Injury risk factors, screening tests and preventative strategies: A systematic review of the evidence that underpins the perceptions and practices of 44 football (soccer) teams from various premier leagues

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. 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. 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’. 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

Monitoring of post-match fatigue in professional soccer: Welcome to the real world

Participation in soccer match-play leads to acute and transient subjective, biochemical, metabolic and physical disturbances in players over subsequent hours and days. Inadequate time for rest and regeneration between matches can expose players to the risk of training and competing whilst not entirely recovered. In professional soccer, contemporary competitive schedules can require teams to compete in-excess of 60 matches over the course of the season while periods of fixture congestion occur prompting much attention from researchers and practitioners to the monitoring of fatigue and readiness to play. A comprehensive body of research has investigated post-match acute and residual fatigue responses. Yet the relevance of the research for professional soccer contexts is debatable notably in relation to the study populations and designs employed. Monitoring can indeed be invasive, expensive, time-inefficient and difficult to perform routinely and simultaneously in a large squad of regularly competing players. Uncertainty also exists regarding the meaningfulness and interpretation of changes in fatigue response values and their functional relevance, and practical applicability in the field. The real-world need and cost-benefit of monitoring must be carefully weighed up. In relation to professional soccer contexts, this opinion paper intends to: 1) debate the need for PMF monitoring, 2) critique the real-world relevance of the current research literature, 3) discuss the practical burden relating to measurement tools and protocols and the collection, interpretation and application of data in the field, and, 4) propose future research perspectives

Energy Resolution Performance of the CMS Electromagnetic Calorimeter

The energy resolution performance of the CMS lead tungstate crystal electromagnetic calorimeter is presented. Measurements were made with an electron beam using a fully equipped supermodule of the calorimeter barrel. Results are given both for electrons incident on the centre of crystals and for electrons distributed uniformly over the calorimeter surface. The electron energy is reconstructed in matrices of 3 times 3 or 5 times 5 crystals centred on the crystal containing the maximum energy. Corrections for variations in the shower containment are applied in the case of uniform incidence. The resolution measured is consistent with the design goals

Fatigue and recovery in soccer

Lorsque les joueurs de football réalisent plus d’un match par semaine, la durée de récupération entre deux rencontres successives pourrait être insuffisante, ce qui entraînerait une augmentation du nombre de blessures et/ou une diminution de la performance en match. L’objectif principal de cette thèse était d’identifier les facteurs (environnementaux, intrinsèques, position sur le terrain) susceptibles d’influencer la fatigue et les cinétiques de récupération de joueurs de football professionnels après un match. La présente thèse comprenait quatre études ayant pour objectifs d’analyser l’influence des courses et actions de jeu réalisées au cours d’un match (duel, saut, frappe/centre, tacle, changement de direction) ainsi que la surface de jeu (herbe naturelle contre surface synthétique) sur les cinétiques de récupération de marqueurs de performance physique, cognitive, subjectifs et biochimiques. Nos résultats ont montré que les courses réalisées au cours d’un match de football ne sont pas la cause principale de la fatigue générée par le match. Cette fatigue est également fonction des actions de jeu (duel, saut, frappe et changement de direction) réalisées au cours du match. La fatigue générée par le match est fonction de la position occupée sur le terrain (gardiens de but contre joueurs de champ). La surface de jeu n’influence pas les cinétiques de récupération de joueurs habitués à la surface synthétique. Ces résultats devraient permettre d’optimiser dans le futur les stratégies de récupération réalisées après le match.During periods when the schedule is particularly congested (i.e. two matches per week over several weeks), the recovery time allowed between two successive matches may be insufficient. As a result, players may experience underperformance and/or injury. The overall aim of the present thesis was to identify underlying factors (environmental and intrinsic factors, playing position) that contribute to fatigue and recovery time of professional soccer players after a match. Four experimental studies were conducted to investigate the influence of soccer running activity profile, playing actions performed during a match (i.e. contact, jump, shot/long pass, tackle, change of direction) and playing surface (natural grass versus artificial turf) on the recovery kinetics of physical performance, cognitive performance, subjective ratings and biochemical parameters. Results showed that soccer running performance does not appear to be the main cause for post soccer match-induced fatigue. Post-match fatigue and recovery time depend on playing actions performed during the match (contact, jump, shot/long pass and change of direction). Post-match fatigue depends on playing position (goalkeepers versus outfield players). Playing surface does not impact recovery kinetics among regular artificial turf players. Present results may promote the prescription of more efficient and individualized recovery practices after soccer match

On the Road to Camarón: The Sleep of an Ultra-Endurance Athlete Cycling 10,000 km in 24 Days

The impact of sleep on performance is fundamental for ultra-endurance athletes, but studies on this issue are rare. The current investigation examined the sleep and performance of a cyclist engaged in a simulated 10,000 km tour. The sleep behavior of the athlete (age, 57; height, 1.85 m; mass, 81 kg) before, during (i.e., 23 nights), and after the tour was monitored using a reduced-montage dry-electroencephalographic (EEG) device. The daily performance (i.e., number of kms) was recorded throughout the race. The cyclist set a new world record, completing 10,358 km in 24 days with a mean daily distance of ≈432 km in approximately 16 h, i.e., an average speed of ≈27 km/h. Sleep duration throughout the tour (5:13 ± 0:30) was reduced compared to the baseline sleep duration (7:00 ± 1:00), with a very large difference (ES = 2.3). The proportion of N3 during the tour (46 ± 7%) was compared to the measured N3 proportion during the baseline (27 ± 5%) and was found to be systematically outside the intra-individual variability (mean ± 1 SD), with a very large difference (ES = 3.1). This ultra-endurance event had a major influence on sleep-duration reduction and a notable modification in sleep architecture. The increase in slow-wave sleep during the race may be linked to the role of slow-wave sleep in physiological recovery

Une approche méta-design du jeu sérieux pour l’enseignement de l’informatique à l’école élémentaire

National audienceLe méta-design est une approche de conception participative dans laquelle des utilisateurs finaux sont rendus concepteurs des ressources, y compris durant les phases d’utilisation. C’est à partir de cette méthode que nous souhaitons développer notre projet autour du jeu sérieux Blockly Maze visant à permettre aux enseignants du primaire d’enseigner la pensée informatique en classe. Blockly Maze est un jeu de programmation par blocs centré sur l’apprentissage de l’algorithmique. Nous voulons que les enseignants puissent l’adapter en fonction de leurs besoins d’enseignement, des parcours d’apprentissage des élèves et des usages observés sur le terrain. À cette fin, nous nous inscrivons dans une optique de recherche collaborative orientée par la conception dans laquelle des enseignantes de cycle 3 sont parties prenantes du projet. Elles contribuent à part entière au processus d’adaptation du jeu sérieux Blockly Maze et à l’élaboration de méthodes de méta-design qui se veulent génériques

Une approche méta-design du jeu sérieux pour l’enseignement de l’informatique à l’école élémentaire

National audienceLe méta-design est une approche de conception participative dans laquelle des utilisateurs finaux sont rendus concepteurs des ressources, y compris durant les phases d’utilisation. C’est à partir de cette méthode que nous souhaitons développer notre projet autour du jeu sérieux Blockly Maze visant à permettre aux enseignants du primaire d’enseigner la pensée informatique en classe. Blockly Maze est un jeu de programmation par blocs centré sur l’apprentissage de l’algorithmique. Nous voulons que les enseignants puissent l’adapter en fonction de leurs besoins d’enseignement, des parcours d’apprentissage des élèves et des usages observés sur le terrain. À cette fin, nous nous inscrivons dans une optique de recherche collaborative orientée par la conception dans laquelle des enseignantes de cycle 3 sont parties prenantes du projet. Elles contribuent à part entière au processus d’adaptation du jeu sérieux Blockly Maze et à l’élaboration de méthodes de méta-design qui se veulent génériques

Stress, sleep and recovery in elite soccer: A critical review of the literature

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

Causes and consequences of bimodal grain-size distribution of tephra fall deposited during the August 2006 Tungurahua eruption (Ecuador)

International audienceThe violent August 16–17, 2006 Tungurahua eruption in Ecuador witnessed the emplacement of numerous scoria flows and the deposition of a widespread tephra layer west of the volcano. We assess the size of the eruption by determining a bulk tephra volume in the range 42–57 × 106 m3, which supports a Volcanic Explosivity Index 3 event, consistent with calculated column height of 16–18 km above the vent and making it the strongest eruptive phase since the volcano’s magmatic reactivation in 1999. Isopachs west of the volcano are sub-bilobate in shape, while sieve and laser diffraction grain-size analyses of tephra samples reveal strongly bimodal distributions. Based on a new grain-size deconvolution algorithm and extended sampling area, we propose here a mechanism to account for the bimodal grain-size distribution. The deconvolution procedure allows us to identify two particle subpopulations in the deposit with distinct characteristics that indicate dissimilar transport-depositional processes. The log-normal coarse-grained subpopulation is typical of particles transported downwind by the main volcanic plume. The positively skewed, fine-grained subpopulation in the tephra fall layer shares close similarities with the elutriated co-pyroclastic flow ash cloud layers preserved on top of the scoria flow deposits. The area with the higher fine particle content in the tephra layer coincides with the downwind prolongation of the pyroclastic flow deposits. These results indicate that the bimodal distribution of grain size in the Tungurahua fall deposit results from synchronous deposition of lapilli from the main plume and fine ash elutriated from scoria flows emplaced on the western flank of the volcano. Our study also reveals that inappropriate grain-size data processing may produce misleading determination of eruptive type

Ramadan Observance Exacerbated the Negative Effects of COVID-19 Lockdown on Sleep and Training Behaviors: A International Survey on 1,681 Muslim Athletes

Methods From an international sample of athletes (n = 3,911), 1,681 Muslim athletes (from 44 countries; 25.1 ± 8.7 years, 38% females, 41% elite, 51% team sport athletes) answered a retrospective, cross-sectional questionnaire relating to their behavioral habits pre- and during- COVID-19 lockdown, including: (i) Pittsburgh sleep quality index (PSQI); (ii) insomnia severity index (ISI); (iii) bespoke questions about training, napping, and eating behaviors, and (iv) questions related to training and sleep behaviors during-lockdown and Ramadan compared to lockdown outside of Ramadan. The lockdown reduced sleep quality and increased insomnia severity (both p 0.05). Muslim athletes reported longer (p < 0.001; d = 0.29) and later (p < 0.001; d = 0.14) daytime naps, and an increase in late-night meals (p < 0.001; d = 0.49) during- compared to pre-lockdown, associated with lower sleep quality (all p < 0.001). Both sleep quality (χ2 = 222.6; p < 0.001) and training volume (χ2 = 342.4; p < 0.001) were lower during-lockdown and Ramadan compared to lockdown outside of Ramadan in the Muslims athletes. Conclusion Muslim athletes reported lower sleep quality and higher insomnia severity during- compared to pre-lockdown, and this was exacerbated by Ramadan observance. Therefore, further attention to Muslim athletes is warranted when a circadian disrupter (e.g., lockdown) occurs during Ramadan