A reliable measure of footwear upper comfort enabled by an innovative sock equipped with textile pressure sensors

Abstract

Footwear comfort is essential and pressure distribution on the foot was shown as a relevant objective measurement to assess it. However, asperities on the foot sides, especially the metatarsals and the instep, make its evaluation difficult with available equipment. Thus, a sock equipped with textile pressure sensors was designed. Results from the mechanical tests showed a high linearity of the sensor response under incremental loadings and allowed to determine the regression equation to convert voltage values into pressure measurements. The sensor response was also highly repeatable and the creep under constant loading was low. Pressure measurements on human feet associated with a perception questionnaire exhibited that significant relationships existed between pressure and comfort perceived on the first, the third and the fifth metatarsals and top of the instep. Practitioner Summary: A sock equipped with textile sensors was validated for measuring the pressure on the foot top, medial and lateral sides to evaluate footwear comfort. This device may be relevant to help individuals with low sensitivity, such as children, elderly or neuropathic, to choose the shoes that fit the best.

An investigation into the effects of, and interaction between, heel height and shoe upper stiffness on plantar pressure and comfort

“…One additional factor affecting comfort might be the dorsal pressures (Hagen, Homme, Umlauf, & Hennig, 2010;Jordan, et al, 1997), and indeed large differences in subjective comfort between the upper materials were scored in regions related to the dorsal foot surface ("foot top" and "ball sides"). If we had been able to record dorsal pressures we may have anticipated changes in these variables, similar to those reported by Herbaut et al (2016) in athletic shoes with different lace tightness. Our subjective results allude to the perceived sensation of the upper being an important factor to consider when designing high heels and significant in terms of overall comfort perception.…”

“…The volume of a shoe upper has also been implicated as a risk factor for reduced foot health and pain when wearing medical-grade footwear (Hurst, Branthwaite, Greenhalgh and Chockalingham, 2017), which is a function of both upper shape and material. A shoe that is too tight is undesirable from comfort and health perspectives (Snow, Williams, & Holmes, Jr., 1992;Wu 1996) with higher pressures on the dorsal foot linked to lower reported comfort in athletic shoes (Herbaut et al, 2016). The upper therefore provides an obvious footwear characteristic to modify and increase volume to improve comfort of the wearer and potentially reduce objective variables such as plantar pressures.…”

“…However, conversely, an upper that does not sufficiently grip the foot will be unable to prevent the foot sliding inside the shoe (Herbaut et al, 2016). It is not clear if upper material characteristics affect plantar pressure nor comfort in high heels because they have never been investigated as independent variables in systematic study designs.…”

Perception of Comfort, Fit, and Jumping Performance of Elite NCAA Division 1 Student-athletes: The Effect of Basketball Shoe Design – Part II

“…Some sensors were found to record higher pressures due to the folding of the sensors. Another wearable device, a pressure sock, was developed using textile sensors with results indicating the same negative correlation between comfort and pressure (Herbaut, Simoneau-Buessinger, Barbier, Cannard, & Guéguen, 2016). However, the question of how much pressure is uncomfortable is not universal between individuals (Herbaut et al, 2016).…”

Piezo-Sensitive Fabrics from Carbon Black Containing Conductive Cellulose Fibres for Flexible Pressure Sensors

“…In another approach, the piezo-resistive properties of compressible structures were used to build flexible textile-based pressure sensors [ 17 , 18 ]. Space-resolved pressure-sensitive layers have been assembled via a combination of piezo-resistive nonwoven material and conductive elements with the aim to develop pressure sensors in shoes [ 19 ]. Other approaches integrated elastic piezo-sensitive layers in sensor pads [ 20 ], shoes [ 21 ], seats [ 22 , 23 ], sensor mats [ 24 ], and carpets [ 25 , 26 , 27 ].…”