This content will become publicly available on September 27, 2023
- Virdi, Amarjit Singh
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- PLOS ONE
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- Sponsoring Org:
- National Science Foundation
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The purpose of this study was to evaluate the use of compressible soft robotic sensors (C-SRS) in determining plantar pressure to infer vertical and shear forces in wearable technology: A ground reaction pressure sock (GRPS). To assess pressure relationships between C-SRS, pressure cells on a BodiTrakTM Vector Plate, and KistlerTM Force Plates, thirteen volunteers performed three repetitions of three different movements: squats, shifting center-of-pressure right to left foot, and shifting toes to heels with C-SRS in both anterior–posterior (A/P) and medial–lateral (M/L) sensor orientations. Pearson correlation coefficient of C-SRS to BodiTrakTM Vector Plate resulted in an average R-value greater than 0.70 in 618/780 (79%) of sensor to cell comparisons. An average R-value greater than 0.90 was seen in C-SRS comparison to KistlerTM Force Plates during shifting right to left. An autoregressive integrated moving average (ARIMA) was conducted to identify and estimate future C-SRS data. No significant differences were seen in sensor orientation. Sensors in the A/P orientation reported a mean R2 value of 0.952 and 0.945 in the M/L sensor orientation, reducing the effectiveness to infer shear forces. Given the high R values, the use of C-SRSs to infer normal pressures appears to make the development of the GRPS feasible.
An active ankle-foot orthosis (AAFO) was developed with the intent of providing propulsive ground reaction force to individuals at risk of experiencing fall. The device makes use of one double-acting cylinder per leg, and a lever arm system to transfer propulsive force to the ground, and potentially assist in fall prevention and rehabilitation. Preliminary tests have been shown to improve ground reaction forces in walking. In this paper, the design and construction of the device is included as well as the control algorithm used and testing procedure. This research may be used to advance the field of gait assistance and fall prevention through use of active foot orthotics.
Functional Resistance Training Differentially Alters Gait Kinetics After Anterior Cruciate Ligament Reconstruction: A Pilot Study
Quadriceps weakness is common after anterior cruciate ligament (ACL) reconstruction and can alter gait mechanics. Functional resistance training (FRT) is a novel approach to retraining strength after injury, but it is unclear how it alters gait mechanics. Therefore, we tested how 3 different types of FRT devices: a knee brace resisting extension (unidirectional brace), a knee brace resisting extension and flexion (bidirectional brace), and an elastic band pulling backwards on the ankle (elastic band)–acutely alter gait kinetics in this population.
The type of FRT device will affect ground-reaction forces (GRFs) during and after the training. Specifically, the uni- and bidirectional braces will increase GRFs when compared with the elastic band.
Level of Evidence:
A total of 15 individuals with ACL reconstruction received FRT with each device over 3 separate randomized sessions. During training, participants walked on a treadmill while performing a tracking task with visual feedback. Sessions contained 5 training trials (180 seconds each) with rest between. Vertical and anterior-posterior GRFs were assessed on the ACL-reconstructed leg before, during, and after training. Changes in GRFs were compared across devices using 1-dimensional statistical parametric mapping.
Resistance applied via bidirectional brace acutely increased gait kinetics during terminal stance/pre-swing (ie,more »
FRT after ACL reconstruction can acutely alter gait kinetics during training. Devices can be applied to selectively alter gait kinetics. However, the long-term effects of FRT after ACL reconstruction with these devices are still unknown.
FRT may be applied to alter gait kinetics of the involved limb after ACL reconstruction, depending on the device used.
This paper presents a simple inverted pendulum gait model, to study walking under slip conditions. The model allows for both the horizontal and vertical movements of the center of mass during normal walking and walking gaits with foot slip. Stability of the system is analyzed using the concept of capturability. Considering foot placement as a control input, we obtain the stable regions which lead to stable gait. The size of those stable regions is used to evaluate the effect of the coefficient of friction and the slip reaction time on capturability. The (in)feasibility of recovery from slip gait is analyzed in relation to the coefficient of friction and the reaction time.
The stance phase of walking is when forces are applied to the environment to support, propel, and maneuver the body. Unlike solid surfaces, deformable substrates yield under load, allowing the foot to sink to varying degrees. For bipedal birds and their dinosaurian ancestors, a shared response to walking on these substrates has been identified in the looping path the digits follow underground. Because a volume of substrate preserves a 3-D record of stance phase in the form of footprints or tracks, understanding how the bipedal stride cycle relates to this looping motion is critical for building a track-based framework for the study of walking in extinct taxa. Here, we used biplanar X-ray imaging to record and analyze 161 stance phases from 81 trials of three Helmeted Guineafowl (Numida meleagris) walking on radiolucent substrates of different consistency (solid, dry granular, and firm to semi-liquid muds). Across all substrates, the feet sank to a range of depths up to 78% of hip height. With increasing substrate hydration, the majority of foot motion shifted from above to below ground. Walking kinematics sampled across all stride cycles revealed six sequential gait-based events originating from both feet, conserved throughout the spectrum of substrate consistenciesmore »