Determination of Gait Events Using an Externally Mounted Shank Accelerometer

2013 ◽  
Vol 29 (1) ◽  
pp. 118-122 ◽  
Author(s):  
Jonathan Sinclair ◽  
Sarah J. Hobbs ◽  
Laurence Protheroe ◽  
Christopher J. Edmundson ◽  
Andrew Greenhalgh
Keyword(s):  
Distal Tibia ◽  
Force Platform ◽  
Biomechanical Analysis ◽  
Alternative Methods ◽  
Heel Strike ◽  
Strong Correlations ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces

Biomechanical analysis requires the determination of specific foot contact events. This is typically achieved using force platform information; however, when force platforms are unavailable, alternative methods are necessary. A method was developed for the determination of gait events using an accelerometer mounted to the distal tibia, measuring axial accelerations. The aim of the investigation was to determine the efficacy of this method. Sixteen participants ran at 4.0 m/s ±5%. Synchronized tibial accelerations and vertical ground reaction forces were sampled at 1000 Hz as participants struck a force platform with their dominant foot. Events determined using the accelerometer, were compared with the corresponding events determined using the force platform. Mean errors of 1.68 and 5.46 ms for average and absolute errors were observed for heel strike and of –3.59 and 5.00 ms for toe-off. Mean and absolute errors of 5.18 and 11.47 ms were also found for the duration of the stance phase. Strong correlations (r= .96) were also observed between duration of stance obtained using the two different methods. The error values compare favorably to other alternative methods of predicting gait events. This suggests that shank-mounted accelerometers can be used to accurately and reliably detect gait events.

Determination of the vertical ground reaction forces acting upon individual limbs during healthy and clinical gait

2016 ◽  
Vol 43 ◽  
pp. 245-250 ◽  
Author(s):  
Guillaume M. Meurisse ◽  
Frédéric Dierick ◽  
Bénédicte Schepens ◽  
Guillaume J. Bastien
Keyword(s):  
Ground Reaction Forces ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces

The Faster Detection of the Step Initiation and the Prediction of the First Step’s Heel Strike Time with the Vertical GRF

2012 ◽  
Vol 245 ◽  
pp. 330-333 ◽  
Author(s):  
Do Wan Cha ◽  
Keon Young Oh ◽  
Kab Il Kim ◽  
Suk Yung Park ◽  
Kyung Soo Kim ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Heel Strike ◽  
Ground Reaction Forces ◽  
Regression Equations ◽  
New Approach ◽  
Step Initiation ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces ◽  
Off Time

A new approach for the detection of the step initiation in the lower extremity exoskeleton is presented. As the detection of the step initiation is the important factor for the lower extremity exoskeleton to shadow the operator’s movement as soon as possible, many studies have been done to detect it faster by using heel-off time or toe-off time. We detect the step initiation faster than other approaches with the vertical ground reaction forces. Also, we predict the first step’s heel strike time with the regression equations based on the vertical ground reaction forces as soon as we detect the step initiation. It could enable the lower extremity exoskeleton to shadow the operator’s movement much faster.

Vertical Ground Reaction Force Estimation From Benchmark Nonstationary Kinematic Data

2021 ◽  
pp. 1-5
Author(s):  
Daniel J. Davis ◽  
John H. Challis
Keyword(s):  
Reaction Force ◽  
Cutoff Frequency ◽  
Heel Strike ◽  
Ground Reaction Forces ◽  
Second Derivative ◽  
Frequency Content ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces ◽  
Filtering Approach

Time-differentiating kinematic signals from optical motion capture amplifies the inherent noise content of those signals. Commonly, biomechanists address this problem by applying a Butterworth filter with the same cutoff frequency to all noisy displacement signals prior to differentiation. Nonstationary signals, those with time-varying frequency content, are widespread in biomechanics (eg, those containing an impact) and may necessitate a different filtering approach. A recently introduced signal filtering approach wherein signals are divided into sections based on their energy content and then Butterworth filtered with section-specific cutoff frequencies improved second derivative estimates in a nonstationary kinematic signal. Utilizing this signal-section filtering approach for estimating running vertical ground reaction forces saw more of the signal’s high-frequency content surrounding heel strike maintained without allowing inappropriate amounts of noise contamination in the remainder of the signal. Thus, this signal-section filtering approach resulted in superior estimates of vertical ground reaction forces compared with approaches that either used the same filter cutoff frequency across the entirety of each signal or across the entirety of all signals. Filtering kinematic signals using this signal-section filtering approach is useful in processing data from tasks containing an impact when accurate signal second derivative estimation is of interest.

scholarly journals Joint angle estimation with wavelet neural networks

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.

scholarly journals Hindlimb muscular activity, kinetics and kinematics of cats jumping to their maximum achievable heights

1981 ◽  
Vol 91 (1) ◽  
pp. 73-86 ◽  
Author(s):  
F. E. Zajac ◽  
M. R. Zomlefer ◽  
W. S. Levine
Keyword(s):  
Vertical Jump ◽  
Muscular Activity ◽  
Dynamic State ◽  
Extensor Muscles ◽  
Ankle Joints ◽  
Flexor Muscles ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces ◽  
Propulsion Phase

Cats were trained to jump from a force platform to their maximum achievable heights. Vertical ground reaction forces developed by individual hindlimbs showed that the propulsion phase consists of two epochs. During the initial “preparatory phase' the cat can traverse many different paths. Irrespective of the path traversed, however, the cat always attains the same position, velocity and momentum at the end of this phase. Starting from this dynamic state the cat during the subsequent “launching phase' (about 150 ms long) generates significant propulsion as its hindlimbs develop force with identical, stereotypic profiles. Cinematographic data, electromyographic data, and computed torques about the hip, knee and ankle joints indicate that during the jump proximal extensor musculature is activated before distal musculature. During terminal experiments when the hindlimb was set at positions corresponding to those in the jump, isometric torques produced by tetanic stimulation of groups of extensor and flexor muscles were compared with computed torques developed by the same cat during previous jumps. These comparisons suggest that extensor muscles of the hindlimb are fully activated during the maximal vertical jump.

scholarly journals Hip and Knee Kinematics and Kinetics During Landing Tasks After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis

2018 ◽  
Vol 53 (2) ◽  
pp. 144-159 ◽  
Author(s):  
Adam S. Lepley ◽  
Christopher M. Kuenze
Keyword(s):  
Ligament Reconstruction ◽  
Cruciate Ligament ◽  
Meta Analysis ◽  
Knee Extension ◽  
Injured Limb ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Anterior Cruciate ◽  
Vertical Ground Reaction Forces ◽  
Kinematics And Kinetics

Objective:  To evaluate the current evidence concerning kinematic and kinetic strategies adopted during dynamic landing tasks by patients with anterior cruciate ligament reconstruction (ACLR). Data Sources:  PubMed, Web of Science. Study Selection:  Original research articles that evaluated kinematics or kinetics (or both) during a landing task in those with a history of ACLR were included. Data Extraction:  Methodologic quality was assessed using the modified Downs and Black checklist. Means and standard deviations for knee or hip (or both) kinematics and kinetics were used to calculate Cohen d effect sizes and corresponding 95% confidence intervals between the injured limb of ACLR participants and contralateral or healthy matched limbs. Data were further stratified by landing tasks, either double- or single-limb landing. A random-effects–model meta-analysis was used to calculate pooled effect sizes and 95% confidence intervals. Data Synthesis:  The involved limbs of ACLR patients demonstrated clinically and significantly lower knee-extension moments during double-legged landing compared with healthy contralateral limbs and healthy control limbs (Cohen d range = −0.81 to −1.23) and decreased vertical ground reaction forces when compared with healthy controls, regardless of task (Cohen d range = −0.39 to −1.75). Conclusions:  During single- and double-legged landing tasks, individuals with ACLR demonstrated meaningful reductions in injured-limb knee-extension moments and vertical ground reaction forces. These findings indicate potential unloading of the injured limb after ACLR, which may have significant implications for secondary ACL injury and long-term joint health.

Comparison of overground and treadmill vertical ground reaction forces

1995 ◽  
Vol 3 (2) ◽  
pp. 86
Author(s):  
H.John Yack ◽  
Carole Tucker ◽  
Scott C White Heather Collins
Keyword(s):  
Ground Reaction Forces ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces
Sign in / Sign up

Export Citation Format

Share Document