Reliability and validity of an on-site posture analysis system.
Forrester C; Stinson R; Li Y; Lemasters G; Bhattacharya A
American Industrial Hygiene Conference and Exposition, May 19-23, 1997, Dallas, Texas. Fairfax, VA: American Industrial Hygiene Association, 1997 May; :71-72
Poor working posture and other known risk factors such as vibration, repetition, and force have been identified as major risk factors for work-related musculoskeletal disorders (WMDs) in carpenters. Simple but reliable and valid posture analysis systems (PASs) are needed to identify problem areas which then may be reduced or corrected. The ability of a PAS to adapt to the numerous risk factors at a construction site is needed. In general, a PAS must be easy to learn and assess posture accurately with minor intrusiveness. The purpose of this study was to evaluate a PAS that can be used with minimal training while maintaining high reliability and validity in identifying carpenters' gross body work postures. The study design consisted of two systems: an on-site observer posture analysis system (OPAS) and a videotape posture analysis system (VPAS). Both measured the same tasks, differing only in mode of observation. The seven tasks evaluated with both systems included floor to waist, waist to shoulder, and shoulder to overhead lift/lower tasks; and floor, waist, overhead, and carry tasks. 1464 OPAS tasks were compared to the exact same VPAS tasks (N=1464) collected from first-year union carpenter apprentices (n=37) observed and videotaped during school shop time. Validity of the OPAS was evaluated by comparing data collected by a trained observer to that of an expert reviewer. Overall agreement was excellent (80%). Intermethod reliability was evaluated by percent agreement between data collected via OPAS to that of the VPAS. Overall agreement also was exceptional (90%). Highest agreement was observed for waist to shoulder lift/lower and carrying tasks, while lowest agreement was found in the shoulder to overhead lift/lower. These results suggest that the OPAS can be used in identifying carpenters gross body work postures while maintaining reliability and validity.
Posture; Risk-factors; Vibration; Repetitive-work; Force; Musculoskeletal-system; Musculoskeletal-system-disorders; Construction-workers; Training; Statistical-analysis
American Industrial Hygiene Conference and Exposition, May 19-23, 1997, Dallas, Texas