Limb contact variables of the gallop of 3-day event horses were determined for competitors in the 1988 Seoul Summer Olympic Games. Horses were filmed during the steeplechase, phase B of the speed and endurance test on day 2 of competition. Two 16-mm high-speed cameras were aimed perpendicularly to the direction of subject motion along a straightaway on the steeplechase track, filmed at 200 frames/s. Thirty-four of 48 competitors were filmed and 108 gallop strides analyzed. Velocity (VEL) averaged 12.09 +/- 0.10 m/s (mean +/- SE), stride length (SL) 6.04 +/- 0.05 m and stride frequency (SF) 2.00 +/- 0.01/s. Superior overall 3-day event performances were associated with faster VEL and longer SL in the steeplechase phase. A linear and quadratic regression of SL and SF against total 3-day penalty points yielded a response surface revealing that the score was optimized with gallop SF between 1.85 and 2.05/s and VEL between 13 and 14.3 m/s. Up to 7 m, there appeared to be no upper limit for optimal SL. This study provided objective documentation of gallop stride kinematic patterns associated with successful performance in world-class 3-day event competition.