The influence of walking speed on plantar pressure measurements using the two-step gait initiation protocol

Abstract

Background: Plantar pressure measurement is being increasingly used in both research and clinical practice to measure the effects of various footwear and physical therapy interventions. However, the influence of walking speed on plantar pressure parameters has not been evaluated in detail, and may have an effect on study design and interpretation of results. Objective: To determine the effect of changes in walking speed on plantar pressure measurements obtained using the two-step gait initiation protocol. Methods: Plantar pressure parameters were measured with the EMED-SF system using the two-step gait initiation protocol in 20 healthy participants (10 males, 10 females) aged 20–37 (mean 27.5, S.D. 5.2 years) when walking at self-selected slow, normal and fast speeds. Results: With increased walking speeds, contact time increased at all regions under the foot. When expressed as a percentage of stance phase, contact time at the forefoot was not affected by walking speed; however, a smaller proportion of stance phase was spent loading the medial and lateral heel and lateral midfoot regions. Maximum force and peak pressure consistently increased at all regions at faster walking speeds, with the exception of the lateral midfoot, first MPJ and third–fifth MPJ regions. Force–time and pressure–time integrals were reduced at faster walking speeds, with the exception of loading under the toes, which remained relatively constant. Conclusions: Variations in walking speed from slow to fast significantly influence the timing and magnitude of plantar pressure values using the two-step gait initiation protocol. However, no significant differences are evident between self-selected slow and normal speeds for maximum force and peak pressure values. These findings suggest that when assessing the effects of various interventions on plantar pressure patterns, correcting for small changes in walking speed at slower speeds may not be critical for maximum force and peak pressure measurements, but is necessary for appropriate interpretation of force–time and pressure–time integrals at most regions of the plantar foot.