Ergonomic Redesign of Primary School Desk-Chairs in Panama: A Posture Health Approach Using the Theory of Constraints

Abstract

This study examines the relationship between school furniture design and long-term student postural health by evaluating the feasibility of redesigning the Panamanian primary school desk-chair to accommodate morphological and anthropometric variation among students in grades one through six. The proposed redesign aligns with the methodological requirements of constructivist learning, emphasizing the need for a physical environment that supports active, flexible pedagogical approaches. An exploratory and descriptive research design was implemented in three General Basic Education Schools (GBES) in Panama. Schools were selected using a convenience sampling method, and approximately 10% of enrolled students (n = 198/1,970) were randomly sampled across grades one to six. Data collection methods included structured interviews with experts in medicine, ergonomics, architecture, education, and engineering, as well as student and classroom observations, questionnaires, and document review. The methodological core of the study is the Theory of Constraints (TOC) Thinking Process, specifically the Process of Ongoing Improvement (POOGI). A Current Reality Tree (CRT) was constructed to identify Undesirable Effects (UDEs) across seven functional areas (posture and health, ergonomics and comfort, anthropometrics, procurement, flexibility, materials, and maintenance costs), and to define the core conflict driving poor furniture design. From this analysis, design criteria and specifications were derived for a new ergonomic desk-chair model. The proposed design introduces height-adjustable, foldable armrests; adjustable seat depth and backrest height; an anatomically contoured seat with a waterfall edge; and a backrest aligned with a 37° thoracic kyphosis angle, all made from more sustainable materials (polyurethane, polypropylene, and cast iron). These features are intended to reduce soft-tissue and intervertebral disc pressure, improve blood circulation, and accommodate anthropometric variation while supporting constructivist classroom practices. In conclusion, the TOC Thinking Process was effective in evaluating what to change, what to change to, and how to implement change in the context of school furniture. The resulting conceptual redesign provides a comprehensive approach to posture health and offers a replicable methodological framework for educational systems aiming to align school furniture with current ergonomic and pedagogical standards. Future research should focus on prototyping and empirically testing the redesigned desk-chair in actual classroom settings.