Quantification of friction force reduction induced by obstetric gels

The objective of this study was to quantify the reduction of friction forces by obstetric gels aimed to facilitate human childbirth. Lubricants, two obstetric gels with different viscosities and distilled water, were applied to a porcine model under mechanical conditions comparable to human childbirth. In tests with higher movement speeds of the skin relative to the birth canal, both obstetric gels significantly reduced dynamic friction forces by 30-40% in comparison to distilled water. At the lowest movement speed, only the more viscous gel reduced dynamic friction force significantly. In tests modifying the dwell time before a movement was initiated, static friction forces of trials with highly viscous gel were generally lower than those with distilled water. The performed biomechanical tests support the recommendation of using obstetric gels during human childbirth. Using the presented test apparatus may reduce the amount of clinical testing required to optimize gel formulatio

High-fidelity device for online recording of foot-stretcher forces during rowing

Foot-stretcher forces have been identified as key variables determining rowing performance. The aim of this study was to develop an instrumented foot-stretcher. Under each forefoot, a six degrees of freedom sensor was mounted on an adjustable frame. Under each rearfoot, a one degree of freedom sensor was placed. Validation resulted in an accuracy of vertical forces of about 1% full scale. Sensor’s crosstalk was up to 11% of vertical load. The instrumented foot-stretcher was integrated into a high-level rowing simulator. Propulsive foot-stretcher forces were displayed online and could be used as concurrent feedback about rowing performanc

Quantification of friction force reduction induced by obstetric gels

The objective of this study was to quantify the reduction of friction forces by obstetric gels aimed to facilitate human childbirth. Lubricants, two obstetric gels with different viscosities and distilled water, were applied to a porcine model under mechanical conditions comparable to human childbirth. In tests with higher movement speeds of the skin relative to the birth canal, both obstetric gels significantly reduced dynamic friction forces by 30-40% in comparison to distilled water. At the lowest movement speed, only the more viscous gel reduced dynamic friction force significantly. In tests modifying the dwell time before a movement was initiated, static friction forces of trials with highly viscous gel were generally lower than those with distilled water. The performed biomechanical tests support the recommendation of using obstetric gels during human childbirth. Using the presented test apparatus may reduce the amount of clinical testing required to optimize gel formulation