The Interunit Reliability of Global Navigation Satellite Systems Apex (STATSports) Metrics During a Standardized Intermittent Running Activity

Post-Match Recovery Responses in Italian Serie A Youth Soccer Players: Effects of Manipulating Training Load 48 h After Match Play

This study described the recovery responses following match play and examined the effects of manipulating training load 48 h post-match in Italian Serie A youth soccer players. Forty-eight players were assessed using the countermovement jump (CMJ), isometric posterior-chain muscle test (IPC), muscle soreness and fatigue before (pre) and after (0.5 h post, 48 h post and 72 h post) a match. At 48 h post-match, players were randomly assigned to a complete training (CT; n = 26) or a reduced training (RT; n = 22) group. Recovery differences were analysed between time points and training groups, with training loads quantified on match day (MD) and match day plus two (MD + 2). Recovery measures were impaired immediately post-match (p < 0.05). IPC and muscle soreness demonstrated incomplete recovery 48 h post-match (p < 0.05), whereas CMJ and fatigue returned to baseline (p > 0.05). Training load on MD did not differ between groups (p > 0.05), whereas the CT group had higher load on MD + 2 compared to RT (p < 0.05). A significant time × group interaction was observed for CMJ height and IPC measures (p < 0.05), with reductions in physical performance observed in the CT group from 48 to 72 h post-match (p < 0.05). A youth soccer match acutely impaired physical performance and recovery status, with prolonged and incomplete recovery of hamstring force and elevated muscle soreness 48 h post-match. A high-volume and high-intensity session administered 48 h post-match negatively influenced physical performance compared to a moderate training session.

Comparison of the Acute Effects of Carbohydrate Mouth Rinse and Coach Encouragement on Kinematic Profiles During Small-Sided Games in Young Male Soccer Players

Background: Carbohydrate mouth rinsing (CHOmr), a nutritional intervention for delaying fatigue and meeting the energy demands of soccer, and the motivational strategy of coach encouragement (CE) are widely recognized as effective approaches for enhancing athletic performance in soccer. Objectives: This study aimed to compare the effects of CHOmr + CE, CHOmr, and CE on heart rate (HR) and kinematic profiles during four-a-side small-sided soccer games (SSGs). Methods: Twenty-four young soccer players (age: 17.2 ± 0.8 years) played six bouts of four-a-side SSGs with CHOmr + CE, CHOmr, or CE at 3-day intervals in a randomized, single-blinded, placebo-controlled, or crossover study design. The HR and kinematic responses were continuously recorded during all games. Results: There were no statistically significant differences between the groups in peak heart rate (HRpeak) (p ≥ 0.05, F = 0.326, p = 0.723, η2 = 0.014) and mean heart rate (HRmean) (p ≥ 0.05, F = 0.845, p = 0.436, η2 = 0.035). No significant differences were found for distances in Zone 1 (p ≥ 0.05, F = 1.21, p = 0.306, η2 = 0.050), Zone 4 (p ≥ 0.05, F = 0.310, p = 0.735, η2 = 0.013), Zone 5 (p ≥ 0.05, F = 1.02, p = 0.368, η2 = 0.042), or Zone 6 (p ≥ 0.05, F = 0.161, p = 0.211, η2 = 0.055), nor acceleration (p ≥ 0.05, F = 0.208, p = 0.137, η2 = 0.083) and deceleration (p ≥ 0.05, F = 0.790, p = 0.460, η2 = 0.033). Similarly, although no significant differences were observed in the distance in Zone 3 (p ≥ 0.05, F = 3.12, p = 0.054, η2 = 0.119) or repeated sprint distance (p ≥ 0.05, F = 2.96, p = 0.062, η2 = 0.114), the CHOmr +CE group exhibited higher average values for these variables. However, a statistically significant difference was observed in the distance covered in Zone 2 (p ≤ 0.05, F = 3.89, p = 0.028, η2 = 0.145), with the CHOmr +CE group performing better, as confirmed by the post-hoc analyses. Conclusions: Although our findings indicate that CE alone may influence kinematic profiles during SSGs, similar to CHOmr or its combination with CE, further research should explore the underlying mechanisms and potential contextual factors influencing these outcomes. Therefore, we suggest that coaches prefer CE because it is easy to implement.

Physical Performance Is Affected by Players' Position, Game Location, and Substitutions During Official Competitions in Professional Championship English Football

ABSTRACT

Chaize, C, Allen, M, and Beato, M. Physical performance is affected by players' position, game location, and substitutions during official competitions in professional Championship English football. J Strength Cond Res 38(12): e744-e753, 2024-This study aimed to verify, first, if physical parameters were different between positions during official matches in the English Football League Championship. Second, whether game location (home vs. away games) and playing status (full match vs. substitute) affected players' physical performance. Twenty-six, male, professional, football players of the same club were included in this data analysis during the 2023-24 season. STATSports 10 Hz global navigation satellite systems Apex units (Northern Ireland, United Kingdom) were used to monitor official matches (21 games). The metrics recorded were distance covered (m·min -1 ), high-speed running distance (>19.8 km·h -1 ), sprint distance (>25.2 km·h -1 ), the number of accelerations (>3 m·s -2 ), decelerations (<-3 m·s -2 ), and high-metabolic-load distance (HMLD) measured in meters (>25.5 w·kg -1 ). Significant differences were found between positions and game location for distance covered and high-speed running (HSR; p < 0.05) as well as between game location ( p = 0.020) for sprinting distance. Differences were found between game location ( p = 0.034) for decelerations. Differences were found between positions and game location for HMLD ( p < 0.05). Significant difference between full-match players vs. substitutes were found for distance covered ( p < 0.001), HSR ( p = 0.002), accelerations ( p = 0.017), decelerations ( p = 0.023), and HMLD ( p = 0.008). In conclusion, this study found that physical performance was influenced by players' positions and player status, whereas it found that game location affected a minor number of physical metrics. Therefore, practitioners should be aware that training should be tailored based on the physical demands of the players' positions. Moreover, practitioners and managers need to be aware of the positive impact of substitutions on match intensity.

The Effects of Carbohydrate Mouth Rinse on Psychophysiological Responses and Kinematic Profiles in Intermittent and Continuous Small-Sided Games in Adolescent Soccer Players: A Randomized, Double-Blinded, Placebo-Controlled, and Crossover Trial

BACKGROUND

Mouth rinsing (MR) with a carbohydrate solution is one of the most popular methods athletes use to improve their game-based performance due to its acute ergogenic effect.

OBJECTIVES

This study aimed to evaluate the effects of the carbohydrate MR intervention on psychophysiological responses and kinematic profiles during intermittent (INT) and continuous (CON) 4-a-side small-sided soccer games (SSGs).

METHODS

Thirty-two adolescent soccer players (age: 16.5 ± 0.5 years) played six bouts of 4-a-side SSGs with MRINT or MRCON at 3-day intervals in a randomized, double-blinded, placebo-controlled, and crossover study design. Psychophysiological responses and kinematic profiles were continuously recorded during all games. The rating of perceived exertion (RPE), the rating scale of mental effort (RSME), and the physical enjoyment scores (PES) were also determined at the end of each game.

RESULTS

The MRCON induced higher psychophysiological responses such as RPE, internal training load (ITL), and RSME (p ≤ 0.05, d values ranging from 0.50 to 1.04 [small to moderate effect]). Conversely, the MRINT induced higher PES (p ≤ 0.05, d values = 1.44 [large effect]) compared to MRCON. Although the MR intervention led to similar improvements in the performance of 4-a-side MRINT and MRCON, there was no significant difference between the groups.

CONCLUSIONS

Our results suggest that the MR intervention can be used as an effective ergogenic supplement for acute game performance enhancement, regardless of the game's structure.

Quantifying Trunk Impact Dynamics and Workload with Inertial Sensors in Goalball Players

The aim of this study was to quantify trunk impact dynamics in goalball players using inertial sensors and evaluate the goalball players' workloads, focusing on changes between the first and second halves of a match to enhance understanding of the demands experienced throughout the game. Utilizing inertial technology, trunk impacts during goalball gameplay were analyzed to provide a holistic insight into how these impacts influence athletes' dynamic stress loads, which refers to the physical demands placed on the body during dynamic movements. Six goalball players were recruited to wear an accelerometer during a whole goalball game to quantify trunk impacts. The results showed a higher number of total impacts and a higher number of impacts at higher levels during the first half, compared to a higher percentage of impacts at a low impact level in the second half. These results suggest that the intensity of gameplay is related to the number of impacts sustained, with players experiencing significantly more impacts, particularly at very low, low, and very high impact levels, in the first half compared to the second half. This decline in impacts aligns with the reduction in game intensity as the match progressed, as indicated by a lower heart rate and a trend towards a lower dynamic stress load in the second half. Future research could explore targeted training interventions aimed at optimizing workload and performance in goalball players.

Three-, Four-, and Five-Day Microcycles: The Normality in Professional Football

PURPOSE

This study aimed to quantify training and match-day (MD) load during 3-, 4-, and 5-day microcycles in professional adult football, as well as to analyze the effect of the microcycle length on training load produced the day after the match (MD + 1) and the day before the match (MD - 1).

METHODS

The study involved 20 male professional football players whose external and internal loads were monitored for a whole season. The training exposure, total distance covered, high-speed-running distance, sprint distance (SD), individual SD above 80% of the individual maximum velocity (D > 80%), and the number of accelerations and decelerations were quantified, as well as rating of perceived exertion and session rating of perceived exertion training load.

RESULTS

Microcycle length affected most of the variables of interest: high-speed-running distance (F = 9.04, P < .01), SD (F = 13.90, P < .01), D > 80% (F = 20.25, P < .01), accelerations (F = 10.12, P < .01), and decelerations (F = 6.01, P < .01). There was an interaction effect between the training day and microcycle type for SD (F = 5.46, P < .01), D > 80% (F = 4.51, P < .01), accelerations (F = 2.24, P = .06), and decelerations (F = 3.91, P < .01).

CONCLUSIONS

Coaches seem to be influenced by shorter microcycles in their training proposal, preferring sessions with a reduced muscle impact during shorter microcycles. Independent of the length of the congested fixture microcycle, the daily load seems to decrease when MD approaches.

Training loads and microcycle periodisation in Italian Serie A youth soccer players

Microcycles are fundamental structures for training prescription and load management, helping to optimise training effects and performance. This study quantified external and internal loads of Italian Serie A youth soccer players across competitive weeks and their periodisation within microcycles. Data were collected from 90 players belonging to four age groups (under-19, -17, -16, -15) across a season. Methods of monitoring external [duration and global navigation satellite systems (GNSS)] and internal load [heart rate (HR) and rating of perceived exertion (RPE)] were employed. Linear mixed models determined differences in training loads across age groups, training days and player positions. Under-19 and under-17 players trained five times per week, while younger players trained four times. Late-stage academy players (under-19 and -17) demonstrated higher weekly accumulated external and sRPE training load compared to their younger counterparts (p < 0.05 between groups). Weekly accumulated HR internal loads were higher in under-15 players (p < 0.05 between groups). Marked fluctuations of daily load were observed across microcycles in under-19 and under-17 groups (p < 0.05 between days). These findings highlight progressive increases in training load throughout the development pathway, with late-stage academy players training with higher frequency, volume and marked periodisation compared to younger players.

Practitioner Usage, Applications, and Understanding of Wearable GPS and Accelerometer Technology in Team Sports

ABSTRACT

Dawson, L, McErlain-Naylor, SA, Devereux, G, and Beato, M. Practitioner usage, applications, and understanding of wearable GPS and accelerometer technology in team sports. J Strength Cond Res 38(7): e373-e382, 2024-Monitoring training load is essential for optimizing the performance of athletes, allowing practitioners to assess training programs, monitor athlete progress, and minimize the risk of injury and overtraining. However, there is no universal method for training load monitoring, and the adoption of wearable global positioning system (GPS) and accelerometer technology in team sports has increased the volume of data and, therefore, the number of possible approaches. This survey investigated the usage, applications, and understanding of this technology by team sports practitioners. Seventy-two practitioners involved in team and athlete performance monitoring using GPS and accelerometer technology completed the survey. All respondents reported supporting the use of GPS technology in their sport, with 70.8% feeling that GPS technology is important for success. Results showed that 87.5% of respondents use data from wearable technology to inform training prescription, although only 50% use the data to influence decisions in competition. In addition, results showed that GPS metrics are used more than accelerometer-derived metrics; however, both are used regularly. Discrepancies in accelerometer usage highlighted concerns about practitioners' understanding of accelerometer-derived metrics. This survey gained insight into usage, application, understanding, practitioner needs, and concerns and criticisms surrounding the use of GPS and accelerometer metrics for athlete load monitoring. Such information can be used to improve the implementation of this technology in team sport monitoring and highlight gaps in the literature that will help to design future studies to support practitioner needs.

The Analysis of Physical Performance During Official Competitions in Professional English Football: Do Positions, Game Locations, and Results Influence Players' Game Demands?

ABSTRACT

Beato, M, Youngs, A, and Costin, AJ. The analysis of physical performance during official competitions in professional English football: Do positions, game locations, and results influence players' game demands? J Strength Cond Res 38(5): e226-e234, 2024-This study aimed, first, to verify if physical parameters were different between players' positions during official matches in English professional football, and second, if the game location (H and A) or results (W, L, D) affected players' physical performance. Twenty-five male professional football players of the same team were included in this data analysis (age = 27 ± 9 years) during the 2022-23 season. Players were divided into positions: center backs, wide backs, center midfielders, attacking midfielders, and strikers. The external load parameters were distance covered, high-speed running (HSR), sprinting distance, accelerations, decelerations, and high metabolic load distance (HMLD, meters > 25.5 w·kg -1 ) that were monitored using global navigation satellite systems Apex (STATSports). Linear mixed models' analysis for positions reported a significant difference in total distance ( p = 0.011), HSR ( p < 0.001), sprinting distance ( p < 0.001), accelerations ( p = 0.003), decelerations ( p = 0.002), and HMLD ( p < 0.001). Centre backs showed the lowest physical performance in the metrics analyzed, whereas players in the other positions frequently displayed a similar physical performance. Regarding locations and results, differences were only found between locations for decelerations ( p = 0.041) and between results for HMLD ( p = 0.010). In conclusion, physical performance was influenced by players' positions, whereas game location or results seem to not affect physical performance during official competitions. Consequently, practitioners can physically prepare their players independently from the location of the match or of the possible game results, whereas specific positional training is requested to optimally prepare their players.

Monitoring Readiness to Train and Perform in Female Football: Current Evidence and Recommendations for Practitioners

PURPOSE

Monitoring player readiness to train and perform is an important practical concept in football. Despite an abundance of research in this area in the male game, to date, research is limited in female football. The aims of this study were, first, to summarize the current literature on the monitoring of readiness in female football; second, to summarize the current evidence regarding the monitoring of the menstrual cycle and its potential impact on physical preparation and performance in female footballers; and third, to offer practical recommendations based on the current evidence for practitioners working with female football players.

CONCLUSIONS

Practitioners should include both objective (eg, heart rate and countermovement jump) and subjective measures (eg, athlete-reported outcome measures) in their monitoring practices. This would allow them to have a better picture of female players' readiness. Practitioners should assess the reliability of their monitoring (objective and subjective) tools before adopting them with their players. The use of athlete-reported outcome measures could play a key role in contexts where technology is not available (eg, in semiprofessional and amateur clubs); however, practitioners need to be aware that many single-item athlete-reported outcome measures instruments have not been properly validated. Finally, tracking the menstrual cycle can identify menstrual dysfunction (eg, infrequent or irregular menstruation) that can indicate a state of low energy availability or an underlying gynecological issue, both of which warrant further investigation by medical practitioners.