Designing and usability testing of a new prototype active footrest for knee extension exercise among office workers.

Objectives. The active factor along with light exercise can reduce static muscle work and increase muscle flexibility and endurance. Accordingly, this study aimed to design and prototype a new active footrest, implemented in conventional sitting workstations, and to test its usability among office workers. Methods. The steps taken to design and prototype the active footrest were: selection of an exercise appropriate for goals of ergonomic interventions; idea development; selection of the best conceptual design; design with SOLIDWORKS version 2016; and fabrication of a prototype. Afterward, usability of the active footrest prototype was assessed among 20 office workers (10 females) using field data by the system usability scale. Results. Upon completion of the design steps, the active footrest prototype was prototyped by taking into account design criteria (e.g., functionality, inclusive design, easy application and reduction of additional body movement), anthropometric data and mechanical properties. The participants rated the usability of the active workstation as 89 ± 8.21 (out of 100), indicating good usability results. Conclusion. In this study, an active footrest was designed and prototyped to perform knee extension exercise with the capability of being implemented in conventional sitting workstations.

The Relationship of Grip and Pinch Strength to Musculoskeletal Disorders in Female Carpet Weavers in Southeastern Iran, 2019.

BACKGROUND: The repetitive and prolonged exertion of grip and pinch strength are current among carpet weaver tasks. The three objectives of this study were (1) to investigate the relationship between symptoms of musculoskeletal disorders and grip and pinch strength of carpet weavers in carpet weaving workshops in Kerman province, (2) to compare the grip and pinch strength of carpet weavers with normal values, and (3) to identify the relationship between hand postures of carpet weavers during work and force exertion. METHODS: In this cross-sectional study, grip strength and key, tip and palmar pinch strengths of 101 female carpet weavers aged 20 to 71 years were measured in Kerman province, in 2018. Nordic Musculoskeletal Questionnaire (Extended version) was also used to evaluate musculoskeletal disorders. RESULTS: Bivariate and multivariate linear regression analyses showed that participants who suffered from musculoskeletal disorders had lower grip and pinch strength than others and this decrease was statistically significant in upper back, wrists/hands, and knees. Moreover, there was a significant difference between grip and three types of pinch strength of carpet weavers and normal values. Furthermore, for both hands, the grip strength in the position recommended by American Society of Hand Therapists was significantly greater than that in the normal position carpet weavers usually adopt. CONCLUSION: Based on the results, the high prevalence of musculoskeletal disorders has led to a significant decrease in the grip and pinch strength of carpet weavers. Therefore, it is necessary to undertake ergonomic interventions in designing the carpet weaving workstation.

Musculoskeletal risk assessment in small furniture manufacturing workshops.

In Iran, furniture is mainly manufactured in small workshops, where most activities are performed manually. This study was conducted among workers of furniture workshops to determine prevalence of musculoskeletal symptoms and to assess ergonomic working conditions to identify major risk factors associated with musculoskeletal symptoms. In this study, 410 randomly selected furniture workers participated. The Nordic questionnaire and an ergonomics checklist consisting of 6 sections were used as data collection tools. An index was calculated for each section of the checklist. Action categories indicating the priority of corrective measures were also defined. The highest prevalence of symptoms was reported in the knees (39%), lower back (35.6%) and wrists/hands (29.5%). It was found that manual material handling, poor workstation design and awkward working postures were associated with the reported symptoms in these regions (OR 1.77-4.52). Poor general working conditions and work organization showed association as well. Any interventional measures should focus on these areas.