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The purpose of this study is to simulate the different walking adaptation strategies and their impact on muscle activities while changing the anchor point position of an exosuit in hip extension assistance motion. In particular, muscle activation and metabolic power consumption are assessed at varying levels of assistive force actuation that alters the position of anchor points. OpenSim software was used to perform simulations of 10 elderly subjects at comfortable gait speed while varying the anchor point positions of the thigh. Compared to unassisted gait, the extension assistance at placements below 40% (proximal) requires an increase in metabolic cost to maintain gait characteristics. At 40%, energy consumption corresponds to unassisted gait. From 50% proximal to distal positions, a reduction in metabolic cost is observed, with a minimum at 80%. The variation of the metabolic cost at different positions of the anchor point is reflected in the muscular activities, with an increase when the cable is placed below 40% of the total length of the thigh and a decrease from this position onwards. The activation level and metabolic cost exerted by the hip flexors and extensors muscles may be optimized during the exosuit actuation. The dynamics of the muscles spanning joints not actuated by the exosuit are not influenced by the actuation. The results and analysis provide information to optimize actuation profiles in the design of exosuits to assist gait for older adults and, thus, promote active aging and improving rehabilitation routines. [ABSTRACT FROM AUTHOR]

AbstractExosuits for the lower limb have developed rapidly as an affordable, light, and more cost-effective alternative to the bulkier, traditional exoskeletons. The synergy-based approach aims at further emphasizing such advantages, providing even lighter and cheaper solutions, thanks to its reduction in actuators and the subsequent simplification of the actuation unit. In this paper, a design approach based on dynamic synergies is proposed to reduce the number of required actuators, thus decreasing the price and weight of walking-assistance exosuits. Also, in this work, we propose a methodology to calculate motor torque output and cable forces during assisted gait. Mechanical designs for the actuation unit are proposed along with experimental and computer-based testing and simulation. Lastly, actuation units with one and two motors are studied and compared, regarding control, mechanical complexity, and metabolic cost reduction. The results show that dynamic synergies can indeed contribute to the design of these assistive devices, with its own set of advantages and disadvantages when compared to the previously proposed postural synergies: while the latter led to a higher cumulative variance of the first principal component and the transmission system is simpler, control may be more unpredictable and forces upon the system, harder to estimate. With dynamic synergies, more related to muscle synergies, metabolic benefit on users may be more significant. [ABSTRACT FROM AUTHOR]

With ever-rising population comes a corresponding rise in people with mobility issues who have difficulty handling tasks in their daily lives. Such persons could benefit significantly from an active movement assistance device. This paper presents the design of a lower-limb exosuit designed to provide the wearer with useful gait assistance. While exoskeletons have existed for a while, soft exoskeletons or exosuits are relatively new. One challenge in the design of a gait-assistance device is the reduction of device weight. In order to facilitate this, the concept of kinematic synergies is implemented to reduce the number of actuators. In this prototype, the exosuit can actuate the hip, ankle, and knee of both legs using just one single motor, and a transmission system consisting of gears and clutches. The implementation of these synergies and their advantages are detailed in this paper, as well as preliminary tests to assess performance. This was performed by testing the exosuit worn by a subject on a treadmill while taking EMG readings and measuring cable tension produced. Significant reductions by up to 35% in certain muscle activations were observed, demonstrating the validity of this prototype for gait assistance. [ABSTRACT FROM AUTHOR]

Older adults (aged 55 years and above) have greater difficulty carrying out activities of daily living than younger adults (aged 25–55 years). Although age-related changes in human gait kinetics are well documented in qualitative terms in the scientific literature, these differences may be quantified and analyzed using the analysis of motor control strategies through kinetic synergies. The gaits of two groups of people (older and younger adults), each with ten members, were analyzed on a treadmill at a constant controlled speed and their gait kinetics were recorded. The decomposition of the kinetics into synergies was applied to the joint torques at the hip, knee, and ankle joints. Principal components determined the similarity of the kinetic torques in the three joints analyzed and the effect of the walking speed on the coordination pattern. A total of three principal components were required to describe enough information with minimal loss. The results suggest that the older group showed a change in coordination strategy compared to that of the younger group. The main changes were related to the ankle and hip torques, both showing significant differences (p-value < 0.05 ) between the two groups. The findings suggest that the differences between the gait patterns of the two groups were closely related to a reduction in ankle torque and an increase in hip torque. This change in gait pattern may affect the rehabilitation strategy used when designing general-purpose rehabilitation devices or rehabilitation/training programs for the elderly. [ABSTRACT FROM AUTHOR]

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Copyright of Revista Iberoamericana de Ingeniería Mecánica is the property of Editorial UNED and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Gait monitoring using hip joint angles offers a promising approach for person identification, leveraging the capabilities of smartphone inertial measurement units (IMUs). This study investigates the use of smartphone IMUs to extract hip joint angles for distinguishing individuals based on their gait patterns. The data were collected from 10 healthy subjects (8 males, 2 females) walking on a treadmill at 4 km/h for 10 min. A sensor fusion technique that combined accelerometer, gyroscope, and magnetometer data was used to derive meaningful hip joint angles. We employed various machine learning algorithms within the WEKA environment to classify subjects based on their hip joint pattern and achieved a classification accuracy of 88.9%. Our findings demonstrate the feasibility of using hip joint angles for person identification, providing a baseline for future research in gait analysis for biometric applications. This work underscores the potential of smartphone-based gait analysis in personal identification systems.