Postural Variability in Sitting: Comparing Comfortable, Habitual, and Correct Strategies Across Chairs

<b>Background/Objectives:</b> Prolonged sitting is linked to musculoskeletal discomfort, yet optimal sitting posture remains poorly defined, and the consistency with which individuals reproduce specific sitting strategies is unclear. This study examined postural variability across three...

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Main Authors: Yi-Lang Chen, Li-Peng Zhang
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/13/7239
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author Yi-Lang Chen
Li-Peng Zhang
author_facet Yi-Lang Chen
Li-Peng Zhang
author_sort Yi-Lang Chen
collection DOAJ
description <b>Background/Objectives:</b> Prolonged sitting is linked to musculoskeletal discomfort, yet optimal sitting posture remains poorly defined, and the consistency with which individuals reproduce specific sitting strategies is unclear. This study examined postural variability across three sitting strategies—comfortable, habitual, and correct—using three common chair types: a stool, computer chair, and ergonomic chair. <b>Methods:</b> Thirty healthy young adults (fifteen men, fifteen women) participated. Global sagittal joint angles—head inclination (HI), trunk angle (TA), and knee angle (KA)—were measured using a motion analysis system across five repetitions per condition. <b>Results:</b> The chair type significantly influenced HI and TA (<i>p</i> < 0.001), with ergonomic chairs encouraging more upright trunk postures. The sitting strategy significantly affected TA and KA (<i>p</i> < 0.01), with comfortable sitting associated with more extended angles. Women exhibited greater TA (114.8° vs. 109.0°, <i>p</i> < 0.001) and lower within-subject variability. Substantial postural variability was observed across all conditions, with mean ranges exceeding minimum detectable change thresholds for HI (10.3°), TA (6.9°), and KA (11.3°). Notably, correct sitting reduced KA variability compared to other strategies (<i>p</i> < 0.01). <b>Conclusions:</b> These findings highlight the individualized and variable nature of sitting posture, even under controlled instructions. The results question the reliability of memory-based seat adjustments and emphasize the need for dynamic, user-centered ergonomic design and personalized clinical guidance to support musculoskeletal health.
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spelling doaj-art-1b100e4808c840cb9afe2cb252946b602025-08-20T02:35:47ZengMDPI AGApplied Sciences2076-34172025-06-011513723910.3390/app15137239Postural Variability in Sitting: Comparing Comfortable, Habitual, and Correct Strategies Across ChairsYi-Lang Chen0Li-Peng Zhang1Department of Industrial Engineering and Management, Ming Chi University of Technology, New Taipei 243303, TaiwanDepartment of Industrial Engineering and Management, Ming Chi University of Technology, New Taipei 243303, Taiwan<b>Background/Objectives:</b> Prolonged sitting is linked to musculoskeletal discomfort, yet optimal sitting posture remains poorly defined, and the consistency with which individuals reproduce specific sitting strategies is unclear. This study examined postural variability across three sitting strategies—comfortable, habitual, and correct—using three common chair types: a stool, computer chair, and ergonomic chair. <b>Methods:</b> Thirty healthy young adults (fifteen men, fifteen women) participated. Global sagittal joint angles—head inclination (HI), trunk angle (TA), and knee angle (KA)—were measured using a motion analysis system across five repetitions per condition. <b>Results:</b> The chair type significantly influenced HI and TA (<i>p</i> < 0.001), with ergonomic chairs encouraging more upright trunk postures. The sitting strategy significantly affected TA and KA (<i>p</i> < 0.01), with comfortable sitting associated with more extended angles. Women exhibited greater TA (114.8° vs. 109.0°, <i>p</i> < 0.001) and lower within-subject variability. Substantial postural variability was observed across all conditions, with mean ranges exceeding minimum detectable change thresholds for HI (10.3°), TA (6.9°), and KA (11.3°). Notably, correct sitting reduced KA variability compared to other strategies (<i>p</i> < 0.01). <b>Conclusions:</b> These findings highlight the individualized and variable nature of sitting posture, even under controlled instructions. The results question the reliability of memory-based seat adjustments and emphasize the need for dynamic, user-centered ergonomic design and personalized clinical guidance to support musculoskeletal health.https://www.mdpi.com/2076-3417/15/13/7239sitting posturechair typesitting strategypostural variabilityergonomic designjoint angle
spellingShingle Yi-Lang Chen
Li-Peng Zhang
Postural Variability in Sitting: Comparing Comfortable, Habitual, and Correct Strategies Across Chairs
Applied Sciences
sitting posture
chair type
sitting strategy
postural variability
ergonomic design
joint angle
title Postural Variability in Sitting: Comparing Comfortable, Habitual, and Correct Strategies Across Chairs
title_full Postural Variability in Sitting: Comparing Comfortable, Habitual, and Correct Strategies Across Chairs
title_fullStr Postural Variability in Sitting: Comparing Comfortable, Habitual, and Correct Strategies Across Chairs
title_full_unstemmed Postural Variability in Sitting: Comparing Comfortable, Habitual, and Correct Strategies Across Chairs
title_short Postural Variability in Sitting: Comparing Comfortable, Habitual, and Correct Strategies Across Chairs
title_sort postural variability in sitting comparing comfortable habitual and correct strategies across chairs
topic sitting posture
chair type
sitting strategy
postural variability
ergonomic design
joint angle
url https://www.mdpi.com/2076-3417/15/13/7239
work_keys_str_mv AT yilangchen posturalvariabilityinsittingcomparingcomfortablehabitualandcorrectstrategiesacrosschairs
AT lipengzhang posturalvariabilityinsittingcomparingcomfortablehabitualandcorrectstrategiesacrosschairs