know the physical demands according to the playing position and team role, and to assess the effect of the body characteristics on the physical performance of semi-professional female soccer players. Forty-five female semi-professional soccer players during 9 home-matches of the 2021-2022 season were analyzed and GPS devices (GPEXE ®) were used. ANCOVA tests were performed with playing time as covariate. The results showed greater physical demands in forwards and wide-midfielders and offensive role players. Total distance, metabolic power, accelerations, deaccelerations, and distance covered to medium and high speed obtained a strong effect size in these analyses according to the playing position. Furthermore, relationships between body weight and physical performance were found (p < 0.05). In conclusion, the main finding of this study showed that semi-professional female soccer players compete differently, caused by differentiated functions, evidenced in the playing positions and role in the team. Offensive role, forwards and wide-midfielder female players performed the highest physical demands in the competition. This study has shown relevant information for coaches, S&C coaches, and training staff of the semi-professional female soccer teams in order to propose new keys and ways of planning training sessions.

Weekly Training Load Differences between Starting and Non-Starting Soccer Players

The aim of this study was to examine the differences in the weekly training load between starters and non-starters classified based on the match starting line-up, with respect to the playing position and a training day. Notably, 31 young adult soccer players (age: 18.79 ± 1.04 years) competing in the 3rd Czech division were monitored across the season. The weekly training load was measured using a GPS system as follows: total distance covered (TD), high-speed running distance (HSR), sprint running distance (SR), and acceleration and deceleration distance (ACDC). We found higher values in three out of four observed variables (HSR, SR, and ACDC, excluding TD) for starters compared to non-starters (p < 0.05), with small to moderate effect sizes (d = 0.40-0.49). Differences were observed especially in players who were fullbacks, offensive midfielders, and forwards. Moreover, the largest differences were found in training prior to a match day for HSR, SR, and ACDC (p < 0.05). Non-starters experienced lower weekly external loads in offensive player positions, predominantly in high-intensity variables, which are essential for their physical performance. It seems that non-starters may experience potential under-loading in the training process. Coaches and practitioners should be aware of this potential risk and find an appropriate method to compensate for load discrepancies, particularly in terms of high-intensity activities.

Two periodization strategies in professional football and their influence on accumulated training load and its distribution: Differences between starters and non-starters

This study compared weekly training-load (TL), training-monotony (TM), and training-strain (TS) in 80 professional football players (28.1 ± 3.2 yrs, 78.0 ± 5.9 kg, and 182.0 ± 4.8 cm), considering two lengths (6 and 7 days between matches), two types of periodization strategies (placing the compensatory session in MD+1 [P1] or MD+2 [P2] post-match-day) and two players' status, starters, and non-starters. Using Global Positioning Technology, the monitored variables were: Player Load (PL), Total Distance (TD), distances at various speeds (>21 [HSR], >24 [VHSR], and > 27 [SPR] km·h-1), number of accelerations (>2 m·s-2, ACC), and decelerations (<-2 m·s-2, DEC). Kruskal-Wallis and Mann-Whitney non-parametric statistical tests were used for loading strategy differences. In both lengths and periodization strategies of the micro-cycles, non-starters trained more than starters. There were differences in the quantity (TL) and distribution (TM and TS) demand considering the micro-cycle's length and periodization strategy. In MD+1 (P1), non-starters accumulated higher TL, showing moderate to large Cohen's d magnitudes in HSR, VHSR, SPR, PL, and TD. For starters, training in MD+2 (P2) resulted in higher values (p < 0.05) of TL, TM and TS. The coaching staff needs to anticipate TL, TM, and TS by considering players' status, periodization strategy, and the number of training sessions between matches.

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.

Are non-starters accumulating enough load compared with starters? Examining load, wellness, and training/match ratios of a European professional soccer team

BACKGROUND

The aims of the study were to: (i) compare accumulated load and wellness between starters and non-starters of a European professional soccer team; (ii) analyze the relationships between wellness and load measures and; (iii) compare training/match ratio (TMr) of external and internal load between starters and non-starters.

METHODS

Ten players were considered starters while seven were classified as non-starters over a 16-week period in which six training sessions and match day (MD) were considered in each weekly micro-cycle. The following measures were used: wellness (fatigue, quality of sleep, muscle soreness, stress, and mood); load (rated of perceived exertion (RPE), session-RPE (s-RPE), high-speed running (HSR), sprinting, accelerations (ACC) and decelerations (DEC)). Accumulated wellness/load were calculated by summing all training and match sessions, while TMr was calculated by dividing accumulated training load by match data for all load measures and each player. Mann-Whitney U test was used for wellness variables, while independent T-test was used for the remaining variables to compare groups. Moreover, relationships among variables were explored using the Spearman's Rho correlation coefficient.

RESULTS

The main results showed that non-starters presented higher significant values for fatigue (p < 0.019; g = 0.24) and lower significant values for duration (p < 0.006; ES = 1.81) and s-RPE (p < 0.001; ES = 2.69) when compared to starters. Moreover, positive and very large correlation was found between quality of sleep and RPE, while negative and very large correlation were found between stress and deceleration, and mood and deceleration (all, p < 0.05). Finally, non-starters presented higher values in all TMr than starters, namely, RPE (p = 0.001; g = 1.96), s-RPE (p = 0.002; g = 1.77), HSR (p = 0.001; g = 2.02), sprinting (p = 0.002; g = 4.23), accelerations (p = 0.001; g = 2.72), decelerations (p < 0.001; g = 3.44), and duration (p = 0.003; g = 2.27).

CONCLUSIONS

In conclusion, this study showed that non-starters produced higher TMr in all examined variables despite the lower match and training durations when compared with starters, suggesting that physical load was adjusted appropriately. Additionally, higher RPE was associated with improved sleep while higher number of decelerations were associated with decreased wellness, namely, stress and mood for non-starters.

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.

Accumulated Workload Differences in Collegiate Women's Soccer: Starters versus Substitutes

The purpose of this study was to estimate the workloads accumulated by collegiate female soccer players during a competitive season and to compare the workloads of starters and substitutes. Data from 19 college soccer players (height: 1.58 ± 0.06 m; body mass: 61.57 ± 6.88 kg) were extracted from global positioning system (GPS)/heart rate (HR) monitoring sensors to quantify workload throughout the 2019 competitive season. Total distance, distance covered in four speed zones, accelerations, and time spent in five HR zones were examined as accumulated values for training sessions, matches, and the entire season. Repeated-measures ANOVA and Student's t tests were used to determine the level of differences between starter and substitute workloads. Seasonal accumulated total distance (p < 0.001), sprints (≥19.00 km/h; p < 0.001), and high-speed distance (≥15.00 km/h; p = 0.005) were significantly greater for starters than substitutes. Accumulated training load (p = 0.08) and training load per minute played in matches (p = 0.08) did not differ between starters and substitutes. Substitutes had similar accumulated workload profiles during training sessions but differed in matches from starters. Coaches and practitioners should pursue strategies to monitor the differences in workload between starters and substitutes.

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.

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.