The aim of this review is to summarize the current scientific knowledge about acceleration and deceleration demands during football training.A systematic search of three electronic databases (PubMe...

Quantifying training load is important to ensure that athletes correctly respond to training prescription and reduce injury risk. Training load can be divided into internal training load, the response of an individual to the training demand, and external training load, the physical “work” of the players. We aimed to analyze training load during a training week (microcycle) in soccer players. Systematic searches of 3 electronic databases (PubMed, SPORTDiscus, and Web of Science) were conducted, and Preferred Reporting Items for Systematic Review and Meta-analysis guidelines were followed. From 1,718 studies initially found, 16 were selected after screening. Descriptive and Z-score analyses were performed for each variable (acceleration and deceleration [DEC], average speed, high-speed running, sprint, total distance, player load, percentage of maximal heart rate, and rating of perceived exertion [RPE]). A sample of this review was 317 male soccer players aged 16.4–27.6 years, competing in elite, professional, and youth levels. Three days prior to match day was the most demanding session of the week, except for DEC, average speed, and player load demands. The day prior to match day was the least demanding session, except for sprint and RPE. In conclusion, midweek sessions can be chosen to apply higher training loads, whereas training sessions immediately before and after the match can be used to taper or recover.

The ergogenic effects of caffeine have been reported in scientific literature over a wide spectrum of sporting activities. The current recommendation for caffeine supplementation is ingesting ~ 3–6 mg/kg about 1 h before the onset of exercise. However, some studies reporting caffeine-induced ergogenic effects during exercise have also reported increased activation and reduced sleep quality in the hours after caffeine ingestion. While most of the research on caffeine supplementation for sporting activities recommends the consumption of this stimulant to enhance performance, research focusing on athletes’ sleep quality advises against this decision, especially before competition in the evening or later. Considering that some athletes often compete in the evening or later, the general recommendation of caffeine supplementation may be modified for these athletes as acute caffeine intake in these conditions may produce undesirable side effects such as insomnia and, potentially, reduced performance in subsequent days. In this review, we examine literature on this topic to help athletes and sports practitioners solve the dilemma between the convenience of using caffeine to enhance sports performance or avoiding caffeine to ensure sleep quality. This review identifies potential solutions for this decision, keeping the focus on athletes’ well-being. Overall, the performance response to caffeine and the effect of this substance on sleep quality can vary interindividually and depend on the conditions of the exercise session (time of onset, duration, etc.). For this reason, nutritional practitioners should assess their athletes individually to resolve the conflict between caffeine ingestion and ensuring sleep quality on an individual basis, using simulated competitions with dual measurement of performance during exercise and unwanted effects in the following hours. In addition, the dose, timing, and source of caffeine supplementation can be individually adjusted to obtain performance benefits while reducing side effects for athletes ingesting caffeine before evening sporting events.

This study compared the most common absolute sprint threshold (> 25.2 km/h) with relative and individualized thresholds (> 70%, > 75%, > 80%, > 85% and > 90% of peak match speed). Twenty elite soccer players, competing in the first division of the Portuguese League, were monitored using GNSS...

The aim of this study was to characterise football players’ acceleration and deceleration demands regarding duration, initial velocity, and effort magnitude without a minimum effort duration. Forty-two male professional players were monitored daily during four training weeks, using a global position system. Players were divided according to their playing positions as central defenders, fullbacks, central midfielders, wide midfielders, and forwards. Acceleration and deceleration efforts were analysed from the start of the change in velocity until it stopped increasing (acceleration) or decreasing (deceleration). Descriptive statistics were performed for occurrences, initial velocities, and average and peak magnitudes. Comparisons between playing positions were conducted with one-way analysis of variance (ANOVA). The frequency of accelerations and decelerations decreased as the duration increased. The initial deceleration velocity increased with duration, but no changes were seen in the acceleration initial velocity. The average effort’s magnitude increased with duration, while the peak magnitudes decreased, showing acceleration and deceleration peaks between 0.5–1.3 and 0.1–0.3 s, respectively. Differences between playing positions occurred between 0.7 and 2.5 s. In conclusion, the measurement of accelerations and decelerations should avoid the use of minimum effort duration since it can modify the real training load of football players.

Purpose: This study investigated how soccer players reach sprint speeds (> 25.2 km⋅h⁻¹) and what that fixed threshold represents to each player regarding their individual match peak speeds registered during competition. Methods: Twenty professional players (n = 20) from a team competing in the Brazilian first division were monitored with a global navigation satellite system during six matches. All efforts with final speeds > 25.2 km⋅h⁻¹ were analyzed according to starting speed, and accelerations’ duration and magnitude. Peak speeds for each player were also retrieved and compared to the sprint threshold. Results: Most efforts > 25.2 km⋅h⁻¹ (> 91%) start with very short accelerations (< 0.5 s). Efforts started predominately from high starting speeds (20–25 and > 25 km⋅h⁻¹) than low starting speeds (< 5 and 5–10 km⋅h⁻¹) with huge effect sizes (p < 0.001). Most accelerations had magnitudes between 1 and 3 m⋅s⁻² (p < 0.05). The 25.2 km⋅h⁻¹ threshold represented an intensity of 71–91% of players’ match peak speed. Conclusion: The inclusion of accelerations and peak speeds associated to the sprinting events that occur > 25.2 km⋅h⁻¹ was shown to be useful for further characterization of soccer sprinting performance. In addition, the fixed threshold fails to individualize players’ capabilities and performances, misleading load demands performed by players.