Objective: To examine the characteristics of the plantar pressure distribution patterns during mid-stance phase of the gait cycle in subjects with chronic non-specific low back pain and asymptomatic subjects.
Material and method: Twenty-three males and 17 females with chronic non-specific low back pain and age- and gender-matched asymptomatic subjects walked barefoot along a gait mat at comfortable speedfor three trials. The left and right plantar pressure distributions were recorded during mid-stance phase and divided into 12 areas. Descriptive statistics including mean and standard deviation of demographic data and plantar pressure were calculated, and plantar pressure distribution patterns were described.
Results: Mean and standard deviation of numeric pain rating scale of chronic non-specific low back pain group were 4.04±1.58. The average mean peak pressure of both chronic non-specific low back pain and asymptomatic subjects located at the fifth area (lateral aspect offorefoot) in both feet. However the modes of the peak pressure of subjects with chronic non-specific low back pain were in the different areas in the left and right feet. The distribution patterns of the average mean peak pressure were not the same in chronic non-specific low back pain and asymptomatic subjects. This altered foot contact in the subjects with chronic non-specific low back pain may be used to avoid pain or to compensate for limited mobility of the lower limbs at pre-swing phase.
Conclusion: At mid-stance phase of walking, the pressures on the plantar surface were unequally distributed in subjects with chronic non-specific low back pain.