Passive exoskeletons offer several advantages, including lightweight design, simple structure, and inherent energy efficiency. Most existing passive exoskeletons rely on clutch mechanisms to control spring-based energy storage and release, typically focusing only on recovering biomechanical energy during the stance phase of gait. In this study, we propose and analyze a lightweight passive ankle exoskeleton capable of harvesting and releasing energy during both the stance and swing phases of walking. The device aims to enhance gait assistance while maintaining structural simplicity and minimizing weight. By integrating the optimal stiffness ratio between the stance and swing phases, derived from musculoskeletal model simulations, with previously established optimal stance-phase stiffness parameters, we determined a suitable stiffness coefficient for the swing-phase spring. To validate the design, we conducted comparative experiments on participants walking with exoskeletons configured with different stiffness coefficients. Spatiotemporal parameters, metabolic energy cost, and muscle activation patterns were analyzed to evaluate performance. The results demonstrate that the proposed exoskeleton effectively reduces Soleus muscle activation while increasing tibialis anterior activity, leading to a 6.84% reduction in walking energy cost compared to a nonassistive condition. Furthermore, energy recovery during the swing phase alone contributes an additional 1.67% reduction in energy expenditure, improving overall walking efficiency. The proposed design also eliminates complex clutch components, significantly simplifying manufacturing and reducing costs, thereby enhancing the applicability of passive exoskeletons in daily mobility and rehabilitation scenarios.
Prolonged field care is increasingly important in military operations, where austere environments and delayed medical evacuations necessitate extended injury management. Tibia and fibula fractures are common, survivable battlefield injuries that demand such care. Current treatment options involve simple splints, which require the injured Service member to be carried on a litter, and exoskeletons, which are not suited for use in combat environments. The Intrepid Battlefield Exoskeleton (IBEX) was developed to address this critical gap in battlefield trauma care by stabilizing lower leg fractures and enabling independent mobility in prolonged care scenarios. This study evaluated the usability of two IBEX prototypes through sequential laboratory and field testing under two user conditions: medic and casualty. In laboratory testing, 20 participants completed a series of functional tasks with and without the IBEX and provided quantitative usability ratings and qualitative feedback via self-report measures and interviews. In field testing, 12 participants used the IBEX during a simulated mass casualty event and completed the same usability assessments. Quantitative results indicated high overall user satisfaction. Thematic analysis of qualitative feedback revealed recurring comments on usability, portability, comfort, security, and durability. Overall, results indicated moderate usability in both environments, with room to improve ease of fitting and adjustability. Findings highlight the value of a mixed-methods approach to device evaluation and underscore the importance of iterative design and testing. Ongoing work will compare the IBEX with the current standard of care and further refine the design for operational use.
We propose a wearable soft robot that assists with individualized scapula adduction and abduction for thoracic stretching in respiratory rehabilitation. Although thoracic stretching is known to be effective for respiratory rehabilitation, the range of motion of older adult patients narrows with age, and long-term external aid by physical therapists is required. The proposed robot consists of a soft and shoulder-wearable brace and cable-pulling mechanism to apply rotational torque on shoulders, resulting in stretching the thorax and scapulae. We designed the pulling mechanism by modeling the humeral head trajectory during stretching by a therapist and reproducing it with two linear actuators pulling the right and left shoulders simultaneously, based on position control aimed at achieving a target tension. The main results of validation experiments with older adults confirmed that the robot-assisted stretching was able to perform scapular stretching similar to that of a physical therapist.
Effective coordination between the human neuromuscular system and wearable assistive devices remains a key challenge in enhancing gait performance. We propose a concerted control strategy synchronizing biological and artificial actuators using shared feedback. Positioned between centralized (e.g., CPG) and distributed (e.g., reflex-based) control, this approach avoids a central controller by relying on a coordinating signal. Ground reaction force (GRF) emerged as a strong candidate for this role. To implement this concept, we use Force Modulated Compliance (FMC) - a control mechanism that adjusts joint stiffness based on real-time GRF input. FMC has been validated in simulations and robotic platforms, confirming its ability to synchronize joint actuation. We applied this strategy in an active soft biarticular thigh exosuit (BATEX) and tested it in human walking experiments. The GRF-informed controller increased preferred walking speed, advanced the walk-to-run transition, and reduced metabolic cost. These results highlight the effectiveness of GRF-based control in enhancing human-exosuit coordination and aligning assistance with natural gait dynamics. This bioinspired approach offers a scalable framework for real-world locomotion support by harmonizing human and robotic contributions.
Poor posture is a significant concern due to its detrimental effects on health and productivity. This article presents a collar-clipped device called PostureClip, designed to restrict users from sitting and working at a bent angle, by blacking out the screen and resuming on correcting posture, thereby promoting better posture. The device integrates sensors and feedback mechanisms to provide real-time posture feedback to users. To evaluate the effectiveness of PostureClip, a controlled experiment was conducted with participants (n = 165) who were working on a laptop/PC for over 6 hours per day. The participants were randomly assigned to both the intervention group (IG1, n = 54; IG2, n = 55), which used the collar-clipped device, and the control group (CG, n = 56), which did not use the device. IG1 did not get feedback, while IG2 got feedback from the device by notifying and further darkening the screen. The study was conducted in the office environment of the participants, for 4 weeks, and metrics such as posture angle, duration of bent angle, and user feedback were collected. Analysis revealed significant improvements in posture angle (p < .001) and a significant reduction in bent angle duration (p < .01) for the participants’ group using PostureClip with feedback and compared to the group without feedback and the control group (who were not intervened). The qualitative analysis of user feedback highlighted the device’s ease of use, effectiveness in providing timely feedback, and positive impact on participants’ awareness and habits regarding posture. These results indicate that PostureClip is an effective tool for promoting better posture during sedentary work.
Transfemoral prosthesis users demonstrate a higher fall rate due to tripping than able-bodied controls in previous laboratory studies. In particular, early swing demonstrates the greatest disparity, where able-bodied controls typically utilize an elevating strategy to cross the obstacle in the same stride that the perturbation occurs, rather than the lowering strategy, where swing is ended prematurely and the obstacle is crossed in the following stride. However, due to the passive nature of most commercial knee prostheses, the elevating strategy is largely inaccessible to prosthesis users, potentially contributing to the increased fall rate in early swing. To investigate the effects of reintroducing the elevating strategy to transfemoral prosthesis users, a bimodal stumble recovery controller was developed for a powered knee prosthesis that utilized the elevating and lowering recovery strategies, selected based on the post-impact kinematics of the prosthesis. The Bimodal controller was compared to a unimodal controller that only used the lowering strategy. Three transfemoral prosthesis users underwent a series of treadmill-based obstacle perturbations with each controller following an acclimation period. All participants successfully used the elevating response in the early swing phase. On average, the elevating response reduced the disturbance to participants’ trunk kinematics and the reliance on harness support. While the Bimodal controller sometimes resulted in a recovery strategy mismatch for two participants, the mismatch still resulted in outcome metrics comparable to the unimodal controller. Overall, results suggest that the inclusion of the elevating and lowering strategies may improve stumble recovery outcomes for some transfemoral prosthesis users.
The objectives of the present study were (a) to determine the effects of a 12-week intervention using wearables promoted through physical education classes on physical activity, body composition, physical fitness and psychological well-being of overweight or obese adolescents; and (b) to analyze the differences in outcomes based on gender and baseline physical activity. Seventy-three overweight and obese adolescents (mean age: 13.44 ± 1.12 years) were randomly assigned to an experimental group (EG) or control group (CG). The EG used a physical activity wearable for 12 weeks. Both groups were assessed before and after the intervention. Regarding primary outcomes, the EG showed an increase in physical activity (p = 0.048) and reductions in body mass index (p = 0.007), fat mass (p < 0.001), and sum of 3 skinfolds (p = 0.002), with moderate-to-large effect sizes (η 2 > 0.09). According to the secondary outcomes, improvements in physical fitness were limited, with increases observed only in abdominal muscular endurance, and these changes were also present in the CG. Subgroup analyses showed that females and adolescents with low baseline physical activity experienced greater benefits, particularly in fat-related variables (p < 0.001-0.037), with large effect sizes (η 2 > 0.14). Additionally, adolescents with greater exposure to the wearable-based intervention showed more consistent improvements in fat-related outcomes (p < 0.001-0.032), with large effect sizes (η 2 > 0.25). In conclusion, a wearable-based intervention promoted through physical education classes may contribute to meaningful improvements in body composition, particularly among females and previously inactive adolescents who are overweight or obese. However, effects on physical fitness and psychological well-being were limited, highlighting the importance of intervention design, adherence, and complementary motivational strategies.
Individuals with limb loss present significant challenges to testing and evaluating prosthetic devices, such as medical approval processes and participant availability. Prosthesis simulators, designed for mimicking prosthesis use with able-bodied individuals, offer an alternative to conducting controlled experiments and enhancing the development of prosthetic technologies. This review examines the design features, applications, and limitations of lower limb prosthesis simulators. A literature search identified 73 studies that have used lower limb prosthesis simulators. Most studies have focused on transfemoral prosthesis simulators (TFsims) and testing prosthetic designs and control mechanisms. The most frequently assessed movement was walking, while other movements, were explored only sporadically. The findings reveal significant variability in simulator configurations, training protocols, and the range of movements assessed. Additionally, a notable research gap exists in evaluations of the effect of transtibial prosthesis simulators (TTsims) and hip disarticulation prosthesis simulators (HDsims) on gait. Despite these challenges, prosthesis simulators offer promising potential for accelerating and improving prosthesis development while putting less stress on the relatively small target group of individuals with limb loss. Further research is needed to standardize methodologies and better understand the effects of simulator design and training on gait performance to facilitate advancements in prosthetic research.
Ankle-foot mechanisms are designed to substitute for missing anatomical behavior of lower-limb prosthesis users. Historically, the majority of ankle-foot mechanism research has been focused on transtibial prosthesis users despite evidence that current knowledge is not directly translated to transfemoral prosthesis users, such as the influence of single-axis knee alignment during gait and the differences in standing balance management. This review attempts to characterize the current state of published knowledge about the effects of ankle-foot prosthesis design on standing and walking performance in transfemoral prosthesis users. The databases of PubMed, Embase, Cochrane Library, CINAHL, and IEEE Xplore were searched on January 6, 2025. Data from the selected articles were extracted and reported following the PRISMA extension for scoping reviews. Thirty-five articles were included that reported on seven different types of feet, ranging from simple designs like a solid ankle-cushioned heel (SACH) foot to more complex ones such as a microprocessor foot. The range of reported study tasks extended from standing and level walking to more complex tasks like incline/decline slopes and parcourse walking. The results suggest some parallels between transfemoral and transtibial prosthesis users, such as improvements with the incorporation of roll-over-shape (ROS) features and adaptation of a hydraulic ankle. The literature also emphasized how ankle-foot components affect ground force vector position and direction, influencing prosthetic knee control, highlighting the importance of considering the interaction between the prosthetic ankle-foot and knee mechanisms. Understanding these interactions will support the development of clinical practice guidelines by identifying the pair of prosthetic components that maximizes performance.
Dropfoot gait pattern during walking commonly persists after stroke and is often associated with muscle weakness and pathological muscle activation. Exoskeletons have demonstrated the potential to improve mobility in people with neurological conditions. We have developed a novel soft ankle exoskeleton and shown its ability to correct simulated dropfoot and excessive inversion in nondisabled people. In this study, we evaluate its feasibility in five persons with chronic stroke and dropfoot gait patterns. 3D gait analysis was performed in three conditions: walking with only shoes, with the exoskeleton unpowered, and powered. Foot and ankle kinematics and step length asymmetry were evaluated. The participants also reported satisfaction with QUEST 2.0 and a study-specific questionnaire. Compared with only shoes, the powered exoskeleton partially corrected dropfoot by increasing dorsiflexion angle and foot clearance height in swing, facilitating heel contact, neutralizing ankle inversion, and increasing step length symmetry slightly. The participants expressed satisfaction with the exoskeleton’s effectiveness, though some comfort-related issues were identified. This feasibility study suggests that the exoskeleton prototype can improve dropfoot gait patterns and be accepted by individuals in the chronic stage after a stroke.
Diastasis of rectus abdominis (DRA) is a common pathological condition in postpartum rehabilitation, but with limited treatment strategies. This study aimed to explore the effect of using a trunk-wearable neuromuscular electrical stimulation (NMES) device on postpartum women with moderate and severe DRA. A total of 84 postpartum women with an inter-rectus distance (IRD) of ≥3 cm were randomly assigned to two equal groups. The treatment group received a trunk-wearable NMES device and exercise therapy, whereas the control group received exercise only. We measured IRD and calculated treatment response proportion, improvement of trunk muscle strength, and low-back pain in both groups. Additionally, we evaluated quality of life (QoL) using the SF-36 questionnaire and Hernia-related Quality of Life Survey (HerQLes). Statistical analysis was performed using SAS 9.4. After 8-week treatment, the IRD of the umbilical (M3) sector showed a greater reduction in the treatment group (−10.6 [−17.9 to −3.3]%, p < 0.05). Patients in the treatment group had higher treatment response proportions (p = 0.0031 and p = 0.0010, W2 and W3, respectively). Additionally, the treatment group had higher Janda assessment scores and greater reduction in low-back pain (both p < 0.0001). QoL evaluation indicated greater improvements in the SF-36 questionnaire (pain and role-emotional scales,p < 0.05) and HerQLes (p < 0.0001) in the treatment group. The application of a trunk-wearable NMES device on DRA patients, accompanied by exercise therapy, significantly reduced IRD and increased the treatment response proportion. Moreover, we observed positive improvements in trunk muscle strength, low-back pain, and QoL.
In recent years, there has been growing interest regarding the impact of human movement quality on health. However, assessing movement quality outside of laboratories or clinics remains challenging. This study aimed to evaluate the capabilities of consumer-grade wearables to assess movement quality and to consider optimal sensor locations. Twenty-two participants wore Polar Verity Sense magnetic, angular rate, and gravity (MARG) sensors on their chest and both wrists, thighs, and ankles, while performing repeated bodyweight movements. The Madgwick sensor-fusion algorithm was utilized to obtain three-dimensional orientations. Concurrent validity, quantified using the root-mean-square-error (RMSE), was established against a Vicon optical motion capture system following time-synchronization and coordinate-system alignment. The chest sensors demonstrated the highest accuracies overall, with mean RMSE ( $ {\mathrm{RMSE}}_{\mathrm{mean}} $ ) less than 9.0° across all movements. In contrast, the wrist sensors varied considerably ( $ 5.5\hskip-2pt {}^{\circ}\le {\mathrm{RMSE}}_{\mathrm{mean}}\le 139.1\hskip-2pt {}^{\circ} $ ). Ankle and thigh sensors yielded mixed results, with the $ {\mathrm{RMSE}}_{\mathrm{mean}} $ ranging from 2.0° to 40.0°. Notably, yaw angles consistently demonstrated higher discrepancies overall, while pitch and roll were relatively more stable. This study highlights the potential of consumer-grade MARG sensors to increase the real-world applicability and accessibility of complex biomechanical models. It also accentuates the requirement for strategic sensor placement and refined calibration and postprocessing methods to ensure accuracy.
Musculoskeletal disorders remain a leading occupational health challenge in physically demanding sectors such as healthcare, social care, and industry. Exoskeletons - wearable devices designed to mitigate physical strain are increasingly explored as potential solutions; however, factors affecting their adoption in real-world settings remain underexplored. This novel scoping review systematically maps the existing evidence on the application of commercially available exoskeletons within real and simulated work environments, focusing on usage patterns, user experiences, and factors influencing implementation. Following the Joanna Briggs Institute methodology for scoping reviews, a systematic literature search was conducted across the Web of Science, Scopus, CINAHL, PsycINFO, and MEDLINE, with an initial search in May 2023 and an update in May 2024. Forty-nine papers met the inclusion criteria based on the Population, Concept, and Context (PCC) framework. Data were extracted using a standardized form and synthesized descriptively, thematically, and through content analysis. Results are presented in narrative, tabular, and conceptual map formats. Exoskeletons were used most frequently in industry (manufacturing) and perioperative care (healthcare). Although, the devices reduced muscle load during repetitive or static tasks, adoption was constrained by discomfort and fit challenges, thermal burden, and limited usability in dynamic settings. Thematic analysis revealed how user experiences were shaped by professional identity, task compatibility, organizational support, and social norms. A conceptual map synthesized sector-specific and cross-sectoral barriers and facilitators. This review highlights the need for inclusive, context-sensitive, and longitudinal research to support safe, acceptable, and effective exoskeleton adoption and implementation across diverse occupational environments.
Robotic exoskeletons offer the potential to train novel motor skill acquisition and thus aid physical rehabilitation. Our prior work demonstrated that individuals converge to certain kinematic coordinations as they learn a novel task. An upper-limb exoskeleton controller that constrains individuals to this known coordination was also shown to significantly improve straight-line reaching task performance. This paper studies the impact of variations of this controller on novel skill acquisition. We quantify learning under three variations of the intervention (each group with N = 10 participants) against a control group (N = 13). Our results show that introducing any constraint during learning can hinder the learning process, as this alters the task dynamics that lead to success. However, when presented with a personalized constraint, participants still learn. When presented with a task-specific constraint, rather than a personalized one, participants cannot overcome the differences in the training and target task, suggesting exoskeleton-based training interventions should be personalized. The changes in kinematic behaviors during learning further suggest that participants do not have a statistically consistent performance. While participants respond more to exoskeleton intervention, others may not respond in short training sessions, necessitating further analysis of how strong a response can be encouraged. Our findings emphasize the need for further study of the effects of exoskeleton intervention for motor training and the potential need for personalization.
The manufacturing industry, notably the aeronautics sector, involves tasks presenting risks of low back pain. One of the preventive strategies could be the use of passive back exoskeletons, which have demonstrated benefits during activities involving trunk bending. This study aims to evaluate the effects of four passive back exoskeletons on trunk neuromuscular activity, kinematics, and perceived discomfort during polishing tasks simulated in a laboratory setting. Nineteen participants performed four tasks (two static bending tasks and two load-carrying tasks) without and with two soft (CORFOR and BionicBack) and two rigid (BackX and Laevo FLEX) exoskeletons. The results showed varying effects depending on the tested exoskeleton model, beyond the distinction between rigid and soft designs. Reductions in lumbar erector spinae (LES) neuromuscular activity were observed with Laevo FLEX and CORFOR during static tasks compared to the condition without exoskeleton (8-18%; p < .05). However, reductions in LES muscle activity were not significant during load carrying. Biceps femoris neuromuscular activity was significantly lower in the four tasks when using the Laevo FLEX, with reductions ranging from 8 to 17% (p < .01). The two rigid exoskeletons decreased perceived back discomfort across all tasks (p < .05). Finally, the BionicBack exoskeleton significantly altered participants' kinematics across all four tasks, reducing both trunk range of motion and average flexion (p < .05). The Laevo FLEX exoskeleton was the only one to significantly reduce both neuromuscular activity and perceived back discomfort, while causing no adverse effects, appearing advantageous when polishing in the aeronautical industry.
Gait analysis is a fundamental tool in biomechanics and rehabilitation, as it evaluates human movements’ kinematic and kinetic behavior. For this reason, high-precision devices have been developed. However, these require controlled environments, which generates a deficiency in the capacity of studies related to gait analysis in outdoor and indoor scenarios. Therefore, this article describes the development and testing of a wearable system to measure gait cycle kinematic and kinetic parameters. The methodology for the development of the system includes the assembly of modules with commercial surface electromyography (sEMG) sensors and inertial measurement sensors, as well as the use of instrumented insoles with force-resistive sensors, and the design of the software to acquire, process, visualize, and store the data. The system design considers portability, rechargeable battery power supply, wireless communication, acquisition speed suitable for kinematic and kinetic signals, and compact size. Also, it allows simultaneous assessment of sEMG activity, hip and knee joint angles, and plantar pressure distribution, using a wireless connection via Wi-Fi and user datagram protocol for data transmission with a synchronization accuracy of 576 μs, data loss of 0.8%, and autonomy of 167 min of continuous operation, enabling uninterrupted data acquisition for gait analysis. To demonstrate its performance, the system was tested on 10 subjects without any neuromusculoskeletal pathology in indoor and outdoor environments, evaluating relevant parameters that facilitate a comprehensive analysis of gait in various contexts. The system offers a reliable, versatile, and affordable alternative for gait assessment in outdoor and indoor environments.
Wearable devices placed in or around the ear, often referred to as hearables, are gaining attention as alternative tools for pseudo-continuous health monitoring. Among their several capabilities, hearables are primarily useful for monitoring brain activity electronically via electroencephalography (EEG), enabling noninvasive, long-term recording of neural signals (e.g., from the ear canal). In addition to EEG, hearables can monitor heart rate, oxygen saturation, and temperature, all while maintaining the comfort and discretion of everyday items like earplugs or headphones. This review explores recent progress in combining multiple sensors, leveraging artificial intelligence (AI), and developing novel materials that make hearables more accurate, practical, and comfortable. On-device AI enables real-time, personalized insights that can support therapeutic interventions for neurological disorders like epilepsy. We seek further improvements in design and materials beyond this proof-of-concept, including three-dimensional printing with flexible electrodes while maintaining the unique property of monolithic circuit integration during system printing. That helps devices conform even better to the ear’s anatomy for enhanced comfort and signal quality, while the rigidity of the main structure ensures a highly durable and reliable product suitable for everyday life. In particular, personalization through additive manufacturing enables custom-fitted hearables based on each user’s unique ear canal features, supporting long-term wearability and reliable EEG acquisition. This review also addresses key challenges like motion artifacts and miniaturization, and current strategies to overcome them. Overall, this review highlights hearables as a key emerging technology, especially for EEG-based brain monitoring, offering a personalized, continuous, and noninvasive approach to future healthcare.
Using wearable sensors to evaluate workers’ performance is challenging with existing sensor techniques. It requires detecting not only limb motions but also the onset and offset of specific actions. Commonly used inertial measurement units (IMUs) can be combined with surface electromyography (sEMG) to detect muscular activity. However, sEMG requires skin preparation and careful sensor placement, and can be affected by sweat or motion artifacts. To address these limitations, we used a wearable system combining IMUs and force-sensing resistors (FSRs), where IMUs capture joint kinematics and FSRs detect grasping actions. The system included three IMUs (on the trunk, upper arm, and forearm) and two FSR arrays (on the upper and lower arms). The system was first validated in a laboratory setting against an optical motion capture system with 10 healthy young adults performing isolated upper limb movements and mimicking lifting tasks. The results showed high agreement in joint angle estimation (coefficient of multiple correlation = 0.95 $ \pm $ 0.04), with a maximum root mean square error of 8.7 $ \pm $ 2.92°, and a mean absolute timing error for grasp detection of −0.59 seconds. To evaluate its applicability in real-world scenarios, a pilot in-field test was then conducted with two manufacturing workers (using and not using a passive shoulder exoskeleton) during a repetitive panel-packing task. The test shows highly consistent grasping detection, which allowed segmenting the task with a small variability in task duration (maximum coefficient of variation = 5.16 $ \% $ ). These findings demonstrate the feasibility of using the proposed method in industrial environments to analyze upper limb motion and grasping activity.
Individuals with cerebral palsy (CP) experience significant impairments in lower limb mobility, which severely limit their daily activities and overall quality of life. Robotic exoskeletons have emerged as a cutting-edge solution to assist in the rehabilitation of individuals with CP by improving their motor functions. This systematic review, conducted following PRISMA guidelines, critically evaluates lower limb robotic exoskeletons specifically designed for individuals with CP, focusing on their design, rehabilitation interfaces, and clinical effectiveness. The review includes research papers published between 2010 and 2024, analyzing 30 lower limb exoskeletons reported in 57 papers. We analyze each exoskeleton, focusing on its technological features, user experience, and clinical outcomes. Notably, we identify a trend in which researchers are increasingly adapting exoskeleton functions to the specific needs of individual users, facilitating personalized rehabilitation approaches. Additionally, we highlight critical gaps in current research, such as the lack of sufficient long-term evaluations and studies assessing sustained therapeutic impacts. While ease of use remains crucial for these devices, there is a pressing need for user-friendly designs that promote prolonged engagement and adherence to therapy. This comprehensive review of existing gait rehabilitation exoskeleton technologies aimed to inform future design and application, ultimately contributing to the development of devices that better address the needs of individuals with CP and enhance their motor functions and quality of life.
