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The current study aimed to describe sleep habits and analyze the associations between sleep indices, changes in perceived fatigue (Δ Fatigue) and external training load measures in women soccer players during a 7-day training camp. Sixteen elite women soccer players (age: 25.4 ± 3.6 years; mean ± SD) from the Portuguese Women's National Team participated in the study. Sleep indices (sleep duration and efficiency) were measured using a wrist-worn accelerometer. External training loads measures were measured using GPS devices. Players also reported perceived fatigue using a Likert scale (1 - very, very low to 7 - very, very high) before and immediately after sleep. Players' within-subject coefficient of variation for sleep duration was 5.6%, and 4.6% for sleep efficiency. Individually, 8 players (50%) slept less than 7 h per night throughout the training camp, and the same number of athletes had a sleep efficiency lower than 85%. Similar values ( p< 0.05) were measured for sleep duration and efficiency between training and match days. A moderate negative within-subjects correlation was found between Δ Fatigue and sleep duration (adjusted for pre-sleep fatigue) [r = -0.32; 95% Confidence Interval (-0.51 - -0.08); p = 0.04]. These findings reinforce the importance of sleep in the recovery process of elite women soccer players, showing that more sleep may help to attenuate fatigue.

There is limited research on female football players, especially related to their physical and cognitive performance under different climactic conditions. We analyzed the impact of a hot environmental temperature on physical performance and anticipation in elite female football players during a fatigue-inducing intermittent protocol. Elite female players (n = 21) performed the countermovement jump (CMJ) and responded to filmed sequences of offensive play under two distinct environmental temperatures (i.e., mild environment temperature- 20°C and 30% rh versus hot environment temperature- 38°C and 80% rh), interspersed by 1-week interval. Linear mixed models were used. CMJ performance declined following the intermittent protocol on both temperature conditions (p < 0.05). Moreover, there were significant main effects for protocol on CMJ speed (m/s) (p = 0.001; η p 2  = 0.12), CMJ power (p = 0.002; η p 2  = 0.11), and CMJ Height max (p = 0.002; η p 2  = 0.12). After performing the intermittent protocol, exposure to a hot temperature caused a greater decline in anticipation accuracy (mild temperature = 64.41% vs. hot temperature = 53.44%; p < 0.001). Our study shows impaired performance in elite female football players following an intermittent protocol under hot compared with mild environmental conditions. We report decreased performance in both CMJ and anticipation performance under hotter conditions. The results reveal that exposure to hot temperatures had a negative effect on the accuracy of their anticipatory behaviors. We consider the implication of the work for research and training interventions., (© 2024 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

Abstract: Brito, P, Costa, J, Figueiredo, P, and Brito, J. Simulated soccer game protocols: A systematic review on validated protocols that represent the demands of the game. J Strength Cond Res 38(1): 192-205, 2024-Several laboratory and field testing protocols have been developed attempting to simulate the activity pattern and physiological demands of soccer. In the present systematic review, we aimed to analyze and discuss the appropriateness, strengths, and limitations of soccer-specific simulated tests. A systematic review of the literature was conducted based on the PRISMA guidelines. Studies conducted in soccer, simulated soccer match tests, and validated simulation protocols performed on-the-field or on a treadmill were considered. No sex restriction was applied, and age >18 years (i.e., adults) was considered. At least 1 outcome measure (e.g., neuromuscular performance, external load, internal load, or psychometric state) of post-simulated-match test or protocol had to be reported. Within the 14 studies included, the average methodological quality of the included articles was 0.61 ± 0.09 (mean ± SD) of 1. Overall, 9 validated protocols were identified. In the protocols, only amateur, university, or semiprofessional soccer players were analyzed. Only one study evaluated female soccer players. None of the studies evaluated the effect on performance over the 2-3 days after the protocol. Accelerations and decelerations, and changes in direction typically present in a game have not been clearly described in any protocol. Future research should address this issue and validate soccer-specific protocols in women., (Copyright © 2023 National Strength and Conditioning Association.)

Dietary supplements are widely used among athletes, and soccer players are no exception. Nevertheless, evidence supporting the use of dietary supplements aiming to enhance performance in soccer is somewhat contradictory, scarce, or even nonexistent. Thus, the present study aimed to systematically review and synthesize the effects of dietary supplements on athletic performance (e.g. distance covered, sprinting, jump performance) in elite soccer players. Studies enrolling highly trained, elite, and world-class soccer players using dietary supplements were searched in MEDLINE/PubMed, Web of Science, Scopus, and EBSCO databases in June 2022. In total, 1043 studies were identified, and 18 met the eligibility criteria. The studies evaluated the impacts on athletic performance of several dietary supplements, including caffeine, creatine, protein, beverages with carbohydrates and electrolytes, tart cherry juice, nitrate-rich beetroot juice, sodium bicarbonate with minerals, yohimbine, and a proprietary nutraceutical blend. Caffeine supplementation in doses between 3 and 6 mg/kg of body mass may improve jump height and sprint ability, particularly in female players, but individual response to caffeine must be considered. Creatine may improve sprint, agility, and in female players, jump performance. Protein supplementation can improve sprint and jump performance between matches, especially if protein ingested from food is not up to recommendations. Beverages containing carbohydrates and electrolytes can be used as part of the strategies to achieve carbohydrate intake during training and match-days but used alone do not benefit athletic performance. Tart cherry juice might be useful for maintaining athletic performance after matches that produce higher force loss and exercise-induced muscle damage, although polyphenols from the diet might attenuate the effects of tart cherry supplementation. Nitrate-rich beetroot concentrate can attenuate performance decrease in the days following matches. Further investigation with sodium bicarbonate alone is necessary, as supplementation protocols with elite players included other substances. Finally, the available data does not support yohimbine supplementation or the use of Resurgex Plus® to improve athletic performance in elite soccer players. Still, more well-designed research with elite soccer players is needed to improve support and advice regarding the use of dietary supplements for athletic performance enhancement.

Purpose: To investigate the internal training loads of a professional Spanish female futsal team throughout 26 weeks of training including preseason and in-season weeks and verify the impact of training period and/or training load magnitudes on heart-rate variability responses. Furthermore, we aimed to assess, intraindividually, the relationship between training load and the coefficient of variation (CV) of weekly natural log of the root mean square difference of successive normal interbeat (RR) intervals (lnRMSSDCV), obtained from ∼5 measures per week, and recorded in the seated position., Methods: A within-subject design involved 12 high-level outfield female futsal players (mean [SD] age: 23.9 [3.4] y)., Results: lnRMSSD was significantly lower and lnRMSSDCV was significantly higher during the preseason (weeks 1-6) compared to in-season (weeks 7-26) (P < .001). Individually, players presented moderate to large negative correlations between lnRMSSDCV and lnRMSSD during the 26 weeks of observation. Correlations ranged between rplayer4 = -.41 (95% CI, -.69 to -.02) and rplayer12 = -.55 (-.78 to -.18). Players also presented moderate to very large positive correlations between lnRMSSDCV and session rating of perceived exertion. Correlations ranged between rplayer7 = .41 (.04 to .71) and rplayer1 = .71 (.45 to .86)., Conclusion: Professional female futsal players in this study presented increased lnRMSSD and reduced lnRMSSDCV during 20 weeks into the competitive season compared to 6 weeks of preseason. Furthermore, lnRMSSDCV was negatively associated with lnRMSSD on an intraindividual basis. Finally, higher internal training loads were positively correlated with lnRMSSDCV, indicating that heart-rate variability is responsive to weekly training loads.

Context: Athletes' sleep is the most important recovery strategy and has received growing attention. However, athletes may experience sleep disruptions due to numerous factors, such as training and competition workloads, travel, changes in sleep-wake schedules, and sleeping environments. They often spend nights in unfamiliar hotels, and sharing a bed, room, or both with another person might affect sleep duration and quality., Objective: To analyze the effect of sleeping in shared (SRs) versus individual (IRs) rooms on objective and subjective sleep and on slow-wave-sleep-derived cardiac autonomic activity during an official training camp in elite youth soccer players. Training and match workloads were characterized., Design: Observational case study., Setting: Hotel accommodations., Patients or Other Participants: Thirteen elite male youth soccer players., Results: Players slept longer in IRs than in SRs (+1:28 [95% CI = 1:18, 1:42] hours:minutes; P < .001). Sleep efficiency was higher in IRs than in SRs (+12% [95% CI = 10%, 15%]; P < .001), whereas sleep latency was shorter in IRs than in SRs (-3 [95% CI = -15, -4] minutes; P < .001). Subjective sleep quality was lower in IRs than in SRs (-2 [-3 to -2] arbitrary units; P < .001). No differences were found for slow-wave-sleep-derived cardiac autonomic activity or for training or match workloads between training camps., Conclusions: During soccer training camps, sleep may be affected by whether the athlete is in an SR versus an IR., (© by the National Athletic Trainers' Association, Inc.)

The current case study aimed to quantify within-subjects correlations between training load and well-being in elite male beach soccer players. Data were obtained over three consecutive days during the preparation camp for the FIFA Beach Soccer World Cup Russia 2021. The session rating of perceived exertion (s-RPE) and external training load metrics using global positioning system (GPS) were recorded. Eleven players reported perceived well-being (sleep quality, fatigue, muscle soreness and stress) using a Likert scale (Hooper Index) before breakfast. Within-subjects correlation coefficients between workload and well-being were calculated. Workload metrics and perceived well-being indices were significantly lower on day three than on days one and two. The Hooper Index presented a very large positive correlation with s-RPE ( r = 0.86 [0.67, 0.94], 95% confidence interval, CI), exposure time ( r = 0.88 [0.71, 0.95]), total distance ( r = 0.83 [0.60, 0.93]), high-speed distance ( r = 0.77 [0.50, 0.91]), and number of sprints ( r = 0.75 [0.47, 0.90]). Sleep quality presented a moderate to large positive correlation with s-RPE ( r = 0.51 [0.11, 0.77]), exposure time ( r = 0.50 [0.10, 0.76]), high-speed distance ( r = 0.53 [0.15, 0.78]), number of sprints ( r = 0.62 [0.28, 0.83]) and total distance ( r = 0.41 [0.18, 0.78]). Fatigue presented a large to very large positive correlation with s-RPE ( r = 0.85 [0.66, 0.94]), exposure time ( r = 0.90 [0.78, 0.96]), total distance ( r = 0.86 [0.68, 0.94]), high-speed distance ( r = 0.65 [0.31, 0.84]) and number of sprints ( r = 0.56 [0.18, 0.79]). Muscle soreness presented a large to very large positive correlation with s-RPE ( r = 0.79 [0.56, 0.91]), exposure time ( r = 0.83 [0.62, 0.93]), total distance ( r = 0.81 [0.59, 0.92]), high-speed distance ( r = 0.75 [0.47, 0.89]) and number of sprints ( r = 0.59 [0.22, 0.81]). Overall, workload presented a meaningful correlation with perceived well-being indices in elite male beach soccer players during a training camp. These findings suggest that workload metrics and perceived well-being indices can be implemented into the daily routine of an elite beach soccer team, which may assist coaches, sports scientists, and practitioners in better preparing players for beach soccer competitions.

Objective: The aim of this study was to investigate the changes in 24-h heart rate variability and aerobic fitness, and their associations, in female soccer players during the preseason period., Methods: Sixteen players were assessed (24-h HRV and Yo-Yo Intermittent Recovery Test, level 1 [YYIR1]) before and after 4 weeks of preseason. The relationship between R-R24h length and high-frequency oscillations (HF24h) was analyzed by a quadratic regression model (revealing or not saturation of vagal activity) assessed 48-h before (PRE-preseason) and 48-h after (POST-preseason) the preseason period. Additionally, the mean HF24h was calculated from the linear portion of the R-R interval versus the HF24h regression curve (HF index). The average of the corresponding R-R24h values was defined as the R-R index., Results: In PRE-preseason, seven players had a saturated HF24h, while in POST-preseason, five new cases of saturated HF24h were observed. The mean R-R24h, HF24h, R-R index, and HF index lengths significantly increased after preseason (p < 0.001). Significant differences were found in YYIR1 PRE- compared with POST-preseason (930 ± 286 m [individual range: 400-1240 m] versus 1265 ± 252 m [640-1640 m], respectively; p < 0.001). Additionally, the relative changes in HF24h and HF index were largely correlated with improvements in the distance covered during the YYIR1 (r = 0.68 and r = 0.56; respectively)., Conclusion: Enhanced vagal activity after 4-week preseason period of soccer training increased the occurrence of vagal saturation in high-level female soccer players. Additionally, the increases in HF24h and HF index were significantly correlated with aerobic fitness change., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Competing Interests: Competing interests: None declared.

Abstract: Costa, JA, Brito, J, Nakamura, FY, Figueiredo, P, and Rebelo, A. Using the rating of perceived exertion and heart rate to quantify training intensity in female soccer players: validity and utility. J Strength Cond Res 36(1): 201-206, 2022-The aims of this study were as follows: (a) to analyze associations between session rating of perceived exertion (sRPE) and training impulse (TRIMP); (b) to verify whether significantly different ranges of percentage of heart rate peak (%HRpeak) would be reached in each discrete RPE category; and (c) to investigate the amount of time spent >90% of HRpeak and associated intraplayer and interplayer variability during soccer technical training sessions with similar contents and duration. This was a single-group observational study that measured the internal training load during 6 weeks of the competitive period in 17 high-level female soccer players. All training sessions started around 9 pm. and lasted on average 94 ± 5 minutes. During each training session, RPE, sRPE, TRIMP, HRex (%HRpeak), and time spent at >90% of HRpeak were assessed. A very large correlation was found between sRPE and TRIMP (r = 0.78; 95% confidence interval: [0.74-0.82]). Significant differences were observed between %HRpeak associated with each RPE value (i.e., RPE = 2 arbitrary unit [68%; 65-69% of %HRpeak]; RPE 3 [72%; 69-75%]; RPE 4 [79%; 76-82%]; RPE 5 [84; 81-87%]; χ2 = 73.34; df = 3; P < 0.001). Intraplayer and interplayer coefficients of variation for the time spent >90% of HRpeak (∼8% of training time, ∼7 minutes per session) during training sessions were 73 and 92%, respectively. In conclusion, it was confirmed that sRPE and TRIMP displayed good convergent validity, and different %HRpeak were observed for each discrete RPE. However, because of the high variability in the time >90% of HRpeak, careful monitoring of individual exercises should be performed to ensure the desired training stimulus for each player., (Copyright © 2019 National Strength and Conditioning Association.)

This study aimed to describe habitual sleep and nocturnal cardiac autonomic activity (CAA), and their relationship with training/match load in male youth soccer players during an international tournament. Eighteen elite male youth soccer players (aged 14.8 ± 0.3 years; mean ± SD) participated in the study. Sleep indices were measured using wrist actigraphy, and heart rate (HR) monitors were used to measure CAA during night-sleep throughout 5 consecutive days. Training and match loads were characterized using the session-rating of perceived exertion (s-RPE). During the five nights 8 to 17 players slept less than <8 h and only one to two players had a sleep efficiency <75%. Players' sleep duration coefficient of variation (CV) ranged between 4 and 17%. Nocturnal heart rate variability (HRV) indices for the time-domain analyses ranged from 3.8 (95% confidence interval, 3.6; 4.0) to 4.1 ln[ms] (3.9; 4.3) and for the frequency-domain analyses ranged from 5.9 (5.6; 6.5) to 6.6 (6.3; 7.4). Time-domain HRV CV ranged from 3 to 10% and frequency-domain HRV ranged from 2 to 12%. A moderate within-subjects correlation was found between s-RPE and sleep duration [r = -0.41 (-0.62; -0.14); p = 0.003]. The present findings suggest that youth soccer players slept less than the recommended during the international tournament, and sleep duration was negatively associated with training/match load.

Aims: This study aimed to analyze the feasibility and safety of a community-based walking football program in middle-aged and older men with type 2 diabetes (T2D)., Methods: Thirty-one male (age, 64.4 ± 4.5 years old; glycated hemoglobin, 6.7 ± 1.0%; body mass index: 28.8 ± 3.3 kg/m 2 ) patients with T2D were recruited from primary health care units in Porto, Portugal. The participants engaged in a 12-wk walking football program (three sessions per week of 60 min; consisting of strength and conditioning exercises, technical skills drills, and small-sided walking football games). Exercise intensity was planned to be gradual throughout the program in three 4-wk phases (phase I, light-intensity; phase II, moderate-intensity; phase III, vigorous-intensity) through the manipulation of game constraints, and monitored by OMNI scale and heart rate reserve (HRR). Sessions' enjoyment level, and exercise-related injuries and adverse events were recorded in all sessions., Results: The median (P25-P75) adherence to the program was 86.1% (77.8-97.2%). The median enjoyment levels reported by participants was 5 (4-5) points in phase I, 5 (5-5) points in phase II and 5 (5-5) points in phase III. Sessions' average subjective exercise intensity was 3.0 ± 0.6 points in OMNI scale in phase I, 3.5 ± 0.4 points in phase II, and 3.8 ± 0.4 points in phase III. Sessions' average HRR was 35.8 ± 6.7% in phase I, 41.6 ± 4.2% in phase II, and 37.3 ± 4.3% in phase III. Most participants attained vigorous-intensity peaks in all phases. Falls (n = 25) and musculoskeletal injuries (n = 8) were the most frequent adverse events. 31% of these events interfered with exercise participation, but no harm has resulted from it., Conclusion: A community-based walking football program for T2D patients revealed high levels of adherence and enjoyment, and light-to-vigorous exercise intensity. The adverse events were according to the expected for the population and activity. Therefore, walking football seems to be a feasible and safe exercise strategy, and has the potential for large scale implementation for T2D control., Trial Registration: NCT03810846., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The aim of this article was to systematically review the methods adopted to collect and interpret external training load (ETL) using microtechnology incorporating global positioning system (GPS). The main deficiencies identified concerned the non-collection of match ETL, and the non-consideration of potential confounders (e.g. playing position, fitness level, starting status or session content). Also, complementary training (individual/reconditioning) and pre-match warm-up were rarely quantified. To provide a full picture of the training demands, ETL was commonly complemented by internal training load monitoring with the rating of perceived exertion predominantly adopted instead of heart rate recordings. Continuous data collection and interpretation of ETL data in professional football vary widely between observational studies, possibly reflecting the actual procedures adopted in practical settings. Evidence about continuous ETL monitoring in female players, and female as well as male goalkeepers is lacking.

Introduction: The rate of perceived exertion (RPE) is widely adopted to quantify internal training load (ITL) in professional football. The aim of this study was to systematically review the use RPE-based methods in professional football., Evidence Acquisition: Observational studies conducted during training routines of professional football players over a minimum of one-week were selected based on the preferred reporting items for systematic reviews and meta-analyses statement., Evidence Synthesis: Thirty-eight articles met the inclusion criteria (average qualitative score was 6.3 out of 10 [3 to 9]). The main deficiencies identified concerned the poor description of study design (~52% of the studies), and the non-quantification of match load (~44%). Ten studies complemented RPE-based ITL information with time-motion analysis (~26%) and seven studies added HR recordings (~18%). Nine studies collected RPE data after complementary training, separately to field sessions (~3%). Operational questions (e.g. How was your workout? ~71%) were preferred to instructions (e.g. Please rate the intensity of today's session; ~8%). Session-RPE (s-RPE; RPE multiplied by training duration) was more commonly adopted as measure of exercise intensity than isolated RPE (~76 vs. ~8%). RPE-derived variables calculated on weekly values included absolute week-to-week change, acute: chronic workload ratio, monotony and strain and were not frequently used (7 to 15%). Four studies (~11%) divided RPE in two components: respiratory and muscular., Conclusions: There is a lack of consensus for the use of RPE in professional football and "good practices" are warranted. This review might help practitioners regarding procedures to adopt in RPE data collection and interpretation.

Purpose: To describe individual sleeping patterns and nocturnal cardiac autonomic activity of National team female soccer players during an international tournament., Materials and Methods: Twenty elite female soccer players (aged 25.2±3.1 years) wore wrist actigraph units and heart rate (HR) monitors during night-sleep throughout 9 consecutive days (6 day-time training sessions [DT], 2 day-time matches [DM], and 1 evening-time match [EM]) of an international tournament. Training and match loads were monitored using the session-rating of perceived exertion (s-RPE) and wearable 18-Hz GPS (total distance covered [TD], training and match exposure time, and high-speed running [HSR]) to characterize training and match loads., Results: Individually, s-RPE, TD, exposure time, and HSR during training sessions ranged from 20 to 680 arbitrary units (AU), 892 to 5176 m, 20 to 76 min, and 80 to 1140 m, respectively. During matches, s-RPE, TD, exposure time, and HSR ranged from 149 to 876 AU, 2236 to 11210 m, 20 to 98 min, and 629 to 3213 m, respectively. Individually, players slept less than recommended (<7 hours) on several days of the tournament, especially after EM (n = 8; TST ranging between 6:00-6:54 h). Total sleep time coefficient of variation (CV) ranged between 3.1 and 18.7%. However, all players presented good sleep quality (i.e., sleep efficiency ≥75%; individual range between: 75-98%) on each day of the tournament. Most of the players presented small fluctuations in nocturnal cardiac autonomic activity (individual nocturnal heart rate variability [HRV] ranged from 3.91-5.37 ms and HRV CV ranged from 2.8-9.0%), while two players presented higher HRV CV (11.5 and 11.7%; respectively)., Conclusion: Overall, this study highlights the substantial individual variability in sleep and HRV measures, suggesting the adoption of an individual approach to monitor sleep, training and match loads and recovery, to better understand how players cope with highly demanding competitions., Competing Interests: FIFA Research Scholarship/grant 2017 (International Centre for Sports Studies [CIES] and Fédération Internationale de Football Association [FIFA]) funding was provided for this study, to purchase technical equipment and devices necessary for the conduct of the research. The study was also supported by two individual doctoral grants from Fundação para a Ciência e a Tecnologia: Júlio Costa (SFRH/BD/128531/2017) and Vincenzo Rago (SFRH/BD/129324/2017). This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Purpose : To analyze whether exercise training conducted at night disturbs sleep and affects nocturnal cardiac autonomic control in high-level female athletes. Methods : A total of 18 high-level female soccer players (mean [SD] age 20.4 [2.1] y) wore actigraphs and heart-rate (HR) monitors during night sleep throughout night training days (n = 8) and resting days (n = 8), for 3 consecutive weeks. This was a longitudinal study that measured internal training load, sleep, nocturnal cardiac autonomic activity, and well-being ratings prior to training sessions. Results : Training load varied across training days (eg, training impulse range, mean [SD]; effect size, ES [95% confidence interval]: 72.9 [18.8] to 138.4 [29.6] a.u.; F 4,62  = 32.331; η p 2 = .673 [.001-.16], large effect; P  < .001). However, no differences in subjective well-being ratings were observed, although ES was large. Total sleep time (training days vs resting days: 07:17 [00:47] h vs 07:51 [00:42] h; ES = 0.742 [0.59-0.92], P  = .005; moderate effect) and sleep-onset time (00:58 [00:19] h vs 00:44 [00:16] h; ES = 0.802 [0.68-0.94], P  = .001; moderate effect) were negatively affected after night training. In addition, small effects were detected for wake-up time, time in bed, and sleep latency ( P  > .05). No differences were detected in HR variability during sleep (range of lnRMSSD: 4.3 [0.4] to 4.5 [0.4] ln[ms] vs 4.6 [0.3] to 4.5 [0.4] ln[ms]; F 3,52  = 2.148; P  > .05; η p 2 = .112 [.01-.25], medium effect), but HR during sleep was significantly higher after training days (range of HR: 56 [4] to 63 [7] beats/min vs 54 [4] to 57 [6] beats/min; F Overall, the results indicate that exercise training conducted at night may disturb sleep and affect HR, whereas limited effects can be expected in HR variability assessed during sleep in high-level female soccer players.2,32  = 15.956; P  < .001; η p 2 = .484 [.20-.63], large effect). Conclusion : Overall, the results indicate that exercise training conducted at night may disturb sleep and affect HR, whereas limited effects can be expected in HR variability assessed during sleep in high-level female soccer players.

Purpose: To assess the sensitivity of nocturnal heart-rate-variability-monitoring methods to the effects of late-night soccer training sessions in female athletes., Methods: Eleven female soccer players competing in the first division of the Portuguese soccer league wore heart-rate monitors during sleep at night throughout a 1-wk competitive in-season microcycle, after late-night training sessions (n = 3) and rest days (n = 3). Heart rate variability was analyzed through "slow-wave sleep episode" (10-min duration) and "hour by hour" (all the RR intervals recorded throughout the hours of sleep). Training load was quantified by session rating of perceived exertion (281.8 [117.9] to 369.0 [111.7] arbitrary units [a.u.]) and training impulse (77.5 [36.5] to 110.8 [31.6] a.u.), added to subjective well-being ratings (Hopper index = 11.6 [4.4] to 12.8 [3.2] a.u.). These variables were compared between training and rest days using repeated-measures analysis of variance., Results: The log-transformed slow-wave sleep-episode cardiac autonomic activity (lnRMSSD [natural logarithm of the square root of the mean of the sum of the squares of differences between adjacent normal RR intervals] varying between 3.92 [0.57] and 4.20 [0.60] ms; [Formula: see text]; 95% confidence interval, .01-.26), lnHF (natural logarithm of high frequency), lnLF (natural logarithm of low frequency), lnSD 1 (natural logarithm of short-term beat-to-beat variability), and lnSD 2 (natural logarithm of long-term beat-to-beat variability), and the nontransformed LF/HF were not different among night-training session days and rest days (P > .05). Considering the hour-by-hour method (lnRMSSD varying between 4.05 [0.35] and 4.33 [0.32] ms; [Formula: see text]; 95% confidence interval, .26-.52), lnHF, lnLF, lnSD 1 , and lnSD 2 and the nontransformed LF/HF were not different among night-training session days and rest days (P > .05)., Conclusion: Late-night soccer training does not seem to affect nocturnal slow-wave sleep-episode and hour-by-hour heart-rate-variability indices in highly trained athletes.

We systematically reviewed the effect of ambient temperature on football players' performance during a footballspecific fatigue protocol. Data sources: Cochrane Library, PubMed, Scopus, SPORTDiscus, Web of Science. Eligibility criteria followed the P.I.C.O.S. approach: (i) Healthy football players regardless of sex, age, or competitive level; (ii) football-specific fatigue-inducing protocol followed by assessment of anticipatory judgments, under controlled temperature conditions; (iii) Comparison groups using a different temperature during the foot-ball-specific fatigueinducing protocols; (iv) Outcomes included measures of anticipation, and/or physical or physiological tests; (v) No limitations regarding study design, if (ii) and (iii) were present. The searches resulted in 1,289 titles. However, none of the articles met the P.I.C.O.S. adopted, resulting in a total of zero eligible articles for the systematic review. Therefore, from a critical review of the existing literature, it must be concluded that evidence bases of sufficient scientific quality for the understanding the effect of temperature on physical and physiological demands and anticipatory judgments of football players is simply lacking. This should strongly motivate the scientific community to engage in research on the topic, to test if theoretical assumptions are accurate. [ABSTRACT FROM AUTHOR]

Childhood obesity continues to represent a growing challenge, and it has been associated with gut microbiota dysbiosis. This study examines the gut microbiota composition in overweight and obese school children and assesses whether a 12-week multidisciplinary intervention can induce changes in the gut microbiota. The intervention, which combined recreational football and nutritional education, was implemented among 15 school children, aged 7–10 years, with a Body Mass Index ≥ 85th percentile. The children were assigned into two groups: Football Group (n = 9) and Nutrition and Football Group (n = 6). Faecal samples were collected at the beginning and end of the program and analysed by sequencing the 16S rRNA gene. Over the intervention, a significant decrease was found collectively for Bifidobacterium genera (p = 0.011) and for Roseburia genera in the Football Group (p = 0.021). The relative abundance of Roseburia (p = 0.002) and Roseburia faecis (p = 0.009) was negatively correlated with moderate to vigorous physical activity (MVPA), while Prevotella copri was positively correlated with MVPA (p = 0.010) and with the daily intake of protein (p = 0.008). Our findings suggest that a multidisciplinary intervention was capable of inducing limited but significant positive changes in the gut microbiota composition in overweight and obese school children. [ABSTRACT FROM AUTHOR]

Football is a sport that involves a combination of continuous and intermittent effort. Therefore, players need to be able to recover quickly between moments of high intensity to continue to perform at a high level of output throughout the entire match. The present study aimed to evaluate the effect of an intermittent exercise protocol on the rate of high-intensive force production through the countermovement test (CMJ) in elite Portuguese female soccer players. The sample consisted of 12 players from the first division of women's football in Portugal (Age = 18.1 ± 0.9 years; Weight = 60.10 ± 5.8 Kg; Height = 1.63 ± 4.8 cm; BMI = 22.48 ± 1.5 kg/m2). The players performed an intermittent exercise protocol on a cycle ergometer, lasting 8 minutes, in which each minute corresponded to 40 seconds of high-intensity (4W/kg, based on the player's body weight) and 20 seconds of low-intensity (75W). Before and after the protocol, the players performed the CMJ. Through the results obtained, it was possible to observe that players presented a significant decrease in the height of the CMJ between the two moments (before- 29.92 ± 3.55cm vs after- 26.92 ± 4.05cm; p < 0.01). The present study allowed us to conclude that intermittent exercise protocol promoted a negative influence on CMJ performance. [ABSTRACT FROM AUTHOR]

The aims of this study were to analyze heart rate variability (HRV) changes in futsal players during preseason training using both "criterion" (10-minute) and ultra-shortened (2-minute) measures, and to determine whether they were related to changes in the Yo-Yo Intermittent Recovery Test, level 1 (Yo-Yo IR1) performance and accumulated training load (TL). Eleven male competitive futsal players (age = 25.19 ± 4.70 years; body mass = 73.15 ± 11.70 kg; and height = 176.90 ± 5.01 cm) volunteered for the study. Data collection took place during the first to the fourth weeks of preseason training. Training load was monitored with session ratings of perceived exertion. The total distance (TD) covered during the Yo-Yo IR1 was recorded during week 1 and week 4. Heart rate variability was measured through the log-transformed root mean square of successive normal-to-normal interval differences using the ultra-short analysis, with its weekly mean (InRMSSDM) and coefficient of variation (InRMSSDCV) recorded, and by means of the criterion method (weeks 1 and 4). InRMSSDM was likely higher at week 4 compared with week 1 using both criterion and ultra-short recordings. Moderate-to-large correlations were found between changes in the InRMSSDM and InRMSSDCV values and changes in TL and TD (r values ranged from -0.48 to 0.65). Changes in ultra-short HRV measures (i.e., increase in InRMSSDM and decrease in InRMSSDCV) during futsal preseason were associated with increased performance. The players who accumulated higher perceived TLs displayed smaller improvements in the Yo-Yo IR1 performance and HRV. [ABSTRACT FROM AUTHOR]

INTRODUÇÃO: Os jogos reduzidos e condicionados (JRCs) fornecem aos jogadores uma variedade de comportamentos na gestão de espaços no campo de Futebol, combinando múltiplas demandas de jogo. Os JRCs, também, permitem a estimulação da transição entre superioridade e inferioridade entre as equipes ao longo do jogo, o que incentiva a conduta dos outros jogadores nessas situações e cria um bom ambiente para o processo de ensino-aprendizagem do próprio jogo. OBJETIVO: Adaptar e validar o FUT-SAT como ferramenta de avaliação tática de jogadores de Futebol em micro formatos de jogo limitados e condicionados. MÉTODO: Um painel de cinco treinadores de Futebol de elite (UEFA-A e não menos de 10 anos de treino) e dois estudantes de Ciências do Desporto caracterizaram e validaram os princípios tácticos do jogo nos formatos de 1v1 + Grs, 2v1 + Grs, 2v2 + Grs e 3v2 + Grs. Para garantir o desempenho durante os JRCs, 54 futebolistas (n=15 de Sub.17, n=16 de Sub.18 e n=23 de Sub.19) de um clube de futebol do distrito do Porto. Os jogos foram gravados com uma câmera (Rollei 5s, GmbH & Co. KG, Alemanha). O material de vídeo foi introduzido em formato digital via conexão USB a um computador portátil (ACER modelo E1-571-6824) e convertido em um arquivo "avi.". Para processamento de imagem para análise de jogos, utilizou-se o programa Soccer Analyzer e para o estudo estatístico foram utilizados os valores do coeficiente de concordância de Kendall (W) e alfa de Cronbach (a), sendo utilizado o Microsoft Excel (folhas de cálculo) e o IBM SPSS Statistics versão 25. RESULTADOS: A confiabilidade entre os dois avaliadores esteve presente neste estudo (1v1 = 0,683; 2v1 = 0,693; 2v2 = 0,868; 3v2 = 0,698), indicando uma correlação moderada. O a, baseado em itens padronizados da ferramenta FUT-SAT (1v1 = 0,819; 2v1 = 0,923; 2v2 = 0,724; 3v2 = 0,903) obteve índice médio acima de 0,750, sendo considerado bom. Ou seja, os resultados indicam uma boa confiabilidade no uso de esta ferramenta em JRCs para estas configurações. CONSIDERAÇÕES FINAIS: O FUT-SAT nessas configurações de jogo (1v1, 2v1, 2v2 e 3v2) permite perceber padrões e conceitos táticos dos jogadores. O campo com menor dimensão permite mais contato do atleta com a bola, os conceitos táticos usados se repetem mais. Proporcionando um melhor conhecimento de jogo dos futebolistas e aumentando as informações disponíveis ao treinador e sua conexão com o jogador. [ABSTRACT FROM AUTHOR]