Grado Department of Industrial and Systems Engineering

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Browsing Grado Department of Industrial and Systems Engineering by Subject "1106 Human Movement and Sports Sciences"

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    Effects of using a whole-body powered exoskeleton during simulated occupational load-handling tasks: A pilot study
    Park, Hanjun; Kim, Sunwook; Nussbaum, Maury A.; Srinivasan, Divya (Elsevier, 2022-01-01)
    Whole-body powered exoskeletons (WB-PEXOs) can be effective in reducing the physical demands of heavy occupational work, yet almost no empirical evidence exists on the effects of WB-PEXO use. This study assessed the effects of WB-PEXO use on back and leg muscle activities during lab-based simulations of load handling tasks. Six participants (4M, 2F) completed two such tasks (load carriage and stationary load transfer), both with and without a WB-PEXO, and with a range of load masses in each task. WB-PEXO use reduced median levels of muscle activity in the back (∼42–53% in thoracic and ∼24–43% in lumbar regions) and legs (∼41–63% in knee flexors and extensors), and mainly when handling loads beyond low-moderate levels (10–15 kg). Overall, using the WB-PEXO also reduced inter-individual variance (smaller SD) in muscle activities. Future work should examine diverse users, focus on finding effective matches between WB-PEXO use and specific tasks, and identify applications in varied work environments.
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    An exploratory study comparing three work/rest schedules during simulated repetitive precision work
    Tsao, Liuxing; Kim, Sunwook; Ma, Liang; Nussbaum, Maury A. (Taylor & Francis, 2021-08-03)
    The pattern of work and rest can influence both physical fatigue and task performance in manual operations. However, there is relatively limited evidence regarding the influences of specific work/rest schedules in tasks requiring high repetitiveness and precision demands, along with relatively low exertion levels. Eighteen participants completed an exploratory study that simulated such tasks, to compare the effects of three distinct work/rest schedules (i.e. short frequent [short] and long infrequent breaks [long], and a self-selected schedule) on muscle fatigue, task performance (in terms of accuracy and speed), and preference. Schedules with long or self-selected breaks generally induced less muscle fatigue, compared with the short break condition. Participants preferred the self-selected condition the most and the long-break condition the least. The different schedules tested did not influence task performance. A self-selected schedule may be beneficial for repetitive precision task, to achieve a balance across muscle fatigue, task performance, and individual preference. Practitioner summary: Influences of three work/rest schedules (i.e. short and long breaks, and a self-selected schedule) on fatigue, performance, and preference were explored during repetitive precision tasks. Schedules with long or self-selected breaks induced less muscle fatigue and none of the three schedules influenced performance. A self-selected schedule was the most preferred.