Validation of a wearable system for 3D ambulatory L5/S1 moment assessment during manual lifting using instrumented shoes and an inertial sensor suit

G. S. Faber, I. Kingma*, C. C. Chang, J. T. Dennerlein, J. H. van Dieën

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


This study aimed to evaluate the accuracy of 3D L5/S1 moment estimates from an ambulatory measurement system consisting of a wearable inertial motion capture system (IMC) and instrumented force shoes (FSs), during manual lifting. Reference L5/S1 moments were calculated using an inverse dynamics bottom-up laboratory model (buLABmodel), based on data from a measurement system comprising optical motion capture (OMC) and force plates (FPs). System performance of (1) a bottom-up ambulatory model (buAMBmodel) using lower-body kinematic IMC and FS data, and (2) a top-down ambulatory model (tdAMBmodel) using upper-body kinematic IMC data and hand forces (HFs) were compared. HFs were estimated using full-body kinematic IMC data and FS forces. Eight males and eight females lifted a 10-kg box from different initial vertical/horizontal positions using either a free or an asymmetric lifting style. As a measure of system performance, root-mean-square (RMS) errors were calculated between the reference (buLABmodel) and ambulatory (tdAMBmodel & buAMBmodel) moments. The results showed two times smaller errors for the tdAMBmodel (averaged RMS errors < 20 Nm or 10% of peak extension moment) than for the buAMBmodel (average RMS errors < 40 Nm or 20% of peak extension moment). In conclusion, for ambulatory L5/S1 moment assessment with an IMC + FS system, using a top-down inverse dynamics approach with estimated hand forces is to be preferred over a bottom-up approach.

Original languageEnglish
Article number109671
Pages (from-to)1-11
Number of pages11
JournalJournal of Biomechanics
Early online date31 Jan 2020
Publication statusPublished - 26 Mar 2020



  • Ergonomics
  • Inertial measurement unit (IMU)
  • Occupational biomechanics
  • Spine
  • Wearable sensors

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