Why? The Science of Athletics

230 WHY?-THE SCIENCE OF ATHLETICS In this figure the parallelogram ABCD Diagrammatic represents the zone of take-off and landing. Co.aching G is the point of the left foot take-off, and E the position of the left foot landing, for if a proper turning movement is instituted the jumper must always land upon the same foot from which his spring is made. It will be seen that the left foot at the moment of taking off points along the line GH, that is to say, the foot placement should be at an angle of 45 degrees to the cross-bar. But in landing at E, if the jump has been performed correctly, the foot is pointing along the line EF, and so lands at right angles to the cross-bar. This contention is mathematically correct for the Eastern cut-off style of jumping I wished Simmons ·to employ, and he was quick enough in seeing the implica– tion. The perpendicular GK represents the distance from the point of take-off to a line drawn directly under the cross-bar, while EH is the distance from the same line to the point of landing. Therefore GEF is the triangle of total effort and GE the distance covered from take-off to landing, approximately 8 ft. Now the closer the per– pendicular EF can be brought to the perpendicular GK the better will be the jump performed, since the more rapidly the performance of the turning, or pivotal, move– ment above the bar is carried out the further will the left– foot-landing-perpendicular EH -move in the dires:tion of the take-off-perpendicular GK. The diagrams I sent to Simmons comprised only the parallelogram ABCD together with the outline of the pit and line of the bar. Each time before he jumped he smoothed off the cinder approach and raked the sand of the pit, and after each jump he measured his take-off and landing footprints and filled in on one of the plans I had sent him the triangle EFG and the perpendiculars GK and EH, with measurements, and also stated the height of the cross-bar.