Search Results (120)

Cerebral palsy (CP) often causes mobility limitations that require assistive devices such as Ankle Foot Orthoses (AFOs) to enhance functional stability. This study aims to develop an optimized 3D-printed AFO design that improves comfort, structural durability, and production efficiency for children with CP. The research applies a Design of Experiment approach using the Taguchi method to optimize 3D printing parameters, supported by tensile testing to identify the best material configuration. Design alternatives were prioritized using the Analytical Hierarchy Process, while Finite Element Analysis was conducted to evaluate mechanical performance under physiological loading. The selected PETG configuration (33% infill density and 0.15 mm layer thickness) demonstrated improved tensile strength and flexibility, contributing to enhanced structural behavior. A prototype was produced and validated using the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) questionnaire. Results showed higher overall user satisfaction for the optimized 3D-printed AFO compared to conventional devices, particularly in safety, comfort, and durability. The integration of optimized material parameters, systematic design evaluation, and user-centered assessment provides an effective pathway toward improving AFO performance and supporting the mobility and quality of life of children with cerebral palsy. Full article

Smart assistive technologies such as sensor-based footwear and walking aids offer promising opportunities for gait rehabilitation through real-time feedback and patient-centered monitoring. While biofeedback applications show great potential, current research rarely explores integrated closed-loop systems with device- and modality-specific feedback. In this work, we present a modular sensor-based system combining a smart foot orthosis and an instrumented forearm crutch to deliver real-time vibrotactile biofeedback. The system integrates plantar pressure and motion sensing, vibrotactile feedback, and wireless communication via a smartphone application. We conducted a user study with eight participants to validate the system’s feasibility for mobile gait detection and app usability, and to evaluate different vibrotactile feedback types across the orthosis and forearm crutch. The results indicate that pattern-based vibrotactile feedback was rated as more useful and suitable for regular use than simple vibration alerts. Moreover, participants reported clear perceptual differences between feedback delivered via the orthosis and the forearm crutch, indicating device-dependent feedback perception. The findings highlight the relevance of feedback strategy design beyond hardware implementation and inform the development of user-centered haptic biofeedback systems. Full article

Early diagnosis of pediatric flatfoot is critical to provide effective and timely orthotic intervention to prevent long-term complications. Current methods like manual measurements or three-dimensional (3D) scanning are often not ideal for rapid screening. This study addresses this gap by developing a regression model to predict foot arch height (AH) among Chinese primary schoolchildren by using simple two-dimensional (2D) footprint parameters, thus enabling orthosis prescription in an accessible and timely manner. A correlational study is conducted with 57 Hong Kong children who are 8–12 years old with flatfeet. Anthropometric footprint measurements, including four footprint indexes, Clarke’s Angle (CA), Chippaux–Smirak Index (CSI), Staheli Index (SI), and Sztriter–Godunov index (KY) are obtained from 2D footprints, whereas the arch height (AH) is measured by a caliper. One-way ANOVA is used to identify the measurements associated with flatfoot severity. A stepwise regression analysis is also used to determine the key footprint predictors of AH. The results show that the footprint indexes, heel width, ball width, medial ball length, arch depth and arch breadth significantly differentiated flatfoot severity. The stepwise regression model explains 44% of the variance by identifying the CA, heel width (HW) and arch depth (AD) as the strongest predictors of AH. The CA, HW and AD measured from the 2D footprints can serve as practical predictors of AH in Chinese flatfooted children. This study offers a transformative, accessible tool for pediatric flatfoot screening. Unlike resource-intensive 3D scanning or clinical assessments, our approach uses simple 2D footprints to estimate AH. This enables rapid, preliminary screening in diverse settings, empowering individuals to identify potential issues and seek timely professional evaluation. By democratizing access to early detection, it streamlines referrals, reduces unnecessary complex assessments, and facilitates earlier, personalized orthotic intervention for improved long-term foot health. Full article

Ankle-foot orthoses (AFOs) are widely used to improve gait; nonetheless, it remains unclear how specific settings, particularly the dorsiflexion angle, affect gait kinematics in individuals with stroke. This study investigated the effect of different AFO dorsiflexion angles on gait kinematics in ambulatory adults with hemiparesis. Twenty-six individuals with post-stroke hemiparesis walked on a treadmill while wearing the same type of AFO at four ankle dorsiflexion angles: 0°, 5°, 10°, and 15°. Temporal-spatial variables, joint angles, and toe clearance and its components were quantified using three-dimensional analysis. The double-stance time before the paretic swing shortened significantly with increasing dorsiflexion angle, whereas the mean stride time and length did not significantly change. During the swing phase, increased AFO dorsiflexion was associated with reduced maximal knee flexion, in addition to its direct effect on ankle angles. The absolute toe clearance height was unaffected by the AFO settings; however, the contribution of ankle dorsiflexion to limb shortening increased stepwise from 0° to 15°, and the hip elevation and compensatory movement ratio declined. In conclusion, increasing the AFO dorsiflexion angle significantly altered gait kinematics, with distal ankle mechanics replacing inefficient hip compensation and reducing double-stance time. Full article

Acute ankle sprains frequently lead to chronic ankle instability and muscle atrophy by causing immobilization, which necessitates real-time stiffness modulation for ankle–foot orthoses (AFOs). This paper proposes Active Variable Compression Shoes (AVC-Shoes), an ankle support system inspired by the “heel-lock taping” technique, which employs a wire–fabric compression mechanism to selectively stiffen ankle joints at crucial points in the gait cycle. The experimental results confirmed that AVC-Shoes achieve variable ankle stiffness in all directions, demonstrating dorsiflexion and plantarflexion stiffness ranges of up to 8.3 and 5.9 Nm/rad, respectively. Additionally, preliminary human testing involving three healthy participants revealed that the gastrocnemius muscle activity during the push-off phase in the active compression mode was significantly higher (by 19%) than that in the brace mode. By selectively increasing stiffness at heel strikes, AVC-Shoes represent a promising advancement toward next-generation AFOs capable of stabilizing the ankle while preventing muscle atrophy, which is associated with prolonged brace use. Full article

Background: Elastic ankle straps are frequently used to improve ankle stability; however, they often fail to provide adequate support due to material limitations. Therefore, this study aimed to investigate the effects of an ankle stabilization strap applied using a bandaging technique on ankle range of motion, balance, and spatiotemporal gait parameters in patients with chronic stroke. Methods: Twenty-eight patients with chronic stroke were randomly assigned to either an ankle stabilization strap with bandaging technique (ASB, n = 14) group or an ankle–foot orthosis (AFO, n = 14) group. Both groups participated in treadmill gait training for 10 min per day, five days per week, for four weeks. Outcome measures included ankle dorsiflexion range of motion, total center of pressure displacement, timed up and go test, gait speed, and step length. A mixed-design analysis of variance was used for statistical analysis. Results: All outcome variables showed significant group-by-time interaction effects, and the ASB group exhibited significant within-group improvements after the intervention (p < 0.05). Conclusions: The ankle stabilization strap applied using a bandaging technique effectively improved ankle mobility, balance, and gait in patients with chronic stroke, suggesting its potential as a useful intervention in stroke rehabilitation. Full article

Background/Objectives: The simulation of human movement offers transformative potential for the design of medical devices, particularly in understanding the cause–effect dynamics in individuals with neurological or musculoskeletal impairments. This study presents a simulation-driven framework to determine the optimal ankle–foot orthosis (AFO) stiffness for mitigating the risk of ankle sprains due to excessive subtalar inversion during high-impact activities, such as landing from a free fall. Methods: We employed biomechanical simulations to assess the influence of translational stiffness on subtalar inversion control, given that inversion angles exceeding 25 degrees are strongly correlated with injury risk. Simulations were conducted using a musculoskeletal model with and without a passive AFO; the stiffness varied in three anatomical directions. A Design of Experiments (DoE) approach was utilized to capture nonlinear interactions among stiffness parameters. Results: The results indicated that increased translational stiffness significantly reduced inversion angles to safer levels, though direction–dependent effects were noted. Based on these insights, we developed a 4D visualization tool that integrates simulation data with an interactive color–coded interface to depict ”safe design” zones for various AFO stiffness configurations. This tool supports clinicians in selecting stiffness values that optimize both safety and functional performance. Conclusions: The proposed framework enhances clinical decision-making and engineering processes by enabling more accurate and individualized AFO designs. Full article

The present study aims to investigate the multi-year effects (5 years) of individualized whole-body vibration (WBV) on locomotion, postural control, and handgrip strength in a 68-year-old man with relapse remitting multiple sclerosis (PwRRMS). The dose–response relationship induced by a single session was quantified by determining the surface electromyographic activity (sEMG) of the participant. The participant wore an orthosis to limit the lack of foot dorsiflexion in the weakest limb during walking in daily life. The gait alteration during walking was assessed at 1, 2 and 3 km/h (without the orthosis) through angle–angle diagrams by quantifying the area, perimeter and shape of the loops, and the sEMG of leg muscles was recorded in both limbs. The evaluation of postural control was conducted during upright standing by quantifying the displacement of the center of pressure (CoP). The handgrip strength was assessed by measuring the force–time profile synchronized with the sEMG activity of upper arm muscles. The participant improved his ability to walk at higher speeds (2–3 km/h) without the orthosis. There were greater improvements in the area and perimeter of angle–angle diagrams for the weakest limb (Δ = 36–51%). The sEMG activity of the shank muscles increased at all speeds, particularly in the tibialis anterior of weakest limbs (Δ = 10–68%). The CoP displacement during upright standing decreased (Δ = 40–60%), whereas the handgrip strength increased (Δ = 32% average). Over the 5-year period of intervention, the individualized WBV improved locomotion, postural control and handgrip strength without side effects. Future studies should consider the possibility of implementing an individualized WBV in PwRRMS. Full article

Background/Objectives: This study focuses on the motion planning and control of an active ankle–foot orthosis (AFO) that leverages biomechanical insights to mitigate footdrop, a deficit that prevents safe toe clearance during walking. Methods: To adapt the motion of the device to the user’s walking speed, a geometric model was used, together with real-time measurement of the user’s gait cycle. A geometric speed-adaptive model also scales a trapezoidal ankle-velocity profile in real time using the detected gait cycle. The algorithm was tested at three different walking speeds, with a prototype of the AFO worn by a test subject. Results: At walking speeds of 0.44 and 0.61 m/s, reduced tibialis anterior (TA) muscle activity was confirmed by electromyography (EMG) signal measurement during the stance phase of assisted gait. When the AFO was in assistance mode after toe-off (initial and mid-swing phase), it provided an average of 48% of the estimated required power to make up for the deliberate inactivity of the TA muscle. Conclusions: Kinematic analysis of the motion capture data showed that sufficient foot clearance was achieved at all three speeds of the test. No adverse effects or discomfort were reported during the experiment. Future studies should examine the device in populations with footdrop and include a comprehensive evaluation of safety. Full article

This article presents a series of innovative systems developed through student laboratory projects, comprising two autonomous vehicles, a quadrupedal walking robot, an active ankle-foot orthosis, a ball-on-beam balancing mechanism, a ball-on-plate system, and a manipulator arm, all actuated by pneumatic artificial muscles (PAMs). Due to their flexibility, low weight, and compliance, fluidic muscles demonstrate substantial potential for integration into various mechatronic systems, robotic platforms, and manipulators. Their capacity to generate smooth and adaptive motion is particularly advantageous in applications requiring natural and human-like movements, such as rehabilitation technologies and assistive devices. Despite the inherent challenges associated with nonlinear behavior in PAM-actuated control systems, their biologically inspired design remains promising for a wide range of future applications. Potential domains include industrial automation, the automotive and aerospace sectors, as well as sports equipment, medical assistive devices, entertainment systems, and animatronics. The integration of self-constructed laboratory systems powered by PAMs into control systems education provides a comprehensive pedagogical framework that merges theoretical instruction with practical implementation. This methodology enhances the skillset of future engineers by deepening their understanding of core technical principles and equipping them to address emerging challenges in engineering practice. Full article

As populations age, particularly in countries like Japan, mobility impairments related to ankle joint dysfunction, such as foot drop, instability, and reduced gait adaptability, have become a significant concern. Active ankle–foot orthoses (AAFO) offer targeted support during walking; however, most existing systems rely on rule-based or threshold-based control, which are often limited to sagittal plane movements and lacking adaptability to subject-specific gait variations. This study proposes an approach driven by neuromuscular activation using surface electromyography (EMG) and a Gated Recurrent Unit (GRU)-based deep learning model to predict plantar pressure distributions at the heel, midfoot, and toe regions during gait. EMG signals were collected from four key ankle muscles, and plantar pressures were recorded using a customized sandal-integrated force-sensitive resistor (FSR) system. The data underwent comprehensive preprocessing and segmentation using a sliding window method. Root mean square (RMS) values were extracted as the primary input feature due to their consistent performance in capturing muscle activation intensity. The GRU model successfully generalized across subjects, enabling the accurate real-time inference of critical gait events such as heel strike, mid-stance, and toe off. This biomechanical evaluation demonstrated strong signal compatibility, while also identifying individual variations in electromechanical delay (EMD). The proposed predictive framework offers a scalable and interpretable approach to improving real-time AAFO control by synchronizing assistance with user-specific gait dynamics. Full article

Passive Dynamic Ankle–Foot Orthoses (PD-AFOs) are medical devices prescribed to individuals with foot drop, a condition characterized by weakness of the ankle dorsiflexor muscles. PD-AFOs can store and release energy during the stance phase of the gait cycle, while supporting the foot in the swing phase. This study aimed at estimating the energetics of a novel fiberglass-reinforced polyamide custom PD-AFO in a population of mild foot drop patients. Eight PD-AFOs were designed and 3D-printed via selective laser sintering for eight participants with a unilateral foot drop condition. Lower limb kinematics and AFO flexion/extension were recorded during comfortable walking speed via skin marker-based stereophotogrammetry. The stiffness of each AFO was measured via an ad hoc experimental setup. The elastic work performed by the PD-AFO during gait was calculated as the dot product of the calf-shell resisting moment and the rotation angle. The average maximum energy stored by the calf-shell across all PD-AFOs was 0.013 ± 0.005 J/kg. According to this study, 3D-printed custom PD-AFOs made with fiberglass-reinforced polyamide can store some elastic energy, which is released to the ankle during push-off. Further studies should be conducted to assess the effect of this energy return mechanism in improving the gait of individuals with deficits of the ankle plantarflexor muscles. Full article

Background/Objectives: Orthoses are commonly used in the treatment of various foot and ankle injuries and deformities. An effective technology in foot orthoses is a vacuum system to improve the fit and function of the orthosis. Recently, a new technology was designed to facilitate the wearing of the foot orthoses while maintaining function without the need for vacuum suction. Methods: A plantar dynamic pressure distribution measurement was carried out in 25 healthy subjects (13 w/12 m, age 23–58 y) using capacitive measuring insoles in two differently designed inlays within the VACOpedes^® orthosis (Group A: vacuum inlay vs. Group B: XELGO^® inlay) and a regular off-the-shelf shoe (Group C, OTS). The peak plantar pressure, mean plantar pressure and maximum force were analyzed in the entire foot and in individual regions of the medial and lateral forefoot, the midfoot and the hindfoot. Finally, the wearing comfort was compared using a visual analog scale from 1 to 10 (highest comfort). Results: The peak pressure of both inlays was significantly lower than in the OTS shoe (A: 230.6 ± 44.6 kPa, B: 218.0 ± 49.7 kPa, C: 278.6 ± 50.5 kPa; p < 0.001). In a sub-analysis of the different regions, the XELGO^® inlay significantly reduced plantar pressure in the medial forefoot compared to the vacuum orthosis (A: 181.7 ± 45.7 kPa, B: 158.6 ± 51.7 kPa, p < 0.002). The wearing comfort was significantly higher with the XELGO^® inlay compared to the vacuum inlay (A: 5.68/10, B: 7.24/10; p < 0.001). Conclusions: The VACOpedes^® orthosis with a new XELGO^® inlay showed at least equivalent relief in all pressure distribution measurements analyzed and greater relief in the forefoot area than the VACOpedes^® orthosis with a vacuum inlay, as well as increased wearing comfort. Full article

(1) Background: Flexible flatfoot is characterized by medial arch collapse, leading to musculoskeletal impairments. We examined the effects of single-arch foot orthosis (SFO) and dual-arch foot orthosis (DFO) on arch height, kinematics, and kinetics in young females during walking and jogging. (2) Methods: Healthy females (n = 19) with flexible flatfoot were tested under three conditions: regular shoes, SFO, and DFO. Motion capture and a 3D force plate gathered biomechanical data. We also used a high-speed dual fluoroscopic imaging system (DFIS) to assess dynamic foot morphology. Outcomes included normalized truncated navicular height, medial arch angle, angles and moments at the metatarsophalangeal, subtalar, ankle, knee, and hip joints. (3) Results: Both types of orthoses improved the normalized navicular height and reduced the medial arch angle, with DFO vs. SFO showing greater effects (p < 0.001). DFO vs. SFO was also more effective in limiting the range of motion (ROM) of the metatarsophalangeal joint and dorsiflexion (p < 0.001). Additionally, DFO reduced the ankle range of motion and the maximum knee flexion during walking. Both orthoses reduced subtalar plantarflexion moments during stance (p < 0.001) and modulated ankle plantarflexion moments throughout different phases of gait. DFO uniquely enhanced metatarsophalangeal plantarflexion moments during jogging (p < 0.001). (4) Conclusions: Dual vs. single transverse arch foot orthosis is more effective in improving gait biomechanics in females with flexible flatfoot. Longitudinal studies are needed to confirm these benefits. Full article

The lack of social acceptability for wearable devices such as orthopedic foot orthoses can lead to irregular usage and missed health benefits, as shown in prior studies. While AI-generated designs have been explored for prototyping aesthetic hand orthoses, their impact on social acceptability, particularly for foot orthoses, remains unknown. The current state of research is limited, as no empirical evidence exists on whether AI-designed orthoses influence acceptance, nor has the role of customized generative pre-trained transformers (GPTs) and specific prompting strategies been examined in this context. To address these gaps, we conducted two mixed-methods studies to investigate (1) the impact of AI-generated orthosis designs on social acceptability compared to existing orthopedic products and development concepts and (2) how a customized GPT and different prompt keywords influence acceptance. Our results show that AI-generated designs significantly enhance social acceptance across orthotic categories. Furthermore, we found that personalized GPTs and targeted prompt keywords significantly influence user perception. Overall, our findings highlight the potential of using AI to create socially acceptable design solutions for wearable technology and offer new applications for future smart devices. We contribute to generative AI in product design and provide concrete recommendations for optimizing prompting strategies to enhance social acceptance. Full article