Effect Of Walking Speed On The Magnitude And Distribution Of Plantar Ground Reaction Forces

Abstract

Vertical ground reaction forces (vGRF) while walking are typically measured on a force plate and in a laboratory setting. However, wearable technology allows for the assessment of the distribution and magnitude of vGRF in real-world conditions. Previous research has shown that in-shoe wearable vGRF sensors are valid instruments, however, single sensor pressure based-insoles have been the primary focus. Unlike the single-sensor insoles, the newer three-sensor insoles can be used to quantify vGRF for specific compartments or locations of the foot during walking. PURPOSE: To examine the effect of walking speeds on the magnitude and distribution of vGRF using the three-sensor in-shoe wearable sensors. METHODS: Twenty healthy college-aged participants (mean age = 21.65 years ±3.20 years) wore the same brand and style of running shoe with the appropriate size pressure-based insole inside each shoe. The three-sensor device connected with the corresponding app via Bluetooth prior to calibrating the sensor for each participant. Next, each participant completed a walking trial on a treadmill with one-minute intervals at increasing speeds of 1.0 mph, 2.0 mph, and 3.0 mph. Peak and average vGRF of the lateral, medial, and heel subareas in addition to total vGRF were collected in the last 30 seconds of each walking condition. A repeated measure analysis of variance (ANOVA) or Friedman’s ANOVA were performed to determine differences in total average vGRF across the three speeds. To further investigate significant differences between magnitude and distribution of vGRF, paired sample t-tests or Wilcoxon tests with dependent measures for lateral, medial, and heel subareas were performed (p < 0.05). RESULTS: Greater vGRF were observed for lateral medial, and heel subareas (p < 0.001) as walking speed increased. The peak and average values revealed the heel subarea had consistently higher vGRF than either the lateral or medial subareas (p < 0.05). CONCLUSIONS: Higher heel subarea vGRF indicates a more distributed center of pressure anterior to the calcaneus while walking at submaximal speeds. Furthermore, the three-sensor insole allows for location specific collection of vGRF, which can provide further insight into the role of plantar anatomy, and suggests possibilities for improved gait compared to a single-sensor device.