Analysis of sitting forces on stationary chairs for daily activities

Abstract

No literature related to the study of sitting forces on chairs sat on by people who weighed over 136 kg was found. The Business Institutional Furniture Manufactures Association needs force data for development of performance test standards to test chairs for users who weigh up to 181 kg. 20 participants who weighed from 136 to 186 kg completed 6 tasks on an instrumented chair in the sequence of sitting down, remaining seated and rising. Effects of sitting motion, armrest use and seat cushion thickness on vertical sitting forces and centre-of-force were investigated. Results indicated hard sitting down yielded the highest sitting force of 213% in terms of participants’ body weights. Armrest use affected sitting forces of normal sitting down, but not of rising and hard sitting down. Cushion thickness affected sitting forces of normal and hard sitting down and shifting, but not of rising, static seating or stretching backward situations.

Practitioner Summary: Results of the sitting force and centre-of-force data obtained for this research can help furniture manufacturers develop new product performance test standards for creating reliable engineering design and manufacturing quality and durable products to meet a niche market need.

Keywords:

• Sitting force
• body weight
• centre-of-force
• stationary chair

Acknowledgements

Special thanks are due to Leland Manufacturing of Leland, Mississippi, Tupelo Manufacturing Company of Tupelo, Mississippi, and to BIFMA, the Business + Institutional Furniture Manufactures Association, who provided significant funds towards this research. Thanks are also due to John Norton of Herman Miller who provided assistance and equipment to the project. Appreciation is also extended to Dave Panning of BIFMA, and to the roundtable of furniture manufacturing professionals that he gathered to help the project along. This manuscript was approved for publication as Journal Article no FP762 of the Forest and Wildlife Research Centre, Mississippi State University.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by BIFMA International (Business + Institutional Furniture Manufactures Association) [grant number 12040479].