Kinetics of jumping regarding agility dogs
Canine agility is a popular sport discipline, involving various jumping activities. Handlers navigate their dogs through a course with different obstacles. Courses are characterized by jumping at high speed and with fast directional changes. Systematic scientific research regarding kinetics in jumping agility dogs is scarce. For the first time, we examined kinetic parameters for single legs in take-off and landing a hurdle jump. Further, we compared straight jumps and wrap jumps, where dogs perform a tight turn during the landing phase. Simultaneous kinetic and kinematic data were recorded from 10 advanced agility Border collies jumping over two consecutive hurdles. We here report the jump kinetics. Ground reaction forces (GRF) were recorded for hindlimbs during take-off and forelimbs during landing. For straight jumps, we found synchronous hindlimb touchdown at take-off phase. Ground reaction force shows similar GRF progression in both hindlimbs. During the landing of a straight jump, the forelimbs show skipping gait pattern, with first touchdown of the trailing limb, followed by touchdown of the leading limb. We found shallower angle of attack and a higher decelerative impulse for the leading limb than the trailing limb. For wrap jumps, hindlimbs touchdown was synchronous during the take-off phase, but the GRF pattern differed. The GRF progression indicated that the take-off pattern of the two limbs acts like a differential gear. Hindlimbs produced a torque already at take-off, to start the wrap. The touchdown of forelimbs was synchronous during landing, but like the hindlimbs they showed a different GRF progression. We found longer contact durations for the left than the right forelimb. Peak vertical and mediolateral forces seem to be higher for the right forelimb than the left forelimb, to resist inertia effects and to continue turning.