Vertical Force Data Research Articles

Working memory load modulates anticipatory postural adjustments during step initiation.

Working memory (WM) can influence selective attention. However, the effect of WM load on postural standing tasks has been poorly understood, even though these tasks require attentional resources. The purpose of this study was to examine whether WM load would impact anticipatory postural adjustments (APAs) during step initiation. Sixteen healthy young adults performed stepping tasks alone or concurrently with a WM task in a dual-task design. The stepping tasks involved volitional stepping movements in response to visual stimuli and comprised of simple and choice reaction time tasks and the Flanker task which consisted of congruent and incongruent (INC) conditions. In the dual-task condition, subjects were required to memorize either one or six digits before each stepping trial. Incorrect weight transfer prior to foot-lift, termed APA errors, reaction time (RT), and foot-lift time were measured from the vertical force data. The results showed that APA error rate was significantly higher when memorizing six-digit than one-digit numerals in the INC condition. In addition, RT and foot-lift time were significantly longer in the INC condition compared to the other stepping conditions, while there was no significant effect of WM load on RT or foot-lift time. These findings suggest that high WM load reduces the cognitive resources needed for selective attention and decision making during step initiation.

Trampoline Stiffness Estimation by Using Robotic System for Quantitative Evaluation of Jumping Exercises.

Trampolines are recognized as a valuable tool in exercise and rehabilitation due to their unique properties like elasticity, rebound force, low-impact exercise, and enhancement of posture, balance, and cardiopulmonary function. To quantitatively assess the effects of trampoline exercises, it is essential to estimate factors such as stiffness, elements influencing jump dynamics, and user safety. Previous studies assessing trampoline characteristics had limitations in performing repetitive experiments at various locations on the trampoline. Therefore, this research introduces a robotic system equipped with foot-shaped jigs to evaluate trampoline stiffness and quantitatively measure exercise effects. This system, through automated, repetitive movements at various locations on the trampoline, accurately measures the elastic coefficient and vertical forces. The robot maneuvers based on the coordinates of the trampoline, as determined by its torque and position sensors. The force sensor measures data related to the force exerted, along with the vertical force data at X, Y, and Z coordinates. The model's accuracy was evaluated using linear regression based on Hooke's Law, with Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and Correlation Coefficient Squared (R-squared) metrics. In the analysis including only the distance between X and the foot-shaped jigs, the average MAE, RMSE, and R-squared values were 17.9702, 21.7226, and 0.9840, respectively. Notably, expanding the model to include distances in X, Y, and between the foot-shaped jigs resulted in a decrease in MAE to 15.7347, RMSE to 18.8226, and an increase in R-squared to 0.9854. The integrated model, including distances in X, Y, and between the foot-shaped jigs, showed improved predictive capability with lower MAE and RMSE and higher R-squared, indicating its effectiveness in more accurately predicting trampoline dynamics, vital in fitness and rehabilitation fields.

Swimmers' Effective Actions during the Backstroke Start Technique.

The analysis of the external forces of swimming starts has revealed how swimmers propel themselves out of the block, but data should be properly interpreted to fully understand force-generation mechanisms. This study aimed to assess horizontal and vertical forces in the backstroke start based on swimmers' structural and propulsive actions. Firstly, a simulated structural force was estimated by two transient backstroke-start inter-segmental realistic body positions: a maximally tucked position and an extended one (just before the hands-off and the take-off, respectively). Secondly, 10 competitive backstroke swimmers performed four 15 m maximal backstroke starts with the external forces estimated. Thirdly, the simulated structural force was subtracted from raw horizontal and vertical force data, measured between hands-off and take-off instants, resulting in the propulsive forces. The application of the algorithm has evidenced that backstrokers' horizontal and vertical simulated-structural-force components contributed to ~40% of total force during start propulsion (~0.2-0.12 s before the take-off), followed by the propulsive horizontal force increment and a progressive vertical component reduction (~0.05 s) with ~20° take-off angle. Based on these findings, researchers and coaches can better guide swimmers as to the proper mechanical strategies to achieve effectiveness in the backstroke start, and to improve direct transfer of resistance training programs.

A Dynamic Ankle Orthosis Reduces Tibial Compressive Force and Increases Ankle Motion Compared to a Walking Boot.

Tibial bone stress injuries are a common overuse injury among runners and military cadets. Current treatment involves wearing an orthopedic walking boot for three to twelve weeks, which limits ankle motion and leads to lower limb muscle atrophy. A Dynamic Ankle Orthosis (DAO) was designed that provides a distractive force that offloads in-shoe vertical force and retains sagittal ankle motion during walking. It remains unclear how tibial compressive force is altered by the DAO. This study compared tibial compressive force and ankle motion during walking between the DAO and an orthopedic walking boot. Twenty young adults walked on an instrumented treadmill at 1.0 m/s in two brace conditions: DAO and walking boot. 3D kinematic, ground reaction forces, and in-shoe vertical force data were collected to calculate peak tibial compressive force. Paired t-tests and Cohen's d effect sizes were used to assess mean differences between conditions. Peak tibial compressive force (p = 0.023; d = 0.5) and Achilles tendon force (p = 0.017; d = 0.5) were moderately lower in the DAO compared to the walking boot. Sagittal ankle excursion was 54.9% greater in the DAO compared to the walking boot (p = 0.05; d = 3.1). The findings from this study indicated that the DAO moderately reduced tibial compressive force and Achilles tendon force and allowed more sagittal ankle excursion during treadmill walking compared to an orthopedic walking boot.

Milky Way total mass derived by rotation curve and globular cluster kinematics from Gaia EDR3

ABSTRACT Using action-based distribution function for the dynamical model of the Milky Way (MW) we have estimated its total mass and its density profile. Constraints are coming from the globular cluster proper motions from Gaia EDR3, from the rotation curve based on Gaia DR2 data, and from the vertical force data. We use Bayesian Markov chain Monte Carlo method to explore the parameters, for which the globular cluster distribution function and the Galactic potential are fully constrained. Numerical simulations are used to study the uncertainties on the potential constraint if considering a possible massive Large Magellanic Cloud (LMC). We found that a massive LMC (1.5 × 1011 M⊙) will affect the MW mass measurement at large radius, which includes both the MW and the LMC. We also use the FIRE2 Latte cosmological hydrodynamic simulations to make mock data set from an MW-like galaxy that includes many unrelaxed substructures. We test the effect of these unrelaxed substructures on the final results, and found that the measured rotation curve fluctuated around input value within 5 per cent. By keeping a large freedom in choosing a priori mass profile for both baryonic and dark matter leads a total mass of the MW that ranges from $5.36_{-0.68}^{+0.81}\times 10^{11}$ M⊙ to $7.84_{-1.97}^{+3.08} \times 10^{11}$ M⊙. This includes the contribution of a putative massive LMC and significantly narrows the MW total mass range published earlier. Such total mass leads to dark matter density at solar position of $0.34_{-0.02}^{+0.02}$ GeV cm−3.

Squat Jump Movement Onset Thresholds Influence on Kinetics and Kinematics

Background of Study: Differing movement onset thresholds have been used when analyzing the squat jump movement from force-time data obtained from a force platform. This makes comparisons difficult between investigations as this will impact the amount of the force-time curve that is analyzed. Objective: Thus, study examined the effect onset threshold had on kinetic and kinematic variables used in the assessment of the squat jump. Methods: Using a within-subject study design, fifteen recreational trained males performed three trials of squat jumps on a force platform. Each trial was analyzed using one of five different onset thresholds (2.5% SW, 5% SW, 10% SW, 20N, 5SD). Force, velocity, and power, as well as time to peak force, velocity, power and jump height were calculated using the vertical force data obtain from the force plate. Reliability was assessed using intraclass correlation coefficients and coefficients of variation. A one-way ANOVA was used to examine the impact of onset thresholds on all variables of interest. Results: The use of 10% SW and 5SD met minimum reliability criteria for all variables. Temporal related variables were impact to the greatest extent by differing thresholds with large (d > 1.20) significant differences. 10% SW showed the highest mean values of force, velocity, and power. Conclusions: The use of 5SD of the weighting phase is recommended as this showed high level of both absolute and relative reliability in addition to preserving a large portion of the force – time curve to be used in the analysis.

Analysis of Choice Stepping with Visual Interference Can Detect Prolonged Postural Preparation in Older Adults with Mild Cognitive Impairment at High Risk of Falling

Background/Aims: We aimed to clarify postural control deficits in older adults with mild cognitive impairment (MCI) at high risk of falling by addressing the inhibitory process. Methods: This study involved 376 community-dwelling older adults with MCI. Participants were instructed to execute forward stepping on the side indicated by the central arrow while ignoring the 2 flanking arrows on each side (→→→→→, congruent, or →→←→→, incongruent). Initial weight transfer direction errors [anticipatory postural adjustment (APA) errors], step execution times, and divided phases (reaction, APA, and swing phases) were measured from vertical force data. Participants were categorized as fallers (n = 37) and non-fallers (n = 339) based on fall experiences in the last 12 months. Results: There were no differences in the step execution times, swing phases, step error rates, and APA error rates between groups, but fallers had a significantly longer APA phase relative to non-fallers in trials of the incongruent condition with APA errors (p = 0.005). Fallers also had a longer reaction phase in trials with the correct APA, regardless of the condition (p = 0.01). Conclusion: Analyses of choice stepping with visual interference can detect prolonged postural preparation as a specific falling-associated deficit in older adults with MCI.

Discriminating short-range from van der Waals forces using total force data in noncontact atomic force microscopy

Noncontact atomic force microscopy (NC-AFM) features the measurement of forces with highest spatial resolution and sensitivity, resolving forces of the order of pico-Newtons with submolecular resolution. However, the measured total force is a mixture composed of various interactions. While some interactions such as electrostatic or magnetic forces can be excluded by a careful design of the experiment, the subtraction of van der Waals forces, which mainly originate from London dispersion interactions between the macroscopic tip shank and the bulk sample, remains a challenge. We present the determination of the inherently present van der Waals forces in total interaction force data from fitting a suitable model, allowing for extraction of the short-range force component. We compare the applicability of several van der Waals models based on experimental interaction data from the calcite$(1\phantom{\rule{0.59998pt}{0ex}}0\phantom{\rule{0.59998pt}{0ex}}\overline{1}\phantom{\rule{0.59998pt}{0ex}}4)$ surface. The feasibility to fit these models to experimental data is critically discussed. We furthermore introduce criteria to assess the transition point from pure long-range interaction to mixed short- and long-range forces based on the variance of lateral and vertical force data. This determination allows us to extract the short-range interaction forces, which remained a challenge so far in NC-AFM experiments.

Evaluation of vertical forces in the pads of Pitbulls with cranial cruciate ligament rupture

BackgroundCranial cruciate ligament rupture (CCLR) is one of the most important stifle injuries and a common cause of lameness in dogs. Our objective was to measure the vertical forces in the pads of Pitbulls with cranial cruciate ligament rupture (CCLR) using a pressure sensitive walkway. A pressure sensitive walkway was used to collect vertical force data from the pads of 10 Pitbulls affected with unilateral CCLR. Ten healthy Pitbulls were included in the study as controls. Velocity varied between 1.3 and 1.6 m/s and acceleration was kept below ± 0.1 m/s2. Differences between groups and between pads in the same limb within groups were investigated using ANOVA and the Tukey test. The paired Student t-test was employed to assess gait symmetry (p < 0.05).ResultsPeak vertical forces (PVF) were lower in the affected limb, particularly in the metatarsal pad. Increased PVF values in the forelimb and the contralateral hind limb pads of affected dogs suggest a compensatory effect.ConclusionsA consistent pattern of vertical force distribution was observed in the pads of dogs with CCLR. These data are important for increased understanding of vertical force distribution in the limb of dogs with CCLR disease. Kinetic analysis using pressure sensitive walkways can be useful in follow-up assessment of surgically treated dogs regardless of the surgical technique employed.

Effects of speed and accuracy strategy on choice step execution in response to the flanker interference task

The purpose of this study is to examine the effects of a speed or accuracy strategy on response interference control during choice step execution. Eighteen healthy young participants were instructed to execute forward stepping on the side indicated by a central arrow (←, left vs. →, right) under task instructions that either emphasized speed or accuracy of response in the neutral condition. In the flanker condition, they were additionally required to ignore the 2 flanking arrows on each side (→→→→→, congruent or →→←→→, incongruent). Errors in the direction of the initial weight transfer (APA errors) and the step execution times were measured from the vertical force data. APA error was increased in response to the flanker task and step execution time was shortened with a speed strategy compared to an accuracy strategy. Furthermore, in response to the visual interference of the flanker task, speed instructions in particular increased APA errors more than other instructions. It may be important to manipulate the level of the speed-accuracy trade-off to improve efficiency and safety. Further research is needed to explore the effects of advancing age and disability on choice step reaction in a speed or accuracy strategy.

Evaluation of vertical forces in the pads of German Shepherd dogs

To evaluate vertical forces in the pads of German Shepherd dogs by relative percentage among total limb vertical forces using a pressure sensitive walkway. A pressure sensitive walkway was used to collect vertical force data for each pad of the limbs of 16 healthy client-owned German Shepherd dogs used for kinetic gait analysis. The vertical force for each pad was evaluated as a percentage of total limb vertical force. Weight distribution among limbs was also recorded. Velocity and acceleration were within a range of 1.3 and 1.6 ± 0.1 m/s². The ANOVA test was used to compare data and the paired t-test was used to assess symmetry (p <0.05). The peak vertical force was higher on the metacarpal pad than on the metatarsal pad. Peak vertical force was highest on the metacarpal pad and metatarsal pad followed by the digital pads 3, 4 and 5 of the forelimb, and on the hindlimb by digital pads 3 and 4. Vertical impulse was greatest in the metacarpal pad and digital pads 3 and 4 of the forelimb and hindlimb respectively, followed by digital pads 3, 4, and 5 of the forelimb and the metatarsal pad. A vertical force distribution pattern was observed on the pads of the German Shepherd dogs. These data are important for improving the understanding of vertical force distribution during gait and to assess orthopaedic conditions.

Effects of visual interference on initial motor program errors and execution times in the choice step reaction

The purpose of this study was to examine whether visual interference has any effect on error in the initial direction of anticipatory postural adjustment (APA) prior to a step (indicating a motor program error) and response time during the choice step execution. Twenty healthy young participants were instructed to execute forward stepping as quickly and accurately as possible on the side indicated by a central arrow (←, left vs. →, right) of a visual cue in the neutral condition. In the flanker condition, they were additionally required to ignore the 2 flanking arrows on each side (→→→→→, congruent or →→←→→, incongruent). Errors in the direction of the initial weight transfer (APA errors) and the step execution times were measured from the vertical force data. In the incongruent condition, the percentage of APA errors and the step execution times were significantly greater than those in the neutral and congruent conditions. A linear mixed model revealed that the step execution time in trials with APA errors was longer than those in trials without APA errors. The visual interference effect of a flanker task may load selective attention and judgment processing during movement initiation, leading to increased initial motor program errors and prolonged step execution times even in healthy young adults.

The influence of precipitation and friction control agents on forces at the wheel/rail interface in heavy haul railways

This paper presents an analysis of the influence of materials that can be present in the so-called “third-body layer” at the wheel/rail interface on curving forces generated in heavy haul operating conditions. The third-body layer is the interfacial layer whose shear properties determine the bulk frictional characteristics that emerge in wheel/rail contact. It is often postulated that precipitation (rain) provides an effective form of lubrication at the wheel tread/rail head interface, reducing curving forces and corresponding wear. The postulate is explored through the analysis of lateral and vertical force data collected under a wide range of environmental conditions in full-scale revenue service. The effects of precipitation are rigorously explored and compared with the effects of top of rail friction modifiers, which are intentionally introduced into the third-body layer. This paper originated from the 2011 IHHA Conference.

Spatiotemporal components of the 3-D gait analysis of community-dwelling middle-aged and elderly Japanese: Age- and sex-related differences

To describe age- and sex-related differences in gait patterns of community-living men and women using 3-D gait analysis. Subjects (n=2006) aged 40-84 years participated in the National Institute for Longevity Sciences-Longitudinal Study of Aging (NILS-LSA). Spatiotemporal components, including velocity, step length, step frequency, and double support time during a gait cycle, were calculated from 3-D coordinates and vertical force data. Velocity, step length and step frequency were normalized by leg length and acceleration due to gravity, and double support time was normalized to gait cycle duration. Spatiotemporal walking variables of brisk velocity and step length were significantly greater in men than in women, while comfortable velocity and comfortable and brisk step frequencies and double support times were greater in women than in men. Age-related changes were marked at 70-84 years in most spatiotemporal variables in both sexes during comfortable walking. During brisk walking, age-related changes were observed from a younger age than during comfortable walking, and there were sex-related differences. The age-related gait alteration was obvious among those aged 70 years and older, and it accelerated markedly in women's brisk walking intensity.

Preferred and optimal stride frequency, stiffness and economy: changes with fatigue during a 1-h high-intensity run

Metabolic cost of submaximal running at constant speed is influenced by various factors including fatigue and kinematic characteristics. Metabolic costs typically drift upwards during extended running while stride characteristics often shift away from initial. When non-fatigued, experienced runners naturally optimize stride frequency in a manner that minimizes oxygen uptake. An initial objective was to determine whether runners demonstrate a similar self-optimizing capability when fatigued where stride characteristics have perhaps shifted away from the initial state. A secondary objective involved measurement of vertical and leg stiffness characteristics as a potential explanation for frequency changes with fatigue. We hypothesized that runners decrease stride frequency and stiffness with fatigue while optimizing these characteristics to minimize metabolic cost. Sixteen experienced runners completed a near maximal effort 1-h treadmill run at a constant speed. Preferred and optimal stride frequencies (PSF and OSF) were measured near the beginning and end of the hour run using frequencies +/-4 and +/-8% around PSF. From vertical force data recorded throughout the run, leg and vertical stiffness were determined. As expected, oxygen uptake significantly increased during the run from 45.9 to 47.4 ml kg(-1) min(-1) (P = 0.004). There was no difference between preferred and optimal stride frequencies at the beginning or the end of running (P = 0.978), however both PSF and OSF significantly decreased from 1.45 to 1.43 Hz (P = 0.026). All runners self-optimized stride frequency at the beginning and end of one-hour of running despite changes of optimal stride frequency. Stiffness and stride frequency changes were subject specific with some runners exhibiting little to no change. No clear relationship of frequency or stiffness changes to economy was found.

Vertical and lateral electrostatic forces in a tip-plane system studied with a Green function plus surface charge method

An effective method to calculate the electrostatic force between a microscopic tip and an infinite metallic plane is proposed and tested. The Green function method is used to integrate out exactly the potential distribution in the plane. The plane plus tip problem is thus reduced to a boundary value problem for the tip surface only, enabling solution by a standard numerical method. The main advantage of this approach is that systems with an arbitrary plane potential distribution may be solved with the same method and comparable numerical efficiency to problems with a constant plane potential. The method is used to calculate the electrostatic force on a tip due to a plane with a step potential and a local quadratic potential island. The calculated perpendicular force components agree with previously published theoretical results. In addition, lateral components of the tip-surface force are computed and shown to be comparable to the vertical component close to a potential step, in agreement with the published experimental data. This suggests the possibility of using lateral, as well as vertical force data in atomic force microscopy for the detection and imaging of potential steps.

The Accuracy and Precision of an Equine In-Shoe Pressure Measurement System as a Tool for Gait Analysis

Abstract Normal horses with no clinical lameness were studied to test the hypothesis that Equine F-Scan sensors (EFS) would produce vertical force data that correlated highly with vertical force data from a force platform. Six horses were trotted across a force platform while wearing the EFS. Vertical force measurements were recorded from each system with data analyzed from hoof strikes that occurred simultaneously on both systems. Coefficients of variation (CV) were evaluated to test precision of the systems. The CV of the EFS was 10.2%, compared with 6.6% for the force platform. The accuracy of the pressure measurement system was tested by measuring agreement and a paired t test. The test for measuring agreement showed large differences between measuring devices, indicating an overall lack of agreement between measurements from the two systems, with differences ranging from 9 Newtons (N) to 1,200 N. Results from a paired t test, however, showed no significant difference between measurements from the two devices as noted by a P -value of .294, indicating a lack of significant differences because of assessment of averaged data. Because of the inability of the EFS to provide precise measurements of vertical ground reaction force as noted by high coefficients of variation and an overall lack of agreement between measurements from the two systems, this system should not be used to objectively measure vertical force in horses in its current format.

Measurement of gait parameters from free moving subjects

In this paper a telemetry system for real-time force measurement in the legs and crutches or cane is presented. The system provides a quantitative gait analysis of orthopaedic patients with details, which are often hidden to a visual observation. Three vertical force components in each leg are measured. For this purpose flat and pliable capacitive sensors, which are placed on the sole of the shoes, were developed. The infrared telemetry is applied to enable free and unconstrained movements of the patient inside a wide indoor environment. Measured forces, after transmission and processing on the receiver side, are presented on the computer monitor as eight channel time diagrams. An original software package ( GAS ) for on-line monitoring and processing of vertical force data was developed. The processing enables calculation of many diagnostically important parameters (e.g. temporal parameters, average force, force-time integral, sum of forces, etc.), spectral and time-frequency analysis and many other. As an example of clinical application, temporal parameters during ten strides for 20 normal subjects and 20 patients with lower extremities degenerative joint diseases were calculated and compared.

Kinetic gait analysis assessment of meloxicam efficacy in a sodium urate-induced synovitis model in dogs

Abstract Objective To examine the ability of meloxicam, a cyclooxygenase inhibitor, to mediate the effects of sodium urate-induced acute stifle synovitis in dogs. Animals 12 clinically normal adult hound-type dogs. Procedure A blinded, randomized, controlled single crossover design study was performed to determine the efficacy of meloxicam, using 2 dosage groups. In 2 experimental phases, dogs, according to group, received meloxicam (0.1 or 0.5 mg/kg of body weight) or matched volume of meloxicam vehicle, with a washout period of 21 to 28 days between phases. Blood samples for hematologic and biochemical analysis, as well as synovial fluid for cytologic analysis, were collected immediately before and approximately 24 hours after articular challenge of dogs under propofol anesthesia. Ground reaction forces (GRF) and subjective clinical scores were determined before and at 4, 8, 12, and 24 hours after articular challenge. Vertical force data included peak force, impulse, limb loading, and unloading rates. Craniocaudal data were divided into braking and propulsion phases and consisted of peak force and associated impulses. Results Except for propulsion impulse at 24 hours, all GRF variables were significantly greater at all postsynovitis induction times in the group receiving the high meloxicam dose. Significant differences in all GRF variables were seen at various times between the low-dose meloxicam group and the corresponding control group, and between the low- and high-dose meloxicam groups. Similar significance was seen in the subjective clinical evaluations. Strong correlations existed between the subjective and objective data. Conclusions Meloxicam was effective in attenuating the effects of sodium urate-induced acute synovitis in dogs. Kinetic gait data provided an objective measurement of lameness in an experimentally induced arthritis model and quantified lameness improvements in response to medication with a nonsteroidal anti-inflammatory drug. (Am J Vet Res 1997;58:626–631)

Prospective evaluation of ground reaction forces in dogs undergoing unilateral total hip replacement

Abstract Objective To evaluate clinical and biomechanical gait variables in a group of dogs before and after (for 1 year) total hip replacement. Animals 16 dogs with degenerative joint disease of the coxofemoral joint secondary to hip dysplasia deemed candidates for total hip replacement. Procedure Before and at 1, 3, 6, and 12 months after surgery, each dog was trotted over a biomechanical force platform. Vertical force data evaluated for each stance phase of the treated and untreated hind limbs included peak force, impulse, and limb loading and unloading rates. Vertical peak and impulse data were also evaluated for the forelimbs. Measurements analyzed in the craniocaudal axis, divided into braking and propulsion phases, consisted of peak force and associated impulses. Also, orthopedic examination for each dog included subjective scoring for limb lameness at each evaluation period. Results Most ground reaction forces (GRF) were significantly lower before surgery for the proposed treated, compared with the proposed untreated, limb. This difference between limbs continued through postoperative month 1. Also at 1 month, some treated limb values were significantly lower than preoperative values. By 3 to 6 months, treated limb GRF increased so that no significant difference between limbs could be found. Vertical and craniocaudal propulsion impulse values were significantly higher in the treated than untreated limb from the 6-month evaluation period through the remainder of the study. Braking component of the craniocaudal axes measurements was unchanged throughout the study. Conclusions GRF indicated that dogs of this study had significantly increased loading function of the treated hind limb by 6 months after unilateral total hip replacement. Data also indicated that some force was transferred from the untreated to treated hip over the study period. Loading rates also increased over the study period, indicating increased willingness to load the treated hip over time. Craniocaudal axis data ndicated no improvement in braking forces with coxofemoral joint replacement, suggesting that the coxofemoral joint with degenerative joint disease did not have altered braking performance at a trotting gait. Comparison of subjective lameness scores and objective GRF indicated that visual grading of coxofemoral joint lameness is limited. (Am J Vet Res 1996;57:1781–1785)