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Subway train operation is a complex, sociotechnical system that involves a variety of cognitively demanding tasks. The train operators are responsible for continuously monitoring the surrounding environment, maintaining awareness, processing information, and making decisions under risk. The resulting mental strain on operators can negatively affect their performance and the interaction of the human-machine system. The objective of this study was to evaluate if physiological, subjective, and performance measures could identify the level of mental workloads arising from routine and nonroutine operations in the subway system. A total of 11 subway train operators underwent different driving scenarios in a high-fidelity simulator. The simulated tasks were divided into two categories: routine operations (preparing to drive and driving between stations without interruptions or emergencies) and nonroutine operation (responding to a tunnel fire, dealing with a high density of passengers, encountering a passenger/technician on the track, and responding to train failure). The mental workload was monitored and evaluated in these tasks using an electrocardiogram, subjective self-rating scales, and driving performance. Both heart rate variability and performance measures (including reaction time and error rate) detected mental workload variations in the different operations. On the other hand, the subjective ratings (including NASA-TLX) assessed the overall mental workload associated with a task, without explaining the mental demand variations within the task over time. Subway train drivers experienced different levels of mental workload during routine and nonroutine driving conditions.

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Although track and field spike shoes are crafted for runners, these shoes are not designed for regular walking. With such shoes, runners may eventually encounter serious chronic injuries such as plantar fasciitis, shin splints, achilles tendinitis, chondromalacia, and iliotibial band syndrome. To address this problem, a modified spike shoe was tested and compared to a regular spike shoe. The modification consists of adding a removable heel to the shoe sole in order to reduce the flexion of the foot and properly level the foot for walking. Nine healthy participants performed walking drills at 2 and 3 mph, using the original and the modified shoes. Electromyography (EMG) measurements were used to evaluate muscle activities. Participants also rated their discomfort on a 0-10 scale. Results show that the use of modified shoes resulted in a reduction of 22% and 24.25% EMG activity for the tibialis and gastrocnemius muscles, respectively. Comfort ratings increased by an average of 2.7, 2.6, 3.9, and 4.2 points at the knees, calves, ankles, and feet, respectively.

No abstract