41.2 Sunday, Jan. 5 10:30 The ‘dog paddle’: Stereotypic swimming gait pattern in different dog breeds FISH, F.E.*; DINENNO, N.K.; West Chester University; West Chester University firstname.lastname@example.org
The term ‘dog paddle’ has been applied to the swimming behavior of a number of terrestrial and aquatic species. Dog paddling refers to a form of drag-based, paddle propulsion in which the limbs are oriented underneath the body and moved through an arc. Despite the ubiquity of the term, particularly in association with unrefined and inefficient swimming capabilities, there has been no analysis of the swimming kinematics of dogs. Underwater video was recorded (30 fr/s) of surface swimming dogs for eight individuals from six breeds, ranging in size from terrier to Newfoundland dog. The quadrupedal paddling stroke was analyzed to determine the kinematics and coordination of the fore and hind limbs. The paddling stroke represented a modified terrestrial gait similar to a fast diagonal sequence single footfall, which was outside the kinematic space for terrestrial locomotion by dogs. Stroke frequency decreased with increasing body size. The stroke cycle was divided into power (propulsive) and recovery (non-propulsive) phases. During the power phase, digits of the paw were abducted and the front limb was retracted posteriorly until perpendicular to the body. In the recovery phase, digits were adducted while the brachium was retracted anteriorly and the antebrachium was supinated. The power phase of the stroke cycle was shorter than the recovery phase for both fore and hind limbs. Maximum velocity during the power phase was greater for the hind limb compared to the forelimb. The modified terrestrial gait used for swimming in the dog paddle appears to be stereotypic among breeds, whereas terrestrial locomotion in dogs shows substantial variation in gait. Without constraints imposed by gravity and substrate contact, swimming dogs can utilize new gait profiles.