The effect of terrain on foot pressures during walking

Background: High plantar pressures are associated with the development of foot ulcers in people with diabetic neuropathy. The effect of terrain on plantar pressures during walking has not been fully explored. Methods: Twenty 23- to 40-year-old subjects with no known musculoskeletal pathology walked across three terrains: padded carpet (R), grass (G), and concrete (C) while wearing Novel Pedar (Novel Electronics Inc. GMBH, Munich, Germany) insoles with and without shoes. Pressures were collected at 50 Hz. The sole of the foot was divided into: heel (H), lateral midfoot (LM), medial midfoot (MM), big toe and first metatarsal head (BT), and lateral toes and metatarsal heads (LT). Repeated measures ANOVA identified differences in pressures, forces, and contact areas across terrains. Post hoc Bonferroni adjustments were used to accept an overall alpha level of 0.05. Results: Peak pressure (PP), maximal mean pressure (MMP) and pressure time integral (PTI) were significantly higher (p < 0.01) when walking barefoot on concrete than on grass or carpet for all foot regions except MM and LM. The percent increase in the three pressure variables ranged from 21% to 43%. Grass and carpet PP, MMP, and PTI were similar for the BT and LT. Wearing shoes significantly increased contact area and decreased all pressure variables on all three terrains. Conclusion: Walking barefoot, especially on concrete was associated with higher plantar pressure variables. Wearing shoes eliminated terrain differences in pressure except under the lesser toes. Persons with insensate feet should avoid walking barefoot on hard surfaces to avoid excessive plantar pressures. Wearing shoes and covering hard floors with nonslip, padded rugs may decrease plantar pressures and the risk of ulceration.