Variation in body composition in professional soccer players: inter- and intra-seasonal changes and the effects of exposure time and player position

The aim of this study was to examine variations in measures of body composition in elite soccer players. Skinfolds and measures of body mass (BM) recorded on a monthly basis across an entire competitive season in a group of senior professional players (n = 26) were used to estimate percentage body fat (%BF) and provide fat-free body mass (FFBM) values. Mean values in players were compared between 6 specific positional roles (goalkeepers, central and lateral defenders/midfielders and center-forwards). In-season variations in measures were studied by comparing values at 5 separate points across the season. The effects of positional group (goalkeepers, defenders, midfielders, and forwards) and exposure time to play (participation time in training and matches) in relation to in-season variations were also examined. To investigate interseasonal changes, repeated measures were taken in players (n = 9) over 3 consecutive seasons. In relation to positional role, a difference in average %BF and BM values was observed (p < 0.001), with substantial differences observed in goalkeepers, lateral midfielders, and forwards. Across all players, there were significant in-season variations in %BF (between start- and mid-season and mid- and end-season, p < 0.001) and FFBM (between start- and mid-season and start- and end-season, p < 0.001), whereas BM remained unchanged. Further analysis of these fluctuations in %BF and FFBM at different points of the season showed that variations differed across the positional groups (p < 0.01), especially in defenders and midfielders. In contrast, no association was observed between measures and exposure time and no differences were reported across seasons. Practitioners should consider individual positional role when interpreting mean body composition data. They should also take into account positional groups when in-season variations in body composition are identified

Match injuries in professional soccer: inter-seasonal variation and effects of competition type, match congestion and positional role

In this prospective observational study, injuries sustained in official match-play in players belonging to a professional soccer club were investigated. Incidence and patterns of injury were compared across four-seasons (2005-2006: S1, 2006-2007: S2, 2007-2008: S3 and 2008-2009: S4) and 3 match formats (domestic League/Cup games and European club competition). In addition, the effects of both fixture congestion and the positional role of players were investigated. Injury incidence (per 1 000 match-hours) did not vary between seasons (range 31.2-59.2 observed in S2 and S4, respectively, p=0.12) or fixture formats (range 32.6-40.8 observed in European and League matches, respectively, p=0.49). In contrast, rates varied in players (n=7) who participated in all four seasons as more injuries were sustained in S1 compared to S2 and S3, respectively (88.4 vs. 49.0 vs. 49.2, both p or = 4 days). Finally, the incidence of injury and muscle strains (both p<0.001) varied across positional roles with the highest rates observed in centre-forwards. These findings provide further knowledge on the risk of injury in contemporary professional soccer match-play and may aid in the care and management of playing resources

Relationship between the ATP content measured at three imbibition times and germination of onion seeds during storage at 3, 15 and 30°C

The possibility of using ATP content as an indicator of seed quality was studied in onion seeds {Allium cepa cv. Wädenswil). The percentage germination and ATP content of imbibed seeds were compared during 145 weeks of storage at three temperatures (3, 15 and 30°C). ATP content, which was undetectable in airdried seeds (moisture content: 9%, w/w), increased rapidly as a function of imbibition time, as did the fresh weight and respiration rate, reaching a steady-state level after about 17 h. After 36 weeks of storage, the rate of ATP formation was greater for the seeds stored at 3°C than for those kept at 15 and 30°C. Furthermore, the onset of ATP synthesis was delayed. These phenomena, which are likely to be an expression of seed ageing, are useful indicators, allowing the prediction of the loss of seed viability before the decrease in percentage germination which occurred beyond 36 weeks of storage. In addition, the correlation between ATP content and germination capacity of seeds during 145 weeks of storage was excellent (r=0.95 at 15°C and 0.97 at 30°C), provided that a 17 h-imbibition time, specific for onion seeds, was chosen. These results are discussed in terms of the controversy concerning the correlation between the ATP content and germination percentage of seed

A four-season prospective study of muscle strain reoccurrences in a professional football club

The aim of this investigation was to characterise muscle strain reinjuries and examine their impact on playing resources in a professional football club. Muscle strains and reoccurrences were prospectively diagnosed over four seasons in first-team players (n = 46). Altogether, 188 muscle strains were diagnosed with 44 (23.4%) of these classed as reinjuries, leading to an incidence of 1.32 strain reoccurrences per 1,000 hours exposure (95% Confidence Interval [CI], 0.93–1.71). The incidence of recurrent strains was higher in match-play compared with training (4.51, 95% CI, 2.30–6.72 vs 0.94, 95% CI, 0.59–1.29). Altogether, 50.0% of players sustained at least 1 reoccurrence of a muscle strain, leading to approximately 3 days lost and 0.4 matches missed per player per season. The incidence of recurrent strains was highest in centre-forwards (2.15, 95% CI, 1.06–3.24), peaked in May (3.78, 95% CI, 0.47–7.09), and mostly affected the hamstrings (38.6% of all reoccurrences). Mean layoff for nonreoccurrences and recurrences was similar: ∼7.5 days. These results provide greater insight into the extent of the problem of recurrent muscle strains in professional football

Meniscal ossicle in a professional soccer player

SummaryMeniscal ossicles are an unusual finding and a rare cause for knee pain. They are often initially diagnosed as a loose body, chondrocalcinosis or meniscal calcification within the knee joint. Few cases have been reported in the literature. We present a case of a meniscal ossicle with an associated femoral cartilage lesion in a healthy 26-year-old male professional soccer player who presented with swelling and pain. The purpose of this article is to discuss the origins, radiological features, clinical symptoms and prognosis of meniscal ossicles

Concussion in European professional football : a view of team physicians

OBJECTIVES : The objective was to explore the view and thoughts of physicians working in professional football about several aspects (eg, education and use of video footages) likely to enhance concussions’ recognition and on-field management. METHODS : An observational study based on a cross-sectional design by means of an electronic survey was conducted among physicians working for a professional football club in Belgium, England or France. RESULTS : A total of 96 physicians (95% male; mean age: 44 years) completed the survey. Nearly all participants (95%) were in favour of informational sessions about concussion for players or technical staff. Only 5%–10% of the participants mentioned that they had felt pressured by the technical staff or players not to substitute a player with a (potential) concussion. Most participants were in favour of an additional permanent concussion substitution and a temporary concussion substitution. Four out of five participants reported that the availability of instant video footages (side-line) would ease the recognition of concussion. CONCLUSION : A better recognition and on-field management of concussions in professional football can only be achieved with a holistic approach, including adequate laws of the football game and protocols. Especially, regular education of players and technical staff should be made mandatory while the medical teams should be provided side-line with instant video footages.http://bmjopensem.bmj.comam2022Sports Medicin

Determination of the prevalence of knee and hip clinical osteoarthritis in the active professional male footballer and its association with pain, function, injury and surgery

DATA AVAILABILITY STATEMENT : All statistical analysis data are available as supplementary material. Raw data can be requested from the corresponding author, at reasonable request.SUPPLEMENTARY FILE A: Designed questionnaire.SUPPLEMENTARY FILE B: KOOS-PS.SUPPLEMENTARY FILE C: HOOS-PS.SUPPLEMENTARY FILE D: PROMIS-GH.STRENGTHS AND LIMITATIONS 24032023.T22066-Statistical-Analysis-Total Final.OBJECTIVE : To comment on and explore (1) the prevalence of clinical knee and hip os- teoarthritis (OA); (2) the association between pain or function and clinical knee or hip OA; (3) the association between injury or surgery and clinical knee or hip OA. METHODS : Participants were recruited from FIFPRO members. A total of 101 footballers consented to answer (1) a developed questionnaire, (2) patient-reported outcome measures, and (3) be evaluated by their team physician for clinical knee or hip OA. RESULTS : Of the 53% evaluated for clinical knee and hip OA, a prevalence of 9.43% and 7.55% of knee and hip OA, respectively, was found. There was a significant and strong association between knee (p = 0.033; Cramers v Value = 0.523) and hip pain (p = 0.005; Cramers v Value = 0.602) and clinical OA. A significant association existed between Hip dysfunction and Osteoarthritis Outcome short form Scores and clinical OA of the hip (p = 0.036). The odds of clinical knee OA were 1.5 and 4.5 times more after one or more injuries or surgeries, respectively. There was no association between playing position and clinical OA. CONCLUSION : There is a low prevalence of a clinical knee or hip OA in the active professional male footballer. Pain may be a valid symptom to predict or monitor knee or hip OA. Validated assessment tools should be utilised to identify a negative effect on function. The odds of developing clinical OA in the knee with the number of injuries or surgeries. The hip presents with earlier clinical signs of OA compared to the knee.https://www.mdpi.com/journal/sportshj2023Sports Medicin

Etude de la degradation du transistor NMOS due a l'injection d'electrons chauds dans l'oxyde de grille et a l'interface oxyde-silicium : proposition d'un test accelerant ce phenomene de vieillissement

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Contribution à la connaissance des Noctuides et Géométrides de l'île de la Réunion (Lepidoptera)

Contribution to the knowledge of the Noctuids and Geometrids of Reunion island (Lepidoptera). Five new taxa are described and illustrated from Réunion island. Four others are recorded for the first time.Cinq nouveaux taxons : une espèce et une sous-espèce de Géométrides et trois espèces de Noctuides sont décrits et illustrés de l'île de la Réunion. Quatre autres espèces sont citées pour la première fois de l'île.Orhant Georges-E.-R.-J. Contribution à la connaissance des Noctuides et Géométrides de l'île de la Réunion (Lepidoptera). In: Bulletin de la Société entomologique de France, volume 108 (2), juin 2003. pp. 139-146

Contact Stability Analysis of a One Degree-of-Freedom Robot

International audienceThe aim of this note is to examine the conditions of stability of a simple robotic task: we consider a one degree-of-freedom (dof) robot that collides with a spring-like environment with stiffness $k$, the goal being to stabilize the system in contact with the environment. We study conditions on the feedback gains that guarantee quadratic Lyapunov stability of the task with a well-conditioned solution to the Lyapunov equation. It is shown that when the environment's stiffness $k$ grows unbounded, those conditions yield unbounded values of the gains. Motivated by the stability analysis of the impact Poincaré map in the perfectly rigid case ($k = +∞$), we propose an analysis that is independent of $k$. It enables us to conclude on global asymptotic convergence of the system's state towards the equilibrium point. This work can also be seen as the study of stability of a contact (force control) phase, taking into account the unilateral feature of the constraint