Clark R. Dickerson

Current mechanotherapy systems for at‐home management of lymphedema and deep vein thrombosis are limited by gaps between actuators and bulky electromechanical control units, leading to untreated regions and restricting use to stationary settings. A key bottleneck is that conventional designs require one valve per actuator, causing control unit size and power demand to scale with actuator count. Here, we present a benchtop study on a wearable mechanotherapy system that addresses these challenges through two innovations: (1) a monolithic sheet of overlapping soft fluidic actuators integrated into a garment to eliminate actuator gaps and (2) embedded microfluidic in‐line membrane valves (μIMVs) that dramatically reduce the number of required electromechanical valves. Overlapping actuators by 40% removes pressure gaps between neighboring actuators, enabling smooth, uniform gradient compression. We further demonstrate μIMVs (3.6 × 0.6 mm) integrated directly with actuators and combined with resistance microchannels on a chip to achieve gradient pressure holding (10–20 mbar increments) and rapid, uniform passive deflation (<3 s), overcoming slow‐throughput treatment cycles limitations of valve‐less microchannel designs while maintaining scalability. This miniaturized system enables a smartphone‐sized control unit, supports direct garment integration, and represents a substantial advance toward truly portable, patient‐centric mechanotherapy for circulatory disorders.

The complex function of the shoulder relies on the coordinated activation of small and large muscles, including the deltoid, pectoralis major, trapezius, and latissimus dorsi. However, detailed knowledge of their neuromuscular control remains limited. This study aimed to develop a methodological framework to investigate the neural control of the larger superficial shoulder muscles by combining a six-degree-of-freedom load cell attached to a robotic arm with high-density surface electromyograms (HDsEMG). Six healthy participants performed isometric contractions (abduction, adduction, flexion, and extension) at 30% of maximal voluntary contraction with the shoulder positioned at 30° and 65° of lateral abduction. HDsEMGs were recorded from the four muscles and analysed at the global activation, spatial distribution of activation and motor unit levels. Global activation was quantified using averaged normalized root-mean-square (RMS) amplitude and spatial distribution using coefficient of variation of the topographic maps. Moreover, HDsEMGs were decomposed into individual motor unit spike trains using convolutive blind source separation, and motor unit behaviour was characterized by mean discharge rate and spatial distribution of motor unit action potentials (MUAPs). RMS maps revealed action-specific activation within and between muscles, with the upper trapezius active across all tasks, while the anterior, middle, and posterior deltoid, clavicular pectoralis major, and latissimus dorsi were predominantly activated during abduction, flexion, and extension. Motor unit discharge rate also showed task-dependent activity. MUAP spatial distributions further showed distinct motor unit territories within arrays, suggesting region-specific recruitment strategies across actions. In conclusion, this framework demonstrates that individual motor unit activity can be reliably measured non-invasively in the superficial shoulder muscles. The approach provides a methodological basis for novel incorporation of neural control information into biomechanical models of shoulder function.

Background: Lumbar axial twist is a known risk factor for low back pain and injuries, yet current ergonomic reaching guidelines do not make recommendations related to lateral reach angle. Purpose: Our analysis assessed non-neutral postures of the lumbar spine (i.e., axial twist and flexion-extension) and shoulder (i.e., elevation) during a variety of single-hand exertions performed in standing. Methods: Twenty-four participants performed a series of standing right-handed exertions on a load cell. These exertions were performed at different lateral angles (0 degrees at body midline and to the right at 30 degrees, 45 degrees, 60 degrees, and 90 degrees), distances (primary, secondary, and tertiary reach envelopes), and heights (elbow and shoulder). At each location, three exertion types (downward, upward, and push) were performed at two heights (elbow and shoulder) and two loads (40 N and 60% of maximum forward push strength). Mean lumbar flexion-extension and axial twist and shoulder elevation were calculated from motion capture data. Results: Data were evaluated relative to non-neutral postural thresholds for lumbar flexion-extension (<-19.6 degrees and >-0.7 degrees flexion), shoulder elevation (>60 degrees), and lumbar axial twist (>9 degrees). In most exertions, lumbar flexion-extension and shoulder elevation angles remained within the in vivo lumbar neutral zone and were not considered overhead. Axial twist at 9 degrees would be exceeded at or shortly after exertions performed at 60 degrees from the body midline (-4.1 degrees to -11.5 degrees) and for far (tertiary reach envelope) and upward exertions performed at the body midline (0 degrees; 8.6 degrees to 14.4 degrees). Conclusions: The potential for injury from lumbar flexion-extension and shoulder elevation remained low. While the type of exertion (downward, upward, or push) significantly influenced the magnitude of axial twist in each angle and distance, generally it is recommended that standing single-handed exertions not be performed beyond 60 degrees from the midline across reach distances and beyond 0 degrees for reaches at far distances. These findings should be incorporated into future ergonomic reach envelope guidelines.

This paper introduces a hands-on laboratory exercise focused on assembling and testing a hybrid soft-rigid active finger prosthetic for biomechanical and biomedical engineering (BME) education. This hands-on laboratory activity focuses on the design of a myoelectric finger prosthesis, integrating mechanical, electrical, sensor (i.e., inertial measurement units (IMUs), electromyography (EMG)), pneumatics, and embedded software concepts. We expose students to a hybrid soft-rigid robotic system, offering a flexible, modifiable lab activity that can be tailored to instructors' needs and curriculum requirements. All necessary files are made available in an open-access format for implementation. Off-the-shelf components are all purchasable through global vendors (e.g., DigiKey Electronics, McMaster-Carr, Amazon), costing approximately USD 100 per kit, largely with reusable elements. We piloted this lab with 40 undergraduate engineering students in a neural and rehabilitation engineering upper year elective course, receiving excellent positive feedback. Rooted in real-world applications, the lab is an engaging pedagogical platform, as students are eager to learn about systems with tangible impacts. Extensions to the lab, such as follow-up clinical (e.g., prosthetist) and/or technical (e.g., user-device interface design) discussion, are a natural means to deepen and promote interdisciplinary hands-on learning experiences. In conclusion, the lab session provides an engaging journey through the lifecycle of the prosthetic finger research and design process, spanning conceptualization and creation to the final assembly and testing phases.

Recently, robotic exoskeletons are gaining attention for assisting industrial workers. The exoskeleton power source ranges from fully passive (FP) to fully active (FA), or a mixture of both. The objective of this experimental study was to assess the efficiency of a new active–passive (AP) shoulder exoskeleton using statistical analyses of 11 quantitative measures from surface electromyography (sEMG) and kinematic data and a user survey for weight lifting tasks. Two groups of females and males lifted heavy kettlebells, while a shoulder exoskeleton helped them in modes of fully passive (FP), fully active (FA), and active–passive (AP). The AP exoskeleton outperformed the FP and FA exoskeletons because the participants could hold the weighted object for nearly twice as long before fatigue occurred. Future developments should concentrate on developing sex-specific controllers as well as on better-fitting wearable devices for women.