Longitudinal midsole bending stiffness and elasticity are two critical features in the construction of running shoes. Stiff elastic materials (eg, carbon fiber) can be used to alter the midsole bending behavior. The purpose of this study was to investigate the effects of midsole stiffness and elasticity manipulation on metatarsophalangeal (MTP) joint mechanics during running in 19 male subjects at 3.5 m/s. Midsole bending stiffness and elasticity were modified by means of carbon fiber insoles of varying thickness. Stiffening the shoe structures around the MTP joint caused a shift of the point of force application toward the front edge of the shoe-ground interface. Negative work was significantly reduced for the stiffest shoe condition and at the same time a significant increase of positive work at the MTP joint was found. It seems plausible that the increase in positive work originates from the reutilization of elastic energy that was stored inside the passive elastic structures of the shoe and toe flexing muscle tendon units. Further, an increase in midsole longitudinal bending stiffness seems to alter the working conditions and mechanical power generation capacities of the MTP plantar flexing muscle tendon units by changing ground reaction force leverage and MTP angular velocity.
Hysteroscopy and falloposcopy are routine procedures in gynecological endoscopy. Injuries to the cervix or uterine perforations due to blind manipulation or wrong use of instruments are the most common complications associated with these procedures. In vitro simulators have been shown to be valuable tools in the laparoscopic training of physicians. Therefore we developed a simulator for hysteroscopy offering realistic anatomical and physiological training conditions. Additionally, we examined different polymer substances as basic materials for organ modules that allow the realistic application of electric instruments, e.g. resector blades and rollerball.
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