Author(s): SANCHEZ-ALVARADO, A., JOOST, T., WILLE, M., HENNING, O., RAJA, A., ENGEL, T., Institution: UNIVERSITY OF HAMBURG, Country: GERMANY, Abstract-ID: 793

INTRODUCTION:
Analysing walking and running gait is pivotal for clinical diagnosis and athletic performance assessments. Motion capture (MOCAP) systems are recognized as the gold standard for gait analysis; however, their complexity, cost, and setup time limit their widespread use. The Optogait (OP) system, known for its portability, ease of setup, and user-friendly interface, has emerged as a popular alternative [1, 2]. However, its validity and reliability remain under scrutiny. Therefore, this study aimed to assess the validity and reliability of selected gait parameters during walking and running derived from the OP system in comparison to a reference MOCAP system.
METHODS:
Twenty-four asymptomatic participants were recruited from Potsdam and its surroundings. Participants underwent two walking (4.75 km/h) and two running (9.00 km/h) trials on a treadmill, during two consecutive measurements (M1 and M2) in a single day, for a test-retest setup, with a 5-minute break in between. Both on M1 and M2 the trial started with walking and was followed by running. Data were simultaneously captured using a 13-camera MOCAP system (500 Hz) and the OP system (1000 Hz). After an initial familiarization, recordings were analysed for specific intervals (0-15 seconds and 90-105 seconds), during both measurements. The outcome variables for walking were: cycle, stance, swing, step times (seconds); step, stride lengths (meters); and for running: stance, swing times (seconds); step, stride lengths (meters). Bland-Altman with limits of agreements, intra-class correlation coefficients (ICC), paired t-tests, and test-retest variability percentages were estimated to compute the Optogait’s validity at M1 and M2 and its reliability (M2-M1).
RESULTS:
Data from 17 out of 24 participants were suitable for analysis (28.0±5.4 years old, 173.2±10.0 cm height, 69.9±9.0 kg weight, 6 females/11 males). In walking, the OP demonstrated moderate to excellent reliability and validity for most variables except for stance time (M2: ICC [95% CI]: 0.257 [-0.780-0.716], p=.261, M2-M1: 0.138 [-1.341-0.686], p=.384 during the first 15 seconds; and M2-M1: 0.457 [-0.430-0.800], p=.111 during the second 15-seconds period). Also, the OP mean values deviated slightly from the MOCAP values (-2% to +5%). In contrast, running trials exhibited weak or poor agreement between OP and MOCAP across all variables. Moreover, the OP mean values deviated from the MOCAP values (-33% to -76% for temporal parameters and -3 to +5% for spatial parameters).
CONCLUSION:
The Optogait system proved a valid and reliable tool for analysing walking gait, offering a feasible alternative to MOCAP technology. Nevertheless, its application in running gait analysis did not meet the criteria for reliability or validity, indicating a need for further refinement of the system for comprehensive gait analysis across different modalities.
REFERENCES
[1] Lee M et al. Med. Sci. Mon. 20, 2014.
[2] Healy A et al. J. Biom. Eng. 141, 2019.