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Selection of a single design to delight customers may not be always possible due to the anthropometric differences in humans, wherein a hybrid design can benefit. Using adjustability, we demonstrate our approach for developing a novel forklift backrest to accommodate drivers with a wide range of body sizes. Field and laboratory evaluations were conducted to assess and improve the design. Our results indicated that the new design could provide improved comfort for longer durations. This study reveals the possibilities for human factors professionals to consider adjustability in vehicle operator compartment interiors, especially backrests and seating, of similar industrial vehicles.

This study assessed the effectiveness of an adjustable backrest towards facilitating comfort to a range of users' body sizes. Twelve participants were recruited in a comparative study to detect the effect of body size (5, 5-95, 95 percentile), sex, backrest type (adjustable, original), and leaning duration on comfort and stability. Body movements related to the perceived discomfort were used to quantify the convenience of individuals while leaning on the backrest. Results showed a decrease in the centre of pressure deviation by 12% for the adjustable backrest, compared to a 47% increase for the original design. Moreover, upper-body movement reduction (~20%, p-value = 0.04) denoted that adjustable backrest was more effective over longer durations. The identified improvement regions on the new backrest included backrest curvature, hook feature, and symmetric material placement. This article presents a comprehensive method for evaluating backrests, which could also be implemented for assessing similar seating products with adjustability features.

Nursing is among the most physically challenging occupations and involves intensive lifting activities often including twisting of torso while performing tasks such as patient handling. Frequent and repetitive twisting of the body is known to induce large demands on the musculature, which may lead to MSD with direct and indirect costs to the hospital governance. One solution proposed through this article includes an exoskeleton specifically designed to assist in twisting movements of the trunk. This involves a double-actuator fully passive system that assists in rotation of the torso with the help of mechanical springs and cable modules. Our study provides a conceptual design of the mechanism, and a preliminary analysis using the concepts of kinematics, dynamics, usability, wearability, and freedom of movement. Results show that the mechanism could offer freedom of rotation for the wearer’s torso up to 52, 25 and 22 degrees (with stationary hip joint) along the transverse, sagittal and coronal planes, respectively. Moreover, similar force generation (up to 80N) was obtained in both actuators for same rotation on transverse plane in both directions for a combination of spring stiffness (0.5 – 1 N/mm) and damping (0.1 - 0.5 N-sec/mm) parameters. Our proposed design could also be integrated to the current exoskeletons in the form of a module and could be beneficial in more general work settings.

A new forklift backrest has been developed by incorporating adjustability concepts into the design to facilitate comfort to a wide range of users. We have conducted a comparative study between the new and original backrests to assess the effectiveness of design features. Using the phenomenon of restlessness, discomfort of the user was associated with the amount of body movement, where we have used a motion- capture system and a force platform to quantify the individuals’ movement for a wide range of body sizes. Meanwhile, subjective comfort and design feedback were collected using a questionnaire. Our results showed a reduction in the mean torso movement and the maximum center of pressure change of location by 300 and 6 mm, respectively, for the new design. Taking advantage of adjustability feature, the new backrest design exhibited enhanced comfort for longer durations and reduced magnitude of discomfort for a wide range of participants’ body sizes.

Introduction:Hindrance in normal movement is common among stroke survivors (SS), leading to a larger prevalence of falling and serious injuries. Current methods for analyzing the movement restrictions (camera-based motion capture) are limited to laboratory/clinical environments. Meanwhile, the presence of Inertial Measurement Unit (IMU) sensors in our everyday lives (e.g., in smartphones) is ever increasing due to their portability, affordability, and accessibility. The purpose of this study was to determine whether a single IMU sensor can differentiate movements between SS and healthy control (HC).Methods:Turning (360°) was selected as the activity since it is a common and complex motion. Data was collected from 12 participants (6 SS, 6 HC) using an IMU sensor (Xsens®) placed on unaffected leg (shank) and was analyzed using a 3-step process: filtration (5 Hz cutoff frequency), segmentation (cycles – consecutive foot placement), and feature extraction. Analyzed features included duration of task (sec), number of cycles, mean angular velocity (deg/sec) of shank per cycle, ratio of stance-time to the duration of task (%), and range of flexion angle (deg) for shank.Results:Obtained values were larger in SS for number of cycles (SS: 5.8, HC: 3.2, p-value<0.01) and duration of task (7.8, 3.4, <0.01). Meanwhile, HC showed higher velocity of shank (unaffected) flexion (1.2, 1.7, <0.01) and the ratio of stance-time to the duration of task (57.7, 32.3, <0.01).Conclusion:A single IMU sensor successfully detected kinematic disparities between two groups. Meanwhile, further work is required to examine the robustness and detection improvements upon using other sensor locations. The use of a single IMU sensor, also present in most smartphones/smartwatches, could enable this accessible technology to be used as a remote assessment/monitoring tool, extending the reach of diagnostic tools and rehabilitation programs.