Stride pattern preferences in racehorses

While performing, racehorses use the transverse gallop gait. When a racehorse begins to gallop, it must use either the right lead stride pattern (RLSP) or the left lead stride pattern (LLSP). When racehorses make a trot-to-gallop transition, 91% start with their RLSP and 9% start with their LLSP (n=209). When breaking from the gate, 90% of all racehorses use their RLSP and 10% use their LLSP (n=9,116). When individual horses were observed breaking from the gate in five to seven races, they used the same lead 94% of the time (n=32). When a mirror image of the hoofprints from a RLSP was superimposed on the hoofprints of a LLSP for the same racehorse, the placement of the hoofprints was not identical. This suggests that running efficiency might be different in the RLSP and the LLSP. The preference of stride patterns, along with a potential differences in efficiency, could have important consequences for racehorse performance.