In reality most welded components are loaded with a combination of different variable forces and moments that often cause a state of multiaxial stress in the fatigue‐critical areas. If the multiaxial loading is non‐proportional, traditional deformation‐based hypotheses are not able to give a reliable lifetime prediction. This investigation is a cooperation between three German research institutes to build an experimental database for the verification of different concepts of lifetime prediction. In accordance with former investigations, a flange‐tube connection made of steel P460 was used. The test program was divided into constant amplitude and variable amplitude tests. The ratio between the nominal bending and shear stress is 1. For the variable amplitude tests, a Gaussian‐standard is used. A lifetime prediction software for multiaxial state of cyclic stress was developed. The software has a modular structure and allows calculations with different hypotheses and methods. The calculations are based on the local elastic stresses. This is an acceptable method for high‐cycle fatigue. In this work, two general types of calculation, the Integral Approach and Critical Plane Approach and a local stress‐based modification of the von Mises Criterion, the hypothesis of effective equivalent stress (EESH) are shown. The damage accumulation is performed with the elementary Miner’s rule (S–N curve without fatigue limit). The statistical distributions of the damage sums are also shown.

Background: The risk of future injury appears to be influenced by agonist fascicle length (FL), joint range of motion (ROM) and eccentric strength. Biomechanical observations of the torque-angle-relationship further reveal a strong dependence on these factors. In practice, a longer FL improves sprinting performance and lowers injury risk. Classical stretching is a popular and evidenced-based training for enhancing ROM but does not have any effects on FL and injury risk. However, recent studies show that eccentric-only training (ECC) improves both flexibility and strength, and effectively lowers risk of injury.Objectives: To review the evidence on benefits of ECC for flexibility and strength.Methods: COCHRANE, PUBMED, SCOPUS, SPOLIT, and SPONET were searched for laboratory trials that compare ECC to at least one comparison group. Studies were eligible if they examined both strength and flexibility metrics in a healthy sample (<65 years) and met criteria for controlled or randomized clinical trials (CCT, RCT). 18 studies have been included and successfully rated using the PEDro scale.Results: 16 of 18 studies show strong evidence of strength and flexibility enhancements for the lower limb. While improvements between ECC and concentric training (CONC) were similar for eccentric (+19 ± 10% vs. +19 ± 11%) and isometric strength (+16 ± 10% vs. +13 ± 6%), CONC showed larger improvements for concentric strength (+9 ± 6% vs. +16 ± 7%). While for ROM ECC showed improvements (+9 ± 7%), no results could be found for CONC. The overall effectiveness of ECC seems to be higher than of CONC.Conclusion: There is clear evidence that ECC is an effective method for changes in muscle architecture, leading to both flexibility and strength improvements for the lower limb. Due to limited data no shoulder study could be included. Further research is needed for the upper body joints with a focus on functional and structural adaptions.Systematic Review Registration:https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021283248, identifier CRD42021283248

In reality most welded components are loaded with a combination of different variable forces and moments which often cause a state of multiaxial stress in the fatigue critical areas of the weldment. If the multiaxial loading is nonproportional, conventional hypotheses are not able to give a satisfying lifetime prediction. This investigation is a cooperation of three German research institutes to build an experimental database for the verification of different concepts of lifetime prediction. In accordance with former investigations, a flange-tube connection made of steel P460 is used. The test program is divided into constant amplitude and variable amplitude tests. The ratio between the nominal bending and shear stress is 1. The ratio between the local shear and normal stress at the critical point is 0.6. For the variable amplitude tests, a Gaussian standard is used. A lifetime prediction software for multiaxial state of cyclic stress was developed. The software has a modular structure and allows calculations with different hypotheses and methods. The calculations are based on the local elastic stresses. This is an acceptable method for high-cycle fatigue. The failure criteria “critical plane approach” and “integral damage approach” are used in the software. Lifetime predictions for the flange-tube connection were performed using various hypotheses and concepts. In this work, one type of calculation, the integral approach with elementary Miner's Rule and damage sum D = 1, is illustrated. The calculations correspond well with the experimental results.

Zusammenfassung Hintergrund Verletzungen der Schulter sind häufige Ursachen für den Verlust von Trainingszeit und Wettkampfpraxis. Dabei sind sowohl akute Verletzungen als auch langfristige Veränderungen der stabilisierenden Strukturen problematisch. Während über die Belastungssituation der Schulter im Baseball bereits einige Studien vorliegen, ist dies im Speerwurf bisher nicht der Fall, weder die Kinematik noch die Kinetik wurden bisher vollständig quantifiziert. Ziel der Arbeit Das Ziel der Arbeit bestand darin, die Belastung der Schulter im Speerwurf zu quantifizieren und somit einen Beitrag zu Identifikation von Verletzungsrisiken zu leisten. Material und Methoden Von 10 männlichen Speerwerfern wurden mithilfe eines Infrarotkamerasystems und 18 reflektierenden Markern an prominenten Körperpunkten die Bewegungsdaten erfasst. Diese Daten dienten unter Nutzung eines 5‑segmentigen Mehrkörpermodells dazu, die Kinematik und Kinetik des Schultergelenks zu modellieren. Aus den berechneten Verläufen wurden jeweils die Maxima extrahiert und einer Zusammenhangsprüfung zur Abwurfgeschwindigkeit unterzogen. Ergebnisse Die Sportler erreichten eine mittlere Abwurfgeschwindigkeit von 23,29 ± 2,17 ms−1. Die maximalen Gelenkwinkelgeschwindigkeiten lagen zwischen 445–4071 °/s in Abhängigkeit von der Bewegungsebene. Auch in den Gelenkbelastungen zeigten sich spezifische Unterschiede in den Ebenen (109–129 Nm). Schlussfolgerung Die Belastungssituation im Speerwurf unterscheidet sich im Vergleich zum Baseball. Während im Speerwurf verringerte Amplituden und Winkelgeschwindigkeiten auftreten, wird eine erhöhte Kraftanforderung sichtbar. Als mögliche Ursachen hierfür werden unterschiedliche Regelwerke diskutiert (Gerätegewicht/-dimensionen, Eingangsgeschwindigkeit).

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