Prävention von schweren Knieverletzungen im Jugendhandball

Hintergrund: Handball ist mit einem hohen Risiko verbunden, eine schwere Knieverletzung zu erleiden. Dieses Risiko sollte reduziert werden, insbesondere im Jugendhandball. Der Grund der Studie war zu zeigen, wie ein Verletzungspräventionsprogramm effektiv schwere Knieverletzungen in jugendlichen Handballspieler/-innen reduziert. Methodik: Von 23 jugendlichen Handballmannschaften beider Geschlechter wurden 13 in die Interventionsgruppe (168 Spieler/-innen) und 10 in die Kontrollgruppe (111 Spieler/-innen) randomisiert. Die Spieler der Interventionsgruppe führten regelmäßig ein Verletzungspräventions-Übungsprogramm durch. Die Handballexposition und erlittene Verletzungen wurden für beide Gruppen monatlich dokumentiert. Der primäre Endpunkt des Verletzungspräventionsprogramms war die Inzidenz von schweren Knieverletzungen. Ergebnisse: Von den 279 eingeschlossenen Spieler/-innen erlitten 68 (24%) insgesamt 82 Verletzungen. Dies ergab eine Inzidenz von 1,85 Verletzungen pro 1000 h Handballexposition (Interventionsgruppe: 50 Verletzungen, Inzidenz: 1,90 Verletzungen pro 1000 h; Kontrollgruppe: 32 Verletzungen, Inzidenz 1,78 Verletzungen pro 1000 h). Knieverletzungen waren die zweithäufigste Verletzung in Jugendhandball. Der primäre Endpunkt “schwere Knieverletzung” wurde signifikant häufiger in der Kontrollgruppe [Durchschnittsalter (SD) 15,1 (1,0), Verletzungsinzidenz 0,33/1000 h] erlitten, als in der Interventionsgruppe [Durchschnittsalter 14,9 (0,9), Verletzungsinzidenz 0,04/1000 h]. Die Odds Ratio war 0,11 (95% CI 0,01-0,90), p = 0,019. Andere Verletzungen der unteren Extremität zeigten keinen signifikanten Unterschied zwischen den zwei Gruppen. Schlussfolgerungen: Regelmässige neuromuskuläre Übungen reduzieren das Verletzungsrisiko von schweren Knieverletzungen in Jugendhandball und sollten daher in den Trainingsalltag als auch in die Ausbildung der Manschaftstrainer integriert werden

Energy Spectrum Evolution of a Diffuse Field in Elastic Body Caused by Weak Nonlinearity

We study the evolution of diffuse elastodynamic spectral energy density under the influence of weak nonlinearity. It is shown that the rate of change of this quantity is given by a convolution of the linear energy at two frequencies. Quantitative estimates are given for sample aluminum and fused silica blocks of experimental interest.Comment: 9 pages, 3 figures; revised for better presentatio

Fractal geometry of spin-glass models

Stability and diversity are two key properties that living entities share with spin glasses, where they are manifested through the breaking of the phase space into many valleys or local minima connected by saddle points. The topology of the phase space can be conveniently condensed into a tree structure, akin to the biological phylogenetic trees, whose tips are the local minima and internal nodes are the lowest-energy saddles connecting those minima. For the infinite-range Ising spin glass with p-spin interactions, we show that the average size-frequency distribution of saddles obeys a power law $<\psi(w) > \sim w^{-D}$, where w=w(s) is the number of minima that can be connected through saddle s, and D is the fractal dimension of the phase space

Relation of injuries and psychological symptoms in amateur soccer players

Objectives The first main goal of this study was to investigate the prevalence of depression and anxiety as well as self-compassion in a heterogeneous sample of male amateur soccer players. The second main goal of this study was the examination of the relationship between injuries and psychological factors in amateur soccer players. Methods Players were recruited from German amateur soccer clubs of the fourth to seventh league. 419 soccer players with the mean age of 22.88 years participated in the psychological and the injury assessment at the beginning of the season and at the end, 9 months later. For the psychological assessment, depression and anxiety rate as well as self-compassion was analysed. Furthermore, the frequencies of injuries were registered. Results The results showed that players of the highest amateur league, the fourth league in German soccer, showed significantly higher anxiety values than players from a lower league (p=0.013). There were no differences in depression values dependent on the league. Furthermore, players who suffered from an injury before the start of the season demonstrated higher anxiety values (p=0.027). This result was independent of the respective league. Conclusion The results of this study demonstrate that even in higher amateur soccer the anxiety level of the players varies between soccer players of different leagues. Because an injury before the start of the season influenced the anxiety level, a psychological treatment during injury should be considered. Summary box Even in higher amateur soccer the anxiety level of the players varies between soccer players of different leagues. Psychological factors are also in lower soccer levels related to injuries. The possible relation of psychological and medical issues must be also investigated in amateur soccer players

Epidemiological analysis of injury occurrence and current prevention strategies on international amateur football level during the UEFA Regions Cup 2019

Introduction Football is the most popular sport worldwide and results in a high frequency of injuries. So far, mainly injuries in professional football have been investigated, and the literature lacks data regarding detailed injury epidemiology and current prevention data in amateur football tournaments. Materials and methods A prospective cohort study investigated an international amateur football tournament, the UEFA Regions’ Cup, which took place in 2019 in Germany. Injury epidemiology, current prevention strategies of the teams and the implementation of the UEFA concussion protocol were investigated in detail by means of standardized injury definitions and data samples for football (Fuller et al., Scand J Med Sci Sports 16:83–92, https:// doi. org/ 10. 1111/j. 1600- 0838. 2006.00528.x, 2006). Results 138 player of 8 teams participated in this study, while 39 players were excluded. Overall injury incidence was 12.5 per 1000 h total football exposure, 43.5 per 1000 h for match exposure. No injuries were registered during training. Injury prevalence was 14.1% per player and 1.1 injuries per match were registered. The lower extremity was predominantly affected by injuries (71.4%) and the majority of injuries (78.6%) were non-severe injury types like contusions (50%) and sprains (18.2%). Two head injuries, one contusion and one skin lesion, were handled by the guidelines of the UEFA concussion protocol. 44.4% of the players indicated at least one previous injury before tournament, 45.3% of them during the last two football seasons before start of the tournament. Injury prevention performance was included in all participating teams during the tournament by warm up or training strategies (100%). During the warm-up program just 5 exercises of the FIFA 11 + program was detected by this investigation in participating teams to be done by more half of the teams. Running exercises were the most frequently performed exercises, while trunk muscle exercises were less represented (14.3%). Conclusion This study presents for the first time epidemiological injury and prevention data of the UEFA Regions Cup. Injury incidence was higher compared to injury reports of regular seasons, but lower compared to other amateur football tournaments. Currently used prevention programs revealed trunk muscle exercises as often neglected

LES-based Study of the Roughness Effects on the Wake of a Circular Cylinder from Subcritical to Transcritical Reynolds Numbers

This paper investigates the effects of surface roughness on the flow past a circular cylinder at subcritical to transcritical Reynolds numbers. Large eddy simulations of the flow for sand grain roughness of size k/D = 0.02 are performed (D is the cylinder diameter). Results show that surface roughness triggers the transition to turbulence in the boundary layer at all Reynolds numbers, thus leading to an early separation caused by the increased momentum deficit, especially at transcritical Reynolds numbers. Even at subcritical Reynolds numbers, boundary layer instabilities are triggered in the roughness sublayer and eventually lead to the transition to turbulence. The early separation at transcritical Reynolds numbers leads to a wake topology similar to that of the subcritical regime, resulting in an increased drag coefficient and lower Strouhal number. Turbulent statistics in the wake are also affected by roughness; the Reynolds stresses are larger due to the increased turbulent kinetic energy production in the boundary layer and separated shear layers close to the cylinder shoulders.We acknowledge “Red Española de Surpercomputación” (RES) for awarding us access to the MareNostrum III machine based in Barcelona, Spain (Ref. FI-2015-2-0026 and FI-2015-3-0011). We also acknowledge PRACE for awarding us access to Fermi and Marconi Supercomputers at Cineca, Italy (Ref. 2015133120). Oriol Lehmkuhl acknowledges a PDJ 2014 Grant by AGAUR (Generalitat de Catalunya). Ugo Piomelli acknowledges the support of the Natural Sciences and Engineering Research Council (NSERC) of Canada under the Discovery Grant Programme (Grant No. RGPIN-2016-04391). Ricard Borrell acknowledges a Juan de la Cierva postdoctoral grant (IJCI-2014-21034). Ivette Rodriguez, Oriol Lehmkuhl, Ricard Borrell and Assensi Oliva acknowledge Ministerio de Economía y Competitividad, Secretaría de Estado de Investigación, Desarrollo e Innovación, Spain (ref. ENE2014-60577-R).Peer ReviewedPostprint (author's final draft

Playing Football as a Risk Factor for Lower Leg Malalignment?—Comparing Lower Leg Axis of Male Adolescent Football Players and Referees

The prevalence of varus knee malalignment among junior and adult football players (FP) has proven to be higher compared to other sports. No causal relationship has yet been found, as genu varum can be assumed to be an independent risk factor for the development of knee osteoarthritis. The purpose of this study is to compare knee alignment measurements and sport-specific data of adolescent football players and referees (REF). Knee alignment was detected by measuring the intercondylar/intermalleolar distance (ICD/IMD) as well as the Hip–Knee–Ankle angle (HKA) using a standardized digital frontal-plane photograph. Anthropometric and sports-related data (training/match exposure, seasons actively played, etc.) were collected by means of questionnaires (Clinical trial registration number: DRKS00020446). A total of 28 male FP and 29 male adolescent REF were included in the survey. The mean age was 17.4 ± 0.7 years. The two groups did not differ significantly in age, height, weight, BMI, and overall football/refereeing exposure per week (FP vs. REF: 274 vs. 285 min/week, p = 0.61). The HKA of the FP was significantly lower (toward varus) than that of the REF (177.6° ± 2.4° vs. 179.0° ± 2.4°; p < 0.001). However, ICD did not significantly differ (FP: 17 ± 25 mm, REF: 13 ± 27 mm; p = 0.55). The football environment with frequent football exposure seems to have an influence on leg axis deviation in FP compared to REF. For prevention of knee osteoarthritis in FP, an advanced understanding of leg axis development in adolescent players is essential and, therefore, needs further research

Executive functioning, motor difficulties and developmental coordination disorder

The current study assessed a comprehensive range of executive functions (EFs) in children with poor motor skills, comparing profiles of children with a diagnosis of developmental coordination disorder (DCD) and those identified with motor difficulties (MD). Children in both groups performed more poorly than typically-developing controls on nonverbal measures of working memory, inhibition, planning and fluency, but not on tests of switching. The similar patterns of strengths and weaknesses in children with MD and DCD have important implications for parents, teachers and clinicians, as children with MD may struggle with EF tasks even though their motor difficulties are not identified

Analytical prediction and experimental measurement for mode conversion and scattering of plate waves at non-symmetric circular blind holes in isotropic plates

A model for guided wave scattering from non-symmetric blind holes in isotropic plates using Poisson and Mindlin plate wave theories for in-plane and flexural wave modes, respectively, is presented. It makes use of the wave function expansion technique and coupling conditions at the defect boundary in order to evaluate the scattered far fields of the three fundamental guided wave modes. The results were compared to other analytical models as well as experimental measurements for mode conversion from S0 to A0. Measurements agreed well with predictions confirming the validity of the model, highlighting at the same time the strong frequency dependence of the scattering and mode conversion behaviour

Partial Anterior Cruciate Ligament Ruptures: Advantages by Intraligament Autologous Conditioned Plasma Injection and Healing Response Technique—Midterm Outcome Evaluation

The historical treatment options for partial anterior cruciate ligament (ACL) ruptures were conservative therapy or ACL reconstruction by injured bundle or entire ACL replacement. In awareness of the regenerative potential of biologic agents such as mesenchymal stem cells or platelet rich plasma (PRP), the healing response technique was developed to preserve the injured ACL with belter outcomes lhan ihe conservative therapy. Further improvement of this technique seems to be obtained by the additional application of PRP products. Thus, the aim of this study was to evaluate the midterm outcome after intraligament autologous conditioned plasma (ACP) by a clinical, scoring, and functional performance assessment. 42 patients were evaluated in this study. The failure rate was 9.5%. Outcome evaluation showed good to excellent results. The scores were IKDC subjective 83.2 (SD 14.5), Lysholm 85.5 (SD 15.5), Tegner 4.7 (SD 1.7), and Cincinnati 85.4 (SD 15.5) afler a mean follow-up of 33 months. Clinical examination showed stable Lachman tesl, negative pivot shift phenomenon, and a significant reduction in AP-laxity compared to preoperative status (rolimeter preoperative: 1.9 (SD1.4); postoperative 0.6 (SD1.8), p=0.001) in all patients. Functional performance testing showed no significant differences between the injured and healthy side. Return to sport was achieved after a mean of 5.8 months (SD 3.6) in 71.1% of the included patients. In summary, this new treatment option revealed in midterm follow-up promising results to treat partial ACL lesions with a reduced need for conversion to ACL reconstruction and with a high percentage of return to preinjury sport activity