Effects of subject stance time and velocity on ground reaction forces in clinically normal greyhounds at the walk.

Force plate gait analysis was used to study the effects of subject stance time and velocity on ground reaction forces in 5 adult Greyhounds at the walk. Data from 146 valid trials were obtained. Stance time and velocity were linearly related, and stance time had a strong, negative correlation with velocity (r = -0.72 for the forelimbs, r = -0.56 for the hind limbs). Stance time correlated more closely with changes in peak vertical force and impulse than did velocity. Stance time and velocity correlated less strongly with braking and propulsion forces and impulses. The trials were divided into 2 distinct velocity ranges (V1 = 0.92 to 1.03 m/s, V2 = 1.06 to 1.17 m/s), 2 distinct forelimb stance time ranges (FST1 = 0.40 to 0.48 second, FST2 = 0.50 to 0.55 second), and 2 distinct hind limb stance time ranges (HST1 = 0.40 to 0.45 second, HST2 = 0.46 to 0.51 second). Five trials from each dog were included in each range, and the mean values were used to evaluate changes in ground reaction forces between groups. Peak vertical force in the forelimbs decreased significantly (P = 0.048) as FST increased; however, difference was not detected in vertical force between velocity groups. Peak vertical force in the hind limbs decreased significantly (P = 0.001) as HST increased and increased significantly (P = 0.000) as velocity increased. Differences were not observed between groups in forelimb or hind limb braking and propulsive forces.(ABSTRACT TRUNCATED AT 250 WORDS)