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Purpose: To evaluate the effects of sporting activities, training loads, and athletes’ characteristics on sleep among high-level adolescent athletes, in a controlled training and academic environment. Methods: A total of 128 high-level adolescent athletes (age = 15.2 [2.0] y), across 9 different sports, completed common sleep questionnaires and were monitored daily (7.3 [2.7] d) during a typical in-season training period. Sleep was analyzed using actigraphy and sleep diaries, whereas training load was evaluated using the session rating of perceived exertion, and muscle soreness and general fatigue were reported with the aid of visual analog scales. Separate linear mixed-effects models were fitted, including the athlete as a random effect and the following variables as fixed effects: the sport practiced (categorical predictor), daily training load, age, and sex. Different models were used to compare sleep variables among sports and to assess the influence of training load, age, and sex. Results: The mean total sleep time was 7.1 (0.7) hours. Swimmers presented increased sleep fragmentation, training loads, perceived muscle soreness, and general fatigue compared with athletes who engaged in other sports. Independent of any sport-specific effects, a higher daily training load induced an earlier bedtime and reduced total sleep time and perceived sleep quality, with higher sleep fragmentation. Moreover, female athletes experienced increased total sleep time and worse sleep quality in response to stress compared with those in males. Conclusion: In a controlled training and academic environment, high-level adolescent athletes did not achieve the recommended sleep duration. Impaired sleep quality and quantity could be partially explained by increased training loads.

Elite athletes are particularly susceptible to sleep inadequacies, characterised by habitual short sleep (

International audience; The aim of this study was to identify young elite athletes’ personality profiles using a person-centered approach, and to investigate whether the profiles significantly differ in stress and sleep. 260 athletes from a variety of sports completed a questionnaire package to assess neuroticismand conscientiousness traits, stress appraisals (i.e. intensity and directional interpretation of stress, challenge and threat appraisals), and various indicators of sleep (i.e. sleep quality, social jet lag, Ford insomnia response to stress test (FIRST)). A latent profile analysis (LPA) approach was used to identify personality profiles based on the scores of neuroticism and conscientiousness. A multivariate analysis of variance was performed to examine if the athletes belonging to different personality profiles differ on stress appraisals and indicators of sleep.Three profiles emerged: Maladaptive profile (high levels of conscientiousness and neuroticism); Highly adaptive profile (moderate level of conscientiousness and low level of neuroticism); Adaptive profile (high level of conscientiousness and moderate level of neuroticism). Results showed that athletes from the adaptive profile reported significantly lower scores of stress intensity and threat appraisal than those from other profiles. Athletes from the maladaptive profile reported significantly higher levels of FIRST than those from other profiles as well as worse sleep quality and lower levels of challenge appraisal than the athletes from the highly adaptive profile. These results suggest that investigating personality profile may be useful in identifying athletes at higher risk of stress sensitivity and worsening sleep that are likely to benefit from preventive actions (e.g. cognitive behavioural therapy interventions).

Athletes are increasingly required to travel domestically and internationally, often resulting in travel fatigue and jet lag. Despite considerable agreement that travel fatigue and jet lag can be a real and impactful issue for athletes regarding performance and risk of illness and injury, evidence on optimal assessment and management is lacking. Therefore 26 researchers and/or clinicians with knowledge in travel fatigue, jet lag and sleep in the sports setting, formed an expert panel to formalise a review and consensus document. This manuscript includes definitions of terminology commonly used in the field of circadian physiology, outlines basic information on the human circadian system and how it is affected by time-givers, discusses the causes and consequences of travel fatigue and jet lag, and provides consensus on recommendations for managing travel fatigue and jet lag in athletes. The lack of evidence restricts the strength of recommendations that are possible but the consensus group identified the fundamental principles and interventions to consider for both the assessment and management of travel fatigue and jet lag. These are summarised in travel toolboxes including strategies for pre-flight, during flight and post-flight. The consensus group also outlined specific steps to advance theory and practice in these areas. Supplementary Information The online version contains supplementary material available at 10.1007/s40279-021-01502-0.

Introduction:The aim of the present study was to investigate the effect of the depth of cold water immersion (CWI) (whole-body with head immersed and partial-body CWI) after high-intensity, intermittent running exercise on sleep architecture and recovery kinetics among well-trained runners.Methods:In a randomized, counterbalanced order, 12 well-trained male endurance runners (V.O2max = 66.0 ± 3.9 ml·min−1·kg−1) performed a simulated trail (≈18:00) on a motorized treadmill followed by CWI (13.3 ± 0.2°C) for 10 min: whole-body immersion including the head (WHOLE;n= 12), partial-body immersion up to the iliac crest (PARTIAL;n= 12), and, finally, an out-of-water control condition (CONT;n= 10). Markers of fatigue and muscle damage—maximal voluntary isometric contraction (MVIC), countermovement jump (CMJ), plasma creatine kinase [CK], and subjective ratings—were recorded until 48 h after the simulated trail. After each condition, nocturnal core body temperature (Tcore) was measured, whereas sleep and heart rate variability were assessed using polysomnography.Results:There was a lowerTcoreinduced by WHOLE than CONT from the end of immersion to 80 min after the start of immersion (p< 0.05). Slow-wave sleep (SWS) proportion was higher (p< 0.05) during the first 180 min of the night in WHOLE compared with PARTIAL. WHOLE and PARTIAL induced a significant (p< 0.05) decrease in arousal for the duration of the night compared with CONT, while only WHOLE decreased limb movements compared with CONT (p< 0.01) for the duration of the night. Heart rate variability analysis showed a significant reduction (p< 0.05) in RMSSD, low frequency (LF), and high frequency (HF) in WHOLE compared with both PARTIAL and CONT during the first sequence of SWS. No differences between conditions were observed for any markers of fatigue and muscle damage (p> 0.05) throughout the 48-h recovery period.Conclusion:WHOLE reduced arousal and limb movement and enhanced SWS proportion during the first part of the night, which may be particularly useful in the athlete's recovery process after exercise. Future studies are, however, required to assess whether such positive sleep outcomes may result in overall recovery optimization.

PurposeUsing a mixed-method approach, this investigation aimed to examine athletes’ sleeping patterns along with the socio-physiological acute and chronic stressors affecting their sleep.MethodsFifteen elite athletes (Mage = 21.7 years; SD = 2.2) were monitored daily during a typical in-season training period (20 ± 1 days) and completed individual semi-structured interviews. Their sleep was analyzed using actigraphy and sleep diaries. A content analysis method was used to assess qualitative interviews.ResultsThree factors influencing sleep emerged from the qualitative interview analyses, i.e., sleep environment, training and study requirements. Half the athletes (8/15) complained about their sleeping environment with noise and/or bedroom temperature and/or mattress quality and/or light exposure presented as an issue. “Complainers” notably exhibited impaired (p < 0.05) sleep efficiency and wake after sleep onset compared with “non-complainers.” Daily training load showed correlations (p < 0.05) with wake after sleep onset and sleep onset latency. “Student athletes” exhibited later bedtime and earlier wake-up time compared with “non-student athletes,” leading to a reduced total sleep time (6:50 ± 1:13 vs. 7:06 ± 0:53; p < 0.05; d = 0.20).ConclusionAn individualized assessment of sleep using actigraphy and interviews, with consideration to various socio-physiological factors, is recommended. Individualized sleep interventions with consideration to physiological (e.g., training load), behavioral (e.g., screen use) and environmental factors (e.g., room temperature, noise, mattress), can then be provided to each athlete.

This study aimed to explore the relationship between elite rugby union match and postmatch sleep architecture and to investigate the effects of a high-heat capacity mattress (MAT) and a whole-body cryotherapy (WBC) session on postmatch sleep architecture.Nineteen elite male U23 rugby union players performed in three official matches, followed by three experimental conditions, in a randomized order: MAT, WBC, and no intervention (CONT). Match load was evaluated using GPS trackers and video analyses. Sleep architecture was assessed by polysomnography (PSG). Core body temperature (CBT) and mattress surface temperature were monitored during sleep. Linear mixed-effects models were conducted to assess the effects of each experimental condition on sleep, with match load variables as covariates.A lower wake after sleep onset (β = -10.5 min, P0.01) and higher rapid eye movement sleep proportion (β = +2.8%, P0.05) were reported for MAT compared with CONT. Moreover, lower mean CBT (β = -0.135°C, P0.001) and mean mattress surface temperature (β = -2.736°C, P0.001) during sleep were observed for MAT compared CONT. WBC did not affect nocturnal CBT nor interfere with sleep architecture. For every 100-m increase in high-speed running distance, a higher slow wave sleep (β = +1.1%, P = 0.05) and lower light sleep proportion (β = -1.2%, P0.05) proportion were observed. Conversely, for every 10 supplementary collisions, lower slow wave sleep (β = -1.9, P = 0.09) and higher light sleep (β = +2.9%, P0.001) proportion were observed.MAT use had a positive effect on sleep architecture after an elite rugby union match, potentially through a more efficient nocturnal heat transfer.

International audience; Introduction: This study aimed to explore the relationship between elite rugby union match and postmatch sleep architecture and to investigate the effects of a high-heat capacity mattress (MAT) and a whole-body cryotherapy (WBC) session on postmatch sleep architecture.Methods: Nineteen elite male U23 rugby union players performed in three official matches, followed by three experimental conditions, in a randomized order: MAT, WBC, and no intervention (CONT). Match load was evaluated using GPS trackers and video analyses. Sleep architecture was assessed by polysomnography (PSG). Core body temperature (CBT) and mattress surface temperature were monitored during sleep. Linear mixed-effects models were conducted to assess the effects of each experimental condition on sleep, with match load variables as covariates.Results: A lower wake after sleep onset (β = −10.5 min, P < 0.01) and higher rapid eye movement sleep proportion (β = +2.8%, P < 0.05) were reported for MAT compared with CONT. Moreover, lower mean CBT (β = −0.135°C, P < 0.001) and mean mattress surface temperature (β = −2.736°C, P < 0.001) during sleep were observed for MAT compared CONT. WBC did not affect nocturnal CBT nor interfere with sleep architecture. For every 100-m increase in high-speed running distance, a higher slow wave sleep (β = +1.1%, P = 0.05) and lower light sleep proportion (β = −1.2%, P < 0.05) proportion were observed. Conversely, for every 10 supplementary collisions, lower slow wave sleep (β = −1.9, P = 0.09) and higher light sleep (β = +2.9%, P < 0.001) proportion were observed.Conclusion: MAT use had a positive effect on sleep architecture after an elite rugby union match, potentially through a more efficient nocturnal heat transfer.

BACKGROUND The physical activity and playing actions performed during a soccer match vary according to player position. The aim of the present study was to analyze the recovery kinetics of cognitive performance, physical performance and subjective ratings after a competitive soccer match. METHODS Eight goalkeepers and eight outfield players played in the match with data collected before, 45 min, 24 h and 48 h after the match. Subjective ratings, Vienna Reaction Test (reaction time, motor time), Vienna Determination Test (number of stimuli, number of correct responses), squat jump, countermovement jump and 6-s sprint were analyzed. RESULTS No significant interaction between position and time was found for Vienna Reaction Test and Vienna Determination Test performance. No significant interaction between position and time was found for squat jump and countermovement jump but squat jump and countermovement jump significantly decreased (P

International audience; The aim of the present study was to investigate the effects of night‐time (21:00 hours) high‐intensity, intermittent exercise on sleep architecture among well‐trained athletes in a laboratory setting. In a randomized, counterbalanced order, 11 well‐trained male runners completed a simulated trail‐running exercise (TRAIL) on a motorized treadmill and a resting condition (REST; no exercise during the day). After each condition, nocturnal autonomic nervous system activity and core body temperature (CBT) were measured and sleep was analysed using polysomnography and actigraphy. Markers of muscle damage (maximal voluntary contraction [MVC], plasma creatine kinase concentration [CK] and perceived muscle soreness) were recorded before and immediately (POST), 24 hr (H24) and 48 hr (H48) after exercise. TRAIL induced a high level of fatigue and mild exercise‐induced muscle damage, as determined by a reduction in MVC (−9.4%, p < .01, d = −1.36) and increases in [CK] (+176.0%, p < .01, d = 1.49) and perceived muscle soreness (+4.5 UA, p < .01, d = 2.17) compared with REST at H24. A trend for increased non‐rapid eye movement (+4.2%; p = .10; d = 0.86) and reduced rapid eye movement (−4.4%; p = .07; d = −0.87) during sleep was observed for TRAIL compared with the REST condition. Moreover, compared with REST, TRAIL significantly increased CBT and nocturnal HR during the first part of the night. In conclusion, sleep architecture was modified after night‐time, high‐intensity exercise among well‐trained runners.

Nedelec, M, Dawson, B, and Dupont, G. Influence of night soccer matches on sleep in elite players. J Strength Cond Res 33(1): 174-179, 2019-This study examined the impact of night matches on the sleep/wake behavior of elite soccer players participating in the UEFA Champions League and French Ligue 1. A mixed method approach was used, combining objective sleep assessment with wrist activity monitors, and a survey to ascertain the sleep complaints after night matches (kick off after 18:00 hours). Most players (90%) indicated worse sleep in the nights after evening matches than after training days. Objective time in bed (-01:39 hours; effect size [ES] = 1.7; p < 0.001) and total sleep time (-01:32 hours; ES = 1.4; p < 0.001) were both lower after night matches than after training days. Night matches had a marked influence on sleep quantity later that night, both objectively and subjectively. The survey revealed that players may not have appropriate methods for better managing their sleep after night matches. It is yet to be determined whether players may benefit from individualized sleep interventions in these circumstances.

International audience; Practicing sport at the highest level is typically accompanied by several stressors and restrictions on personal life. Elite athletes' lifestyle delivers a significant challenge to sleep, due to both the physiological and psychological demands, and the training and competition schedules. Inter-individual variability of sleep patterns (e.g., sleep requirements, chronotype) may have important implications not only for recovery and training schedules but also for the choice of measures to possibly improve sleep. This article provides a review of the current available literature regarding the variability of sleep among elite athletes and factors possibly responsible for this phenomenon. We also provide methodological approaches to better address the inter-individual variability of sleep in future studies with elite athletes. There is currently little scientific evidence supporting a specific influence of one particular type of sport on sleep; sleep disorders may be, however, more common in strength/power and contact sports. Sleep behavior may notably vary depending on the athlete's typical daily schedule. The specificity of training and competition schedules possibly accounts for the single most influential factor leading to inconsistency in sleep among elite athletes (e.g., "social jet lag"). Additionally, athletes are affected by extensive exposure to electric light and evening use of electronic media devices. Therefore, the influence of ordinary sleep, poor sleep, and extended sleep as important additional contributors to training load should be studied. Future experimental studies on sleep and elite sport performance should systematically report the seasonal phase. Boarding conditions may provide a good option to standardize as many variables as possible without the inconvenience of laboratory. The use of interdisciplinary mixed-method approaches should be encouraged in future studies on sleep and elite sport. Finally, high inter-and intra-individual variability in the athletes' sleep characteristics suggests a need for providing individual responses in addition to group means.

Objectif Evaluer l’effet de la discipline sportive, de la charge de l’entrainement et des caracteristiques du sportif sur la qualite et la quantite de sommeil, dans un environnement academique et sportif controle. Methodes 128 sportifs de haut niveau adolescents, pratiquant 9 sports differents, ont ete evalues durant 7,3 ± 2,7 jours d’entrainement. Le sommeil a ete evalue par actimetrie et par questionnaires subjectifs, et la charge interne de l’entrainement a travers la methode RPE-S (session rating of perceived exertion). Des modeles lineaires mixtes ont ete utilises pour etudier la relation entre la charge journaliere et le sommeil. Resultats Le temps total de sommeil (TST) etait de 7,1 ± 0,7 h. Les nageurs presentaient un sommeil particulierement fragmente comparativement aux autres sportifs. Independamment de la discipline, l’augmentation de la charge interne etait accompagnee d’une diminution du TST et de la qualite de sommeil percue, d’une legere avance de phase ainsi que d’une augmentation de la fragmentation de sommeil. Le TST etait plus faible chez hommes comparativement aux femmes (-32,9 min ; p Conclusion Dans un environnement academique et sportif controle, les jeunes sportifs de haut niveau n’ont pas atteint la duree de sommeil recommandee. Le TST etait plus faible pour les hommes alors que les femmes presentaient un sommeil plus perturbe en reponse a une situation stressante.

Objectif Identifier les profils de personnalite de jeunes sportifs, et investiguer si le stress et le sommeil different entre les profils. Methodes Une evaluation par questionnaire des traits neuroticisme et consciencieux, du stress estime (i.e. intensite et direction, estimation du challenge et de la menace), de la qualite de sommeil, du jet lag social, du test de Ford d’insomnie en reponse au stress (FIRST) a ete realisee aupres de 260 sportifs. Une analyse de profil latent a permis d’identifier les profils de personnalite sur la base des scores aux traits neuroticisme et consciencieux. Une MANOVA a permis d’examiner si les sportifs appartenant aux differents profils differaient en termes de stress estime et indicateurs de sommeil. Trois profils ont emerge : profil mal adaptatif (hauts niveaux de traits neuroticisme et consciencieux) ; profil hautement adaptatif (faible niveau de neuroticisme et niveau modere de trait consciencieux) ; profil adaptatif (niveau modere de neuroticisme et haut niveau de trait consciencieux). Resultats Les sportifs du profil mal adaptatif ont rapporte des scores au FIRST significativement plus importants que ceux des autres profils, ainsi qu’une qualite de sommeil degradee et de moindres niveaux d’estimation du challenge que les sportifs du profil hautement adaptatif. Conclusion Ces resultats suggerent que l’investigation des profils de personnalite pourrait etre utile a l’identification des sportifs les plus sensibles au stress et a la perturbation du sommeil, et qui pourraient beneficier d’actions de prevention (therapie cognitivo-comportementale par exemple).

Objectif Evaluer l’effet de la realisation d’un exercice intermittent a haute intensite en soiree sur le sommeil de coureurs a pied entraines. Methodes Dans un ordre randomise et croise, 11 coureurs a pied entraines (VO2max : ≈ 68 ml/min/kg) ont realise 55 min de simulation de TRAIL (debut a 21h00) ou bien une condition controle (REST). La nuit apres TRAIL et REST, le sommeil, la temperature centrale (TC) ainsi que les reponses du systeme nerveux autonome au cours de la nuit (frequence cardiaque [FC] et variabilite de la frequence cardiaque [VFC]) ont ete evaluees. Resultats Aucune difference significative entre les conditions n’a ete observee dans l’architecture du sommeil pour toute la nuit sauf une tendance vers une diminution moderee de la proportion de sommeil paradoxal (≈ −4,4 % ; p = 0,07 ; d = −0,87). Lors des 180 premieres minutes de sommeil, les proportions d’eveil (≈ + 1,3 % ; p Conclusion Le sommeil est perturbe en premiere partie de nuit suite a TRAIL. La TC etait plus elevee et le systeme neveux sympathique plus active, ce qui suggere un lien potentiel entre ces mecanismes et la perturbation de sommeil.

Objectif Evaluer l’effet de la cryotherapie corps entier (CCE) et d’un matelas a haute conductivite thermique (MAT) sur le du sommeil apres un match de rugby de haut niveau. Methodes Dix-neuf joueurs de rugby de haut niveau ont dispute 3 matches officiels suivis de 3 conditions experimentales, realisees dans un ordre randomise et croise : CCE, MAT et une condition controle (CONT). Le protocole de CCE consistait a passer 3 min dans une chambre a −110 °C, deux heures avant le coucher. Lors de la condition MAT, les joueurs ont dormi sur un matelas contenant une plaque de gel au niveau de la couche superieure, permettant d’optimiser les echanges thermiques au cours de la nuit. Le sommeil ainsi que la temperature centrale (TC) et celle au niveau de la face superieure du matelas (TM) au cours de la nuit ont ete evalues. La charge physique des matches a ete evaluee via GPS (distance a haute intensite) et analyse video (nombre de collision). Des modeles lineaires mixtes ont ete utilises afin d’evaluer l’effet de chaque condition experimentale sur les variables dependantes compare a CONT, a charge de match comparable. Resultats Une diminution de la duree d’eveil intrasommeil (WASO ; ≈ −10,5 min ; p Conclusion MAT a permis d’optimiser les echanges thermiques au cours de la nuit et par consequent d’ameliorer la continuite de sommeil. Aucun effet de la CCE sur l’architecture du sommeil n’a ete observe.

Nedelec, M, Leduc, C, Dawson, B, Guilhem, G, and Dupont, G. Case study: sleep and injury in elite soccer. A mixed method approach. J Strength Cond Res 33(11): 3085-3091, 2019-This case study allowed an examination of the link between sleep and injury occurrence in an elite male soccer player competing in French League 1 and Union of European Football Associations matches. During 4 months, a mixed method approach was used, combining actigraphic sleep assessment with qualitative interviews on a daily basis. Three injuries were reported over the study period. Sleep onset latency (SOL), both in the single night (117 ± 43 minutes) and in the week (78 ± 50 minutes) before injury occurrence, was longer than preseason baseline values (18 ± 13 minutes; effect size (ES): 3.1 and 1.6, respectively). Similarly, sleep efficiency in the single night (73 ± 7%) and the week (75 ± 7%) before injury occurrence was lower than baseline (90 ± 3%; ES: 3.2 and 2.8, respectively). In this case study, SOL and efficiency were altered on the night and in the week before injury occurrence. Individualized assessment of sleep during congested playing schedules may be useful to aid in preventing injury occurrence.

Purpose Little is known about injury prevention practices in professional football clubs. The purpose of this study was therefore to determine the current perceptions and practices of premier league football clubs internationally concerning risk factors, testing and preventative exercises for non-contact injuries. Methods A survey was administered to 93 premier league football clubs internationally. The survey included four sections: (1) persons involved in the injury prevention programme: position, quantity, role, qualification; (2) perceptions regarding non-contact injury risk factors; (3) tests used to identify non-contact injury risk and (4) non-contact injury prevention exercises used, their perceived effectiveness and implementation strategies. Results 44 surveys were successfully returned (47%). The position of physiotherapist was the most represented position in the injury prevention programme. The top five perceived risk factors in rank order were previous injury, fatigue, muscle imbalance, fitness and movement efficiency. The five most commonly used tests to identify injury risk (in rank order) were functional movement screen, questionnaire, isokinetic dynamometry, physical tests and flexibility. The top five exercises used by clubs were (also in rank order) eccentric exercise, balance/ proprioception, hamstring eccentric, core stability and, sharing the fifth position, Nordic hamstring and gluteus activation. Conclusions The survey revealed the most common perceptions and practices of premier league football clubs internationally regarding risk factors, testing and preventative exercises. The findings can enable reduction of the gap between research and practice.

In elite soccer, players are frequently required to play consecutive matches interspersed by 3 days and complete physical performance recovery may not be achieved. Incomplete recovery might result in underperformance and injury. During congested schedules, recovery strategies are therefore required to alleviate post-match fatigue, regain performance faster and reduce the risk of injury. This article is Part I of a subsequent companion review and deals with post-match fatigue mechanisms and recovery kinetics of physical performance (sprints, jumps, maximal strength and technical skills), cognitive, subjective and biochemical markers. The companion review will analyse recovery strategies used in contemporary professional soccer. Soccer involves many physically demanding activities including sprinting, changes in running speed, changes of direction, jumps and tackles, as well as technical actions such as dribbling, shooting and passing. These activities lead to a post-match fatigue that is linked to a combination of dehydration, glycogen depletion, muscle damage and mental fatigue. The magnitude of soccer match-induced fatigue, extrinsic factors (i.e. match result, quality of the opponent, match location, playing surface) and/or intrinsic factors (i.e. training status, age, gender, muscle fibre typology), potentially influence the time course of recovery. Recovery in soccer is a complex issue, reinforcing the need for future research to estimate the quantitative importance of fatigue mechanisms and identify influencing factors. Efficient and individualized recovery strategies may consequently be proposed.

Purpose:To compare the effects of cold-water immersion (CWI) and whole-body cryotherapy (WBC) on recovery kinetics after exercise-induced muscle damage.Methods:Ten physically active men performed single-leg hamstring eccentric exercise comprising 5 sets of 15 repetitions. Immediately postexercise, subjects were exposed in a randomized crossover design to CWI (10 min at 10°C) or WBC (3 min at –110°C) recovery. Creatine kinase concentrations, knee-flexor eccentric (60°/s) and posterior lower-limb isometric (60°) strength, single-leg and 2-leg countermovement jumps, muscle soreness, and perception of recovery were measured. The tests were performed before and immediately, 24, 48, and 72 h after exercise.Results:Results showed a very likely moderate effect in favor of CWI for single-leg (effect size [ES] = 0.63; 90% confidence interval [CI] = –0.13 to 1.38) and 2-leg countermovement jump (ES = 0.68; 90% CI = –0.08 to 1.43) 72 h after exercise. Soreness was moderately lower 48 h after exercise after CWI (ES = –0.68; 90% CI = –1.44 to 0.07). Perception of recovery was moderately enhanced 24 h after exercise for CWI (ES = –0.62; 90% CI = –1.38 to 0.13). Trivial and small effects of condition were found for the other outcomes.Conclusions:CWI was more effective than WBC in accelerating recovery kinetics for countermovement-jump performance at 72 h postexercise. CWI also demonstrated lower soreness and higher perceived recovery levels across 24–48 h postexercise.

Dans le sport de haut niveau, des strategies de recuperation de la performance physique sont requises lorsque le calendrier se densifie afin de limiter la fatigue induite par l’exercice et reduire le risque de blessure. Parmi les nombreuses strategies existantes, les strategies nutritionnelles, le bain froid et le sommeil ont un niveau d’evidence scientifique eleve. Cependant, l’importante variabilite interindividuelle du sommeil pourrait avoir diverses consequences sur une population de sportifs. Les sportifs presentent une variabilite interindividuelle plus importante qu’une population controle sur diverses variables de sommeil [1] . Dans les sports collectifs, l’ensemble des joueurs se plaignent de mettre beaucoup de temps a trouver le sommeil apres une competition realisee en soiree mais une importante variabilite interindividuelle existe (endormissement : 03 h 00 ± 01 h 02) ; les preferences vis-a-vis de la sieste sont egalement tres variables d’un sportif a l’autre [2] . Plusieurs variables sociodemographiques et socioeconomiques (âge, niveau d’education par exemples) pourraient etre des facteurs susceptibles d’influencer le sommeil [3] . De plus, chaque sportif de haut niveau presente un chronotype particulier, preference de l’individu a realiser une activite intellectuelle et/ou physique a certaines periodes de la journee plutot qu’a d’autres. Les differences de chronotype entre individus sont en partie innees, mais sont aussi influencees par des facteurs environnementaux (heure habituelle d’entrainement par exemple). Alors que le sommeil est hautement variable d’un sportif a l’autre, l’emploi du temps d’une equipe/d’un groupe d’entrainement est unique, ce qui peut eventuellement conduire a d’importantes restrictions chroniques de sommeil, en particulier parmi les chronotypes du soir. Quelques recommandations pratiques existent afin de limiter ces perturbations du sommeil au cours des stages d’entrainement et/ou des competitions a l’exterieur, comme par exemple de reunir au sein d’une meme chambre les sportifs ayant un chronotype similaire.

In elite soccer, players are frequently exposed to various situations and conditions that can interfere with sleep (e.g., playing night matches interspersed with 3 days; performing activities demanding high levels of concentration close to bedtime; use of products containing caffeine or alcohol in the period preceding bedtime; regular daytime napping throughout the week; variable wake-up times or bedtime), potentially leading to sleep deprivation. We outline simple, practical, and pharmaceutical-free sleep strategies that are coordinated to the constraints of elite soccer in order to promote sleep. Sleep deprivation is best alleviated by sleep extension; however, sleep hygiene strategies (i.e., consistent sleep pattern, appropriate napping, and active daytime behaviors) can be utilized to promote restorative sleep. Light has a profound impact on sleep, and sleep hygiene strategies that support the natural environmental light-dark cycle (i.e., red-light treatment prior to sleep, dawn-simulation therapy prior to waking) and prevent cycle disruption (i.e., filtering short wavelengths prior to sleep) may be beneficial to elite soccer players. Under conditions of inordinate stress, techniques such as brainwave entrainment and meditation are promising sleep-promoting strategies, but future studies are required to ascertain the applicability of these techniques to elite soccer players. Consuming high-electrolyte fluids such as milk, high-glycemic index carbohydrates, some forms of protein immediately prior to sleep, as well as tart cherry juice concentrate and tryptophan may promote rehydration, substrate stores replenishment, muscle-damage repair and/or restorative sleep. The influence of cold water immersion performed close to bedtime on subsequent sleep is still debated. Conversely, the potential detrimental effects of sleeping medication must be recognized. Sleep initiation is influenced by numerous factors, reinforcing the need for future research to identify such factors. Efficient and individualized sleep hygiene strategies may consequently be proposed.

Purpose: To systematically review the scientific level of evidence for the ‘Top 3’ risk factors, screening tests and preventative exercises identified by a previously published survey of 44 premier league football (soccer) teams. Also, to provide an overall scientific level of evidence and graded recommendation based on the current research literature.\ud \ud Methods: A systematic literature search (Pubmed [MEDLINE], SportDiscus, PEDRO and Cochrane databases). The quality of the articles was assessed and a level of evidence (1++ to 4) was assigned. Level 1++ corresponded to the highest level of evidence available and 4, the lowest. A graded recommendation (A: strong, B: moderate, C: weak, D: insufficient evidence to assign a specific recommendation) for use in the practical setting was given.\ud \ud Results: Fourteen studies were analysed. The overall level of evidence for the risk factors previous injury, fatigue and muscle imbalance were 2++, 4 and ‘inconclusive’, respectively. The graded recommendation for functional movement screen, psychological questionnaire and isokinetic muscle testing were all ‘D’. Hamstring eccentric had a weak graded ‘C’ recommendation, and eccentric exercise for other body parts was ‘D’. Balance/proprioception exercise to reduce ankle and knee sprain injury was assigned a graded recommendation ‘D’.\ud \ud Conclusions: The majority of perceptions and practices of premier league teams have a low level of evidence and low graded recommendation. This does not imply that these perceptions and practices are not important or not valid, as it may simply be that they are yet to be sufficiently validated or refuted by research.

International audience; This study aimed (1) to determine the reliability of a simple and quick test to assess isometric posterior lower limb muscle force in professional football players and (2) verify its sensitivity to detect reductions in force following a competitive match. Twenty-nine professional football players performed a 3-s maximal isometric contraction of the posterior lower limb muscles for both legs with players lying supine. Both legs were tested using a knee angle of 90° and 30° measured on a force plate. Players were tested twice with one week between sessions to verify reliability. Sensitivity was tested following a full competitive football match. The test showed high reliability for dominant leg at 90° (CV = 4.3%, ICC = 0.95, ES = 0.15), non-dominant leg at 90° (CV = 5.4%, ICC = 0.95, ES = 0.14), and non-dominant leg at 30° (CV = 4.8%, ICC = 0.93, ES = 0.30) and good reliability for dominant leg at 30° (CV = 6.3%, ICC = 0.86, ES = 0.05). The measure was sensitive enough to detect reductions in force for dominant leg at 90° (P = 0.0006, ES > 1), non-dominant leg at 90° (P = 0.0142, ES = 1), and non-dominant leg at 30° (P = 0.0064, ES > 1) and for dominant leg at 30° (P = 0.0016, ES > 1). In conclusion, the present test represents a useful and practical field tool to determine the magnitude of match-induced fatigue of the posterior lower limb muscles and potentially to track their recovery.

In elite soccer, players are frequently exposed to various situations and conditions that can interfere with sleep, potentially leading to sleep deprivation. This article provides a comprehensive and critical review of the current available literature regarding the potential acute and chronic stressors (i.e., psychological, sociological and physiological stressors) placed on elite soccer players that may result in compromised sleep quantity and/or quality. Sleep is an essential part of the recovery process as it provides a number of important psychological and physiological functions. The effects of sleep disturbance on post-soccer match fatigue mechanisms and recovery time course are also described. Physiological and cognitive changes that occur when competing at night are often not conducive to sleep induction. Although the influence of high-intensity exercise performed during the night on subsequent sleep is still debated, environmental conditions (e.g., bright light in the stadium, light emanated from the screens) and behaviours related to evening soccer matches (e.g., napping, caffeine consumption, alcohol consumption) as well as engagement and arousal induced by the match may all potentially affect subsequent sleep. Apart from night soccer matches, soccer players are subjected to inconsistency in match schedules, unique team schedules and travel fatigue that may also contribute to the sleep debt. Sleep deprivation may be detrimental to the outcome of the recovery process after a match, resulting in impaired muscle glycogen repletion, impaired muscle damage repair, alterations in cognitive function and an increase in mental fatigue. The role of sleep in recovery is a complex issue, reinforcing the need for future research to estimate the quantitative and qualitative importance of sleep and to identify influencing factors. Efficient and individualised solutions are likely needed.

Squad management, injury and physical, tactical and technical match performance were investigated in a professional soccer team across five consecutive league seasons (2008–2013, 190 league games) with specific focus on a championship-winning season (2010/11). For each player, match participation and time-loss injuries were recorded, the latter prospectively diagnosed by the team’s physician. Defending and attacking tactical and technical performance indicators investigated included ball possession and possession in opponents’ half, passes, forward passes, completed passes and forward passes, crosses and completed crosses, goal attempts and goal attempts on target, successful final third entries, free-kicks and 50/50 duels won/lost. Physical performance measures included total distance and distance covered at high-speeds (≥19.1 km/h). Results showed that during the 2010/11 season, squad utilisation was lowest potentially owing to the observed lower match injury occurrence and working days lost to injury thereby increasing player availability. In 2010/11, the team won both its highest number of points and conceded its lowest number of goals especially over the second half of this season. The team also won its highest number of games directly via a goal from a substitute and scored and conceded a goal first on the highest and lowest number of occasions, respectively. While multivariate analysis of variance (MANOVA) detected a significant difference in some attacking and defensive performance indicators across the five seasons, these were generally not distinguishing factors in 2010/11. Similarly, univariate ANOVAs showed a significant difference in running distances covered across seasons, but the trend was for less activity in 2010/11.

This investigation examined the association between aerobic fitness and repeated sprint ability and match-related fatigue in 9 professional outfield soccer players. Aerobic fitness using maximal aerobic speed (MAS) was determined via a continuous progressive incremental running test conducted on a motorised treadmill. A repeated sprint ability test (6 successive 6 s sprints separated by 20 s passive recovery) was performed on a non-motorised treadmill to determine mean and best sprint times and a percentage decrement score (%PD). A total of 114 observations of physical performance derived using computerised time motion analyses were collected from 33 matches. Correlations between fitness test and match-play measures were examined for 1) accumulated fatigue: percentage difference between halves for total distance covered per minute, distance run at high-intensities (HIR, actions for 1s duration, >19.1 km/h) per minute, mean recovery time between high-intensity runs, and percentage difference between the distance covered in HIR in the first 5- and 15-minute periods versus the final 5- and 15-minute periods respectively in normal time; and for 2) transient fatigue: percentage difference between the distance covered in HIR in a peak 5-minute period and the subsequent 5-minute period and for the latter compared to the mean for all other 5-minute periods. No significant relationships were observed between MAS and fatigue scores (magnitude of associations: trivial to large). For mean and best sprint times and %PD, the only reported significant correlation (r=0.77, magnitude of association: very large, p

International audience; This study examined the relationship between the frequency of playing actions performed during a soccer match and the recovery kinetics after the match. Time motion analyses were performed on 10 professional soccer players during 4 competitive matches (14 observations) to determine the number of playing actions completed by players. Subjective ratings, creatine kinase, and physical tests (countermovement jump [CMJ], isometric maximum voluntary contraction of the hamstrings , 6-second sprint on a nonmotorized treadmill) were performed before the match and 24 hours, 48 hours, and 72 hours after the match. During the 72-hour recovery period, CMJ, iso-metric strength of the hamstring muscles, and peak sprint speed significantly (p

International audience; In the formerly published part I of this two-part review, we examined fatigue after soccer matchplay and recovery kinetics of physical performance, and cognitive, subjective and biological markers. To reduce the magnitude of fatigue and to accelerate the time to fully recover after completion, several recovery strategies are now used in professional soccer teams. During congested fixture schedules, recovery strategies are highly required to alleviate post-match fatigue, and then to regain performance faster and reduce the risk of injury. Fatigue following competition is multifactorial and mainly related to dehydration , glycogen depletion, muscle damage and mental fatigue. Recovery strategies should consequently be targeted against the major causes of fatigue. Strategies reviewed in part II of this article were nutritional intake, cold water immersion, sleeping, active recovery, stretching , compression garments, massage and electrical stimulation. Some strategies such as hydration, diet and sleep are effective in their ability to counteract the fatigue mechanisms. Providing milk drinks to players at the end of competition and a meal containing high-glycaemic index carbohydrate and protein within the hour following the match are effective in replenishing substrate stores and optimizing muscle-damage repair. Sleep is an essential part of recovery management. Sleep disturbance after a match is common and can negatively impact on the recovery process. Cold water immersion is effective during acute periods of match congestion in order to regain performance levels faster and repress the acute inflammatory process. Scientific evidence for other strategies reviewed in their ability to accelerate the return to the initial level of performance is still lacking. These include active recovery, stretching, compression garments, massage and electrical stimulation. While this does not mean that these strategies do not aid the recovery process, the protocols implemented up until now do not significantly accelerate the return to initial levels of performance in comparison with a control condition. In conclusion, scientific evidence to support the use of strategies commonly used during recovery is lacking. Additional research is required in this area in order to help practitioners establish an efficient recovery protocol immediately after matchplay, but also for the following days. Future studies could focus on the chronic effects of recovery strategies, on combinations of recovery protocols and on the effects of recovery strategies inducing an anti-inflammatory or a pro-inflammatory response.

This study aimed to compare the recovery kinetics of physical performance and subjective ratings in response to a soccer-specific exercise simulation on natural grass and artificial turf. Physical performance tests and subjective ratings were assessed on 13 professional soccer players before, immediately after, 24 h and 48 h after the test. Physical performance tests included squat jump, countermovement jump, 6-s sprint on a non-motorised treadmill and isokinetic eccentric hamstring assessment (2.09 rad · s(-1)). Hamstring peak torque decrement was higher (P < 0.05) on natural grass than on artificial turf immediately (-4.0%, CI 95%: -10.0 to 2.0%, effect size [ES] = 0.29), 24 h (-3.1%, CI 95%: -9.3 to 3.1%, ES = 0.29) and 48 h (-3.8%, CI 95%: -8.5 to 0.9%, ES = 0.43) after the test. Squat jump performance decrement was significantly lower (P < 0.05) on natural grass than artificial turf 48 h after the test (+3.7%, CI 95%: 1.1 to 6.3%, ES = 0.40). Sprint performance showed no change from baseline performance for both trials throughout the protocol. No significant interaction between surface and time was found for countermovement jump and subjective ratings. These results suggest that a one-off exercise on artificial turf does not induce greater fatigue nor does it delay the recovery process when compared to natural grass among regular artificial turf players. 31;5

Background: Recovery duration may be too short during the congested fixtures of professional soccer players with regard to maintaining physical performance and a low injury rate. Purpose: To analyze the effects of 2 matches per week on physical performance and injury rate in male elite soccer players. Study Design: Cohort study; Level of evidence, 3. Methods: Match results, match-related physical performance, and injuries were monitored during 2 seasons (2007–2008 and 2008–2009) for 32 professional soccer players in a top-level team participating in the UEFA (Union of European Football Associations) Champions League. Total distance, high-intensity distance, sprint distance, and number of sprints were collected for 52 home matches. Injuries and player participation in matches and training were recorded throughout the full season. Results: Physical performance, as characterized by total distance covered, high-intensity distance, sprint distance, and number of sprints, was not significantly affected by the number of matches per week (1 versus 2), whereas the injury rate was significantly higher when players played 2 matches per week versus 1 match per week (25.6 versus 4.1 injuries per 1000 hours of exposure; P < .001). Conclusion: The recovery time between 2 matches, 72 to 96 hours, appears sufficient to maintain the level of physical performance tested but is not long enough to maintain a low injury rate. The present data highlight the need for player rotation and for improved recovery strategies to maintain a low injury rate among athletes during periods with congested match fixtures.