Die vorliegende Pilotstudie beschäftigt sich mit der Analyse präventiver Screening-Maßnahmen im professionellen Frauenhandball. Es wird das Risiko, Verletzungen zu erleiden, und die Wirkung von Präventionsmaßnahmen untersucht, d. h. die Einschränkung der Gesundheit. Die Datenbasis bilden Screening-Ergebnisse zu den Verletzungen aus den Saisons 2022/2023 und 2023/2024. Die erhobenen Daten zur Häufigkeit von Verletzungen vor und nach Screening-Maßnahmen sowie zu den Unterschieden der Verletzungsverteilung nach Extremitätenregion, altersabhängigen Überlastungstendenzen sowie positionsspezifischen Verletzungsarten wurden mittels inferenzstatistischer Methoden ausgewertet – u. a. Binomialverteilung, Wilcoxon-Test und Chi-Quadrat-Test. Zusätzlich wurde auch eine Online-Befragung unter den Spielerinnen aus den o. g. Saisons durchgeführt sowie qualitative Interviews mit dem Athletikcoach und einer Physiotherapeutin, die praxisnahe Einblicke lieferten. Es wurde keine Häufung der Überlastungsverletzungen mit zunehmendem Alter gefunden. Es fand sich ein deutlich häufigeres Auftreten von Auffälligkeiten in den Untere-Extremitäten-Tests. Speziell die Interviews machen deutlich, dass u. a. begrenzte Zeit und Ressourcen sowie unzureichende Nachbearbeitung die Wirksamkeit der präventiven Screening-Maßnahmen einschränken. Die Analyse bestätigt, dass reine Screening-Maßnahmen ohne Folgemaßnahmen nur begrenzte Wirkung entfalten können. Die Ergebnisse unterstreichen die Komplexität sportbedingter Verletzungen im Handball und zeigen, dass deren Entstehung multifaktoriell bedingt ist. Für die Praxis liefern die Ergebnisse wertvolle Impulse zur Weiterentwicklung individualisierbarer Präventionsstrategien im Spitzensport. Auch die aktuellen Erkenntnisse aus der Literatur deuten auf den Erfolg von an den sportartspezifischen Anforderungs- und Risikoprofilen orientierten Präventivmaßnahmen hin.
The classical continuum mechanics fails in case of discontinuities. Peridynamics has been proven to be a powerful tool for solving such problems. However, it is extremely computational expensive and there are difficulties in fulfilling local boundary conditions. The paper aims to overcome these problems by coupling the Peridynamics (PD) with the Finite Element Method (FEM). Three different coupling strategies are considered in the paper: modified Schwarz Alternating Method, the Arlequin based coupling method and the Splice Method. The methods are presented and applied to one-dimensional dynamic cases, including high-frequency wave propagation analysis. The criteria applied to evaluate the methods are convergence to the local solution and difficulties choosing specific numerical parameters. The significance of long-range forces in the nature of the damage is also examined.
Power decline during maximal cycling sprints is commonly modeled using either the Parallel Shift Approach (PASA), representing fatigue as a time-dependent downward shift of the linear force-velocity (F-v) relationship, or the Pedal Stroke-Based Approach (PESA), which assumes a constant relative power loss per pedal stroke (Δ). This study compared their predictive accuracy, convergence behavior, and practical applicability across sprint duration and cadences. Twelve elite track sprint cyclists (6 female and 6 male) performed 45 s maximal sprints at a fixed cadence of 135 rpm. Both models were calibrated using individual F-v profiles and evaluated using RMSE and R2. Model convergence was examined across sprint phases and cadence ranges using empirically derived and optimized parameters. Both models demonstrated excellent fit to individual sprint power profiles (R2 > 0.98). PASA yielded lower prediction errors (RMSE: 32 ± 11 W) than standard PESA variants (RMSE: 57-60 W, p < 0.001). Optimizing Δ substantially improved PESA performance (35 ± 12 W). Models converged during early sprint phases (0-15 s: 4 ± 3 W difference, p = 0.065) and at moderate cadences (90-130 rpm) but diverged during late phases (45 s: 22 ± 11 W, p = 0.013) and at high cadences (> 150 rpm). PASA and PESA provide comparable predictions under short-duration, moderate-cadence conditions but diverge during prolonged sprints and at extreme cadences. PASA offers higher precision for detailed fatigue analysis, whereas PESA represents a computationally efficient alternative for practice. Model selection should be guided by analytical objectives and practical constraints. Further research should prioritize validation under variable-cadence conditions and refinement of physiological assumptions underlying sprint fatigue modeling.
Objectives: This study evaluated the effectiveness of a multimodal, theory-based intervention in reducing image and performance enhancing drug (IPED) use and improving psychological determinants among recreational fitness participants. Design: A cluster-randomized longitudinal trial was conducted in four German fitness studios. Methods: A total of 250 participants were allocated to an experimental group (n = 115) and a control group (n = 135). Assessments were conducted at baseline (T1), during the intervention (T2-T3), and at follow-up (T4) and at follow-up (T4; 4 weeks post-intervention) The program combined motivational enhancement, psycho-education, choice architecture, and harm reduction, guided by the Theory of Planned Behavior (TPB), Health Belief Model (HBM), Extended Parallel Process Model (EPPM), Prototype Willingness Model (PWT), and nudging principles (MINDSPACE). Reliability (Cronbach's alpha), mixed-model analyses (T1-T3), and logistic regression (T4) were applied. Results: All scales demonstrated good to excellent reliability (alpha = 0.74-.89). Significant Group x Time effects (T1-T3) were found for intention, perceived control, risk perception, fear, protection motivation, and nudging perception, with greater improvements in the experimental group. At T4, booster use was 53.0% in the experimental group compared to 69.6% in controls (absolute risk reduction = 16.6 percentage points; relative risk = 0.76; number needed to treat approximate to 6). Logistic regression confirmed group allocation as the only significant predictor of booster use (OR = 0.47, 95% CI [0.28, 0.80], p = .005), independent of age, gender, and baseline use. No attrition occurred. Conclusion: A multimodal, theory-based intervention improved psychological determinants and reduced IPED use in recreational fitness. Positioning TPB as the core model, complemented by HBM, EPPM, PWT, and nudging, underscores the value of integrated prevention and harm reduction strategies in real-world fitness settings.
This paper introduces new features for PeriLab, a modern Peridynamics solver developed in the Julia programming language. Emphasizing easy installation, usability, and implementation of new features, the code’s structure is detailed, accompanied by illustrative examples highlighting some of the code’s core functionality. Key features of the version v2.0 are the introduction of a correspondence matrix based linear static solver, the implementation of the Guyan reduction, a contact formulation and a massive code restructuring reducing the compilation time. Using the Revise.jl package is made possible by this reorganization. This makes adding new code much easier and faster.
