Influence of Insole Parameters on Lower Limb Comfort during Prolonged Standing/Walking

The influence of insole design parameters on lower limb comfort during standing/walking for a long time was investigated. Nine young women were selected to wear insole with different hardness (30° Shore C and 40° Shore C) and arch support height (+1.5 mm and +3 mm), and the lower extremity biomechanics and subjective comfort indexes were tested during initial standing, standing/walking for 60 min, 120 min and 180 min. The results showed that with the extension of standing/walking time, the subjects' subjective discomfort increased significantly under the three insole conditions. There was no significant difference in leg circumference before and after standing/walking. Pressure time-integrals (PTI) and root mean myography of peroneus longus were significantly increased within 120 min of standing/walking, and peak pressure (PP) was significantly increased within 180 min of lateral palm and middle foot. When only the insole hardness was changed, PP of the medial and lateral heel were 30° Shore C>40° Shore C over time, and PP and PTI of the middle foot were 30° Shore C<40° Shore C, while increasing the arch support height could reduce PP and PTI of the middle foot. Therefore, it is recommended that the long-term standing/walking occupational groups should choose the insole with higher arch support, which can greatly reduce the foot pressure load under the accumulation of time. In addition, the support height of the insole also has different effects on the flat foot and high arch foot people, so it is also necessary to consider the arch state of the wearer to select the appropriate arch support height.