Managing the Greyhound Racing Surface
Understanding the Greyhound Racing Gallop
Robert L. Gillette, DVM, MSE
The most important element of canine sports medicine is recognizing the athleticism of the patient
|To prepare the racing surface for the Greyhound, it is important to understand how the Greyhound will interact with the surface. Understanding this interaction begins by understanding the movements and forces related to Greyhound racing.
The gait describes a particular series of leg and body movements used for locomotion. A Greyhound racing stride is seen in Figure 1.
The Dog Step Cycle
A stride is composed of the summed movements of the four legs. The phases of limb movement are divided into components of the step cycle. Each leg goes through it’s own step cycle. The stance phase and the swing phase make up the step cycle.
Each leg of the dog goes through the same step cycle for every gait (Figure 2).
A gait is a description of the combined movements of the legs and the resultant movements of the body. There are symmetrical gaits and asymmetrical gaits. In a symmetrical gait the movements of the right side mirrors the movements of the left side. Examples of symmetrical gaits are the Trot, Pace, or Walk In an asymmetrical gait the movement of one side is different than the other side. Examples of an asymmetrical gait are the gallop or canter.
The Greyhound Racing Gallop
The gallop is the gait typically used by dogs that are running at high speeds. It has two support phases and two flight phases in each stride. The gallop can have either a right lead or a left lead and is described as a double suspension-rotary gallop. It is the running gait used by most dogs.
The Gallop Sequence
In left-lead dogs, the feet contact the surface in a clockwise fashion (Figure 3). The left front leg comes into contact first, followed by the right front foot in the front support phase. The dog then leaves the ground in the front flight phase. The next foot to make contact is the right rear foot followed by the left rear foot in the rear support phase. The dog then propels forward leaving the ground a second time in the rear flight phase, after which the sequence is again repeated. A right-lead dog goes though the same sequence but contact is in a counter-clockwise rotation.
The Variations of Normal Canine Locomotion
The forces involved with locomotion vary depending upon the particular movements. The movements that occur during a race include:
Planes of MovementMovement can be measured in three planes.
Stopping or Braking
Biomechanics of the Greyhound Racing Gallop
Determination of a Kinematic Reference Base
A study was performed in 1990 by Drs. Carol Zebas and Rob Gillette to determine the kinematic values associated with the Racing Greyhound. This data could then be used to help reduce racing injuries. Greyhounds were filmed during schooling races at the Woodlands Greyhound Track in Kansas City, Kansas. The schooling races took place during the month of August prior to initiating the racing season. Twenty-two Greyhounds were filmed for analysis. This group of Greyhounds varied in ability from Grade A to Maidens.
The Kinematic Factors Related to the Racing Gallop
These factors are measured in distance or time (Figure 4). Examples of Distance measurements are Stride Length, Flight Distance. Examples of Time measurements are Stride Time, Support Time (Front, Rear, & Total), and Flight Time (Front, Rear, and Total). Stride Frequency is a factor of stride time and is the number of strides taken per second of time
The time data can been seen in Table 1. The Stride Time is the amount of time it took for the greyhound to go through one stride. The average stride time was 0.33 seconds. Therefore the Stride Frequency is 3 strides per second. The support time (ST = FS + RS) is the time spent in support during one stride. The flight time (FT = FF + RF) is the time spent in flight during one stride. FS is the time spent in front support during one stride, FF is the time spent in front flight, RS is the time spent in rear support, and RF is the time spent in rear flight. The ratios help to evaluate support to flight values
Table 1. Mean kinematic values of the Greyhound racing gait related to time.
The distance data can be seen in Table 2. The Stride Length is the distance the greyhound traveled during one stride. The Linear Velocity is the speed that the Greyhound was traveling (16.93 m/s = 37.64 mph). Vertical Movement is the distance that an object moves up and down. The Trunk relates to the body or trunk and the Head relates to the head bob. Range of motion (ROM) is the angular displacement of a joint measured in degrees (deg).
Table 2. Mean kinematic values of the Greyhound racing gait related to distance.
The data in Table 3 show that velocity is related to stride frequency, support time, front/rear support distance and time ratios, and rear flight time, and rear distance. The faster greyhounds are the ones who have a short quick, strong support phase that has a properly balanced rear to front support ratio. As stride frequency increases velocity increases (r=.76). When support time (r=-.85) and support/flight (r=-.57) decrease, velocity increases. A strong rear support phase is evident by rear flight time and distance. As rear flight distance (r=.81) and rear flight time (r=.70) increase so does the velocity. It should be mentioned that stride length is not significantly correlated with velocity (r=.40).
Greyhounds with a high stride frequency, low support time, proper rear/flight support ratio, and long rear flight times and distances have an advantage over greyhounds who do not.
Table 3. Correlation of temporal and distance characteristics during the support and flight phases with velocity.
Kinematic Factors of Fatigue
The data related to fatigue are seen in Table 4. The results indicated significant decreases (p < .05) from beginning to end in velocity (VEL=16.45 to 14.58 m/s), stride frequency (SF=3.25 to 2.82 strides/second), and rear leg flight distance (RFD=2.50 to 2.32 m). Significant increases (p < .05) were found in total support time (ST=.187 to .225 s), front leg support time (FST=.093 to .114 s), rear leg support time (RST=.093 to .116 s), and front leg flight distance (FFD=1.23 to .142 m). No significant differences (p < .05) were found in stride length (SL) or total flight time (FT). It was concluded that velocity decreased because SF decreased with little or no accompanying changes in SL. It would appear the body absorbed more energy later in the race, which limited the amount of stored elastic energy available to project the dog forward. This is evidenced by the fact that more time was spent on ground support than in flight. Even though the push off generated by the back legs caused the front flight distance to increase, there was no overall increase in SL because the rear flight distance decreased. This suggests a fatigue effect or the inefficient use of the stored elastic energy in the vertebral muscles of the back (longissimus muscles). These results are similar in pattern to human runners in long sprint races where SF and leg lift decreased, characterizing the fatigue state.
Table 4. Correlation of selected kinematic values with fatigue.
The racing Greyhound travels at speeds of more than 40 miles per hour. Their lead leg impacts the surface with 2.25 times their body weight. Greyhounds go through three strides per second during a race event. Each stride is made up of a series of body movements that act to propel the greyhound forward, turn the greyhound to the left, or slow down and stop the greyhound. The paw to surface interaction allows these actions to occur. Therefore, it is very important that the surface is prepared to handle the forces related to these actions. The surface acts to absorb the forces of impact and then provides traction for the paw to grip the surface. The proper racing surface will minimize racing injuries, help to delay fatigue, and optimize racing ability.
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