In-shoe plantar pressure depends on walking speed and type of weight-bearing activity in people with diabetes at high risk of foot ulceration

Abstract

Background: In evaluating therapeutic footwear, in-shoe plantar pressure is usually obtained during mid-gait steps at self-selected walking speed in a laboratory setting. However, this may not accurately represent plantar pressures or indicate the cumulative stress experienced in daily life. We investigated the effects of walking speed and different weight-bearing activities on in-shoe plantar pressure in people with diabetes at high risk of ulceration.

Methods: In a cross-sectional study including 30 participants we compared in-shoe plantar pressures between three standardized walking speeds (0.8, 0.6 and 0.4 m/s) and between walking at self-selected speed and eight other weight-bearing activities (3 components of the Timed Up and Go test, accelerating, decelerating, stair ascending and descending, and standing). Mean forefoot regional peak plantar pressure and pressure-time integral were statistically assessed per foot using linear mixed models (α < 0.05) with Holm-Bonferroni correction.

Findings: With increasing walking speed, peak pressures increased and pressure-time integrals decreased (P ≤ 0.014). Peak pressures during standing, decelerating, stair ascending and Timed Up and Go test were lower (P ≤ 0.001), and with other activities not different to walking at self-selected speed. Pressure-time integrals during stair ascending and descending were higher (P ≤ 0.001), during standing lower (P ≤ 0.009), and with other activities not different to walking at self-selected speed.

Interpretation: In-shoe plantar pressure depends on walking speed and type of weight-bearing activity. Only measuring pressures to evaluate footwear at self-selected walking speed in a laboratory setting may not accurately represent the stress on the foot in daily life of the high-risk patient; a more comprehensive assessment is suggested.

Keywords: Ambulatory monitoring; Cumulative plantar tissue stress; Diabetic foot; Footwear; Peak pressure; Pressure-time integral.