Ambulatory measurement of shoulder and elbow kinematics through inertial and magnetic sensors

Abstract

Inertial and magnetic measurement systems (IMMSs) are a new generation of motion analysis systems which may diffuse the measurement of upper-limb kinematics to ambulatory settings. Based on the MT9B IMMS (Xsens Technologies, NL), we therefore developed a protocol that measures the scapulothoracic, humerothoracic and elbow 3D kinematics. To preliminarily evaluate the protocol, a 23-year-old subject performed six tasks involving shoulder and elbow single-joint-angle movements. Criteria for protocol validity were limited cross-talk with the other joint-angles during each task; scapulohumeral-rhythm close to literature results; and constant carrying-angle. To assess the accuracy of the MT9B when measuring the upper-limb kinematics through the protocol, we compared the MT9B estimations during the six tasks, plus other four, with the estimations of an optoelectronic system (the gold standard), in terms of RMS error, correlation coefficient (r), and the amplitude ratio (m). Results indicate that the criteria for protocol validity were met for all tasks. For the joint angles mainly involved in each movement, the MT9B estimations presented RMS errors <3.6 degrees , r > 0.99 and 0.9 < m < 1.09. It appears therefore that (1) the protocol in combination with the MT9B is valid for, and (2) the MT9B in combination with the protocol is accurate when, measuring shoulder and elbow kinematics, during the tasks tested, in ambulatory settings.

Automatic anatomical calibration for IMU-based elbow angle measurement in disturbed magnetic fields

“…1 We assume a heading error and thus replace by . Taking the scalar product with on both sides and making use of the fact that yields…”

“…However, the orientation of each IMU with respect to its body segment must be known to derive useful kinematic quantities. This is commonly achieved by accurate manual placement of the IMUs [1] or by asking the subject to perform tedious calibration movements [3]. However, it was recently demonstrated that sensor-to-segment orientations can also be determined from the data of arbitrary upper or lower limb motions [4,6].…”

Estimating 3D L5/S1 moments and ground reaction forces during trunk bending using a full-body ambulatory inertial motion capture system

“…Many studies have shown the validity of the IMC system for measurement of kinematics (Cutti et al, 2008;Faber et al, 2013b;Godwin et al, 2009;Luinge and Veltink, 2005;Plamondon et al, 2007;Roetenberg et al, 2005). However, the number of studies testing the validity of the system for the assessment of the kinetics (e.g.…”

Shoulder biomechanics and the success of translational research

“…This is an almost unexplored topic in motion analysis in general [2,9,14,15], and for the upper extremity specifically. The paper by Parel et al [21] gives a contribution on this regard, by assessing the agreement between two scapula-tracking systems (scapula tracker [18] and spine tracker [10]), based on two different motion analysis technologies, namely opto-eletronic and inertial and magnetic sensors [10,11]. Filling a gap in current literature, the paper points out a clear set of conditions for agreement between systems for scapula tracking, based on state-ofthe-art parameters, i.e., within-protocol repeatability and Bland-Altman Limits of Agreement.…”