KINEMATIC ANALYSIS OF WORLD CHAMPIONSHIP 3-DAY EVENT HORSES JUMPING ACROSS-COUNTRY DROP FENCE

An analysis was conducted to characterize the leads and temporal patte rns of ground contact variables of elite horses negotiating a drop jum p obstacle during competition in the Cross-Country portion of the 1990 Stockholm World Equestrian Games Three-Day Event, and to associate th ose measurements with performance outcome variables. On Phase D of the second day of competition, a 16-mm motion picture camera filmed at 19 7 frames/second perpendicular to Obstacle 15, the ''Dog Kennel'' or '' Hundgarden.'' The movement filmed required a jump 0.96 m downward from a 3.12-m-wide face across a 1.98-m-wide open space. Of 84 horses that started in the competition in Dressage, 66 horses successfully comple ted the Cross-Country Phase D and 60 completed the entire Three-Day Ev ent. Sixty-eight horses were filmed at Obstacle 15; with approach, jum p, and departure strides of 65 of those horses analyzed for leads; and temporal measurements made on approach, jump, and departure strides o f 58 of those horses, Strides in the sequence differed according to be ing disunited (rotary gallop) or united (transverse gallop). Of stride s with discernible leads, 15% of approach strides, 31% of jump strides , and 43% of departure strides were disunited. Forty-four percent (44% ) of horses changed forelimb leads over the jump, and 40% changed hind limb leads over the jump. Thirty-four of 60 horses :negotiated the ob stacle with a bipedal takeoff not dissimilar from the action of jumpin g an upright obstacle, even though it was not required to clear the ju mp spread. Kinematic variables tended to be related to horizontal velo city through the drop jump. Horses with superior performance tended to utilize the left lead in approach and departure strides and had less airborne time during the jump.