title: Effects of a dynamic chair on pelvic mobility, fatigue, and work efficiency during work performed while sitting: a comparison of dynamic sitting and static sitting.
abstract: [Purpose] Working while sitting for long periods can cause lumbar pain, fatigue, and reduced work efficiency. How a dynamic chair with a seat that moves three-dimensionally affects pelvic mobility before and after work, work efficiency, and post-work fatigue were examined. [Subjects and Methods] Subjects were 17 healthy adults (10 males, 7 females, mean age 21.8 ± 2.7 years). Subjects performed a 30-min Kraepelin test under two conditions: sitting in a standard office chair and sitting in a dynamic sitting balance chair. Root mean square (RMS) values of pelvic movement measured by a triaxial accelerometer during 30 minutes of work, finger-floor distance before and after work, lumbar fatigue, and pelvic movement RMS values during finger-floor distance measurement were used as outcome measures. [Results] Pelvic movement RMS values collected every 5 minutes during 30 minutes of work were significantly higher while sitting in the dynamic balance chair. Changes in pelvic movement RMS values during finger-floor distance measurement after work and amount of work performed during 30 minutes were significantly higher and lumbar fatigue was significantly lower for the dynamic balance chair. [Conclusion] Dynamic sitting maintained or increased pelvic flexibility. The dynamic balance chair may effectively help workers work continuously in seated postures with little fatigue.
authors.affiliation: Department of Rehabilitation, Aichi Koseiren Asuke Hospital, Japan; Department of Occupational Health, Graduate School of Medicine, Gifu University, Japan.
authors.forename: Hironori
authors.initials: H
authors.lastname: Tanoue
authors.affiliation: Nishimikawa Home Nursing Station, Japan.
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Mitsuhashi
authors.affiliation: Department of Occupational Health, Graduate School of Medicine, Gifu University, Japan; Department of Physical Therapy, Nagoya Isen School Corporation Vocational College, Japan.
authors.forename: Shunji
authors.initials: S
authors.lastname: Sako
authors.affiliation: Department of Rehabilitation, Aichi Koseiren Asuke Hospital, Japan.
authors.forename: Ryokichi
authors.initials: R
authors.lastname: Goto
authors.affiliation: Department of Rehabilitation, Aichi Koseiren Asuke Hospital, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Nakai
authors.affiliation: Department of Occupational Health, Graduate School of Medicine, Gifu University, Japan.
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Inaba
keywords: Ergonomics; Pelvis; Sitting