title: Validation of Inertial Measurement Units for Upper Body Kinematics.
abstract: The purpose of this study was to validate a commercially available inertial measurement unit (IMU) system against a standard lab-based motion capture system for the measurement of shoulder elevation, elbow flexion, trunk flexion/extension, and neck flexion/extension kinematics. The validation analyses were applied to 6 surgical faculty members performing a standard, simulated surgical training task that mimics minimally invasive surgery. Three-dimensional joint kinematics were simultaneously recorded by an optical motion capture system and an IMU system with 6 sensors placed on the head, chest, and bilateral upper and lower arms. The sensor-to-segment axes alignment was accomplished manually. The IMU neck and trunk IMU flexion/extension angles were accurate to within 2.9 ± 0.9 degrees and 1.6 ± 1.1°, respectively. The IMU shoulder elevation measure was accurate to within 6.8 ± 2.7° and the elbow flexion measure was accurate to within 8.2 ± 2.8°. In the Bland-Altman analyses, there were no significant systematic errors present; however, there was a significant inversely proportional error across all joints. As the gold standard measurement increased, the IMU underestimated the magnitude of the joint angle. This study reports acceptable accuracy of a commercially available IMU system; however, results should be interpreted as protocol specific.
authors.affiliation: 1 Mayo Clinic.
authors.forename: Melissa M B
authors.initials: MMB
authors.lastname: Morrow
authors.affiliation: 1 Mayo Clinic.
authors.forename: Bethany
authors.initials: B
authors.lastname: Lowndes
authors.affiliation: 1 Mayo Clinic.
authors.forename: Emma
authors.initials: E
authors.lastname: Fortune
authors.affiliation: 1 Mayo Clinic.
authors.forename: Kenton R
authors.initials: KR
authors.lastname: Kaufman
authors.affiliation: 1 Mayo Clinic.
authors.forename: M Susan
authors.initials: MS
authors.lastname: Hallbeck
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D004550:Elbow / Q000502:physiology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures; D009068:Movement; D009333:Neck / Q000502:physiology*; D016059:Range of Motion, Articular; D060726:Torso / Q000502:physiology*
keywords: IMU; biomechanics; ergonomics; shoulder