New approach to assessing comfort of use of protective footwear with a textile liner and its impact on foot physiology

Abstract

We propose a new approach to assessing comfort of use of protective footwear with a textile liner. All-rubber footwear with wool liner and cotton/polyamide socks were evaluated in a study involving 30 firefighters. The study was designed to comprehensively assess comfort of use of textiles in the footwear using certain known and new research tools at the same time, that is, measurement of the microclimate inside the footwear (temperature and humidity), weight gain of the footwear, socks, and liner (weighing method), measurement of blood flows in the lower extremities (impedance plethysmography), as well as evaluation of user comfort (questionnaire survey). The influence of the above-mentioned parameters on the comfort of use was analyzed statistically. Following a walk, the temperature in the foot regions was found to increase by 10%, while relative humidity of the air in the plantar region rose by 50%, and the textiles absorbed 28 g/1.5 h of sweat produced by the foot. Due to the unfavorable conditions inside the footwear and as a result of physical exercise, total blood flow in the lower extremities rose significantly (by 33%). The structure and type of the fiber used in the socks and liner influenced the subjective sensations of the subjects. We found very high correlations between the subjective sensations of temperature inside the footwear and the objective measurements of temperature and humidity, blood flow, and liner weight gain. This study is the first step towards a better understanding of the influence of various parameters on the comfort of use of a textile liner and socks in protective footwear.

Shoe microclimate: An objective characterisation and subjective evaluation

“…The heel and sole foot regions were highlighted as being areas of high temperature and high moisture with running thus suggesting low rates of heat and moisture transfer from the foot at these regions. Irzmanska et al (2013) similarly reported a higher inshoe temperature at the plantar region (37°C) compared to the dorsal region (36°C)…”

“…Consequently, heat loss from the skin to the shoe is reduced as the gradient becomes smaller (Lu et al 2013). The development of the shoe microclimate has therefore been suggested to have a decisive influence on the users sensations and perceptions of thermal comfort (Arezes et al 2013;Irzmanska et al 2013;Shimazaki and Murata 2015). The materials used within shoes and socks, the air they enclose and the air bound on the outside of the material layers are therefore important (Havenith 2002).…”

“…Shoe microclimate development has been investigated in protective and hiking footwear but has been restricted to mechanical testing using thermal foot manikins (Schols et al 2004) or assessment of temperature and relative humidity at one or two locations within footwear during physical activity. Under constant moderate climate conditions (23-25°C, 50% RH) and with exercise, in-shoe temperature and in-shoe relative humidity are reported to range between 27-37°C and 67-96% respectively (Bertaux et al 2010;Irzmanska et al 2013;Irzmańska 2015). Based on these data, foot skin temperatures (foot ) have been reported to exceed 34°C resulting in perceptions of thermal discomfort.…”

“…Based on these data, foot skin temperatures (foot ) have been reported to exceed 34°C resulting in perceptions of thermal discomfort. The combination of physical exercise and high temperatures inside footwear has also been shown to add strain to the cardiovascular system in the lower extremities, increasing blood flow by 33% from rest (Irzmanska et al 2013). Further consequences of high temperatures and levels of moisture inside shoes include tinea pedis, commonly known as athlete's foot.…”

Modified Polymer Materials for Use in Selected Personal Protective Equipment Products

“…Relative humidity inside protective footwear ranges from 96% to 100%, which increases the development of sweatdecomposing bacteria [21]. Analysing the microbiological contamination of footwear, one should always consider the presence of pathogenic bacteria and fungi.…”