scholarly journals Influence of Speed, Ground Surface and Shoeing Condition on Hoof Breakover Duration in Galloping Thoroughbred Racehorses

Animals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2588
Author(s):  
Kate Horan ◽  
James Coburn ◽  
Kieran Kourdache ◽  
Peter Day ◽  
Dan Harborne ◽  
...  
Keyword(s):  
Mixed Models ◽  
High Speed ◽  
Intervention Study ◽  
Ground Surface ◽  
Relative Reduction ◽  
Video Cameras ◽  
Significance Threshold ◽  
Thoroughbred Racehorses ◽  
Rubber Composite ◽  
Artificial Surface

Understanding the effect of horseshoe–surface combinations on hoof kinematics at gallop is relevant for optimising performance and minimising injury in racehorse–jockey dyads. This intervention study assessed hoof breakover duration in Thoroughbred ex-racehorses from the British Racing School galloping on turf and artificial tracks in four shoeing conditions: aluminium, barefoot, aluminium–rubber composite (GluShu) and steel. Shoe–surface combinations were tested in a randomized order and horse–jockey pairings (n = 14) remained constant. High-speed video cameras (Sony DSC-RX100M5) filmed the hoof-ground interactions at 1000 frames per second. The time taken for a hoof marker wand fixed to the lateral hoof wall to rotate through an angle of 90 degrees during 384 breakover events was quantified using Tracker software. Data were collected for leading and non-leading forelimbs and hindlimbs, at gallop speeds ranging from 23–56 km h−1. Linear mixed-models assessed whether speed, surface, shoeing condition and any interaction between these parameters (fixed factors) significantly affected breakover duration. Day and horse–jockey pair were included as random factors and speed was included as a covariate. The significance threshold was set at p < 0.05. For all limbs, breakover times decreased as gallop speed increased (p < 0.0005), although a greater relative reduction in breakover duration for hindlimbs was apparent beyond approximately 45 km h−1. Breakover duration was longer on turf compared to the artificial surface (p ≤ 0.04). In the non-leading hindlimb only, breakover duration was affected by shoeing condition (p = 0.025) and an interaction between shoeing condition and speed (p = 0.023). This work demonstrates that speed, ground surface and shoeing condition are important factors influencing the galloping gait of the Thoroughbred racehorse.

scholarly journals Influence of Speed, Ground Surface and Shoeing Condition on Hoof Breakover Duration in Galloping Thoroughbred Racehorses

2021 ◽  
Author(s):  
Kate Horan ◽  
James Coburn ◽  
Kieran Kourdache ◽  
Peter Day ◽  
Dan Harborne ◽  
...  
Keyword(s):  
High Speed ◽  
Ground Surface ◽  
Relative Reduction ◽  
Accelerometer Data ◽  
Video Cameras ◽  
Significance Threshold ◽  
Hind Limbs ◽  
Thoroughbred Racehorses ◽  
Artificial Surface ◽  
Future Work

Understanding the effect of horseshoe-surface combinations on hoof kinematics at gallop is relevant for optimising performance and minimising injury in racehorse-jockey dyads. This intervention study assessed hoof breakover duration in Thoroughbred ex-racehorses from the British Racing School galloping on turf and artificial tracks in four shoeing conditions: barefoot, aluminium-rubber composite (GluShu), aluminium and steel. Shoe-surface combinations were tested in a randomized order and horse-rider pairings (n=14) remained constant. High-speed video cameras (Sony DSC-RX100M5) filmed the hoof-ground interactions at 1000 frames per second. The time taken for a hoof marker wand fixed to the lateral hoof wall to rotate through an angle of 90 degrees during 384 breakover events was quantified using Tracker software. Data were collected for leading and non-leading front and hind limbs, at gallop speeds ranging from 23&ndash;56 km h-1. Linear mixed-models assessed whether speed, surface, shoeing condition or any interaction between these parameters (fixed factors) significantly affected breakover duration. Day and horse-rider pair were included as random factors and speed was included as a covariate. The significance threshold was set at p&amp;lt;0.05. For all limbs, breakover times decreased as gallop speed increased (p&amp;lt;0.0005), although a greater relative reduction in breakover duration for hindlimbs was apparent beyond approximately 45 km h-1. Breakover duration was longer on turf compared to the artificial surface (p&le;0.04). In the non-leading hindlimb only, breakover duration was affected by shoeing condition (p=0.025) and an interaction between shoeing condition and speed (p=0.023). Future work seeks to relate these results to hoof accelerometer data.

Study on Edge Contact Area and Surface Integrity of Workpiece in Point Grinding Process

2009 ◽  
Vol 407-408 ◽  
pp. 577-581
Author(s):  
Shi Chao Xiu ◽  
Zhi Jie Geng ◽  
Guang Qi Cai
Keyword(s):  
Surface Integrity ◽  
Contact Area ◽  
High Speed ◽  
Ground Surface ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Edge Contact ◽  
Cylindrical Grinding ◽  
Theoretic Foundations

During cylindrical grinding process, the geometric configuration and size of the edge contact area between the grinding wheel and workpiece have the heavy effects on the workpiece surface integrity. In consideration of the differences between the point grinding and the conventional high speed cylindrical grinding, the geometric and mathematic models of the edge contact area in point grinding were established. Based on the models, the numerical simulation for the edge contact area was performed. By means of the point grinding experiment, the effect mechanism of the edge contact area on the ground surface integrity was investigated. These will offer the applied theoretic foundations for optimizing the point grinding angles, depth of cut, wheel and workpiece speed, geometrical configuration and size of CBN wheel and some other grinding parameters in point grinding process.

Ultra-High Speed Grinding Using a CBN Wheel for a Mirror-Like Surface Finish

2005 ◽  
Vol 291-292 ◽  
pp. 67-72 ◽  
Author(s):  
M. Ota ◽  
T. Nakayama ◽  
K. Takashima ◽  
H. Watanabe
Keyword(s):  
Surface Finish ◽  
High Speed ◽  
High Efficiency ◽  
Ground Surface ◽  
Machining Process ◽  
Grinding Wheel ◽  
Cbn Wheel ◽  
Ultra High Speed ◽  
High Speed Grinding ◽  
Grinding Conditions

There are strong demands for a machining process capable of reducing the surface roughness of sliding parts, such as auto parts and other components, with high efficiency. In this work, we attempted to grind hardened steel to a mirror-like surface finish with high efficiency using an ultra-high speed grinding process. In the present study, we examined the effects of the work speed and the grinding wheel grain size in an effort to optimize the grinding conditions for accomplishing mirror-like surface grinding with high efficiency. The results showed that increasing the work speed, while keeping grinding efficiency constant, was effective in reducing the work affected layer and that the grinding force of a #200 CBN wheel was lower than that of a #80 CBN wheel. Based on these results, a high-efficiency grinding step with optimized grinding conditions was selected that achieved excellent ground surface quality with a mirror-like finish.

Effect of training on plasma myeloperoxidase concentrations measured before and following intense exercise in Thoroughbred racehorses

2016 ◽  
Vol 12 (1) ◽  
pp. 17-25 ◽  
Author(s):  
R.G. Fonseca ◽  
D.A. Kenny ◽  
B.A. McGivney ◽  
B.A. Murphy ◽  
E.W. Hill ◽  
...  
Keyword(s):  
High Speed ◽  
Venous Blood ◽  
White Blood Count ◽  
Training Intensity ◽  
High Intensity Training ◽  
Thoroughbred Racehorses ◽  
Sampling Points ◽  
And Performance ◽  
Response To Exercise ◽  
And Training

Exercise in horses induces neutrophil degranulation and subsequent increases in plasma myeloperoxidase concentrations (MPO). It is not known whether this response is affected by training or the sampling time in relation to exercise. Our objective was to evaluate plasma MPO concentration at different time points in response to exercise in Thoroughbreds before and following high-intensity training and to evaluate relationships between plasma MPO concentration, physiological measurements and performance. Throughbred racehorses in active training and racing (n=26) performed an exercise test on a high-speed treadmill at least once at the beginning (first three months), middle (second three months) or end (last three months) of a nine month training period with training intensity (number of fast work sessions) collated for each period. Heart rate, speed and distance were recorded and venous blood collected before (T0), during and up to maximal speed (TVmax), 5 min (T5min) and 4 h (T4h) following exercise for measurement of plasma lactate, serum creatine kinase concentration, plasma MPO concentration, white blood count (WBC), neutrophil count (Neut), lymphocyte count and neutrophil percentage (%Neut). WBC increased above T0 values at all sampling points with no training effect. Neut and %Neut increased above T0 values at T4h, while values at TVmax, T5min and T4h increased as training duration increased. Plasma MPO concentration increased above T0 values at all sampling points in response to exercise with all values increasing as training duration increased. Training intensity did not affect any of the measurements, correlations were not identified between any of the biological markers including MPO and physiological and training measurements and no differences were identified between elite versus non-elite horses. It was concluded that plasma MPO concentration is affected by exercise and training duration, and that further investigation of plasma MPO as an assessor of fitness and readiness for competition is warranted.

An analysis of the particle trajectories in spherical blast waves reflected from real and ideal surfaces

1981 ◽  
Vol 59 (10) ◽  
pp. 1380-1390 ◽  
Author(s):  
J. M. Dewey ◽  
D. J. McMillin
Keyword(s):  
High Speed ◽  
Ground Surface ◽  
Blast Waves ◽  
Particle Trajectories ◽  
Shock Interactions ◽  
Pressure Time ◽  
Time Histories ◽  
Particle Velocities ◽  
Spherical Shock ◽  
Fixed Times

High speed photogrammetry has been used to measure the particle trajectories in the flows resulting from the interaction of two identical explosively produced spherical shock waves. It is postulated that the interaction simulated the reflection of a spherical shock from an ideal nonenergy-absorbing surface. The "ideal" reflections were compared with reflections from two types of ground surface. From the observed particle trajectories the particle velocities, gas densities, and hydrostatic, dynamic, and total pressures in the complex air flows behind the shock interactions have been computed. These flows are described as two dimensional fields at fixed times and as time histories at fixed locations. The Mach stem shocks at the ground surfaces were weaker than those at corresponding positions near the interaction planes, but the magnitudes of the flow properties in these waves decreased more slowly and, at later times, became greater than those in the waves at the interaction planes. Computed pressure–time histories were compared to measurements made using electronic transducers and good agreement was found.

scholarly journals Standard of the Initial Ball Velocity for a Fly Ball in Baseball Hitting

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 137
Author(s):  
Hirotaka Nakashima ◽  
Gen Horiuchi ◽  
Shinji Sakurai
Keyword(s):  
Initial Velocity ◽  
High Speed ◽  
Baseball Players ◽  
Ball Impact ◽  
Video Cameras ◽  
High Speed Video ◽  
Before And After ◽  
Ball Velocity ◽  
Opposite Field ◽  
Measuring Tape

This study aimed to determine the minimum required initial velocity to hit a fly ball toward the same field (left-field for right-handed batters), center field, and opposite field (right field for right-handed batters). Six baseball players hit fastballs launched by a pitching machine. The movements of the balls before and after bat-to-ball impact were recorded using two high-speed video cameras. The flight distance was determined using a measuring tape. Seventy-nine trials were analyzed, and the minimum required initial velocities of batted balls were quantified to hit balls 60, 70, 80, 90, 100, 110, and 120 m in each direction through regression analysis. As a result, to hit a ball 120 m, initial velocities of 43.0, 43.9, and 46.0 m/s were required for the same field, center field, and opposite field, respectively. The result provides a useful index for batters to hit a fly ball in each of the directions.

Modeling a Viscoelastic Gymnastics Landing Mat during Impact

2006 ◽  
Vol 22 (2) ◽  
pp. 103-111 ◽  
Author(s):  
Chris Mills ◽  
Matthew T.G. Pain ◽  
Maurice R. Yeadon
Keyword(s):  
High Speed ◽  
Force Plate ◽  
System Model ◽  
Video Cameras ◽  
Key Characteristics ◽  
Single Mass ◽  
Force Time ◽  
Mass Spring ◽  
The Impact ◽  
Landing Mat

Landing mats that can undergo a large amount of area deformation are now essential for the safe completion of landings in gymnastics. The objective of this study was to develop an analytical model of a landing mat that reproduces the key characteristics of the mat-ground force during impact with minimal simulation run time. A force plate and two high-speed video cameras were used to record the mat deformation during vertical drop testing of a 24-kg impactor. Four increasingly complex point mass spring-damper models, from a single mass spring-damper system, Model 1, to a 3-layer mass spring-damper system, Model 4, were constructed using Matlab to model the mat's behavior during impact. A fifth model composed of a 3-layer mass spring-damper system was developed using visual Nastran 4D. The results showed that Models 4 and 5 were able to match the loading phase of the impact with simulation times of less than 1 second for Model 4 and 28 seconds for Model 5. Both Models 4 and 5 successfully reproduced the key force-time characteristics of the mat-ground interface, such as peak forces, time of peak forces, interpeak minima and initial rates of loading, and could be incorporated into a gymnast-mat model.

scholarly journals Development and Evaluation of an Autonomous Sensor for the Observation of Sediment Motion*

2014 ◽  
Vol 31 (4) ◽  
pp. 1012-1019 ◽  
Author(s):  
Donya Frank ◽  
Diane Foster ◽  
Pai Chou ◽  
Yu-Min Kao ◽  
In Mei Sou ◽  
...  
Keyword(s):  
High Speed ◽  
Coastal Sediments ◽  
Angle Of Repose ◽  
Incipient Motion ◽  
Stress Criterion ◽  
Video Cameras ◽  
Mobile Bed ◽  
Autonomous Sensor ◽  
Lagrangian Observations ◽  
Lagrangian Measurements

Abstract Measurements within the mobile bed layer have been limited by previous Eulerian-based technologies. A microelectromechanical system device, called a smart sediment grain (SSG), that can measure and record Lagrangian observations of coastal sediments at incipient motion has been developed. These sensors have the potential to resolve fundamental hypotheses regarding the incipient motion of coastal sediments. Angle of repose experiments verified that the sensor enclosure has mobility characteristics similar to coarse gravel. Experiments conducted in a small oscillating flow tunnel verified that the sensors detect incipient motion under various hydrodynamic conditions. Evidence suggests the influence of pressure-gradient-induced sediment motion, contrary to the more commonly assumed bed shear stress criterion. Lagrangian measurements of rotation measured with the newly developed SSG agreed to within 5% of the rotation estimates made simultaneously with high-speed video cameras.

Sign in / Sign up

Export Citation Format

Share Document