INFLUENCE OF SHOEING ON GROUND REACTION FORCES AND TENDON STRAINS IN THE FORELIMBS OF PONIES

Strains in the superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), accessory ligament of the deep digital flexor mu scle (interior check ligament [ICL]) and the interosseus medius muscle (suspensory ligament [SL]) in the right forelimb of 5 ponies mere mea sured using mercury-insilastic strain gauges a few hours after implant ation, Tendon strains were recorded at the walk with normal flat shoes , egg-bar shoes, a 7 degrees increased hoof angle accomplished by appl ication of a heel-wedge and a 7 degrees decreased hoof angle using a t oe-wedge, consecutively, Ground reaction forces were recorded with all 4 shoe types preoperatively and with fiat shoes post operatively. The strain patterns of the SDFT, DDFT and SL showed a rapid increase at t he beginning of the stance phase, followed by a plateau with a small i ncline or decline and a rapid decrease at the end of the stance phase, The SDFT had its maximal strain in the first half of the stance phase in all ponies, The DDFT and SL reached their maximal strain in the fi rst half of the stance phase in 2 ponies and in the second half of the stance phase in the other 3 ponies, The ICL was strained maximally in the second half of the stance phase in all ponies. Averaged over all 5 ponies, the maximal strains in the SDFT, DDFT, ICL and SL with norma l flat shoes were 2.4, 1.3, 5.4 and 3.7%, respectively, If an egg-bar was applied the mean peak strain in the DDFT was 0.13% lower and strai n in the SL was 0.22% higher, With a heel-wedge, strain decreased in t he DDFT and ICL (0.19% and 0.4%, respectively) and increased by 0.24% in the SL. A toe-wedge increased strain in the ICL by 0.8%. All change s mentioned were statistically significant (P<0.1). The changes in ten don strain as a result of different types of shoeing correlated with c hanges in calculated torque's of the ground reaction force acting on t he coffin joint.