Upper Extremity Muscular Strength in Push–Pull Tasks: Model Approach Towards Task Design

BACKGROUND: Pushing and pulling in workplaces are common actions. Repetitive forceful exertions in long-duration works lead to increased risk of musculoskeletal disorders and injuries. AIM: To investigate the upper extremity strength in generic push–pull modes while using hand tools and forecasting the limits of the workers while frequent or continuous operation. SETTINGS AND DESIGN: The study was conducted among men workers in Ahmedabad city, India, and the design was cross-sectional study. MATERIALS AND METHODS: In all, 100 men were recruited (Group 1: 18–39 years and Group 2: 40–60 years). Upper extremity muscular strength (isometric mode) testing of the preferred hand during push–pull type of manual hand-tool operations was carried out for 60 s. Forecasting of strength to generate predictions for future events (120 s) based on known past events (measured 60 s) was carried out using Holt–Winters time-series model. STATISTICAL ANALYSIS: Descriptive statistics was used for analysis. For prediction model evaluation, WEKA 3.8.2 was used. RESULTS: Anthropometric parameters of both groups were similar, having no effect on generated strength. Largely, pull strength was recorded to be higher than push strength, wherein Group 2 men generated slightly higher strength. Seated strength was also higher than standing exertion. Forecasting reveals steady strength values for Group 1 men, whereas steep decline among Group 2 men with increasing duration of trial. CONCLUSION: The strength data generated would aid in work schedule design. Strength forecasting model would assist in developing engineering guidelines in the design of tools at workplace.