Development of Washable Silver Printed Textile Electrodes for Long-Term ECG Monitoring

Long-term electrocardiography (ECG) monitoring is very essential for the early detection and treatment of cardiovascular disorders. However, commercially used silver/silver chloride (Ag/AgCl) electrodes have drawbacks, and these become more obvious during long-term signal monitoring, making them inconvenient for this use. In this study, we developed silver printed textile electrodes from knitted cotton and polyester fabric for ECG monitoring. The surface resistance of printed electrodes was 1.64 Ω/sq for cotton and 1.78 Ω/sq for polyester electrodes. The ECG detection performance of the electrodes was studied by placing three electrodes around the wrist where the electrodes were embedded on an elastic strap with Velcro. The ECG signals collected using textile electrodes had a comparable waveform to those acquired using standard Ag/AgCl electrodes with a signal to noise ratio (SNR) of 33.10, 30.17, and 33.52 dB for signals collected from cotton, polyester, and Ag/AgCl electrodes, respectively. The signal quality increased as the tightness of the elastic strap increased. Signals acquired at 15 mmHg pressure level with the textile electrodes provided a similar quality to those acquired using standard electrodes. Interestingly, the textile electrodes gave acceptable signal quality even after ten washing cycles.

Spatial-temporal and kinematic characteristics of gait carrying loaded backpack with elastic straps

Objective: Applying 3D Motion Capture technology to analyze the kinematic and spatial temporal characteristics of gait when carrying loaded backpacks with elastic straps, the study investigates the effect of backpacks with elastic-strap on fatigue during walking. Methods: Ten healthy male undergraduates did not do strenuous or fatigue exercise two days before the trials and served as subjects (aged 19 ? 1.8 years). All subjects provided a written and oral explanation of the trial procedures. In two trials departed by two days apart, the subjects randomly carried one of the two kinds of backpacks ( with non-elastic straps or with elastic straps backpacks loaded the same weight books (about 10% of their bodyweight). After pasted with markers as the guide of the Vicon 3D motion capture system, the subjects walked on the treadmill at 4.5 km/h for 20 min in each trial. Before and after each walking trial, the gait parameters of the subjects were measured by a 6 meters-long plantar pressure test plate(Zebras FDM System). Results: The change of the COP and the change of the gait parameters in the subjects with elastic straps backpacks after 20 min walking were relatively less than those with no elastic-strap backpacks, showing better stability and delaying fatigue. From this statement, it can be reasoned that being able to reduce the effect of the load on the person by returning the gait pattern closer to an unloaded walking pattern may reduce problems associated with loaded carriage. The elastic straps decreased the elevation of the mean vertical position of the backpack and create a gap between the shoulders and the shoulder pads. Conclusion: The decompression backpack with elastic straps shows the effect of protecting the user?s spine and in delaying the cervical back muscle fatigue, during walking at appropriate pace maybe reduce the risk of musculoskeletal injuries and muscle fatigue associated with carrying heavy backpack loads while reducing the metabolic cost of loaded walking.