Numerous variables can introduce errors into the measurement chain of a digital image correlation (DIC) system. These can be grouped into two categories: measurement quality and the correlation principle. Although previous studies have attempted to investigate each error source in isolation, there are still no comprehensive, standardized procedures for calibrating DIC systems for full-field strain measurement. The aim of this study, therefore, was to develop an applied experimental method that would enable a DIC practitioner to perform a traceable full-field measurement calibration to evaluate the accuracy of a particular system setup in a real-world environment related to their specific application. A sequence of Speckle Pattern Boards (SPB) that included artificial deformations of the speckle pattern were created, allowing for the calibration of in-plane deformations. Multiple deformation stages (from 10% to 50%) were created and measured using the GOM ARAMIS system; the results were analysed and statistical techniques were used to determine the accuracy. The measured strain was found to be slightly over-estimated (nominally by 0.02%), with a typical measurement error range of 0.34% strain at a 95% confidence interval. Location within the measurement volume did not have a significant effect on error distributions. It was concluded that the methods developed could be used to calibrate a DIC system in-situ for full-field measurements of large deformations. The approach could also be used to benchmark different DIC systems against each other or allow operators to better understand the influence of particular measurement variables on the measurement accuracy.

For the past century, football boots have constantly changed, with new designs and materials being developed by sporting goods manufacturers to meet player demands. Investigating the effect of such changes on performance was important to further develop football boots. Bending stiffness has been demonstrated as an important performance parameter in running footwear; a concept with potential to investigate football footwear. As football boots consisted of an upper and an outsole, with the latter being manufactured from a far stiffer material than the upper, it could be speculated that the outsole limits the boot's flexibility. The aim of this paper was to create a testing device to quantify whether the whole shoe needed to be considered when designing football boots. The test device consisted of a simplified foot based on biomechanical factors linked to an Instron machine to quantify the load during bending. The bending stiffness of the uppers and boots were found to be non-linear, highlighting the need to specify the angle at which the stiffness was recorded. The upper was shown to have a significant effect on the bending stiffness of the overall boot construction, whilst different upper constructions were shown to affect the bending stiffness. With regard to the findings in this paper, it was concluded that the upper was an important consideration in boot design.

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2Penn State Brandywine (EE. UU.), 3 Upper Darby High School (EE.UU). Arts, volumen 19, número 2 (34-45), 2010 Resumen No hay en la literatura estudios que cuantifiquen las características del impacto en las tablas del makiwara. Lógicamente, la evaluación de las características mecánicas de varios diseños de tablas de makiwara debería ser un paso inicial en la determinación de la validez del makiwara como medio de desarrollo de la técnica del kárate. Consecuentemente, el propósito de este estudio fue determinar la dureza de los diseños del makiwara que se estrecha y en tabla apilada, utilizando técnicas estáticas de carga para evaluar su idoneidad para practicantes de diferentes niveles. Cuando nuestros resultados se observan en términos de progresión del entrenamiento, parece que el diseño apilado de fresno, más flexible, se ajusta mejor al principiante, mientras que el modelo que se estrecha de encina, más rígido, se ajusta mejor al experto. Palabras clave: Kárate, entrenamiento, técnica, fuerza, materiales, diseños. Es traducción del artículo Evaluating Makiwara Punching Board Performance, publicado en el Journal of Asian Martial Evaluating Makiwara Punching Board Performance Abstract:No studies quantifying the impact characteristics of makiwara boards are available in the published literature. Logically, an initial step in determining the validity of the makiwara to develop karate technique would be to assess the mechanical characteristics of various types of makiwara board designs. It was, therefore, the purpose of this study to determine the stiffness of selected tapered board and stacked board makiwara training devices using static loading techniques to assess their suitability for practitioners of different levels. When our results are viewed in terms of progression of training, it would appear that a novice would be more suited to the more compliant ash stacked design and the expert more suited to the stiffer oak tapered design.