Effect of starting distance on vertical ground reaction forces in the normal dog

2005 ◽  
Vol 18 (03) ◽  
pp. 183-185 ◽  
Author(s):  
D. DuLaney ◽  
T. Purinton ◽  
H. Dookwah ◽  
S. Budsberg
Keyword(s):  
Hind Limb ◽  
Reaction Force ◽  
Ground Reaction Forces ◽  
Test Field ◽  
Vertical Force ◽  
Body Type ◽  
Reaction Forces ◽  
Similar Weight ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces

SummaryThe purpose of this study was to evaluate the effect of starting distance on the peak vertical force (PVF) and associated vertical impulses (VI) of normal dogs. Five dogs of similar weight and body type were trotted at a velocity of 1.6–2.2 m/s from each of three starting distances; 2, 4, and 6 m, from the first plate in a two plate test field. A total of ten trials were recorded from each starting distance, five left first contacts and five right first contacts. Each ground reaction force (GRF) of interest was evaluated both within and between the three starting distances using a complete block ANOVA. There was not any significant effect of distance found on peak vertical forces in our study. However, distance did affect VI. Forelimb VI generated at a 2 m trot was significantly less than VI generated at a 6 m trot. Neither extreme distance was found to be significantly different than the 4 m VI. The VI of the hind limb was not significantly affected.

Vertical Ground Reaction Force Redistribution During Experimentally Induced Shoulder Lameness in Dogs

1994 ◽  
Vol 07 (04) ◽  
pp. 154-157 ◽  
Author(s):  
R. M. McLaughlin ◽  
J. K. Roush ◽  
Dominique Griffon
Keyword(s):  
Ground Reaction Force ◽  
Reaction Force ◽  
Total Force ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Vertical Ground Reaction Force ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces ◽  
Surgically Induced

SummaryThe redistribution of vertical ground reaction forces after surgically induced forelimb lameness was evaluated in five Greyhounds at the walk. Vertical ground reaction forces were measured by force plate analysis before, three days, and seven days after a craniolateral approach to the shoulder was performed unilaterally in each dog.At day # 3, peak vertical force was significantly decreased in the operated forelimbs and in the ipsilateral hindlimbs. Peak vertical force was significantly increased in the contralateral fore- and hindlimbs. The total peak vertical force applied to both forelimbs did not change, nor did the total force applied to both hindlimbs. At day # 7, peak vertical force in each of the four limbs had returned to preoperative levels. Results of this study document the redistribution of ground reaction forces (at the walk) between the four limbs in the dog after an acute, surgically induced forelimb lameness.The redistribution of ground reaction force was evaluated in five Greyhounds before and during forelimb lameness. Lameness was induced by a craniolateral approach to one shoulder in each dog. At day # 3 after surgery, peak vertical force was decreased in the operated forelimbs and ipsilateral hindlimbs. Peak vertical force was increased in the contralateral fore- and hindlimbs. The distribution of ground reaction force in the four limbs returned to preoperative values seven days after surgery.

scholarly journals Effect of Surgery to Implant Motion and Force Sensors on Vertical Ground Reaction Forces in the Ovine Model

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Safa T. Herfat ◽  
Jason T. Shearn ◽  
Denis L. Bailey ◽  
R. Michael Greiwe ◽  
Marc T. Galloway ◽  
...  
Keyword(s):  
Hind Limb ◽  
Force Sensors ◽  
Ground Reaction Forces ◽  
Normal Gait ◽  
Treadmill Speed ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Surgical Implantation ◽  
Vertical Ground Reaction Forces ◽  
Stance Duration

Activities of daily living (ADLs) generate complex, multidirectional forces in the anterior cruciate ligament (ACL). While calibration problems preclude direct measurement in patients, ACL forces can conceivably be measured in animals after technical challenges are overcome. For example, motion and force sensors can be implanted in the animal but investigators must determine the extent to which these sensors and surgery affect normal gait. Our objectives in this study were to determine (1) if surgically implanting knee motion sensors and an ACL force sensor significantly alter normal ovine gait and (2) how increasing gait speed and grade on a treadmill affect ovine gait before and after surgery. Ten skeletally mature, female sheep were used to test four hypotheses: (1) surgical implantation of sensors would significantly decrease average and peak vertical ground reaction forces (VGRFs) in the operated limb, (2) surgical implantation would significantly decrease single limb stance duration for the operated limb, (3) increasing treadmill speed would increase VGRFs pre- and post operatively, and (4) increasing treadmill grade would increase the hind limb VGRFs pre- and post operatively. An instrumented treadmill with two force plates was used to record fore and hind limb VGRFs during four combinations of two speeds (1.0 m/s and 1.3 m/s) and two grades (0 deg and 6 deg). Sensor implantation decreased average and peak VGRFs less than 10% and 20%, respectively, across all combinations of speed and grade. Sensor implantation significantly decreased the single limb stance duration in the operated hind limb during inclined walking at 1.3 m/s but had no effect on single limb stance duration in the operated limb during other activities. Increasing treadmill speed increased hind limb peak (but not average) VGRFs before surgery and peak VGRF only in the unoperated hind limb during level walking after surgery. Increasing treadmill grade (at 1 m/s) significantly increased hind limb average and peak VGRFs before surgery but increasing treadmill grade post op did not significantly affect any response measure. Since VGRF values exceeded 80% of presurgery levels, we conclude that animal gait post op is near normal. Thus, we can assume normal gait when conducting experiments following sensor implantation. Ultimately, we seek to measure ACL forces for ADLs to provide design criteria and evaluation benchmarks for traditional and tissue engineered ACL repairs and reconstructions.

Comparison of Simultaneously Collected Kinetic Data with Force Plates and a Pressure Walkway

2018 ◽  
Vol 31 (05) ◽  
pp. 327-331 ◽  
Author(s):  
Gabriella Sandberg ◽  
Bryan Torres ◽  
Amanda Berjeski ◽  
Steven Budsberg
Keyword(s):  
Kinetic Data ◽  
Reaction Force ◽  
Vertical Force ◽  
Pressure Data ◽  
Vertical Ground Reaction Force ◽  
Reaction Forces ◽  
Pelvic Limb ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces ◽  
Collection Methods

Objective This article compares simultaneously collected kinetic data (percent limb distribution and limb symmetry) with force plates (FP) and a pressure walkway. Animals This study included 18 healthy client-owned adult dogs. Methods Vertical ground reaction force and pressure data were collected during two sessions 1 week apart (days 1 and 7) using both FP and pressure mat systems. Vertical ground reaction forces and vertical pressure data were each collected alone as well as simultaneously. A mixed effects model was used to test for differences in force, force percent data and symmetry indices (SI) that were calculated for the thoracic and pelvic limb pairs, between collection systems. A Pearson's correlation was used to test for correlations between force, force percentage and SI. Results There was no difference in peak vertical force (PVF) or total pressure index (TPI) data collected alone or when collected with pressure mat overlay the FP. Small but significant differences were found in percent limb distribution between PVF% and TPI%. Significant differences were found in the calculated SI for forelimbs and hindlimbs. Correlations between the PVF% and TPI% distribution were significant in both the fore- and hindlimbs. While there was a significant correlation between the forelimb SI, there was no significant correlation between the SI in the hindlimbs. Clinical Significance The method of calculating PVF and TPI percentages allowed for comparison between the collection methods. Significant differences were noted in the calculated SI between the collection methods and direct comparisons is not advisable.

Kinetic Gait Analysis of Agility Dogs Entering the A-Frame

2019 ◽  
Vol 32 (02) ◽  
pp. 097-103 ◽  
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.

Computer-assisted gait analysis of the dog: Comparison of two surgical techniques for the ruptured cranial cruciate ligament

2012 ◽  
Vol 25 (01) ◽  
pp. 11-21 ◽  
Author(s):  
J. Böddeker ◽  
S. Drüen ◽  
A. Meyer-Lindenberg ◽  
M. Fehr ◽  
I. Nolte ◽  
...  
Keyword(s):  
Gait Analysis ◽  
Cruciate Ligament ◽  
Computer Assisted ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Cranial Cruciate Ligament ◽  
Stifle Joint ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces

SummaryObjectives: To compare the improvement in degree of lameness following surgical repair of cranial cruciate ligament rupture in dogs using computer-assisted gait analysis.Methods: Two groups of 14 dogs were used. One group was treated by a capsular-fascial imbrication method, and the other group by tibial plateau levelling osteotomy (TPLO). All dogs underwent gait analysis prior to surgery, as well as at four days, four weeks, and four months after surgery. Symmetry indices of vertical ground reaction forces as well as vertical ground reaction forces in % body weight, joint angles and certain gait cycle parameters were evaluated.Results: Four months after surgery, the degree of lameness expressed as symmetry index for peak vertical force for the TPLO group (5.83%) was not significantly different to the capsular-fascial imbrication group (19.05%). Within the TPLO group, there was a significantly increased ability to extend the stifle joint four months after surgery. The stifle motion pattern of the capsular-fascial imbrication group as well as the range-of-motion in both groups showed very little change at the time of the last gait analysis. The complication rate was greater in the TPLO group than in the capsular-fascial group.Clinical significance: In conclusion the results suggest that the TPLO method leads to a faster recovery and improved limb function in comparison to the capsular-fascial imbrication method four months after surgery. Further analyses are needed to determine if the TPLO method is superior concerning long-term joint stability.Online supplementary material: A video of the three-dimensional kinematic model is available online at: http://www.vcot-online.com

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 The human foot and heel–sole–toe walking strategy: a mechanism enabling an inverted pendular gait with low isometric muscle force?

2012 ◽  
Vol 9 (75) ◽  
pp. 2396-2402 ◽  
Author(s):  
J. R. Usherwood ◽  
A. J. Channon ◽  
J. P. Myatt ◽  
J. W. Rankin ◽  
T. Y. Hubel
Keyword(s):  
Muscle Force ◽  
Reaction Force ◽  
Ground Reaction Forces ◽  
Human Foot ◽  
Force Profile ◽  
Muscle Loading ◽  
Reaction Forces ◽  
Vertical Ground ◽  
The Cost ◽  
Vertical Ground Reaction Forces

Mechanically, the most economical gait for slow bipedal locomotion requires walking as an ‘inverted pendulum’, with: I, an impulsive, energy-dissipating leg compression at the beginning of stance; II, a stiff-limbed vault; and III, an impulsive, powering push-off at the end of stance. The characteristic ‘M’-shaped vertical ground reaction forces of walking in humans reflect this impulse–vault–impulse strategy. Humans achieve this gait by dissipating energy during the heel-to-sole transition in early stance, approximately stiff-limbed, flat-footed vaulting over midstance and ankle plantarflexion (powering the toes down) in late stance. Here, we show that the ‘M’-shaped walking ground reaction force profile does not require the plantigrade human foot or heel–sole–toe stance; it is maintained in tip–toe and high-heel walking as well as in ostriches. However, the unusual, stiff, human foot structure—with ground-contacting heel behind ankle and toes in front—enables both mechanically economical inverted pendular walking and physiologically economical muscle loading, by producing extreme changes in mechanical advantage between muscles and ground reaction forces. With a human foot, and heel–sole–toe strategy during stance, the shin muscles that dissipate energy, or calf muscles that power the push-off, need not be loaded at all—largely avoiding the ‘cost of muscle force’—during the passive vaulting phase.

Vertical Ground Reaction Forces During Unexpected Human Slips

2017 ◽  
Vol 61 (1) ◽  
pp. 924-928 ◽  
Author(s):  
Arian Iraqi ◽  
Kurt E. Beschorner
Keyword(s):  
Coefficient Of Friction ◽  
Healthy Subjects ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Workplace Injuries ◽  
Slip Resistance ◽  
Reaction Forces ◽  
Vertical Ground ◽  
The Moment ◽  
Vertical Ground Reaction Forces

Falls due to slippery conditions are among the primary causes of disabling workplace injuries. Despite the extensive amount of human slip studies in the literature, only a handful of studies have reported ground reaction forces at the instant of slip initiation. The purpose of this study was to quantify the vertical ground reaction forces (VGRF) at slip initiation during unexpected human slips across different footwear-contaminant conditions. Forty-seven healthy subjects were unexpectedly exposed to a liquid–contaminant, while the vertical force was measured at the moment that the foot began to start slipping. The average VGRF were between 100 and 300 N and varied significantly across the footwear. These forces were significantly less than the typical forces (400-700 N) applied during slip-resistance measurements. This finding may suggest that available coefficient of friction (ACOF) measurements should use lower force levels in order to achieve higher relevance to the onset of slipping.

scholarly journals Running ground reaction forces across footwear conditions are predicted from the motion of two body mass components

2019 ◽  
Vol 126 (5) ◽  
pp. 1315-1325 ◽  
Author(s):  
Andrew B. Udofa ◽  
Kenneth P. Clark ◽  
Laurence J. Ryan ◽  
Peter G. Weyand
Keyword(s):  
Ground Reaction Force ◽  
Lower Limb ◽  
Reaction Force ◽  
Ground Reaction Forces ◽  
Vertical Ground Reaction Force ◽  
Time Patterns ◽  
Foot Strike ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Force Time

Although running shoes alter foot-ground reaction forces, particularly during impact, how they do so is incompletely understood. Here, we hypothesized that footwear effects on running ground reaction force-time patterns can be accurately predicted from the motion of two components of the body’s mass (mb): the contacting lower-limb (m1 = 0.08mb) and the remainder (m2 = 0.92mb). Simultaneous motion and vertical ground reaction force-time data were acquired at 1,000 Hz from eight uninstructed subjects running on a force-instrumented treadmill at 4.0 and 7.0 m/s under four footwear conditions: barefoot, minimal sole, thin sole, and thick sole. Vertical ground reaction force-time patterns were generated from the two-mass model using body mass and footfall-specific measures of contact time, aerial time, and lower-limb impact deceleration. Model force-time patterns generated using the empirical inputs acquired for each footfall matched the measured patterns closely across the four footwear conditions at both protocol speeds ( r2 = 0.96 ± 0.004; root mean squared error  = 0.17 ± 0.01 body-weight units; n = 275 total footfalls). Foot landing angles (θF) were inversely related to footwear thickness; more positive or plantar-flexed landing angles coincided with longer-impact durations and force-time patterns lacking distinct rising-edge force peaks. Our results support three conclusions: 1) running ground reaction force-time patterns across footwear conditions can be accurately predicted using our two-mass, two-impulse model, 2) impact forces, regardless of foot strike mechanics, can be accurately quantified from lower-limb motion and a fixed anatomical mass (0.08mb), and 3) runners maintain similar loading rates (ΔFvertical/Δtime) across footwear conditions by altering foot strike angle to regulate the duration of impact. NEW & NOTEWORTHY Here, we validate a two-mass, two-impulse model of running vertical ground reaction forces across four footwear thickness conditions (barefoot, minimal, thin, thick). Our model allows the impact portion of the impulse to be extracted from measured total ground reaction force-time patterns using motion data from the ankle. The gait adjustments observed across footwear conditions revealed that runners maintained similar loading rates across footwear conditions by altering foot strike angles to regulate the duration of impact.

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