Power flow in the equine forelimb

A method is described for the estimation of segmental powers and power flow during the stance phase in the equine forelimb, to demonstrate the sources and paths of energy flow through the limb segments. S-VHS video and force platform data were collected for 5 walking trials in a sound Dutch Warmblood horse. Two camera views were combined using direct linear transformation and the resultant sagittal plane positional and angular data used together with the vertical and cranio-caudal ground reaction forces to calculate moments about the ends of the 4 lowermost segments of the forelimb, and the reaction forces at the segment ends. Power flows were calculated across the proximal and distal ends of each segment and total segmental power computed. During initial and terminal stance, power flowed into the cannon segment proximally, and out distally. For the rest of stance, the flow in the cannon was distal to proximal. At the pastern, power flowed in proximally during initial loading, and out distally. For most of the rest of stance, the pattern of flow was distal to proximal, except for terminal stance, when power flowed in through both ends. The largest effect at the hoof is a loss of energy in terminal stance as power flowed out proximally and into the pastern. The pastern appears to receive most of the energy during loading and pushoff and transfers this energy up the limb during midstance.