Two-dimensional biomechanical thumb model for pipetting

Eunsik Kim, Andris Freivalds

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Manual pipetting imposes repetitive movements, high force, and awkward postures on the thumb, fingers, and wrist, increasing the risk of musculoskeletal injuries. The purpose of this study is to provide a linear regression model to estimate the optimal pipetting grip height based on the two-dimensional biomechanical static thumb model developed in this study. This biomechanical static thumb model uses hand anatomy and static equilibrium conditions to estimate internal tendon forces against a given external force. Based on the model, we conclude that the optimal grip height is 3 cm in males and 2 cm in females in terms of grip strength and force efficiency. In addition, the model is validated by RMS EMG data from correlation analysis between the predicted internal tendon forces, with RMS EMG values of 0.65 for Flexor Pollicis Longus, 0.57 for Flexor Pollicis Brevis, and 0.61 for Adductor Pollicis.

Original languageEnglish (US)
Pages (from-to)165-175
Number of pages11
JournalInternational Journal of Industrial Ergonomics
StatePublished - Nov 2018

All Science Journal Classification (ASJC) codes

  • Human Factors and Ergonomics
  • Public Health, Environmental and Occupational Health


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