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Several international sports federations have implemented a standardized injury reporting system during their championships. However, very few studies have investigated athletes with disabilities during major championships apart from the Paralympic Games. Therefore, the aim of this study was to assess the rate and characteristics of injuries during the Wheelchair Basketball World Championships 2018 (WBWC). This prospective cohort study was conducted during the WBWC held in Hamburg, Germany, from August 16 to August 26, 2018. Physicians or physiotherapists of all 28 participating teams (total 336 players) were asked to report all newly incurred injuries (with location, diagnosis, cause, and estimated duration of absence) daily on a standardized injury report form. Prevalence and incidence rates were calculated. Medical staff of 11 teams (132 players) reported 100 injuries, equivalent to 75.8 per 100 players (95% CI: 60.9-90.7) or 68.9 per 1000 player-days (55.4-82.4). Eight time-loss injuries were reported (6.1 injuries per 100 players [95% CI: 1.9-10.3] or 5.5 injuries per 1000 player-days [1.7-9.3]). More injuries were incurred during matches (n = 68) than during training. Most injuries affected the neck/cervical spine (16%), thoracic spine/upper back (15%), and shoulder (14%). The most frequent diagnosis was muscle spasms (25%), the most frequent cause was overuse (52%). A high rate of non-time-loss injuries compared to Paralympic Games was reported. Future studies should focus on the etiology of muscle spasms and further identify injury mechanisms of traumatic and overuse injuries in wheelchair basketball players to develop adequate preventive measures.

In the scope of the optimization of multi phase steels, e.g. for the automotive industry, control of the microstructure is essential to tailor the mechanical properties. In this study, two cold rolled steels varying in carbon content were annealed and cooled under different laboratory conditions. The microstructure is investigated using optical and electron microscopy and EBSD. The results are correlated to the mechanical properties obtained from tensile, hole expansion and bending test. It is found that tensile strength and elongation are mainly dependent on martensite volume fraction, while yield strength is less affected by chemical composition or annealing treatment. In contrast, hole expansion capacity and maximum bending angle are significantly improved by the homogenization of the microstructure which is independent of strength and elongation. The microstructure homogeneity is expressed by analyzing the Lorenz curves derived from the kernel average misorientation from EBSD measurements.

Actual multiphase steels guarantee tensile strengths in different grades between 500 and 1000 MPa. Specifications and standards permit a wide field of chemical compositions. On one hand, carbon amounts higher than 0.12% are not seldom for grades exceeding 600 MPa tensile strength. However, frequently encountered difficulties during body manufacturing, due to limited formability, like enhanced crack formation at trim edges, increased spring-back, or deteriorated fracture behavior of weld joints are typically related to unfavorable microstructures. On the other hand, a strict limitation of the carbon content to below 0.1 wt% across all strength classes up to 1000 MPa allows avoiding the mentioned manufacturing difficulties. Carbon reduction as well as grain refinement and precipitation hardening by means of Nb-microalloying and solid solution hardening through further addition of manganese, silicon, chromium, or molybdenum are the major key factors on metallurgical site. A more homogenous combination of ferrite and martensite with certain amounts of bainite is adjusted by heat treatment to defuse the critical interfaces to increase forming properties measured by bending angle and hole expansion.