Hindlimb response to tactile stimulation of the pastern and coronet.
BACKGROUND
Lightweight tactile stimulators attached to the hind pasterns increase the height of the hind hoof flight arc but details of the induced changes in swing phase kinematics and kinetics have not been investigated.


OBJECTIVE
Stimulators on the hind pasterns are associated with increased hindlimb joint flexions and increased positive work performed by the hip and tarsal musculature.


METHODS
Nine nonlame horses trotted 4 times with and without 55 g tactile stimulators loosely attached around the hind pasterns. Height of the flight arc and peak flexion angles of the hindlimb joints were measured and net positive and negative work performed across each joint during the swing phase were calculated using inverse dynamics analysis and compared across paired conditions.


RESULTS
Speed and stride duration did not change but stimulators were associated with a reduction in hind stance duration. The flight arc was higher with stimulators due to increased flexions of the stifle, tarsal, metatarsophalangeal and distal interphalangeal joints. Positive work increased in the tarsal musculature, but not in the hip musculature, and negative work increased across the stifle, metatarsophalangeal and distal interphalangeal joints.


CONCLUSIONS
The effects of tactile stimulation of the hind pasterns on joint motion and muscle activation may be used in physiotherapy and rehabilitation to restore or increase flexion of the hindlimb joints with the exception of the hip joint. The ability to stimulate concentric activity of the tarsal musculature may have therapeutic applications in conditions such as toe dragging.
Clayton
H M
HM
Mary Anne McPhail Equine Performance Center, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan 48824, USA.
White
A D
AD
Kaiser
L J
LJ
Nauwelaerts
S
S
Lavagnino
M
M
Stubbs
N C
NC
D000818:Animals; D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait / Q000502:physiology*; D006614:Hindlimb; D006724:Hoof and Claw; D006736:Horses; D007596:Joints; D008297:Male