Effects of partial immersion in water on vertical ground reaction forces and weight distribution in dogs.

Objective: To assess the impact of partial immersion in water on vertical ground reaction force (vGRF) and vGRF distribution in dogs.
Animals: 10 healthy adult dogs.
Procedures: Weight placed on each limb of each dog was measured 3 times (1 scale/limb). Dogs were then immersed in water to the level of the tarsal, stifle, and hip joints, and vGRFs were measured. Coefficients of variation for triplicate measurements were calculated. Mixed-effects ANOVAs were used to compare the vGRF for thoracic versus pelvic limbs and the vGRF at various immersion levels as well as the vGRF distributions among limbs at various immersion levels.
Results: Mean±SD vGRF before immersion was 249±34 N. It was significantly decreased by 9% after immersion to the tarsal joints (227±32 N), by 15% after immersion to the stifle joints (212±21 N), and by 62% after immersion to the hip joints (96±20 N). The vGRFs were significantly higher for the thoracic limbs than for the pelvic limbs before immersion and at all immersion levels. Dogs placed 64% of their weight on the thoracic limbs before immersion. That ratio did not differ significantly after immersion to the tarsus (64%) or stifle (63%) joints, but was significantly larger after immersion to the hip joints (71%).
Conclusions and Clinical Relevance: vGRF decreased as the depth of immersion increased. The thoracic limb-to-pelvic limb vGRF ratio was unchanged in dogs after immersion to the tarsal or stifle joints, but it increased after immersion to the hip joints.