Limb dynamics in agility jumps of beginner and advanced dogs

Abstract

A considerable body of work has examined the dynamics of different dog gaits, but there are no studies that have focused on limb dynamics in jumping. Jumping is an essential part of dog agility, a dog sport in which handlers direct their dogs through an obstacle course in a limited time. We hypothesized that limb parameters like limb length and stiffness indicate the skill level of dogs. We analyzed global limb parameters in jumping for 10 advanced and 10 beginner dogs. In experiments, we collected 3D kinematics and ground reaction forces during dog jumping at high forward speeds. Our results revealed general strategies of limb control in jumping and highlighted differences between advanced and beginner dogs. In takeoff , the spatially leading forelimb was 75% (P<0.001) stiffer than the trailing forelimb. In landing, the trailing forelimb was 14% stiffer (P<0.001) than the leading forelimb. This indicates a strut-like action of the forelimbs to achieve jumping height in takeoff and to transfer vertical velocity into horizontal velocity in landing (with switching roles of the forelimbs). During landing, the more (24%) compliant forelimbs of beginner dogs (P=0.005) resulted in 17% (P=0.017) higher limb compression during the stance phase. This was associated with a larger amount of eccentric muscle contraction, which might in turn explain the soft tissue injuries that frequently occur in the shoulder region of beginner dogs. For all limbs, limb length at toe-off was greater for advanced dogs. Hence, limb length and stiffness might be used as objective measures of skill.

Kinetics and Kinematics of Working Trials Dogs: The Impact of Long Jump Length on Peak Vertical Landing Force and Joint Angulation

“…However, further work should be undertaken on this obstacle to assess this theory. Consideration of the level the dogs have reached in competition may provide an extra opportunity to measure the effect of training and previous experience on dog jumping styles, as is evident in agility dogs [16,22]. and to understand the potential impacts on dogs who are new to working trials.…”

“…While researchers have investigated the jump competence within agility-based competitions, there remains a lack of research on the impact of spread jumps (long jump and water jump in agility and long jump in working trials) on PVF and apparent joint angulation of dogs on landing. Research into the impact of vertical jumps has indicated impacts on the physical health of dogs and highlighted the different jumping techniques adopted by lesser and more experienced dogs [16]. Furthermore, work by Carter et al [17] identified changes in peak vertical landing force and joint angulation in dogs traversing different heights in the working trials scale obstacle.…”

Evaluation of Variability in Gait Styles Used by Dogs Completing Weave Poles in Agility Competition and Its Effect on Completion of the Obstacle

“…A previous study evaluating limb forces when jumping found a significant difference in limb stiffness when landing between beginner and experienced dogs ( 18 ). This increase in stiffness was associated with higher limb compression during stance phase.…”

“…This increase in stiffness was associated with higher limb compression during stance phase. It was hypothesized that larger eccentric muscle contraction due to the increased compliance that occurred during landing may be associated with injury ( 18 ). It is unknown whether there are similar variations in forelimb forces between beginner and experienced dogs as they complete the weave poles.…”

Towards rich motion skills with the lightweight quadruped robot Serval

“…The first implementation toward versatile movement with Serval consisted of replaying modified kinematic data from dogs (Söhnel, Andrada, De Lussanet, Wagner, & Fischer, 2017). This approach, due to the readiness state of the robot hardware and control (no sensors integrated at the time, no reflexes), was performed in open loop and is thus a basic control to be extended in future work.…”