Spatial resolution in plantar pressure measurement revisited

Pataky, Todd C.

doi:10.1016/j.jbiomech.2012.05.038

Cited by 24 publications

(20 citation statements)

References 15 publications

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“…As in previous studies 19–20 spatial force pulse modeling was found to reproduce local loading qualitatively well (Fig.7a), but only if a suitably large number of pulses was modeled; the distinct DP2 and DP3 pulses could not be reproduced in an example subject with only three pulses (Figs.2b,7a). Indeed the fits between the modeled and experimental data improved in an exponential-like manner (Fig.7b), with the bulk of improvement achieved with only four pulses.…”

Section: Resultssupporting

confidence: 73%

“…Acknowledging that soft tissue’s spatial dissipation of forces under bony structures can be approximated by the Gaussian function, 19–20 we presently asked the following question: if we assume that power grasping is controlled at a number of discrete contacts, and that forces at these contact points can be modeled locally as Gaussian pulses, how much of the variability in the data can be explained by n contacts? Experimental force distributions were thus modeled as summations of n Gaussian pulses:

f false(θ false) \equiv \sum_{t = 0}^{n} a_{i} e^{- {false(θ - b_{i} false)}^{2} / 2 c_{i}^{2}}

where parameters a i , b i , and c i modulate pulse amplitude, position, and breadth, respectively.…”

Section: Methodsmentioning

confidence: 99%

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Is Power Grasping Contact Continuous or Discrete?

Pataky

Slota

Latash

et al. 2013

Journal of Applied Biomechanics

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During power grasp the number of local force maxima reflects either the central nervous system's preferential use of particular hand regions, or anatomical constraints, or both. Previously both biomdal and trimodal force maxima have been hypothesized for power grasp of a cylindrical handle. Here we measure the number of local force maxima, with a resolution of 4.8°, when performing pushing and pulling efforts in the plane perpendicular to the cylinder's long axis. Twelve participants produced external forces to eight targets. The number of contacts was defined as the number of local maxima exceeding background variance. A minimum of four and a maximum of five discrete contacts were observed in all subjects at the distal phalanges and metacarpal heads. We thus reject previous hypotheses of bimodal or trimodal force control for cylindrical power grasping. Since we presently observed only 4-5 contacts, which is rather low considering the hand's kinematic flexibility in the flexion plane, we also reject hypotheses of continuous contact, which are inherent to current grasping taxonomy. A modification to current grasping taxonomy is proposed wherein power grasp contains separate branches for continuous and discrete contacts, and where power and precision grasps are distinguished only by grasp manipulability.

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Section: Resultssupporting

confidence: 73%

f false(θ false) \equiv \sum_{t = 0}^{n} a_{i} e^{- {false(θ - b_{i} false)}^{2} / 2 c_{i}^{2}}

where parameters a i , b i , and c i modulate pulse amplitude, position, and breadth, respectively.…”

Section: Methodsmentioning

confidence: 99%

Is Power Grasping Contact Continuous or Discrete?

Pataky

Slota

Latash

et al. 2013

Journal of Applied Biomechanics

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“…The cause of both is inadequate spatial resolution in ROI data. Healthy and pathological adult PP data have spatial wavelengths on the order of 30 mm [18] and 20 mm [19], respectively. Plantar pressures must therefore be measured with (Nyquist) resolutions of at least 15 mm and 10 mm, respectively, to avoid signal aliasing.…”

Section: Introductionmentioning

confidence: 99%

“…Although original pixel-level data typically have adequate resolutions, on the order of 5 mm, ROI-level data typically have resolutions on the order of 50 mm, which are too gross. Problems associated with inadequate spatial resolution have been addressed elsewhere for adult feet [18,19], but spatial resolution has not, to our knowledge, been previously explored for children's data.…”

Section: Introductionmentioning

confidence: 99%

A cross-sectional study of age-related changes in plantar pressure distribution between 4 and 7 years: A comparison of regional and pixel-level analyses

et al. 2014

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Quantifying morphological and functional development in children's feet, and thereby establishing development norms is difficult. In addition to practical challenges of experimentation on children, measurement equipment like plantar pressure (PP) platforms are almost exclusively geared towards adult-sized feet. These PP quantification problems may be exacerbated by typical regional data analysis techniques, which further reduce spatial resolution. The goal of this study was to quantify PP distributions in developing children, and also to compare the results obtained from typical (regional) techniques with those obtained from a higher-resolution (pixel-level) technique. Ninety-eight children between four and seven years of age were assessed in a cross-sectional design. Maximum PP distributions were collected for each child, and these pressures were linearly regressed against age. Present results agree with previous investigations in that maximum pressures and maximum pressure changes occurred in the forefoot. However, results from the present pixel-level technique suggest that these changes are limited to the central metatarsals, and that regional methods can suggest significance where none exists in the actual raw (pixel-level) data, due to signal aliasing and, in particular, to conflation of regional boundaries. We postulate that increased central metatarsal pressures are reflective of the coupling between generalised joint laxity decreases and relatively increasingly inclined central metatarsal bones with age.

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“…Las técnicas predominantes que se utilizan para investigar la interacción entre la postura del pie y la biomecánica del miembro inferior son la cinemática (movimiento de los segmentos del cuerpo), electromiografía (actividad muscular) y análisis de presión plantar, también conocido como baropodometría. Mediante el uso de la baropodometría es posible realizar análisis de presiones plantares, medición de la magnitud y distribución de la fuerza que se aplica a la superficie plantar, las cuales se presentan en una persona cuando se encuentra en bipedestación estática o en marcha; estos estudios permiten determinar afectaciones posturales o patologías propias de la zona plantar de los pies, como también afectaciones en zonas lumbares o de rodilla, ya que la posición del pie y la distribución de presión en la zona plantar del pie, cuando la persona se encuentra en bipedestación, muestran la existencia de una patología que puede llevar al estrés de la tibia y al dolor patelofemoral [5][6][7][8].…”

Section: Introductionunclassified

Plataforma baropodométrica PIPLAB

Rey

Pico²,

Luengas

2018

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ResumenA través de la medición de presión plantar se realizan diagnósticos e investigaciones clínicas con el fin de observar el comportamiento de la presión en las diferentes zonas de la planta del pie y así poder emitir conceptos de patologías, prescribir ayudas para reducir la presión, entre otros. Existen dispositivos que permiten estas mediciones, por lo general basados en sensores de presión de tipo resistivo y capacitivo; unos pocos trabajan el procesamiento de imágenes a partir de imágenes impresas, lo cual lleva a errores en el momento de la captura de la imagen, además no entregan valores de distribución de presión plantar. Se presenta el desarrollo de PIPLAB, una plataforma baropodométrica que permite adquirir una imagen de la huella plantar y visualizar mediante un software de computador la presión que soporta la planta de los pies, dando a conocer los puntos máximos de presión bajo cada pie y la repartición de cargas entre el antepié y retropié de la persona a evaluar, asimismo, dar las mediciones cuantitativas para brindar al profesional de la salud una herramienta de valoración y seguimiento de patologías a nivel plantar.Palabras clave: baropodometría, bipedestación, podoscopía, presión plantar, procesamiento de imágenes. AbstractBaropodometric analysis is a tool to assess the dysfunctions of the feet, it may be valuable in terms of postural assessment. Plantar pressure measurement is hardly considered a powerful or meaningful diagnostic tool in clinics, medical data of plantar pressure is analyzed by professionals. These data inform the specialist on the possible pathology and define through the analysis a strategy that can correct such pathology. Devices to measurement the plantar pressure present differences in sensor technology, matrix spatial resolution, pressure range, sampling rate, calibration procedures, raw data pre-processing, this lead to significant differences in the overall accuracy of pressure measurement. Utilizing the image processing, PIPLAB was developed, this device provides a method of objectively measuring plantar pressure. Device validity was shown through comparison with commercial devices, as such, PIPLAB has utility as a measurement tool for pressure plantar.

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Spatial resolution in plantar pressure measurement revisited

Cited by 24 publications

References 15 publications

Is Power Grasping Contact Continuous or Discrete?

Is Power Grasping Contact Continuous or Discrete?

A cross-sectional study of age-related changes in plantar pressure distribution between 4 and 7 years: A comparison of regional and pixel-level analyses

Plataforma baropodométrica PIPLAB

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