Efecto de la morfología de las plantas de los pies en la distribución de presión plantar en atletas jóvenes con diferentes tipos de pie / Effect of the morphology of the soles of the feet on plantar pressure distribution in young athletes with different foot types

INTRODUCCIÓN Y OBJETIVOS: Estudios previos han sugerido que las diferencias en la estructura de los pies podrían afectar el comportamiento de la distribución de la presión plantar, por lo que esto podría aumentar la probabilidad de sufrir una lesión. El objetivo de este trabajo fue determinar el efecto de la morfología de las plantas de los pies sobre la distribución de la presión plantar entre el pie normal, el pie plano, cavo extremo y el pie cavo en condiciones estáticas y dinámicas. METODOLOGÍA: Ciento dieciocho deportistas, con una edad promedio de 14,45 ± 2,17 años y una masa promedio de 58,78 ± 12,18kg, participaron en esta investigación. Ninguno de los participantes presentó alguna lesión que le impidiera realizar las pruebas. RESULTADOS: Se encontró que la distribución de la carga en el retropié del pie plano, el cavo extremo y el pie cavo fue mayor que la presión del pie normal en condiciones estáticas. Sin embargo, el análisis ANOVA no mostró una diferencia significativa entre estas condiciones de los pies (pie derecho p = 0,25 y pie izquierdo p = 0,36). El análisis de la presión en condiciones dinámicas reveló que los deportistas con pie cavo en el pie derecho presentaron un valor más elevado en la región de los metatarsos; esto podría ser un factor de riesgo para producir alteraciones musculoesqueléticas. Por el contrario, la disminución de presión en sujetos con pie plano presentaría un riesgo menor. CONCLUSIÓN: El análisis de la distribución de la presión plantar entre los 4tipos de pies en condiciones estáticas y dinámicas demuestra que la presión plantar se modifica por el tipo de pie que presenta cada individuo. Los resultados del presente trabajo contribuyen de forma directa en conocer más a profundidad la biomecánica de la distribución de presión plantar en sujetos con diferente tipo de pie

INTRODUCTION AND OBJECTIVE: Previous studies have suggested that differences in the structure of the feet might affect the behaviour of plantar pressure distribution, this might increase the probability of getting injured. The objective of this work was to determine the effect of the morphology of the soles of the feet on plantar pressure distribution among normal foot, flatfoot, extreme cavus and cavus foot in static and dynamic conditions. METHODOLOGY: One hundred and eighteen athletes, mean age 14.45 ± 2.17 years, mean mass 58.78 ± 12.18kg took part in this research. None of the participants presented an injury that prevented them from carrying out the tests. RESULTS: It was found that the load distribution in the hindfoot of the flat foot, extreme cavus and cavus foot was higher than the normal foot in static condition. However, One-way ANOVA analysis did not show a significant difference among these feet conditions (right foot, P=.25 and left foot, P=.36). The analysis of pressure in dynamic conditions revealed that athletes with right cavus foot had a higher value in the metatarsal region, this could be a risk factor for producing musculoskeletal abnormalities. Conversely, lowering pressure in flatfoot subjects would present a lower risk. CONCLUSION: The analysis of the plantar pressure distribution among the 4types of feet in static and dynamic conditions proves that plantar pressure is modified by the type of foot of each individual. The results of the current work contribute directly to learning more about the biomechanics of plantar pressure distribution in subjects with different foot types

Temperature Measurement of Fluid Flows by Using a Focusing Schlieren Method.

A method for measuring planar temperature fields of fluid flows is proposed. The focusing schlieren technique together with a calibration procedure to fulfill such a purpose is used. The focusing schlieren technique uses an off-axis circular illumination to reduce the depth of focus of the optical system. The calibration procedure is based on the relation of the intensity level of each pixel of a focused schlieren image to the corresponding cutoff grid position measured at the exit focal plane of the schlieren lens. The method is applied to measure planar temperature fields of the hot air issuing from a 10 mm diameter nozzle of a commercial Hot Air Gun Soldering Station Welding. Our tests are carried out at different temperature values and different planes along the radial position of the nozzle of the hot air. The experimental values of temperature measurements are in agree with those measured using a thermocouple.

Wide-range average temperature measurements of convective fluid flows by using a schlieren system.

In the schlieren method, the deflection of light by the presence of an inhomogeneous medium is proportional to the gradient of its refractive index. In the presence of temperature variations in a fluid flow, the refraction index is related to the gas density by the Gladstone-Dale constant, which depends on the nature of the gas and the wavelength of light propagating in the medium. The deflection of light in a schlieren system is represented by intensity variations on the observation plane. Then, for a digital camera, the intensity level registered in each pixel depends mainly on the refractive index variation of the medium and exposure time. Therefore, if we regulate the intensity value of each pixel by controlling the exposure time, it is possible to adjust the temperature value measurements. In this way, a specific exposure time of a digital camera allows us to measure a determined range of temperature values. For that reason, in this study we determine the range of temperatures that can be measured with a digital camera for different exposure times. By doing this, a wide range of average temperature value fields can be obtained by summing up the temperature contribution of each exposure time. The basic idea in our approach to measure temperature by using a schlieren system is to relate the intensity level of each pixel in a schlieren image to the corresponding knife-edge position measured at the exit focal plane of the system. Our approach is applied to the measurement of temperature fields of the air convection caused by a heated rectangular metal plate (7.3 cm×12 cm) and a candle flame. We found that the maximum temperature values obtained for exposure times of 31.3, 15.7, 7.9, 3.9, and 2 ms were 67.3°C, 122.6°C, 217.4°C, 364.3°C, and 524.0°C, respectively.