Evaluation of biomechanical effects of four stimulation devices placed on the hind feet of trotting horses.
OBJECTIVE
To compare effects of 4 types of stimulation devices attached to the hind feet on hoof flight, joint angles, and net joint powers of trotting horses.


METHODS
8 clinically normal horses.


METHODS
Horses were evaluated under 5 conditions in random order: no stimulators, loose straps (10 g), lightweight tactile stimulators (55 g), limb weights (700 g), and limb weights with tactile stimulators (700 g). Reflective markers on the hind limbs were tracked during the swing phase of 6 trotting trials performed at consistent speed to determine peak hoof heights and flexion angles of the hip, stifle, tarsal, and metatarsophalangeal joints. Inverse dynamic analysis was used to calculate net joint energies. Comparisons among stimulators were made.


RESULTS
Peak hoof height was lowest for no stimulators (mean ± SD, 5.42 ± 1.38 cm) and loose straps (6.72 ± 2.19 cm), intermediate for tactile stimulators (14.13 ± 7.33 cm) and limb weights (16.86 ± 15.93 cm), and highest for limb weights plus tactile stimulators (24.35 ± 13.06 cm). Compared with no stimulators, net tarsal energy generation increased for tactile stimulators, limb weights, and limb weights plus tactile stimulators, but only the weighted conditions increased net energy generation across the hip joint.


CONCLUSIONS
The type and weight of foot stimulators affected the magnitude of the kinematic and kinetic responses and the joints affected. These findings suggest that different types of foot stimulators are appropriate for rehabilitation of specific hind limb gait deficits, such as toe dragging and a short stride.
Mary Anne McPhail Equine Performance Center, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA. claytonh@cvm.msu.edu
Hilary M
HM
Clayton
Michael
M
Lavagnino
LeeAnn J
LJ
Kaiser
Narelle C
NC
Stubbs
D000818:Animals; D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait; D006614:Hindlimb / Q000502:physiology*; D006736:Horses / Q000502:physiology*; D007596:Joints / Q000502:physiology*; D010812:Physical Stimulation