A new insole measurement system to detect bending and torsional moments at the human foot during footwear condition: a technical report

A novel in-situ dynamic mechanical analysis for human plantar soft tissue: The device design, definition of characteristics, test protocol, and preliminary results

The in-situ mechanical characterization of elastomers is not highly regarded due to the existence of a well-established set of sample-based standard tests for research and industry. However, there are certain situations or materials, like biological soft tissue, where an in-situ approach is necessary due to the impossibility of sampling from a living body. We have developed a dynamic mechanical analysis (DMA)-like device to approach in-vivo and in-situ multidimensional stress-strain properties of human plantar soft tissues. This work elucidates the operational mechanism of the novel measurement, with the definition of a new set of moduli, test standardization and protocol. Exploratory results of a volunteer's living plantar, silica rubber samples are presented with well preciseness and consistence as expected.

Effects of contoured insoles with different materials on plantar pressure offloading in diabetic elderly during gait

To investigate the effect of contoured insoles constructed of different insole materials, including Nora Lunalastik EVA, Nora Lunalight A fresh, Pe-Lite, and PORON Medical 4708 with Langer Biomechanics longitudinal PPT arch pads on offloading plantar pressure on the foot of the elderly with Type 1 or 2 diabetes during gait. Twenty-two elderly with Type 1 or 2 diabetes participated in the study. Their plantar pressure was measured by using an insole measurement system, while the participants walked 10 m in their bare feet or used each experimental insole in random order. The plantar surface was divided into four specific regions including the toes, forefoot, midfoot, and rearfoot. The mean peak pressure (MPP) and pressure-time integral (PTI) of ten steps with or without wearing one of the four insoles were analyzed on the dominant foot and the four specific plantar regions. After completion of the activities, the participants scored each insole from 1 (the least comfortable) to 10 (the most comfortable). The analysis of variance (ANOVA) factor of the insoles had significant effects on the MPP (P < 0.001) and PTI (P = 0.004) in the dominant foot during gait. Pairwise comparison results showed that the MPP and PTI in the dominant foot were significantly lower (P < 0.001) with PORON Medical 4708 than barefoot, Nora Lunalight A fresh, and Pe-Lite. Additionally, the insole materials had a significant effect for the forefoot (P < 0.001) and rearfoot (P < 0.001) in terms of the MPP and PTI compared with the barefoot condition during gait. Regardless of the plantar region, the MPP and PTI values were the lowest when PORON Medical 4708 was used as the insole material among four insole materials. Meanwhile, a significantly lower MPP and PTI can be found in the forefoot and rearfoot with the use of the four experimental insoles when compared with barefoot. The soft insole materials (i.e., PORON medical 4708 and Nora Lunalastik EVA) had a better performance than the rigid insole materials (i.e., Nora Lunalight A fresh, and Pe-Lite) on plantar pressure offloading for diabetic elderly.

The effect of frictional coefficients and sock material on plantar surface shear stress measurement

At present, there are no viable systems that can acquire in-shoe measurement of distributed shear forces. Foot-shoe interactions are such that skin shear is a notoriously difficult quantity to measure under the best of conditions. This is further complicated by the presence of forces normal to the skin surface that are large compared to the shear forces, which often results in crosstalk between pressure and shear signals. The present study used multibody dynamic simulations to investigate the combined effects of (i) coefficient of friction (COF) at skin-sock and sock-sensor interfaces, as well as (ii) sock stiffness on the accuracy of measured shear against the skin. These factors were systematically altered within a wide range (COF: 0.04, 0.34, 0.54, and 0.9; sock stiffness: 100, 250, 500, 1000, 1500 and 2000 N/m) to simulate a total of 96 scenarios. The correlation between the shear at the skin and at the sensor was used to compare each set of conditions. The results indicated that a high COF at the sock-sensor interface and a low sock stiffness would individually result in a significantly higher accuracy of shear measurements (p < 0.001). A low COF at the skin-sock interface was observed to reduce the occurred shear against the skin up to a factor of five, with very minimal effect on the accuracy of shear measurements (p = 0.98). These findings allow researchers to understand the potential effects of (i) sock stiffness, and (ii) coefficients of friction, on skin shear, and potentially correct for the effects of interface materials when trying to determine shear at the skin-sock interface.

Foot and ankle ability measure to measure functional limitations in patients with foot and ankle disorders: a Chinese cross-cultural adaptation and validation

PURPOSE

To perform a cultural adaptation and validation study (internal and external) of the FAAM questionnaire to create the Chinese version of the questionnaire (FAAM-Ch).

MATERIALS AND METHODS

Two independent professional native translators performed a translation from English to Chinese and reverse translation. Psychometric properties analysis: Internal consistency of measure was analysed through the Cronbach's α coefficients. After extraction by maximum likelihood (EML), the structure factor and construct validity was analysed; to extract a factor, it was necessary to complete the following three requirements: ≥10% of variance, Eigenvalue >1.0 and scree plot inflection point. Standard error measurement (SEM) and minimal detectable change 90 (MDC90) were calculated. FFI-Taiwan version, SF12v2, and EuroQol5D were used for criterion validity analysis.

RESULTS

The internal consistency (Cronbach's α) for specific FAAM-Ch subscales was 0.879 (ADL) and 0.901 (Sport); test-retest analysis (interclass correlation) item ranging between 0.758 and 0.970 (ADL: 0758-0946; Sport: 0.911-0.970). Measures error: 3.449% (MDC90) and 1.478% (SEM). Chi-squared value =15228.74 and gl 406) (p < 0.001) and the Kaiser-Meyer-Oklin values (0.919). The correlation level with the FFI is strong, with SF12v2 is between poor and strong and with EuroQoL5d is between moderate and strong Conclusions: FAAM-Chinese version has satisfactory "transversal" psychometric properties, facilitating the inclusion of FAAM-Chinese into research and clinical practice. Implications for Rehabilitation Cross-cultural adaptation of the FAAM-Ch has been performed from the original version. The psychometric properties of the FAAM-Ch indicate satisfactory and consistent results (particularly in the internal consistence, reliability and criterion validity) with the original version. FAAM-Ch can be used by Chinese speaking clinicians and researches.