Pressure-Sensitive Insoles for Real-Time Gait-Related Applications

Wearable robotic devices require sensors and algorithms that can recognize the user state in real-time, in order to provide synergistic action with the body. For devices intended for locomotion-related applications, shoe-embedded sensors are a common and convenient choice, potentially advantageous for performing gait assessment in real-world environments. In this work, we present the development of a pair of pressure-sensitive insoles based on optoelectronic sensors for the real-time estimation of temporal gait parameters. The new design makes use of a simplified sensor configuration that preserves the time accuracy of gait event detection relative to previous prototypes. The system has been assessed relatively to a commercial force plate recording the vertical component of the ground reaction force (vGRF) and the coordinate of the center of pressure along the so-called progression or antero-posterior plane (CoPAP) in ten healthy participants during ground-level walking at two speeds. The insoles showed overall median absolute errors (MAE) of 0.06 (0.02) s and 0.04 (0.02) s for heel-strike and toe-off recognition, respectively. Moreover, they enabled reasonably accurate estimations of the stance phase duration (2.02 (2.03) % error) and CoPAP profiles (Pearson correlation coefficient with force platform ρCoP = 0.96 (0.02)), whereas the correlation with vGRF measured by the force plate was lower than that obtained with the previous prototype (ρvGRF = 0.47 (0.20)). These results confirm the suitability of the insoles for online sensing purposes such as timely gait phase estimation and discrete event recognition.

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The effect of anteroposterior perturbations on the control of the center of mass during treadmill walking

10.1101/848853 ◽

2019 ◽

Author(s):

Maud van den Bogaart ◽

Sjoerd M. Bruijn ◽

Jaap H. van Dieën ◽

Pieter Meyns

Keyword(s):

Center Of Pressure ◽

Center Of Mass ◽

Reaction Force ◽

Force Plate ◽

Gait Pattern ◽

Therapeutic Interventions ◽

Heel Strike ◽

Foot Placement ◽

Relative Contribution ◽

Counter Rotation

AbstractShifts of the center of pressure (CoP) through modulation of foot placement and ankle moments (CoP-mechanism) cause accelerations of the center of mass (CoM) that can be used to stabilize gait. An additional mechanism that can be used to stabilize gait, is the counter-rotation mechanism, i.e., changing the angular momentum of segments around the CoM to change the direction of the ground reaction force. The relative contribution of these mechanisms to the control of the CoM is unknown. Therefore, we aimed to determine the relative contribution of these mechanisms to control the CoM in the anteroposterior (AP) direction during a normal step and the first recovery step after perturbation in healthy adults. Nineteen healthy subjects walked on a split-belt treadmill and received unexpected belt acceleration perturbations of various magnitudes applied immediately after right heel-strike. Full-body kinematic and force plate data were obtained to calculate the contributions of the CoP-mechanism and the counter-rotation mechanism to control the CoM. We found that the CoP-mechanism contributed to corrections of the CoM acceleration after the AP perturbations, while the counter-rotation mechanism actually contributed to CoM acceleration in the direction of the perturbation, but only in the initial phases of the first step after the perturbation. The counter-rotation mechanism appeared to prevent interference with the gait pattern, rather than using it to control the CoM after the perturbation. Understanding the mechanisms used to stabilize gait may have implications for the design of therapeutic interventions that aim to decrease fall incidence.Summary statementUnderstanding the mechanisms used to stabilize gait during unperturbed and perturbed walking may have implications for the design of therapeutic interventions that aim to decrease fall incidence.

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Walking Pattern of Midfoot and Ankle Disarticulation Amputees

Foot & Ankle International ◽

10.1177/107110079701801006 ◽

1997 ◽

Vol 18 (10) ◽

pp. 635-638 ◽

Cited By ~ 29

Author(s):

Michael S. Pinzur ◽

Brian Wolf ◽

Robert M. Havey

Keyword(s):

Center Of Pressure ◽

Reaction Force ◽

Vertical Component ◽

Metabolic Cost ◽

Heel Strike ◽

Peripheral Vascular ◽

First Metatarsal ◽

Walking Pattern ◽

Lateral Posterior ◽

Amputation Surgery

Measurements of the vertical component of ground reaction force (GRF) and dynamic center of pressure (COP) were recorded for five subjects with midfoot level amputations and six with Syme's ankle disarticulation amputations. All of the subjects underwent amputation surgery as a consequence of peripheral vascular disease and diabetes. GRF measurement was accomplished with the F-Scan system (Tekscan, Boston, MA). Each group exhibited a consistent, reproducible pattern of gait. Subjects with Syme's ankle disarticulation initiated initial loading response, i.e., heel strike, with a concentration of GRF in the center of the anatomic heel. COP progressed along the midline to the center of the anatomic forefoot, where GRF was concentrated at push-off. Midfoot amputees initiated loading at the lateral-posterior heel. COP progressed medially to the midline, where it progressed distally to the level of the distal residual limb (proximal metatarsal metaphyses). It then shifted medially under the base of the first metatarsal, where a small concentration of GRF occurred at push-off, similar to the normal foot. These findings explain the decreased magnitude of propulsion seen in midfoot level amputees and may explain the seemingly paradoxical increased metabolic cost of walking observed in midfoot amputees as compared with Syme's ankle disarticulation amputees.

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Investigating the Effect of Real-Time Center of Pressure (CoP) Feedback Training on the Swing Phase of Lower Limb Kinematics in Transfemoral Prostheses with SACH foot

Journal of Biomechanical Engineering ◽

10.1115/1.4053364 ◽

2021 ◽

Author(s):

Ashutosh Tiwari ◽

Abhijeet Kujur ◽

Jyoti Kumar ◽

Deepak Joshi

Keyword(s):

Real Time ◽

Lower Limb ◽

Knee Flexion ◽

Center Of Pressure ◽

Feedback System ◽

Swing Phase ◽

Flexion Angle ◽

Heel Strike ◽

Knee Flexion Angle ◽

Joint Angles

Abstract Transfemoral amputee often encounters reduced toe clearance resulting in trip-related falls. Swing phase joint angles have been shown to influence the toe clearance therefore, training intervention that targets shaping the swing phase joint angles can potentially enhance toe clearance. The focus of this study was to investigate the effect of the shift in the location of the center of pressure (CoP) during heel strike on modulation of the swing phase joint angles in able-bodied participants (n=6) and transfemoral amputees (n=3). We first developed a real-time CoP-based visual feedback system such that participants could shift the CoP during treadmill walking. Next, the kinematic data were collected during two different walking sessions- baseline (without feedback) and feedback (shifting the CoP anteriorly/posteriorly at heel strike to match the target CoP location). Primary swing phase joint angle adaptations were observed with feedback such that during the mid-swing phase, posterior CoP shift feedback significantly increases (p<0.05) the average hip and knee flexion angle by 11.55 degrees and 11.86 degrees respectively in amputees, whereas a significant increase (p<0.05) in ankle dorsiflexion, hip and knee flexion angle by 3.60 degrees, 3.22 degrees, and 1.27 degrees respectively compared to baseline was observed in able-bodied participants. Moreover, an opposite kinematic adaptation was seen during anterior CoP shift feedback. Overall, results confirm a direct correlation between the CoP shift and the modulation in the swing phase lower limb joint angles.

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Closing the Wearable Gap—Part V: Development of a Pressure-Sensitive Sock Utilizing Soft Sensors

Sensors ◽

10.3390/s20010208 ◽

2019 ◽

Vol 20 (1) ◽

pp. 208 ◽

Cited By ~ 6

Author(s):

Tony Luczak ◽

Reuben F. Burch V ◽

Brian K. Smith ◽

Daniel W. Carruth ◽

John Lamberth ◽

...

Keyword(s):

Center Of Pressure ◽

Moving Average ◽

Pearson Correlation ◽

Soft Sensors ◽

Shear Forces ◽

Autoregressive Integrated Moving Average ◽

Pressure Sensitive ◽

Sensor Orientation ◽

R Value ◽

Anterior Posterior

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.

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The development of a long, dual-platform triaxial walkway for the measurement of forces and temporal-spatial data in the clinical assessment of gait

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1243/0954411001535354 ◽

2000 ◽

Vol 214 (2) ◽

pp. 193-201 ◽

Cited By ~ 7

Author(s):

D Hynd ◽

S C Hughes ◽

D J Ewins

Keyword(s):

Spatial Data ◽

Spatial Information ◽

Reaction Force ◽

Force Plate ◽

Vertical Component ◽

Clinical Information ◽

Step Length ◽

Accurate Estimate ◽

Human Gait ◽

Rapid Reduction

Force-plate measurement of the ground reaction force (GRF) has, for many years, been considered a vital component of the comprehensive assessment of human gait in the clinical context. For example, the data can be used in the adjustment of prostheses and orthoses and in identifying the mechanisms underlying a gait dysfunction. However, commercial force plates are usually only capable of measuring GRF data from one step in a single traverse. That can lead to problems of ‘targeting’ and, with less able subjects, fatigue before the necessary data have been collected. Previous work at the University of Surrey resulted in a prototype dual-platform force walkway capable of measuring the vertical component of the GRF and estimating the position of application of that force for multiple foot contacts in a single traverse. In addition, temporal-spatial information, e.g. speed and step length, could also be determined. This paper describes the development of a longer walkway that can measure the three orthogonal components of the GRF and provide a more accurate estimate of the position of application of that force. Software to allow the rapid reduction of gait data to useful clinical information has also been developed.

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The Effect of Teeth Clenching on Dynamic Balance at Jump-Landing: A Pilot Study

Journal of Applied Biomechanics ◽

10.1123/jab.2016-0137 ◽

2017 ◽

Vol 33 (3) ◽

pp. 211-215

Author(s):

Tomomasa Nakamura ◽

Yuriko Yoshida ◽

Hiroshi Churei ◽

Junya Aizawa ◽

Kenji Hirohata ◽

...

Keyword(s):

Muscle Activity ◽

Masseter Muscle ◽

Center Of Pressure ◽

Dynamic Balance ◽

Reaction Force ◽

Force Plate ◽

Vertical Ground Reaction Force ◽

Jump Landing ◽

Teeth Clenching ◽

Vertical Ground

The aim of this study was to analyze the effect of teeth clenching on dynamic balance at jump landing. Twenty-five healthy subjects performed jump-landing tasks with or without teeth clenching. The first 3 trials were performed with no instruction; subsequently, subjects were ordered to clench at the time of landing in the following 3 trials. We collected the data of masseter muscle activity by electromyogram, the maximum vertical ground reaction force (vGRFmax) and center of pressure (CoP) parameters by force plate during jump-landing. According to the clenching status of control jump-landing, all participants were categorized into a spontaneous clenching group and no clenching group, and the CoP data were compared. The masseter muscle activity was correlated with vGRFmax during anterior jump-landing, while it was not correlated with CoP. In comparisons between the spontaneous clenching and the no clenching group during anterior jump-landing, the spontaneous clenching group showed harder landing and the CoP area became larger than the no clenching group. There were no significant differences between pre- and postintervention in both spontaneous clenching and no clenching groups. The effect of teeth clenching on dynamic balance during jump-landing was limited.

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Biomechanical Analysis on the Foot under Normal and Abnormal Gait for Orthotics Design

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.353-358.2179 ◽

2007 ◽

Vol 353-358 ◽

pp. 2179-2182 ◽

Cited By ~ 1

Author(s):

Jae Ok Lee ◽

Young Shin Lee ◽

Se Hoon Lee ◽

Young Jin Choi ◽

Soung Ha Park

Keyword(s):

Gait Analysis ◽

Human Body ◽

Center Of Pressure ◽

Reaction Force ◽

The Body ◽

Biomechanical Analysis ◽

Gait Characteristics ◽

Abnormal Gait ◽

Experimental Apparatus ◽

Analysis System

The foot plays an important role in supporting the body and keeping body balance. An abnormal walking habit breaks the balance of the human body as well as the function of the foot. The foot orthotics which is designed to consider biomechanics effectively distributes the load of the human body on the sole of the foot. In this paper, gait analysis is performed for subjects wearing the orthotics. In this study, three male subjects were selected. The experimental apparatus consists of a plantar pressure analysis system and digital EMG system. The gait characteristics are simulated by ADAMS/LifeMOD. The COP (Center of Pressure), EMG and ground reaction force were investigated. As a result of gait analysis, the path of COP was improved and muscle activities were decreased with orthotics on the abnormal walking subjects.

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Abstract 482: Differences in Ground Reaction Forces and Chest Compression Release Velocity in Professional and Lay Rescuers With and Without the Use of Real-Time CPR Feedback

Circulation ◽

10.1161/circ.140.suppl_2.482 ◽

2019 ◽

Vol 140 (Suppl_2) ◽

Author(s):

Lyra Clark ◽

Ben Senderling ◽

Jeff R Gould ◽

Chris Kaufman ◽

Nick Stergiou

Keyword(s):

Real Time ◽

Chest Compression ◽

Reaction Force ◽

Force Plate ◽

Compression Cycle ◽

Reaction Forces ◽

Force Range ◽

Favorable Neurological Outcome ◽

Compression Characteristics ◽

Pearson Correlations

Purpose: Chest compression release velocity (CCRV) has been associated with survival and favorable neurological outcome after cardiac resuscitation. Both complete chest release and high CCRV contribute to improved venous return during CPR. Differences in compression forces delivered by professional and lay rescuers are reported, which may contribute to differences in CCRV. The aim of this pilot study was to investigate differences in ground reaction force (GRF) and CCRV between professional and lay rescuers during CPR performed on a manikin with and without real-time feedback. Methods: Professional (n = 5) and lay rescuers (n = 11) performed two minutes of continuous compressions on a manikin positioned over a force plate for two trials. CPR feedback provided by a defibrillator was disabled in the first trial and enabled in the second. CPR pads containing an accelerometer were used to calculate individual compression characteristics. Relative maximum and minimum GRFs were calculated for each compression cycle and averaged over each trial. Paired and independent sample t tests and Pearson correlations were conducted in STATA 15.1. Results: CCRV was higher in professionals vs. lay rescuers with feedback disabled and enabled ( p <0.05). Professionals had greater maximal and lower minimum forces than lay rescuers without feedback ( p <0.05), though there were no differences between groups with feedback enabled (Table 1). CCRV was associated with minimum force (r = -0.63, p <0.01) and force range (r = 0.78, p <0.01) in all rescuers. Analysis of GRFs by CCRV for all rescuers indicated lower force minimum (9.71 + 3.16 N, p <0.05) with CCRV >400 mm/s in comparison to CCRV 300-400 mm/s (39.73 + 8.91 N) and CCRV 200-300 mm/s (63.82 + 16.98 N). Conclusions: CPR feedback attenuated differences in GRF between professional and lay rescuers. CCRV was greater in professionals and was associated with measures of GRF, and thus may serve as an indicator of both velocity and amount of chest release.

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Single-Legged Hop and Single-Legged Squat Balance Performance in Recreational Athletes With a History of Concussion

Journal of Athletic Training ◽

10.4085/1062-6050-185-19 ◽

2020 ◽

Vol 55 (5) ◽

pp. 488-493 ◽

Cited By ~ 4

Author(s):

Robert C. Lynall ◽

Kody R. Campbell ◽

Timothy C. Mauntel ◽

J. Troy Blackburn ◽

Jason P. Mihalik

Keyword(s):

Injury Risk ◽

Center Of Pressure ◽

Balance Control ◽

Dynamic Balance ◽

Reaction Force ◽

Force Plate ◽

Analysis Of Covariance ◽

Control Group ◽

Time To Stabilization ◽

History Of

Context Researchers have suggested that balance deficiencies may linger during functional activities after concussion recovery. Objective To determine whether participants with a history of concussion demonstrated dynamic balance deficits as compared with control participants during single-legged hops and single-legged squats. Design Cross-sectional study. Setting Laboratory. Patients or Other Participants A total of 15 previously concussed participants (6 men, 9 women; age = 19.7 ± 0.9 years, height = 169.2 ± 9.4 cm, mass = 66.0 ± 12.8 kg, median time since concussion = 126 days [range = 28–432 days]) were matched with 15 control participants (6 men, 9 women; age = 19.7 ± 1.6 years, height = 172.3 ± 10.8 cm, mass = 71.0 ± 10.4 kg). Intervention(s) During single-legged hops, participants jumped off a 30-cm box placed at 50% of their height behind a force plate, landed on a single limb, and attempted to achieve a stable position as quickly as possible. Participants performed single-legged squats while standing on a force plate. Main Outcome Measure(s) Time to stabilization (TTS; time for the normalized ground reaction force to stabilize after landing) was calculated during the single-legged hop, and center-of-pressure path and speed were calculated during single-legged squats. Groups were compared using analysis of covariance, controlling for average days since concussion. Results The concussion group demonstrated a longer TTS than the control group during the single-legged hop on the nondominant leg (mean difference = 0.35 seconds [95% confidence interval = 0.04, 0.64]; F2,27 = 5.69, P = .02). No TTS differences were observed for the dominant leg (F2,27 = 0.64, P = .43). No group differences were present for the single-legged squat on either leg (P ≥ .11). Conclusions Dynamic balance-control deficits after concussion may contribute to an increased musculoskeletal injury risk. Given our findings, we suggest that neuromuscular deficits currently not assessed after concussion may linger. Time to stabilization is a clinically applicable measure that has been used to distinguish patients with various pathologic conditions, such as chronic ankle instability and anterior cruciate ligament reconstruction, from healthy control participants. Whereas the single-legged squat may not sufficiently challenge balance control, future study of the more dynamic single-legged hop is needed to determine its potential diagnostic and prognostic value after concussion.

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BIOMECHANICAL CHARACTERISTICS IN YOGA SIRSASANA

Journal of Mechanics in Medicine and Biology ◽

10.1142/s0219519417500531 ◽

2017 ◽

Vol 17 (03) ◽

pp. 1750053 ◽

Cited By ~ 1

Author(s):

YO CHEN ◽

CHO-WEI LEE ◽

YU-LAN CHEN ◽

HUI-TING LIN ◽

JIA-HAO CHANG

Keyword(s):

Pressure Distribution ◽

Surface Area ◽

Motion Capture ◽

Reaction Force ◽

Force Plate ◽

The Body ◽

Friedman Test ◽

Joint Angles ◽

Males And Females ◽

The Difference

The aim of this study was to understand how to process Yoga headstand and the difference between genders in headstand. Twelve skilled participates were recruited in this study (Males 34.1 [Formula: see text] 3.3 years, [Formula: see text]; Females 36.5 [Formula: see text] 3.9 years, [Formula: see text]). The 10 camera Vicon motion capture system, Kistler force plate, and Medilogic pressure mat were used synchronously to record the movement, ground reaction force, and pressure distribution during headstand. The Mann–Whitney U test and Friedman test ([Formula: see text]) was applied to assess the statistics. The trunk, hip, knee, and ankle joint angles were [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], respectively, in all subjects. The pressure distribution was 38 [Formula: see text] 19%, 29 [Formula: see text] 12%, and 33 [Formula: see text] 9% on subjects’ heads, right elbows, and left elbows, respectively. The COP trajectory was 31.2 [Formula: see text] 17.4[Formula: see text]cm and surface area was 5.3 [Formula: see text] 1.4[Formula: see text]cm2. No significant differences were found in joint angles, overall force distribution, and COP trajectory and surface area between genders. Both males and females distribute body weight to the supports of head and elbows equally and kept the body straight and erect on the ground during Yoga headstand.

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