Accelerometer validity and placement for detection of changes in physical activity in dogs under controlled conditions on a treadmill

The objective of the research was to determine the optimal location and method of attachment for accelerometer-based motion sensors, and to validate their ability to differentiate rest and increases in speed in healthy dogs moving on a treadmill. Two accelerometers were placed on a harness between the scapulae of dogs with one in a pouch and one directly attached to the harness. Two additional accelerometers were placed (pouched and not pouched) ventrally on the dog's collar. Data were recorded in 1s epochs with dogs moving in stages lasting 3 min each on a treadmill: (1) at rest, lateral recumbency, (2) treadmill at 0% slope, 3 km/h, (3) treadmill at 0% slope, 5 km/h, (4) treadmill at 0% slope, 7 km/h, (5) treadmill at 5% slope, 5 km/h, and (6) treadmill at 5% slope, 7 km/h. Only the harness with the accelerometer in a pouch along the dorsal midline yielded statistically significant increases (P<0.05) in vector magnitude as walking speed of the dogs increased (5-7 km/h) while on the treadmill. Statistically significant increases in vector magnitude were detected in the dogs as the walking speed increased from 5 to 7 km/h, however, changes in vector magnitude were not detected when activity intensity was increased as a result of walking up a 5% grade. Accelerometers are a valid and objective tool able to discriminate between and monitor different levels of activity in dogs in terms of speed of movement but not in energy expenditure that occurs with movement up hill.