Simplified appraisal method for fatigue on sitting for extended periods by using finger plethysmogram

E. Fujita, Y. Ogura, N. Ochiai, T. Kamei*, K. Murata, Y. Ueno, Shigehiko Kaneko

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


For the purpose of quantifying and indicating the degree of fatigue as a result of sitting in an automobile seat for long periods of time, a method was developed by using a baseline oscillation and the amplitude of a finger plethysmogram. Between a finger plethysmogram and the degree of fatigue, there is about one hundred times difference in a fluctuation cycle. So, an idea was proposed to convert a finger plethysmogram into a gradient of comprehensive change to make fluctuation cycle scales easily comparable. The gradients of the square of the finger plethysmogram amplitude were converted into absolute values. Then, we drew a fatigue curve based on the results calculated at 18-second integrated values of the time series signals. This curve and the muscle fatigue curve from subjective judgment were in general accord. By using a finger plethysmogram featuring high sensitivity to the fatigue progress, differences in various subjects and seat performances could be found on this fatigue curve using only a 30-minute fatigue test. This new method has made it possible to greatly shorten the measurement time necessary to predict fatigue level by sensory evaluation.

Original languageEnglish
Pages (from-to)1290-1294
Number of pages5
JournalJournal of Optoelectronics and Advanced Materials
Issue number5
Publication statusPublished - 2008 May
Externally publishedYes


  • Fatigue curve
  • Muscle fatigue
  • Plethymogram
  • Sensor

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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