Related Experiment Video
Updated: Jun 5, 2026
Home-Based Monitor for Gait and Activity Analysis
Published on: August 8, 2019
Wearable Sensor-Derived Gait Parameters Across Self-Reported Physical Activity Levels in Individuals With Knee
Charles Amoatey Odonkor1, Siri Bohacek2, Salman Hirani2
1Division of Physiatry, Department of Orthopedics and Rehabilitation, Yale University, 47 College Street, New Haven, CT, 06520, United States, 1 203-737-5484, 1 203-785-7132.
Background:
Wearable inertial measurement units (IMUs) offer scalable, objective gait assessment, but detailed stride-level validation against motion capture and their ability to reflect physical activity (PA)-related gait differences in knee osteoarthritis (KOA) remain incompletely characterized.
Objective:
This study aimed to evaluate the technical validity of foot-mounted IMU-derived gait parameters compared with optical motion capture in individuals with KOA and healthy controls. As a secondary exploratory aim, we assessed whether IMU-derived gait parameters differed across self-reported PA levels.
Methods:
In this pilot cross-sectional validation study, 20 participants (KOA: n=10, 50%; healthy controls: n=10, 50%) completed 3 standardized walking conditions (self-paced, fast-paced, and endurance-equivalent). IMU-derived gait parameters were compared with motion capture at the stride level (≥5000 strides) using Pearson correlation, intraclass correlation coefficients (ICCs), mean absolute error, root mean square error, and Bland-Altman analysis. Participants completed the Stanford Brief Activity Survey to categorize PA level. Secondary analyses emphasized effect sizes and 95% CIs given the pilot design. Feasibility was assessed by protocol completion, data completeness, and tolerability.
Results:
IMU-derived gait speed demonstrated strong agreement with motion capture (r=0.99; ICC=0.98, 95% CI 0.95-0.99; mean absolute error=0.07 m/s; bias=0.01 m/s; 95% limits of agreement -0.14 to 0.16 m/s). Stride length and cadence showed similarly high agreement (ICC range 0.96-0.97). All participants completed the protocol with minimal adverse events. Exploratory analyses suggested that participants reporting higher PA demonstrated directionally faster gait speed and longer stride length, with small-to-moderate effect sizes, whereas inactive participants exhibited higher stance-related rhythm parameters.
Conclusions:
Foot-mounted IMUs demonstrated strong stride-level agreement with motion capture across walking conditions, supporting technical validity in both KOA and healthy populations. Exploratory findings suggest that wearable-derived gait parameters may reflect activity-related differences; however, larger longitudinal studies are required to confirm these preliminary signals.
