Differences between Systems Using Optical and Capacitive Sensors in Treadmill-Based Spatiotemporal Analysis of Level and Sloping Gait

Abstract

Modern technology has enabled researchers to analyze gait with great accuracy and in various conditions based on the needs of the trainees. The purpose of the study was to investigate the agreement between systems equipped with optical and capacitive sensors in the analysis of treadmill-based level and sloping gait. The spatiotemporal parameters of gait were measured in 30 healthy college-level students during barefoot walking on 0% (level), -10% and -20% (downhill) and +10% and +20% (uphill) slopes at hiking-related speeds using an optoelectric cell system and an instrumented treadmill. Inter-system agreement was assessed using the Intraclass Correlation Coefficients (ICCs) and the 95% limits of agreement. Our findings revealed excellent ICCs for the temporal and between moderate to excellent ICCs for the spatial parameters of gait. Walking downhill and on a 10% slope demonstrated better inter-system agreement compared to walking uphill and on a 20% slope. Inter-system agreement regarding the duration of gait phases was increased by increasing the number of LEDs used by the optoelectric cell system to detect the contact event. The present study suggests that systems equipped with optical and capacitive sensors can be used interchangeably in the treadmill-based spatiotemporal analysis of level and sloping gait.

Keywords: gait analysis; inclined surfaces; inter-system agreement; treadmill walking.

Figure 1

Experimental setup for the measurements of the spatiotemporal parameters of gait using the Optogait’s optoelectric cell system and the Zebris instrumented treadmill.

Figure 2

Schematics representing the steps of the experiment.

Figure 3

Bland and Altman plot depicting the systematic bias relative to the average duration of the gait cycle phases measured with the optoelectric cell system (OCS) using 1, 2, 3, 4, and 5 LEDs and the instrument treadmill (ITR), during walking at an inclination of 0%. The solid and dashed lines correspond to the systematic bias and 95% LoA, respectively, for the 5 LEDs setting.

Figure 4

Bland and Altman plot depicting the systematic bias relative to the average duration of the gait cycle phases measured with the optoelectric cell system (OCS) using 1, 2, 3, 4, and 5 LEDs and the instrument treadmill (ITR), during walking at an inclination of −10%. The solid and dashed lines correspond to the systematic bias and 95% LoA, respectively, for the 5 LEDs setting.

Figure 5

Bland and Altman plot depicting the systematic bias relative to the average duration of the gait cycle phases measured with the optoelectric cell system (OCS) using 1, 2, 3, 4, and 5 LEDs and the instrument treadmill (ITR), during walking at an inclination of −20%. The solid and dashed lines correspond to the systematic bias and 95% LoA, respectively, for the 5 LEDs setting.

Figure 6

Bland and Altman plot depicting the systematic bias relative to the average duration of the gait cycle phases measured with the optoelectric cell system (OCS) using 1, 2, 3, 4, and 5 LEDs and the instrument treadmill (ITR), during walking at an inclination of +10%. The solid and dashed lines correspond to the systematic bias and 95% LoA, respectively, for the 5 LEDs setting.

Figure 7

Bland and Altman plot depicting the systematic bias relative to the average duration of the gait cycle phases measured with the optoelectric cell system (OCS) using 1, 2, 3, 4, and 5 LEDs and the instrument treadmill (ITR), during walking at an inclination of +20%. The solid and dashed lines correspond to the systematic bias and 95% LoA, respectively, for the 5 LEDs setting.