Skin Strain Analysis of the Scapular Region and Wearables Design

Abstract

Monitoring scapular movements is of relevance in the contexts of rehabilitation and clinical research. Among many technologies, wearable systems instrumented by strain sensors are emerging in these applications. An open challenge for the design of these systems is the optimal positioning of the sensing elements, since their response is related to the strain of the underlying substrates. This study aimed to provide a method to analyze the human skin strain of the scapular region. Experiments were conducted on five healthy volunteers to assess the skin strain during upper limb movements in the frontal, sagittal, and scapular planes at different degrees of elevation. A 6 × 5 grid of passive markers was placed posteriorly to cover the entire anatomic region of interest. Results showed that the maximum strain values, in percentage, were 28.26%, and 52.95%, 60.12% and 60.87%, 40.89%, and 48.20%, for elevation up to 90° and maximum elevation in the frontal, sagittal, and scapular planes, respectively. In all cases, the maximum extension is referred to the pair of markers placed horizontally near the axillary fold. Accordingly, this study suggests interesting insights for designing and positioning textile-based strain sensors in wearable systems for scapular movements monitoring.

Virtual Reality for Shoulder Rehabilitation: Accuracy Evaluation of Oculus Quest 2

“…Obtaining quantitative information about the kinematics of patients with shoulder musculoskeletal impairments is of great interest to clinicians and patients themselves [ 13 , 14 , 35 ]. In recent years, a growing interest has been devoted to unobtrusive wearable systems for joint kinematics monitoring [ 36 , 37 , 38 ]. The quantitative evaluation and tracking of human joint movements could be relevant in different applications fields ranging from rehabilitation to sports medicine to provide data about rehabilitation progress or athlete’s performance.…”

Optical Motion Capture Systems for 3D Kinematic Analysis in Patients with Shoulder Disorders

“…Objective measurements of the shoulder joint kinematics have a crucial role in understanding movement disorders or assessing the outcomes of a particular surgical technique or rehabilitation process. Although other sensing elements or technology such as magnetoinertial measurement units, strain sensors, and virtual reality are emerging solutions for motion tracking in an unstructured environment [8,12,53], OMCs employing body markers are currently considered the gold standard in research and clinical applications [8,14]. According to the retrieved studies, the 3D shoulder kinematic analysis with OMCs is a core part of evaluating treatment outcomes and shoulder functionalities during the recovery process of patients.…”

“…Shoulder kinematic analysis is a booming research field due to the emerging need to improve clinical diagnostics and rehabilitation procedures [8,12]. From a technological point of view, monitoring the movement of the shoulder is particularly challenging due to the complexity of the joint kinematics, which requires the development of protocols that exploit a detection technology that is as reliable and non-intrusive as possible [8,12]. The kinematic analysis of movement makes it possible to overcome the shortcomings of clinical tests and to obtain objective data on the characteristics and quality of movement [13,14].…”

Strain-Insensitive Stretchable Fiber Conductors Based on Highly Conductive Buckled Shells for Wearable Electronics

“…In this study, we applied a new design strategy, namely, the continuous distribution of Ag nanoparticle (AgNP) networks in a buckled structure, to obtain strain-insensitive and stretchable fiber conductors that do not undergo electrical degradation during human motion (a biomechanically maximum strain of 60.87%). 37 These highly stretchable fiber conductors comprised AgNP-embedded PU composites and a buckled shell structure (wavelength = 1.2 μm) on the surface of the PU fiber core. Further, we employed a simple chemical process (percolating a Ag precursor solution through the PU fiber core) to form the AgNP networks in the polymer rather than coating or wrapping the conductive materials.…”