The mechanical properties of the human heel pad: A paradox resolved

Aerts, Peter; Ker, R. F.; Clercq, Dirk De; Ilsley, D.W.; Alexander, R. McNeill

doi:10.1016/0021-9290(95)00009-7

Cited by 98 publications

(93 citation statements)

References 8 publications

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“…These properties are also the basis for the development of finite element models of feet [5][6][7][8][9][10]. In clinical settings, tissue assessments are predominantly performed through palpation [11], even though such evaluations are inherently subjective and rely on observer experiences [12].…”

Section: Introductionmentioning

confidence: 99%

An indentation apparatus for evaluating discomfort and pain thresholds in conjunction with mechanical properties of foot tissue in vivo

Xiong

Goonetilleke²,

Witana³

et al. 2010

JRRD

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Abstract-The mechanical properties of human foot tissue in vivo as well as discomfort and pain thresholds are important for various applications. In this study, an apparatus for measuring the discomfort and pain thresholds and the mechanical properties of human tissues is presented. The apparatus employs a stepper motor that controls the indentation speed, as well as a load cell and potentiometer that determine the corresponding reaction force and tissue deformation (displacement), respectively. A LabVIEW program (LabVIEW 8, National Instruments Corporation; Austin, Texas) was developed to control the indentation via a data acquisition card. The apparatus can accommodate indentor displacements up to 35 mm and can impart forces up to 150 N at a controlled indentation speed in the range of 0 to 10 mm/s. Tests showed that the displacement measurement error is 0.17 mm in the nominal range (0.5% in the full scale) and the measurement error of force is 1.6 N in the nominal range (1.1% in the full scale). Experimental results indicate that the apparatus is reliable and flexible for measuring the mechanical properties of foot tissue in vivo in conjunction with pain and discomfort thresholds.

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Section: Introductionmentioning

confidence: 99%

An indentation apparatus for evaluating discomfort and pain thresholds in conjunction with mechanical properties of foot tissue in vivo

Xiong

Goonetilleke²,

Witana³

et al. 2010

JRRD

View full text Add to dashboard Cite

show abstract

“…The human heel pad has been identified as an important site for this energy dissipation (e.g. Aerts, Ker, Ilsley & Alexander, 1995). In an analysis of landing from a drop Zatsiorsky & Prilutsky (1987) estimated that up to 75 % of the mechanical energy of the body could be dissipated passively.…”

Section: Introductionmentioning

confidence: 99%

Soft Tissue Motion during Impacts: Their Potential Contributions to Energy Dissipation

Pain

Challis

2002

Journal of Applied Biomechanics

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The aims of this study were to quantify intrasegmental motion using an array of 28 surface-mounted markers to examine frequency and amplitude measurements of the intrasegmental motion to calculate forces and energy transfer; and to show that the underlying muscles are a major contributor to the skin marker motion. One participant performed 27 trials under three conditions in which his forearm was struck against a solid object fixed to a force plate while the locations of the markers were recorded at 240 Hz. For impacts with equal peak forces, the muscle tension significantly affected the amount of intrasegmental motion. Tensing the arm reduced the intrasegmental motion by 50%. The quadrilateral sectors defined by the markers changed in area by 11% with approximately equal motion in the vertical and horizontal direction. The maximum linear marker motion was 1.7 cm. The intrasegmental motion had distinct frequency components around 14 and 20 Hz. Soft tissue deformation could account for 70% of the energy lost from the forearm during these impacts. The study has demonstrated the important role that intrasegment soft tissue motion can have on the kinetics of an impact.

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“…Clarys and Marfell-Jones, 1986;Yeadon, 1990). Heel pad mechanical properties measured in vivo and in vitro are accurate and repeatable (Aerts, Ker, De Clercq, Ilsley, & Alexander, 1995), but estimates of in vivo and in vitro stiffness vary by an order of magnitude (e.g. Valiant, 1984;Bennett & Ker, 1990).…”

Section: Methodsmentioning

confidence: 99%

Wobbling Mass Influence on Impact Ground Reaction Forces: A Simulation Model Sensitivity Analysis

Pain

Challis

2004

Journal of Applied Biomechanics

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To gain insight into joint loadings during impacts, wobbling mass models have been used. The aim of this study was to investigate the sensitivity of a wobbling mass model, of landing from a drop, to the model's parameters. A two-dimensional wobbling mass model was developed. Three rigid linked segments designed to represent the skeleton each had a second mass attached to them, via two translational non-linear spring dampers, representing the soft tissue. Model parameters were systematically varied one at a time and the effect this had on the peak vertical ground reaction force and segment kinematics was examined. Model output showed low sensitivity to most model parameters but was sensitive to the timing of joint torque initiation. Varying the heel pad stiffness in the range of stiffness values reported in the literature had the largest influence on the peak vertical ground reaction force. The analysis indicated that the more proximal body segments had a lower influence on peak vertical ground reaction force per unit mass than the segments nearer the contact point, 340 N/kg, 157 N/kg and 24 N/kg for the shank, thigh and trunk respectively. Model simulations were relatively insensitive to variations in the properties of the connection between the wobbling masses and the skeleton. Given the proviso that estimates for the other model parameters and joint torque activation timings lie in a realistic range, then if the goal is to examine the effects of the wobbling mass on the system this insensitivity is an advantage. If precise knowledge about the motion of the wobbling mass is of interest, however, more experimental work is required to determine precisely these model parameters.

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The mechanical properties of the human heel pad: A paradox resolved

Cited by 98 publications

References 8 publications

An indentation apparatus for evaluating discomfort and pain thresholds in conjunction with mechanical properties of foot tissue in vivo

An indentation apparatus for evaluating discomfort and pain thresholds in conjunction with mechanical properties of foot tissue in vivo

Soft Tissue Motion during Impacts: Their Potential Contributions to Energy Dissipation

Wobbling Mass Influence on Impact Ground Reaction Forces: A Simulation Model Sensitivity Analysis

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