Joint moments in the distal forelimbs of jumping horses during landing

Tendon injuries are an important problem in athletic horses and are probabl y caused by excessive loading of the tendons during demanding activities. A s a first step towards understanding these injuries, the tendon loading was quantified during jump landings. Kinematics and ground reaction forces wer e collected from the leading and trailing forelimbs of 6 experienced jumpin g horses. Joint moments were calculated using inverse dynamic analysis. It was found that the variation of movement and loading patterns was small, bo th within and between horses. The peak flexor joint moments in the coffin a nd fetlock joints were larger in the trailing limb (-0.62 and -2.44 Nm/kg b wt, respectively) than in the leading limb (-0.44 and -1.93 Nm/kg bwt, resp ectively) and exceeded literature values for trot by 82 and 35%. Additional ly, there was an extensor coffin joint moment in the first half of the stan ce phase of the Leading limb (peak value 0.26 +/- 0.18 Nm/kg bwt), From the se results, it was concluded that the loading of the flexor tendons during landing was higher in the trailing than in the leading limb and that there was an unexpected loading of the extensor tendon in the leading limb.