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  • Author or Editor: Ronald M. McLaughlin x
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Summary

Force plate gait analysis was used to study the effects of subject stance time and velocity on ground reaction forces in 6 adult Greyhounds at the trot. Data for 210 valid trials were obtained. Stance time negatively correlated with velocity (r = −0.85 for the forelimbs, r = −0.61 for the hind limbs), decreasing as velocity increased. Stance time in the forelimbs and hind limbs correlated more closely with changes in vertical peak force and impulse than did velocity. The trials were divided into 3 distinct velocity ranges (V1 = 1.5 to 1.8 m/s, V2 = 2.1 to 2.4 m/s, and V3 = 2.7 to 3.0 m/s), 3 distinct forelimb stance time ranges (fst1 = 0.144 to 0.176 second, fst2 = 0.185 to 0.217 second, and fst3 = 0.225 to 0.258 second), and 3 distinct hind limb stance time ranges (hst1 = 0.105 to 0.132 second, hst2 = 0.139 to 0.165 second, and hst3 = 0.172 to 0.198 second). Peak forces increased as velocity increased and decreased as stance time increased. Vertical impulse decreased as velocity increased and increased as stance time increased. The relation between stance time, subject velocity, and ground reaction forces was documented for clinically normal Greyhounds at the trot. Changes in stance time accurately reflected changes in subject velocity and ground reaction forces in clinically normal dogs and could be used to normalize trial data within a sampling period.

Free access
in American Journal of Veterinary Research

Summary

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 = 0.43 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. Vertical impulse in the forelimbs and hind limbs decreased as velocity increased and increased as stance time increased. Braking impulse in the forelimbs decreased as velocity increased and increased as fst increased. Braking force in the hind limbs did not change between velocity or stance time groups. Propulsive impulse in the hind limbs decreased as velocity increased and increased as hst increased. Stance time was a sensitive and accurate indicator of subject velocity in clinically normal dogs at the walk and correlated more closely with changes in some ground reaction forces than did velocity measurements. Stance time measurements could be used to normalize trial data within a sampling period and document consistency in velocity during force plate analysis of clinically normal dogs at the walk.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate clinical effects of immobilization followed by remobilization and exercise on the metacarpophalangeal joint (MPJ) in horses.

Animals—5 healthy horses.

Procedure—After lameness, radiographic, and force plate examinations to determine musculoskeletal health, 1 forelimb of each horse was immobilized in a fiberglass cast for 7 weeks, followed by cast removal and increasing amounts of exercise, beginning with hand-walking and ending with treadmill exercise. Lameness examination, arthrocentesis of both MPJ, single-emulsion radiographic examination, nuclear scintigraphic examination, ground-reaction force-plate analysis, and computed tomographic examination were done at various times during the study.

Results—All horses were lame in the immobilized MPJ after cast removal; lameness improved slightly with exercise. Force plate analysis revealed a significant difference in peak forces between immobilized and contralateral limbs 2 weeks after cast removal. Range of motion of the immobilized MPJ was significantly decreased, and joint circumference was significantly increased, compared with baseline values, during the exercise period. Osteopenia was subjectively detected in the immobilized limbs. Significant increase in the uptake of radionucleotide within bones of the immobilized MPJ after cast removal and at the end of the study were detected. Loss of mineral opacity, increased vascular channels in the subchondral bone, and thickening within the soft tissues of the immobilized MPJ were detected.

Conclusions and Clinical Relevance—Results indicate that 8 weeks of enforced exercise after 7 weeks of joint immobilization did not restore joint function or values for various joint measurements determined prior to immobilization. (Am J Vet Res 2002;63:282–288)

Full access
in American Journal of Veterinary Research

Abstract

Objective

To evaluate the effects of orally administered glucosamine hydrochloride (GIAm)–chondroitin sulfate (sCS) and GIAM–CS–S-adenosyl-L-methionine (SAMe) on chemically induced synovitis in the radiocarpal joint of dogs.

Animals

32 adult mixed-breed dogs.

Procedure

For 21 days, all dogs received a sham capsule (3 groups) or GIAm-CS (prior treatment group) in a double-blinded study. Unilateral carpal synovitis was induced by injecting the right radiocarpal joint with chymopapain and the left radiocarpal joint (control joint) with saline (0.9% NaCl) solution. Joints were injected on alternate days for 3 injections. After induction of synovitis, 2 groups receiving sham treatment were given GIAm-CS or GIAm-CS–SAMe. Another group continued to receive sham capsules (control group). Joint inflammation was quantified, using nuclear scintigraphy, before injection of joints and days 13, 20, 27, 34, 41, and 48 after injection. Lameness evaluations were performed daily.

Results

Dogs given GIAm-CS before induction of synovitis had significantly less scintigraphic activity in the soft-tissue phase 48 days after joint injection, significantly less uptake in the bone phase 41 and 48 days after joint injection, and significantly lower lameness scores on days 12 to 19, 23, and 24 after injection, compared with other groups.

Conclusions and Clinical Relevance

Analysis of results of this study suggest that prior treatment with GIAm-CS for 21 days had a protective effect against chemically induced synovitis and associated bone remodeling. Prior treatment with GIAm-CS also reduced lameness in dogs with induced synovitis. (Am J Vet Res 1999;60:1552–1557)

Free access
in American Journal of Veterinary Research