A wearable force plate system to successively measure multi-axial ground reaction force for gait analysis

Experiments have been performed in which the ground reaction force during walking has been measured simultaneously by two different means; a shoe having a spring-loaded heel and fitted with a transducer was worn by subjects walking over a force plate. Discrepancies in the two sets of results led to an analysis of the dynamic characteristics of the force plate which was facilitated by comparing the results of the two measuring systems. The increase in the total mass of the system as the body lands on the plate reduces both the damping ratio and the natural frequency of the force plate system, causing an increase in the dynamic magnification. These effects are analysed quantitatively and recommendations are made for the future design of force plate systems.

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Ground reaction force profiles after partial and pancarpal arthrodesis in dogs

Veterinary and Comparative Orthopaedics and Traumatology ◽

10.3415/vcot-09-03-0030 ◽

2010 ◽

Vol 23 (01) ◽

pp. 1-6 ◽

Cited By ~ 15

Author(s):

U. Rytz ◽

R. Vannini ◽

K. Voss ◽

A. A. Andreoni

Keyword(s):

Gait Analysis ◽

Ground Reaction Force ◽

Reaction Force ◽

Force Plate ◽

Control Group ◽

Term Outcome ◽

Long Term Outcome ◽

Treatment Groups ◽

Force Profiles

Summary Objectives: To evaluate and compare long-term functional outcome after partial carpal arthrodesis and pancarpal arthrodesis in dogs using kinetic gait analysis. Methods: Fourteen dogs with 19 partial carpal or pancarpal arthrodeses were retrospectively examined and underwent force-plate gait analysis. Mean times since surgery were 29.4 and 24.4 months for pancarpal and partial carpal arthrodesis respectively. Vertical and braking-propulsive ground reaction force profiles were compared between treatment groups, and to those of normal dogs (control group) using Kruskal-Wallis one-way analysis of variance. Results: With the exception of time to vertical peak that occurred earlier in dogs with pancarpal than in dogs with partial carpal arthrodesis (p <0.01), there was no difference between the two treatment groups. Several parameters differed significantly between operated and healthy dogs (p <0.01): vertical impulses were significantly lower in both treatment groups, braking forces and impulses were also reduced after both techniques. Propulsive forces and impulses were only reduced in dogs with pancarpal arthrodesis. When comparing gait parameters of sound limbs of unilateral operated dogs to those of control dogs, braking forces and impulses (p <0.01; p <0.05) were significantly higher in the sound legs of unilateral operated dogs. Clinical Significance: Long-term outcome after partial carpal and pancarpal arthrodesis is good and comparable to each other. Propulsive action may be altered more in dogs with pancarpal arthrodesis.

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Ground reaction force and hoof deceleration patterns on two different surfaces at the trot

Equine and Comparative Exercise Physiology ◽

10.1017/s147806150667607x ◽

2006 ◽

Vol 3 (4) ◽

pp. 209-216 ◽

Cited By ~ 25

Author(s):

Pia Gustås ◽

Christopher Johnston ◽

Stig Drevemo

Keyword(s):

Ground Reaction Force ◽

Reaction Force ◽

Force Plate ◽

Ground Surface ◽

Ground Reaction Forces ◽

Triaxial Accelerometer ◽

Loading Rates ◽

Sand Surface ◽

Reaction Forces ◽

Force Data

AbstractThe objective of the present study was to compare the hoof deceleration and ground reaction forces following impact on two different surfaces. Seven unshod Standardbreds were trotted by hand at 3.0–5.7 m s− 1 over a force plate covered by either of the two surfaces, sandpaper or a 1 cm layer of sand. Impact deceleration data were recorded from one triaxial accelerometer mounted on the fore- and hind hooves, respectively. Ground reaction force data were obtained synchronously from a force plate, sampled at 4.8 kHz. The differences between the two surfaces were studied by analysing representative deceleration and force variables for individual horses. The maximum horizontal peak deceleration and the loading rates of the vertical and the horizontal forces were significantly higher on sandpaper compared with the sand surface (P < 0.001). In addition, the initial vertical deceleration was significantly higher on sandpaper in the forelimb (P < 0.001). In conclusion, it was shown that the different qualities of the ground surface result in differences in the hoof-braking pattern, which may be of great importance for the strength of the distal horse limb also at slow speeds.

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The Relationship Between Vertical Loadrates and Tibial Acceleration Across Footstrike Patterns

Foot & Ankle Orthopaedics ◽

10.1177/2473011418s00200 ◽

2018 ◽

Vol 3 (3) ◽

pp. 2473011418S0020 ◽

Cited By ~ 1

Author(s):

Irene Davis ◽

Todd Hayano ◽

Adam Tenforde

Keyword(s):

Impact Loading ◽

Ground Reaction Force ◽

Reaction Force ◽

Force Plate ◽

Correlation Coefficients ◽

Strongly Correlated ◽

Vertical Ground Reaction Force ◽

Vertical Ground ◽

Tibial Acceleration ◽

The Relationship

Category: Other Introduction/Purpose: While the etiology of injuries is multifactorial, impact loading, as measured by the loadrate of the vertical ground reaction force has been implicated. These loadrates are typically measured with a force plate. However, this limits the measure of impacts to laboratory environments. Tibial acceleration, another measure of running impacts, is considered a surrogate for loadrate. It can be measured using new wearable technology that can be used in a runner’s natural environment. However, the correlation between tibial acceleration measured from mobile devices and vertical ground reaction force loadrates, measured from forceplates, is unknown. The purpose of this study was to determine the correlation between vertical and resultant loadrates to vertical and resultant tibial acceleration across different footstrike patterns (FSP) in runners. Methods: The study involved a sample of convenience made up of 169 runners (74 F, 95 M; age: 38.66±13.08 yrs) presenting at a running injury clinic. This included 25 habitual forefoot strike (FFS), 17 midfoot strike (MFS) and 127 rearfoot strike (RFS) runners. Participants ran on an instrumented treadmill (average speed 2.52±0.25 m/s), with a tri-axial accelerometer attached at the left distal medial tibia. Only subjects running with pain <3/10 on a VAS scale during the treadmill run were included to reduce the confounding effect of pain. Vertical average, vertical instantaneous and resultant instantaneous loadrates (VALR, VILR and RILR) and peak vertical and resultant tibial accelerations (VTA, RTA) were averaged for 8 consecutive left steps. Correlation coefficients (r) were calculated between tibial accelerations and loadrates. Results: All tibial accelerations were significantly correlated across all loadrates, with the exception of RTA with VILR for FFS (Table 1) which was nearly significant (p=0.068). Correlations ranged from 0.37-0.82. VTA was strongly correlated with all loadrates (r = 0.66). RTA was also strongly correlated with both loadrates for RFS and MFS, but only moderately correlated with loadrates for FFS (r = 0.47). Correlations were similar across the different loadrates (VALR, VILR, RILR). Conclusion: The stronger correlation between vertical tibial acceleration and all loadrates (VALR, VILR, RILR) suggests that it may be the best surrogate for loadrates when studying impact loading in runners.

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Correlation between Ground Reaction Force and Tibial Acceleration in Vertical Jumping

Journal of Applied Biomechanics ◽

10.1123/jab.23.3.180 ◽

2007 ◽

Vol 23 (3) ◽

pp. 180-189 ◽

Cited By ~ 27

Author(s):

Niell G. Elvin ◽

Alex A. Elvin ◽

Steven P. Arnoczky

Keyword(s):

Ground Reaction Force ◽

Reaction Force ◽

Force Plate ◽

Coefficient Of Determination ◽

Ground Reaction Forces ◽

Accelerometer Data ◽

Jump Height ◽

Vertical Jumping ◽

Average Coefficient ◽

Reaction Forces

Modern electronics allow for the unobtrusive measurement of accelerations outside the laboratory using wireless sensor nodes. The ability to accurately measure joint accelerations under unrestricted conditions, and to correlate them with jump height and landing force, could provide important data to better understand joint mechanics subject to real-life conditions. This study investigates the correlation between peak vertical ground reaction forces, as measured by a force plate, and tibial axial accelerations during free vertical jumping. The jump heights calculated from force-plate data and accelerometer measurements are also compared. For six male subjects participating in this study, the average coefficient of determination between peak ground reaction force and peak tibial axial acceleration is found to be 0.81. The coefficient of determination between jump height calculated using force plate and accelerometer data is 0.88. Data show that the landing forces could be as high as 8 body weights of the jumper. The measured peak tibial accelerations ranged up to 42 g. Jump heights calculated from force plate and accelerometer sensors data differed by less than 2.5 cm. It is found that both impact accelerations and landing forces are only weakly correlated with jump height (the average coefficient of determination is 0.12). This study shows that unobtrusive accelerometers can be used to determine the ground reaction forces experienced in a jump landing. Whereas the device also permitted an accurate determination of jump height, there was no correlation between peak ground reaction force and jump height.

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Concurrent Validity of a Portable Force Plate Using Vertical Jump Force–Time Characteristics

Journal of Applied Biomechanics ◽

10.1123/jab.2017-0371 ◽

2018 ◽

Vol 34 (5) ◽

pp. 410-413 ◽

Cited By ~ 11

Author(s):

Jason Lake ◽

Peter Mundy ◽

Paul Comfort ◽

John J. McMahon ◽

Timothy J. Suchomel ◽

...

Keyword(s):

Concurrent Validity ◽

Vertical Jump ◽

Reaction Force ◽

Force Plate ◽

Vertical Force ◽

Jump Height ◽

Strength Index ◽

Limits Of Agreement ◽

Force Time ◽

Plate System

This study examined concurrent validity of countermovement vertical jump reactive strength index modified and force–time characteristics recorded using a 1-dimensional portable and laboratory force plate system. Twenty-eight men performed bilateral countermovement vertical jumps on 2 portable force plates placed on top of 2 in-ground force plates, both recording vertical ground reaction force at 1000 Hz. Time to takeoff; jump height; reactive strength index modified; and braking and propulsion impulse, mean net force, and duration were calculated from the vertical force from both force plate systems. Results from both systems were highly correlated (r ≥ .99). There were small (d < 0.12) but significant differences between their respective braking impulse, braking mean net force, propulsion impulse, and propulsion mean net force (P < .001). However, limits of agreement yielded a mean value of 1.7% relative to the laboratory force plate system (95% confidence limits, 0.9%–2.5%), indicating very good agreement across all of the dependent variables. The largest limits of agreement were for jump height (2.1%), time to takeoff (3.4%), and reactive strength index modified (3.8%). The portable force plate system provides a valid method of obtaining reactive strength measures, and several underpinning force–time variables, from unloaded countermovement vertical jump. Thus, practitioners can use both force plates interchangeably.

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Development of a Bendable Outsole Biaxial Ground Reaction Force Measurement System

Sensors ◽

10.3390/s19112641 ◽

2019 ◽

Vol 19 (11) ◽

pp. 2641 ◽

Cited By ~ 5

Author(s):

Junghoon Park ◽

Sangjoon Kim ◽

Youngjin Na ◽

Yeongjin Kim ◽

Jung Kim

Keyword(s):

Measurement System ◽

Ground Reaction Force ◽

Force Measurement ◽

Reaction Force ◽

Force Plate ◽

Force Sensors ◽

Measurement Systems ◽

Cantilever Structure ◽

Force Measurement System ◽

Anterior Posterior

Wearable ground reaction force (GRF) measurement systems make it possible to measure the GRF in any environment, unlike a commercial force plate. When performing kinetic analysis with the GRF, measurement of multiaxial GRF is important for evaluating forward and lateral motion during natural gait. In this paper, we propose a bendable GRF measurement system that can measure biaxial (vertical and anterior-posterior) GRF without interrupting the natural gait. Eight custom small biaxial force sensors based on an optical sensing mechanism were installed in the proposed system. The interference between two axes on the custom sensor was minimized by the independent application of a cantilever structure for the two axes, and the hysteresis and repeatability of the custom sensor were investigated. After developing the system by the installation of force sensors, we found that the degree of flexibility of the developed system was comparable to that of regular shoes by investigating the forefoot bending stiffness. Finally, we compared vertical GRF (vGRF) and anterior-posterior GRF (apGRF) measured from the developed system and force plate at the same time when the six subjects walked, ran, and jumped on the force plate to evaluate the performance of the GRF measurement system.

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