The validity of FreeMed(R) Baropodometric Platform for measuring spatiotemporal parameters and walking speed: comparison to an inertial measurement unit system

Purpose: The analysis of spatiotemporal parameters of gait are often used to identify walking impairments and provide a tailored therapy program for patients. Despite main researches in this field were led with an inertial measurement unit (IMU) sensors, in clinical practice, the use of the baropodometric platforms is frequently used. To best of our knowledge, the FreeMed® Baropodometric Platform, normally used to postural analysis assessment, has not been yet validated for measuring spatiotemporal parameters and walking speed. The aim of this study was, therefore, to assess the validity of a baropodometric platform compared to a previously validated IMU-system (Gait-up)1 in healthy adults. Methods: Participants between 18 and 30 years old, without any walking impairments were recruited through web announcement at University of Pavia. Each subject performed 2 trials: walking at self-selected normal and slow speeds. Trials were performed wearing Physilog 5 (Gait-up, Lausanne, Suisse) and walking barefoot on the FreeMed® Platform (Sensor Medica, Roma, Italy) in a 15-m walkway. Subjects followed these instructions: ‘‘Walk towards the end of the 15-m walkway at a pace that is comfortable (normal) / slow for you’’. Spatiotemporal parameters [cadence (steps/min), stride length (m), gait cycle time (gct; s), right and left stance (ms) and swing (ms)] and walking speed were recorded. Data were analyzed considering only intermediate 5 m of the walkway to avoid acceleration and deceleration during the trials. Pearson’s correlation and the Bland-Altmann plot were used to determine the level of agreement between the measurements. All analysis was performed using Jamovi software (Version 0.9). Results: Forty healthy adults (24.63.8 yrs; slow speed 0.60.1; self-selected speed 1.10.1 meanSD) performed all walk trials. We found that walking speed, cadence, stride length and step time variables (gct, right and left stance) show a high level of agreement for both trials (Pearson’s correlation ranges from 0.68 to 0.95). We reported a moderate level of the agreement only in swing values for self-selected speed (r=0.43) and slow speed (r=0.47). Conclusion: Results of this validity study confirm that the FreeMed® Platform is a valid tool to asses gait parameters at different walking speeds. The output of the Platform is positively correlated with the output provided by the IMU. Most measures resulted in comparable and slow speed validity could confirm the feasibility to use the platform to study gait patterns in pathological condition.