Modeling of vertical ground reaction forces during double stance phase of the gait cycle for real-time treadmill measurements

The symptomatic flatfoot deformity (pes planus with peri-talar subluxation) can be a debilitating condition. Cadaveric flatfoot models have been employed to study the etiology of the deformity, as well as invasive and noninvasive surgical treatment strategies, by evaluating bone positions. Prior cadaveric flatfoot simulators, however, have not leveraged industrial robotic technologies, which provide several advantages as compared with the previously developed custom fabricated devices. Utilizing a robotic device allows the researcher to experimentally evaluate the flatfoot model at many static instants in the gait cycle, compared with most studies, which model only one to a maximum of three instances. Furthermore, the cadaveric tibia can be statically positioned with more degrees of freedom and with a greater accuracy, and then a custom device typically allows. We created a six degree of freedom robotic cadaveric simulator and used it with a flatfoot model to quantify static bone positions at ten discrete instants over the stance phase of gait. In vivo tibial gait kinematics and ground reaction forces were averaged from ten flatfoot subjects. A fresh frozen cadaveric lower limb was dissected and mounted in the robotic gait simulator (RGS). Biomechanically realistic extrinsic tendon forces, tibial kinematics, and vertical ground reaction forces were applied to the limb. In vitro bone angular position of the tibia, calcaneus, talus, navicular, medial cuneiform, and first metatarsal were recorded between 0% and 90% of stance phase at discrete 10% increments using a retroreflective six-camera motion analysis system. The foot was conditioned flat through ligament attenuation and axial cyclic loading. Post-flat testing was repeated to study the pes planus deformity. Comparison was then made between the pre-flat and post-flat conditions. The RGS was able to recreate ten gait positions of the in vivo pes planus subjects in static increments. The in vitro vertical ground reaction force was within ±1 standard deviation (SD) of the in vivo data. The in vitro sagittal, coronal, and transverse plane tibial kinematics were almost entirely within ±1 SD of the in vivo data. The model showed changes consistent with the flexible flatfoot pathology including the collapse of the medial arch and abduction of the forefoot, despite unexpected hindfoot inversion. Unlike previous static flatfoot models that use simplified tibial degrees of freedom to characterize only the midpoint of the stance phase or at most three gait positions, our simulator represented the stance phase of gait with ten discrete positions and with six tibial degrees of freedom. This system has the potential to replicate foot function to permit both noninvasive and surgical treatment evaluations throughout the stance phase of gait, perhaps eliciting unknown advantages or disadvantages of these treatments at other points in the gait cycle.

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Gait characteristics of transtibial amputees on level ground in a cohort of 53 amputees - Comparison of kinetics and kinematics with non-amputees

Canadian Prosthetics & Orthotics Journal ◽

10.33137/cpoj.v2i2.32955 ◽

2020 ◽

Vol 2 (2) ◽

Author(s):

Eva Pröbsting ◽

Malte Bellmann ◽

Thomas Schmalz ◽

Andreas Hahn

Keyword(s):

Knee Flexion ◽

Stance Phase ◽

Ground Reaction Forces ◽

Gait Characteristics ◽

Peak Knee ◽

Sound Side ◽

Flexion Moment ◽

Reaction Forces ◽

Vertical Ground ◽

Vertical Ground Reaction Forces

STUDY DESIGN: Retrospective analysis BACKGROUND: The gait characteristics of transtibial amputees (TTs) have been described many times. In general, the literature reported nearly consistent results for the kinematic and kinetic parameters of the prosthetic side. However, the literature revealed inconsistent findings on kinetic parameters for determining the risk of developing knee osteoarthritis, such as the peak knee adduction moment, knee flexion moment and vertical ground reaction forces. OBJECTIVES: The objective of our study was to describe the sagittal kinetic and kinematic gait characteristics of the ankle and residual knee joint of the prosthetic limb and the knee loading parameters of the sound side of unilateral TTs. This specific consideration may contribute to resolving the controversy of these parameters in the literature. METHODS: We analysed our database containing gait analyses from 53 unilateral TTs and compared data to a control group (CG), also taken from our database. The sagittal kinetic and kinematic gait characteristics of the ankle and residual knee joint of the prosthetic limb, and selected knee loading parameters of the sound side (the peak knee adduction moment, knee flexion moment and vertical ground reaction forces) were evaluated. Beside these parameters we reported typical spatiotemporal gait parameters as gait velocity, step length, step length asymmetry, stance phase duration and asymmetry of stance phase duration. RESULTS: The TTs walked slower and more asymmetrically than the CG. The kinematic pattern of the prosthetic ankle differed from that found in the CG. The largest difference was observed for the range of motion of the plantarflexion at push-off, which was significantly reduced for the prosthetic foot. The residual knee joint was generally affected with respect to decreased moments and reduced knee flexion during stance phase. The peaks of the vertical ground reaction forces and knee adduction moments showed no differences between the sound side of amputees and the CG. The peak knee flexion moment at midstance was significantly reduced for the sound side of amputees in comparison with the CG. CONCLUSION: The biomechanical data measured for the prosthetic side in a cohort of 53 unilateral TT amputees conformed with the literature. The parameters determining the risk of developing knee osteoarthritis investigated in our retrospective analysis were not increased on the sound side in comparison with non-amputees. We deem it reasonable to assume that an appropriate prosthesis will reduce the likelihood of overloading the knee on the sound side during normal walking. LAYMAN’S ABSTRACT: The gait characteristics of a transtibial amputee (TT) with a prosthesis significantly deviate from normal gait patterns as shown in the literature. In general, the kinematic and kinetic parameters of the prosthetic side are described nearly consistently. However, literature revealed inconsistent results with respect to the sound side, specifically the parameters determining the risk of developing knee osteoarthritis. To resolve this controversy in the literature, an analysis of a large cohort seems necessary. Therefore, we analysed gait characteristics of TTs from our gait lab database and compared them to able-bodied individuals (CG). The results showed that the TTs walked slower and more asymmetrically than the CG. The movement pattern of the prosthetic ankle differed from that found in the CG. The residual knee joint was is affected with respect to decreased moments and reduced knee flexion during stance phase. The peaks of the vertical ground reaction forces and knee adduction moments showed no differences between the sound side of amputees and the CG. The peak knee flexion moment was significantly reduced for the sound side of amputees in comparison with the CG. The biomechanical data measured for the prosthetic side concurred with findings of other studies. The controversially discussed parameters determining the risk of developing knee osteoarthritis were not increased on the sound side in comparison with non-amputees. We deem it reasonable to assume that an appropriate prosthesis will reduce the likelihood of overloading the knee on the sound side during normal walking. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/32955/25788 How to Cite: Pröbsting E, Bellmann M, Schmalz T, Hahn A. Gait characteristics of transtibial amputees on level ground in a cohort of 53 amputees - comparison of kinetics and kinematics with non-amputees. Canadian Prosthetics & Orthotics Journal. 2019;Volume2, Issue2, No.1. https://doi.org/10.33137/cpoj.v2i2.32955. CORRESPONDING AUTHOR:Dipl.-Ing (FH) Eva Pröbsting, Clinical Research & Services / Biomechanics, Ottobock SE & Co. KGaA, Hermann-Rein-Straße 2a, 37075 Göttingen, Germany.ORCID: https://orcid.org/0000-0002-6349-2992E-MAIL: [email protected]

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Kinetic Gait Analysis of Agility Dogs Entering the A-Frame

Veterinary and Comparative Orthopaedics and Traumatology ◽

10.1055/s-0038-1677492 ◽

2019 ◽

Vol 32 (02) ◽

pp. 097-103 ◽

Cited By ~ 1

Author(s):

Mark Glyde ◽

Giselle Hosgood ◽

Alasdair Dempsey ◽

Sarah Wickham ◽

Carla Appelgrein

Keyword(s):

Stance Phase ◽

Ground Reaction Forces ◽

Vertical Force ◽

Propulsive Force ◽

Forward Movement ◽

Impact Peak ◽

Force Peak ◽

Reaction Forces ◽

Vertical Ground ◽

Vertical Ground Reaction Forces

Objective The main purpose of this study was to investigate the effect of a decrease in the A-frame angle of incline on the vertical and cranio-caudal ground reaction forces observed in a homogeneous cohort of agility dogs during entrance and contact with the A-frame. Materials and Methods A crossover study design was applied to eight large breed dogs to compare the vertical and cranio-caudal ground reaction forces entering the A-frame at three angles of incline: 40° (standard), 35° and 30°. The peak vertical force, passive impact peak, peak propulsive force, peak braking force, the time point (percentile) in the stance phase at which these events occurred and the proportion of time for limb contact spent in braking (% braking) and propulsion (% propulsion) were examined.The variables measured from three trials at each incline were evaluated for a significant effect of A-frame angle with height and velocity included as covariates. Results The peak propulsive force and the % propulsion were significantly higher at the 40° angle of incline compared with 30° (p = 0.013, p = 0.0165 respectively) and the % braking was significantly lower at the 40° angle of incline compared with 30° (p = 0.0165). There was no significant effect of A-frame angle on the vertical ground reaction forces measured. Clinical Significance Compared with 30° incline, ascent up the A-frame at a 40° incline requires a higher propulsive force and extended time in propulsion to maintain forward movement and convert potential energy into forward kinetic energy.

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Use of an instrument sandwiched between the hoof and shoe to measure vertical ground reaction forces and three-dimensional acceleration at the walk, trot, and canter in horses

American Journal of Veterinary Research ◽

10.2460/ajvr.2000.61.979 ◽

2000 ◽

Vol 61 (8) ◽

pp. 979-985 ◽

Cited By ~ 29

Author(s):

Makoto Kai ◽

Osamu Aoki ◽

Atsushi Hiraga ◽

Hironori Oki ◽

Mikihiko Tokuriki

Keyword(s):

Three Dimensional ◽

Ground Reaction Forces ◽

Reaction Forces ◽

Vertical Ground ◽

Vertical Ground Reaction Forces

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Joint angle estimation with wavelet neural networks

Scientific Reports ◽

10.1038/s41598-021-89580-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Saaveethya Sivakumar ◽

Alpha Agape Gopalai ◽

King Hann Lim ◽

Darwin Gouwanda ◽

Sunita Chauhan

Keyword(s):

Gait Analysis ◽

Real Time ◽

Monitoring Applications ◽

Reaction Forces ◽

Multiple Sensor ◽

Vertical Ground ◽

Overall Performance ◽

Gait Monitoring ◽

Vertical Ground Reaction Forces ◽

And Control

AbstractThis paper presents a wavelet neural network (WNN) based method to reduce reliance on wearable kinematic sensors in gait analysis. Wearable kinematic sensors hinder real-time outdoor gait monitoring applications due to drawbacks caused by multiple sensor placements and sensor offset errors. The proposed WNN method uses vertical Ground Reaction Forces (vGRFs) measured from foot kinetic sensors as inputs to estimate ankle, knee, and hip joint angles. Salient vGRF inputs are extracted from primary gait event intervals. These selected gait inputs facilitate future integration with smart insoles for real-time outdoor gait studies. The proposed concept potentially reduces the number of body-mounted kinematics sensors used in gait analysis applications, hence leading to a simplified sensor placement and control circuitry without deteriorating the overall performance.

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